Tag Archives: Kepler

Hunting for exoplanets: past and future

Kepler-11 is a Sun-like star around which six planets orbit. At times, two or more planets pass in front of the star at once, as shown in this artist’s conception of a simultaneous transit of three planets observed by NASA’s Kepler spacecraft. Credit: NASA.

In 2018, NASA’s Kepler Space Telescope mission came to a predictable end after it ran out of fuel some 94 million miles from Earth. During its nine-year planet-hunting mission, Kepler discovered nearly 3,000 exoplanet candidates and more than 2,600 confirmed exoplanets in our galaxy, cementing the notion that our solar system isn’t all that special. So far, 55 exoplanets that are potentially habitable — meaning they orbit their stars at just the right distance that may allow water to flow on the surface — have been found, of which 20 are Terran or Earth-sized.

There are at least as many planets as there are stars in the galaxy

After studying thousands of exoplanets astronomers are now confident that:

  • Relatively small planets are common;
  • There are likely more planets than stars in the galaxy;
  • Planetary systems are flat like the solar system;
  • Planets and planetary systems are extremely diverse;
  • No exoplanets similar to Earth in size, distance, and type of star they orbit have been found.
Artist concept of Kepler in space. Image credit: NASA/JPL

“I think that exoplanets tell us about our place in the universe. That’s probably the main reason the discovery of the first exoplanets were awarded the Nobel Prize in Physics this year. We are seeing just how diverse planets are. Planets are more common than they were thought to be before the first exoplanets were found. The number of planets in our galaxy is at least as large as the number of stars. But while planets and planetary systems are so diverse, planets like Earth may be very, very rare,” Dr. Jack Lissauer, a scientist at the NASA Ames Research Center and co-investigator of the Kepler mission, told ZME Science at the World Science Forum in Budapest. The World Science Forum is a biannual international conference on global science policy, which is affiliated with UNESCO and ICSU.

An exoplanet is any planet orbiting a star other than the Sun. Just 24 years ago, we only knew of planets in our solar system — but not for lack of trying. Detecting exoplanets is very challenging because they’re much smaller and fainter than stars. Since exoplanets are not self-luminous, scientists had to think outside the box.

The most successful exoplanet detection method is transit photometry, which looks for periodic, repetitive dips in the visible light of stars caused by planets passing, or transiting, in front of them. Essentially, a transit is just a partial eclipse.

Credit: Imgur.

“It was getting all the precision to detect the small variations in the light of the stars for planetary transits. To be able to detect planets — actually the smallest one that we’ve found was about the size of Earth’s moon, it’s the smallest planet known,” Lissauer said.

This has led to some incredibly unexpected discoveries that exceeded even our wildest expectations. Planets such as Kepler-22b, which is a water world between the size of Earth and Neptune located more than 600 light-years away or Kepler-16b, which is part of a ‘Tatooine-like’ system 200 light-years away — it is home to the largest planet ever discovered orbiting two stars. Then there’s the exciting Kepler-11 system, home to no fewer than six planets and the fullest, most compact planetary system yet discovered beyond our own.

Dr. Jack Lissauer. Credit: NASA Ames Research Center.

“A year before that, or even eight months before that, no multi-planetary transiting system had been discovered. By the time of Kepler-11 discovery, there were two others. One had three planets, one had two planets, Kepler-11 had six. And we were able to derive the masses of the inner five by the perturbations they gave on one another so the transits were not periodic. It contains five of the lowest mass exoplanets at the time for which we had measurements of both their size and their mass, so we could have good estimates of what they’re made of, by getting their density,” Lissauer told ZME Science.

The car-sized telescope was launched primarily to detect small planets. For this purpose, it was designed to find out how many planets are out there not by observing the entire galaxy but by taking a sample in and near the habitable zone — the region at the right distance from the star so that the surface has liquid water.

Beyond Kepler

Although it has been decommissioned, Kepler’s legacy lives on. Scientists are still sifting through thousands of candidate exoplanets, a task which will keep them busy for many years to come. Kepler has also shaped future missions such as the Transiting Exoplanet Survey Satellite, or TESS.

Launched in April 2018, TESS is NASA’s latest planet hunter. Its mission is to survey planets orbiting 200,000 of some of the brightest stars close to Earth. Later, planets identified by TESS can be inspected for a closer look by the upcoming James Webb Telescope.

“I’m a co-investigator on TESS as well as Kepler and I think of Kepler as having done great science by detecting these very small planets — planets not hugely different from Earth in their properties, in some cases,” Lissauer said.

“TESS won’t detect planets as small and as long-period orbits as Kepler — it has much smaller cameras — but it detects planets around brighter stars. So, the purpose of TESS is really finding planets around very bright stars so there’s enough light from these stars that we can detect light passing through their thin atmosphere where they transit their stars. So, TESS is enabling us — with other instruments, especially the James Webb Telescope, which will be launched in two years, and some of the very large and extremely large telescopes on the ground — to study the composition of the atmospheres of mid-sized exoplanets. Not Earth analogs — that’s too difficult — but not these hot Jupiters. So, planets a big step closer to our own,” he added, explaining TESS’ major role in future planet-hunting efforts.

Besides TESS, there are exciting exoplanet-hunting missions. Europe’s CHaracterising ExOPlanets Satellite (CHEOPS) mission is destined to launch in December. Its mission is to that of a follow-up: it will be tasked with studying stars known to harbor planets, rather than surveying the sky in search of new ones.

By performing observations of multiple planetary transits, CHEOPS will be able to provide more precise measurements of a planet’s size, which can be combined with existing mass determinations to render accurate densities. Knowing these parameters, it is possible to determine the exoplanet’s composition and discriminate between Earth-like planets where life may blossom and other types of Earth-mass planets that challenge our current notions of habitability.

Artist impression of CHEOPS. Credit: ESA – C. Carreau.

In 2026, ESA will launch PLATO, which is short for the PLAnetary Transits and Oscillations of stars) mission. PLATO is designed to find and determine the properties of Earth-like planets that orbit the habitable zone around stars similar to the Sun. For the first time, PLATO will allow scientists to calculate accurately the properties of a large number of stars with planets, including their ages.

Meanwhile, ESA’s ARIEL (Atmospheric Remote-sensing Infrared Exoplanet Large-survey) mission is destined to study and characterize exoplanets, rather than discover them. ARIEL is scheduled to launch in 2028. The mission is designed to perform high-accuracy transit, eclipse, and phase-curve multiband observations of exoplanets. Scientists are confident that ARIEL will be able to provide a complex picture of the chemical nature of its targeted exoplanets, but also their host stars. This will allow researchers to investigate the nature of these exoplanets, how they formed, and how they evolved.

Kepler opened the gate for mankind’s exploration of the cosmos, and its successors are bound to offer even more surprises. There are billions — perhaps trillions — of stars in the Milky Way galaxy alone and, on average, each of those stars has at least one planet orbiting them. However, there really is no place like home.

“We only have Earth. It’s possible that there are other planets like Earth out there but even if they are very similar, they are very far away. We can’t do a migration. We can’t solve our problem as the Irish did in the late 1800s to solve the potato famine. We would be like Easter Island. If we don’t take care of this planet, we are toast! All the mass extinctions in the last 5 million years are coincident with the rise of CO2 in the atmosphere of our planet. We must stop this crazy behavior. We can’t just say something has to be done. We have to do things ourselves. We have to cut our carbon footprint,” Lissauer told the audience during an event at the 2019 World Science Forum, held between 20-24 November.

There are over 700 quintillion planets in the universe — but there’s no place like home

The current consensus among astronomers is that there should be at least as many planets as there are stars. There are 100 billion galaxies in the universe, each containing about a billion trillion stars. With such a stupendous amount of exoplanets, many other Earth-like worlds should be bound to exist — maybe.

Credit: Pixabay.

Erik Zackrisson, an astrophysicist at Uppsala University in Sweden, crunched the numbers on a computer model that simulated the evolution of the universe since the Big Bang. He found that — given our current understanding of the universe and the laws of physics — there should be 720 planets in the universe. That’s 7 followed by 20 zeroes or 70 quintillion.

With such an abundance of exoplanets, you’d think that the odds of finding a second Earth among them is huge. Zackrisson, however, found that a planet such as ours may actually be incredibly rare.

Most of the planets generated by the researchers’ model are extremely different from Earth. They’re generally larger, older, and quite unlikely to support life due to their orbit around their parent stars.

Scientists classify an exoplanet — which is any planet outside our solar system — as “potentially habitable” if it happens to orbit in the so-called “habitable zone” of a star, also known as the “Goldilocks” region. In this orbit, the surface temperature is just right, allowing liquid water to flow.

As of 21 November 2019, scientists have confirmed 4,099 exoplanets but only around 55 of them orbit in the habitable zone of stars. By extrapolating this insight to the number of stars in Milky Way, there should be 50 billion such planets in our galaxy alone.

Earth may be different, though. Zackrisson’s model suggests that our planet may be a statistical anomaly. The average age of the planets generated by the model is well above Earth’s and they’re typically located in galaxies vastly unlike the Milky Way, the researcher reported in The Astrophysical Journal. Most planets also orbit stars with different compositions from the Sun.

This may explain Fermi’s paradox — the notion that there is a virtually limitless number of stars, but nevertheless you don’t see much life floating around. If there is truly an abundance of Earth-like planets in the galaxy, then a civilization with a head start of a few billion years should have colonized the entire Milky Way by now. Perhaps, Earth is truly unique — it is, at least, a possibility.

There is a major caveat to this study — that our inferences are only as good as our data. Most of these exoplanets discovered thus far were identified by the now-defunct Kepler space telescope. Due to the way it was designed, however, Kepler was biased towards massive planets at least several times larger than Earth that closely orbit their stars. Naturally, most of them are uninhabitable. Finding smaller planets that orbit farther away from their parent stars requires different observation techniques, which are still experimental, and more advanced telescopes.

In addition, most of what we know about exoplanets is based on observations of a very small patch of our galaxy.

Nevertheless, this intriguing study shows that, perhaps, we are not as insignificant as we might think. And, that’s all the more reason to cherish this pale blue dot of ours even more.

Artist's illustration of the Kepler space telescope in orbit. Image Credit: NASA.

Kepler — the spacecraft that discovered thousands of alien worlds — is running on its last drops of fuel

Artist's illustration of the Kepler space telescope in orbit. Image Credit: NASA.

Artist’s illustration of the Kepler space telescope in orbit. Image Credit: NASA.

We owe a lot to NASA’s Kepler space telescope: since it launched in 2009, the space telescope has helped astronomers identified at least 2,342 exoplanets, with thousands more still to be confirmed. A few dozens of these planets are less than twice Earth’s size and orbit their parent star just close enough to potentially be habitable. Unfortunately, the planet-hunting telescope will run out of fuel within a couple of months, becoming stranded 93 million miles from home.

“With nary a gas station to be found in deep space, the spacecraft is going to run out of fuel,” Charlie Sobeck, system engineer for the Kepler space telescope mission, wrote in a news release for NASA. “We expect to reach that moment within several months.”

Kepler was initially slated for a 3.5-year-long mission but heroically marched on for many years after its warranty expired. The telescope is designed to look for planets in one small patch of sky that contains about 4.5 million stars. To identify potentially new worlds outside our solar system, Kepler detects the dimming that occurs when a planet transits a star. Imagine a moth flying in front of a spotlight — it will cause a subtle change in brightness, and the bigger the moth, the more light it blocks. Likewise, patterns of changes in the brightness of each star indicate orbiting planets. By June 2010, just 15 months after its launch, Kepler had already found over 700 potential planets.

In 2013, a malfunction almost ended the entire mission. NASA, however, was able to salvage some segments of the spacecraft’s operational capabilities and devised a new technique to observe distant worlds. Thus, the Kepler mission was reborn as “K2”, which discovered an additional 307 confirmed exoplanets and another 479 candidates.

Originally, the space telescope was set to launch with a partially filled fuel tank that would enable its thrusters to fire for a maximum of six years. But before it launched, engineers noticed that Kepler was actually below its allowed weight threshold, and filled its tank. Now, nine years after it launched, the spacecraft’s tank is nearly dry. In the meantime, scientists will surely have time to discover a couple more candidates. Who knows maybe these will be the most promising yet.

Once the fuel runs out, NASA will cut the comm-link and Kepler will officially become another heap of space junk — but at least it will be so far from Earth it won’t cause any problems (unlike the gazillion pieces of space junk currently in Earth’s low orbit). On April 16, Kepler’s replacement, the Transiting Exoplanet Survey Satellite, is scheduled to launch from Cape Canaveral, Florida. A new age of exoplanet exploration is upon us, and it couldn’t be more exciting.  

Planet.

Hunt for planets through Kepler’s data with this newly released Google code

If you’ve ever dreamt of trying your hand at hunting exoplanets, a new bit of code could make your wish come true.

Planet.

Image via Wikimedia.

Yesterday, we told you about the power of citizen science in biology — today, researchers are back to enlist us mere Muggles in the search for new worlds. It all started back in December, when a pair of NASA researchers reported the discovery of two, previously overlooked, alien planets after dredging through NASA’s archived data from the Kepler program. What made this discovery possible was software built around Google’s machine-learning systems, whose architecture and function mimics that of the human brain.

Motherboard astronomy

Get your hard drive limber and your internet connection fired up because that same computer program (AstroNet) was released for public use just a few days ago. You can access it, along with instructions detailing how to use it, on GitHub.

 

“We’re excited to release our code for processing the Kepler data, training our neural network model and making predictions about new candidate signals,” wrote lead author of that December discovery study and Google senior software engineer Chris Shallue in a blog post on March 8th.

“We hope this release will prove a useful starting point for developing similar models for other NASA missions, like [Kepler’s second mission] and the upcoming Transiting Exoplanet Survey Satellite mission,” he added.

Telescopes, Kepler included, detect alien worlds by spying on the tiny dips in brightness they cause when passing in front of their host stars — also referred to as the planets ‘transiting’ their host. Because the sky is littered with stars, software is used to automatically flag the most promising dimming events, which are then manually investigated by researchers looking for planets. Some flaggings turn out to be false positives, caused by events such as a body passing exactly in the right point of space to mimic the dimming of a transiting planet.

Given the sheer amount of stars researchers have to work with, that initial, automated sieving is vital to NASA. Our systems are only as fail-proof as we are (to be read: not very), so intriguing worlds can and do sometimes slip through undetected. Shaulle and his co-author, University of Texas astronomer Andrew Vanderburg, discovered one such planet using the machine-learning-sporting software. Their planet is the eighth in the Kepler-90 system, which lies — to the extent you can use that term in space — some 2,545 light-years away from Earth. The discovery was quite significant, as it’s only the second solar system known to harbor eight or more planets; the other one being our own.

Shaulle and Vanderburg only had to go through 670 stars to find the two new exoplanets — for context, Kepler looked at roughly 150,000 stars during its first (K1) mission, from 2009 to 2013. To that number, add thousands more it observed during the K2 phase, during which it took a more narrow approach to planet-hunting. The K2 phase started after a malfunction to the Kepler telescope’s reaction wheels, heavy wheels that maintain its orientation. Essentially, researchers can’t steer the craft properly any longer — so they’re taking advantage of the situation to just look at whatever it happens to be pointing at.

While Kepler might be limping, that juicy database of stars it’s already looked at is still available.

“It’s possible that some potentially habitable planets like Earth, which are relatively small and orbit around relatively dim stars, might be hiding just below the traditional detection threshold — there might be hidden gems still undiscovered in the Kepler data!” Shallue added in his post.

So if you’ve ever fancied discovering a planet, download AstroNet and grab a warm cup of tea while your PC does the heavy lifting.  Who knows, maybe NASA will let you name something you discover. So let’s show them the power of citizen science.

Let’s make Planet McPlanetface a thing!

 

Revolutionary optical upgrade enables ground-based telescopes to hunt for alien planets

A low-cost upgrade allows ground-based telescopes to achieve unprecedented precision in light intensity measurement. The telescope attachment comprises state-of-the-art micro-optic devices that spread light across an image and minimizes distortions from Earth’s atmosphere. The quality reportedly rivals that of photometric observations from space.

Left: Light from a laser pointer is shaped into a wide and stable output using a beam-shaping diffuser. Right: The diffuser installed at the 3.5m telescope at Apache Point Observatory. Credit: Penn State University.

When a planet crosses in front of its star as viewed by an observer, the event is called a transit. Transits by terrestrial planets produce a small change in a star's brightness of about 1/10,000 (100 parts per million, ppm), lasting for 2 to 16 hours. Credits: NASA Ames

When a planet crosses in front of its star as viewed by an observer, the event is called a transit. Transits by terrestrial planets produce a small change in a star’s brightness of about 1/10,000 (100 parts per million, ppm), lasting for 2 to 16 hours. Credits: NASA Ames

The over 2,300 exoplanets confirmed by NASA so far have mostly been identified by the new defunct Kepler space telescope. Kepler was designed to look for planets in one small patch of sky, that contains about 4.5 million stars, by measuring the dimness produced by an alien planet transit in front of a star. Doing the same from Earth has proven challenging, which is why scientists had to deploy the telescope in outer space, where the planet’s atmosphere doesn’t interfere with the light beamed by alien stars. But this also makes it extremely expensive for alien hunters to do their job properly.

Beam-shaping diffusers could thus be a lifesaver since they enable existing ground-based telescopes to radically improve their light sensing precision. These devices are essentially small pieces of glass which cost very little and are easily adaptable to existing hardware. The innovation lies in the complex engineering that went into designing the diffusers.

“This inexpensive technology delivers high photometric precision in observations of exoplanets as they transit — cross in front of — the bright stars that they orbit,” said Gudmundur Stefansson, graduate student at Penn State, NASA Earth and Space Science Fellow, and lead author of the paper. “This technology is especially relevant considering the impending launch of NASA’s Transiting Exoplanet Survey Satellite (TESS) early in 2018. It is up to ground-based facilities to rapidly and reliably follow-up on candidate planets that are identified by TESS.”

The diffusers are manufactured in a nanofabrication process, through which a specifically designed surface geometry is etched on the glass. This pattern consists of “precise micro-scale structures, engineered to mold the varying light input from stars into a predefined broad and stable output shape spread over many pixels on the telescope camera,” according to Suvrath Mahadevan, associate professor of astronomy and astrophysics at Penn State.

The diffuser tech was put to the test in three American telescopes: the Hale telescope at Palomar Observatory in California, the 0.6m telescope at Davey Lab Observatory at Penn State, and the ARC 3.5m Telescope at Apache Point Observatory in New Mexico. The upgrade was obvious as in all cases the images produced with the new attachment were significantly more stable than before. What astronomers refer to when they say stability is that images should maintain a constant size, shape, and intensity. So, by shaping the output of light, the diffuser negates the noise created by the atmosphere.

“This technology works over a wide range of wavelengths, from the optical — visible by humans — to the near infrared,” said Jason Wright, associate professor of astronomy and astrophysics at Penn State and an author of the paper. “As such, diffusers can be used for a wide range of exoplanet science. We can use them to precisely measure the times exoplanetary worlds transit their stars, which will help us measure their masses and compositions, and even find new planets in their systems; and we can use them to study the temperature structures of giant planets’ atmospheres.”

Next, the goal is to establish collaborations around the world to bring this technology to all telescopes that would need it.

Scientific reference: Gudmundur Stefansson, Suvrath Mahadevan, Leslie Hebb, John Wisniewski, Joseph Huehnerhoff, Brett Morris, Sam Halverson, Ming Zhao, Jason Wright, Joseph O’rourke, Heather Knutson, Suzanne Hawley, Shubham Kanodia, Yiting Li, Lea M. Z. Hagen, Leo J. Liu, Thomas Beatty, Chad Bender, Paul Robertson, Jack Dembicky, Candace Gray, William Ketzeback, Russet McMillan, Theodore Rudyk. Toward Space-like Photometric Precision from the Ground with Beam-shaping DiffusersThe Astrophysical Journal, 2017; 848 (1): 9 DOI: 10.3847/1538-4357/aa88aa

supernova shockwave

Supernova shockwave recorded for the very first time

Some stars go out with a bang — a supernova explosion! Using optical images recorded by the Kepler telescope, astronomers witnessed for the very time the shock wave that follows a star’s implosion once it runs out of fuel.

supernova shockwave

GIF: NASA

Spotting a supernova isn’t easy. Imaging the shockwave is even harder, since it lasts less than an hour. Considering a star can stay active for many billions of years, you’d need to monitor a huge patch of the sky in hope that one of those trillions of star will eventually blow up but using this method, the researcher were actually lucky since in any galaxy a supernova will occur every 100 to 200 years.

The Kepler Space Telescope analyzed light coming from 500 different galaxies, or 50 trillion stars, over a three year period. Two supernovae were caught in the act: KSN 2011a and KSN 2011d. Only for one of them though was the shockwave recorded, the other being obstructed by gas and dust. Amazingly, the star in question, KSN 2011d, is a red giant 500 times larger than our sun, and 1.2 billion light years away.

“Like police getting surveillance footage of a crime after the event, we can study brightness histories from Kepler to find out what was happening in the exact hour that the shock wave from the stellar core reached the surface of the star,” said Edward Shaya, an associate research scientist in astronomy at UMD and a co-author on the study. “These events are bright enough that they change the brightness of the whole galaxy by a measurable amount.”

Supernovae are basically stellar eruptions, triggered either by the gravitational collapse of a massive star, or by sudden re-ignition of nuclear fusion in a degenerate star. They are amazing manifestation of energy – for brief moments, a supernova can outshine an entire galaxy, radiating as much energy as the Sun or any ordinary star is expected to emit over its entire lifespan, before fading after a few weeks or months. The shock breakout immediately precedes the ‘big event’ and is essentially a massive flash of brightness.

Artists re-created the shockwave using CGI, but based on actual data recorded by Kepler. What you can see below is as a close as you’ll get to a realistic supernova shock breakout.

Supernovae have a double role in the Universe, which I can’t help but describe as romantic. The event marks the final stage in a star’s life. The massive explosion, however, spews immense amounts of matter into outer space — in some cases enough to found thousands of new planet Earths. We’re all made of star dust, remember.

“All heavy elements in the universe come from supernova explosions. For example, all the silver, nickel, and copper in the earth and even in our bodies came from the explosive death throes of stars,” Steve Howell, project scientist for NASA’s Kepler and K2 missions, said in a statement. “Life exists because of supernovae.”

Scientists find a tiny star with a huge storm — just like Jupiter’s

Scientists have found one storm that no umbrella can keep you safe from — because that umbrella is going to burn in your hand.

While the windy and overcast weather of a stormy day isn’t surprising on telluric planets, it’s not something most of us readily associate with stars. But it does happen — the best evidence for this is W1906+40, a distant dwarf star recently described in a study published in the Astrophysical Journal.

This illustration shows a cool star, called W1906+40, marked by a raging storm near one of its poles. Image via washingtonpost

This illustration shows a cool star, called W1906+40, marked by a raging storm near one of its poles. Image via washingtonpost

Being small for a star (about as big as Jupiter) W1906+40 is classified as an L-dwarf, more towards planets on the planet-star spectrum. The coolest stars in this class are known as brown dwarfs, “failed stars” that aren’t big or don’t have enough heat to sustain fusion and generate light as most stars do and resemble giant gas planets. However, they form very differently than planets and scientists often have to use the cosmic object’s age to classify it correctly.

With an estimated 3,500 degrees Fahrenheit of surface temperature,  W1906+40 might still have some fusion going on, but nothing powerful enough to stop mineral clouds from forming in its atmosphere, blurring the line between a planet and a star. But just like on Jupiter, the planet-and-star combination of features led to the formation of a massive storm.

On Jupiter, the Great Red Spot has been churning and raging on for as long as humanity has been able to see it — some 400 years. It’s been slowly getting smaller and smaller, though it being roughly three times the size of Earth means the term “smaller” is used loosely here.

“The star is the size of Jupiter, and its storm is the size of Jupiter’s Great Red Spot,” study author John Gizis of the University of Delaware said in a statement. “We know this newfound storm has lasted at least two years, and probably longer.”

The storm on W1906+40 was spotted using the Kepler exoplanet hunting telescope. It searches for exoplanets by measuring the dimming of distant stars’ light, which can be used to determine if there are any objects passing in front of it.

 

In the case of W1906+40, Gizis and his team saw a dark spot that didn’t waver. This wasn’t unusual — patches of concentrated magnetic field can make dark blotches on a star’s surface known as star spots (on sunspots on the Sun,) behave the same way and are relatively common.

But further investigation in infrared light revealed that the dark spot had nothing to do with magnetic fields. The whopping storm makes a dark mark on top of the star, rotating around it about every nine hours.

Scientists aren’t sure why these storms last so long or how common they are, but the researchers involved in the study plan on seeking out more stormy dwarfs to learn more.

alien planets ancient

Five ancient alien planets discovered in 11 billion-year-old solar system

The ever resourceful Kepler missions just reported its most interesting find to date: not one, but five planets smaller than Earth orbiting a star 117 light-years away that’s estimated to be 11 billion years old. This makes it far older than our own sun, meaning its planets could be 2.5 times as old as Earth. The findings bear important implications for alien life, since they prove Earth-like planets could formed very early in the Universe’s history. If intelligent alien life formed elsewhere in the Universe, it had a pretty good head start.

Alien life might have billions of years head start

alien planets ancient

Artist drawing of the Kepler-444 system. Image: Tiago Campante/Peter Devine

Shortly after the Big Bang, the only elements around were hydrogen and helium. A few billions of years later, heavy elements like iron, nickel or gold eventually expanded in cosmos fused in supernovae – powerful explosions in the wake of a star’s death (see how gold is made). Considering this, astronomers generally assert that Earth-like planets couldn’t have formed during the early universe since there simply weren’t enough heavy elements to spare.  Yet, these latest findings suggest that this is far from being a rule.

Dr. Tiago Campante, the research leader from the University of Birmingham said, “We now know that Earth-size planets have formed throughout most of the universe’s 13.8-billion-year history, which could provide scope for the existence of ancient life in the galaxy.” The findings were published in the Astrophysical Journal.

The off-world solar system called Kepler-444 actually has three stars and five planets! A pair of cool red M dwarfs orbiting each other, which in turn orbits a K star. The dim, binary stars are small and about 10 billion kilometers from the K star, about twice the distance Neptune is from the Sun. Considering their close orbit, however, these can’t be classed as habitable. Kepler-444b has a diameter of 0.403 Earth, Kepler-444c is 0.497 Earth, d is 0.530, e is 0.546, and f is the biggest at 0.741 our home planet’s size. Yet even the farthest orbiting one, planet f, is closer to its parent star than Mercury is to the sun.

Astronomers used a technique called asteroeismology to study Kepler-444, similar to how scientists detect earthquakes on Earth. Each star’s surface vibrates in a distinct way, and these vibrations can be detected in the form of changing luminosities. Judging from the character of the waves, scientists can easily infer a star’s mass, size and age. The planets themselves were identified using the now well established transit method where blips and changes in a star’s periodical brightness can be used to characterize the objects that pass between the star and Earth.

astroseismology

Where is everybody?

Although these planets aren’t habitable, the findings prove that planets with heavy elements can form much earlier than previously thought. This means that life also could have surfaced much earlier, which brings us to the Fermi Paradox. Confronted with a nearly limitless universe billions of years old with an almost infinitely vast number of opportunities for life, the Italian physicist Enrico Fermi, sitting for lunch at Los Alamos with three colleagues in 1950, asked a question that still perplexes everyone who looks up at the night sky: “Where is everybody”?

The question is a valid one when considering:

  • There’s nothing special about our sun – it’s young, medium sized and similar to billions other in our galaxy.
  • It’s believed there are between 100 and 400 billion planets in the Milky Way. Considering intelligent life appeared in one of these (Earth), it’s reasonable to consider there should be at least some other kind of intelligent life elsewhere in the galaxy.
  • Millions of years of technological progress means that an intelligent species should have the capability to travel to distant stars and even other galaxies. Just look at how our worlds has changed in the past 100 years.
  • According to mathematicians Duncan Forgan and Arwen Nicholson from Edinburgh University, self-replicating spacecraft traveling at one-tenth of the speed of light — admittedly a quick speed — could traverse the entire Milky Way in a mere 10 million years. This means that a civilization could potentially colonize the whole galaxy in a mere couple millions years.

Where is everybody? Well, there are numerous explanations. It could be that we’re alone – that is,  life likely developed elsewhere as well, but intelligent life capable of developing interstellar technology might be extremely rare, if not unique. Dinosaurs ruled the planet for hundreds of millions of years, but the farthest they went with technology was building a nest. Then, there’s the self-destruct hypothesis. It’s reasonable to assume that an early technological civilization would first use its fossil fuels for energy use, being easier to access. After burning up most of their resources, climate change might have stopped them in their tracks before they had any chance of leaving the planet. Then, of course, there’s the threat of nuclear annihilation or some other form of weapon of mass destruction. And this could go on forever, as you can tell. As frustrating as this situation might be, you need not feel too discouraged. While Kepler can’t explore planets, the space telescopes of the future like the much anticipated James Webb will. Fermi’s paradox might not last for long.

Kepler-11 is a sun-like star around which six planets orbit. At times, two or more planets pass in front of the star at once, as shown in this artist's conception of a simultaneous transit of three planets observed by NASA's Kepler spacecraft on Aug. 26, 2010. Image credit: NASA/Tim Pyle

Kepler crossed the 1,000 discovered alien planets milestone

Since it was first launched in 2009, the $600 Kepler mission has discovered more than 1,000 alien worlds. Arguably it’s one of the most successful space mission in history so far, further cementing its status as a legend. The milestone was breached after eight newly confirmed exoplanets were added to the tally, two of which are very similar to Earth and thus could support alien life.

The exoplanet hunter

Table Top model of the Kepler Telescope: A Mission in search of Habitable Planets around other stars. NASA Ames photographer Tom Trower

Table Top model of the Kepler Telescope: A Mission in search of Habitable Planets around other stars. NASA Ames photographer Tom Trower

The Kepler telescope was deployed to probe our Milky Way galaxy for alien planets, in order to see how frequent planets are. It wasn’t long until the first candidates came pouring in, and as of now there are 1,004 confirmed alien planets. Unfortunately, two of the four gyroscope-like reaction wheels that keep Kepler pointed in the right direction have broken down and can’t be fixed. But even if the telescope won’t be collecting any more planet-hunting data, there’s still lots of information to sift through. Scientists have  3,200 additional planet candidates marked by Kepler that they need to probe, 90% of which should end up being confirmed according to the statistical data available so far. Indeed, this should keep them busy for years and years ahead, long enough until the next generation exoplanet hunting telescope will come online: the James Webb Space Telescope.

“Each result from the planet-hunting Kepler mission’s treasure trove of data takes us another step closer to answering the question of whether we are alone in the Universe,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “The Kepler team and its science community continue to produce impressive results with the data from this venerable explorer.”

NASA Kepler's Hall of Fame: Of the more than 1,000 verified planets found by NASA's Kepler Space Telescope, eight are less than twice Earth-size and in their stars' habitable zone. All eight orbit stars cooler and smaller than our sun. The search continues for Earth-size habitable zone worlds around sun-like stars. Image: NASA

NASA Kepler’s Hall of Fame: Of the more than 1,000 verified planets found by NASA’s Kepler Space Telescope, eight are less than twice Earth-size and in their stars’ habitable zone. All eight orbit stars cooler and smaller than our sun. The search continues for Earth-size habitable zone worlds around sun-like stars. Image: NASA

Two of the newly validated planets, Kepler-438b and Kepler-442b, are less than 1.5 times the diameter of Earth. Kepler-438b, 475 light-years away, is 12 percent bigger than Earth and orbits its star once every 35.2 days. Kepler-442b, 1,100 light-years away, is 33 percent bigger than Earth and orbits its star once every 112 days. Both planets orbit smaller and cooler suns than our own

“With each new discovery of these small, possibly rocky worlds, our confidence strengthens in the determination of the true frequency of planets like Earth,” said co-author Doug Caldwell, SETI Institute Kepler scientist at NASA’s Ames Research Center at Moffett Field, California. “The day is on the horizon when we’ll know how common temperate, rocky planets like Earth are.”

Right now, following observations made between May 2009 to April 2013, the candidate count stands at a whooping 4,175.  Eight of these new candidates are between one to two times the size of Earth, and orbit in their sun’s habitable zone. This includes a planet that’s most similar to Earth in terms of size and mass, a Neptune-sized planet with water vapour in its atmosphere.

Kepler-11 is a sun-like star around which six planets orbit. At times, two or more planets pass in front of the star at once, as shown in this artist's conception of a simultaneous transit of three planets observed by NASA's Kepler spacecraft on Aug. 26, 2010. Image credit: NASA/Tim Pyle

Kepler-11 is a sun-like star around which six planets orbit. At times, two or more planets pass in front of the star at once, as shown in this artist’s conception of a simultaneous transit of three planets observed by NASA’s Kepler spacecraft on Aug. 26, 2010. Image credit: NASA/Tim Pyle

To discover alien planets, Kepler used the transient method in which blips in a star’s brightness are analyzed for telltale signs of an alien planet passover. When an exoplanet orbits its host star and reaches a point in line with the observer (kepler) and the host star, it blocks the incoming light in specific way. Judging from how long the brightness dip lasts, what wavelengths of light become absorbed and so on, scientists can infer size, mass and even atmospheric composition of planets even thousands of light years away. Obviously, bigger planets like those the size of Jupiter are easier to find; they’re the most numerous discovered thus far. Earth-like planets are harder to come by. Earth-like planets that orbit Sun-like stars are even rarer.

exoplanet_neptune

Neptune-sized alien planet found to harbor water vapor in its atmosphere

Astronomers have discovered water vapor in the atmosphere of a new exoplanet – a planet from outside our solar system – roughly the size of Neptune, orbiting a star 124 light-years away. This is the first time water vapor has been found on an alien planet smaller than Jupiter. The discovery is set to improve scientists’ understanding of how planet forms and which planets may be best suited to support alien life.

exoplanet_neptune

Artist impression of HAT-P-11b. Image: Harvard Center for Astrophysics

The smallest alien planet with water

“Water is the most cosmically abundant molecule that we can directly observe in exoplanets, and we expect it to be prevalent in the upper atmospheres of planets at these temperatures,” lead author Jonathan Fraine said.

The exoplanet, called HAT-P-11b, was found using data collected by the Hubble Space Telescope, Spitzer Space Telescope and Kepler spacecraft, the international team of astronomers. Typically, astronomers never image planets directly, but instead study the light and wobbles emitted by distant stars, some even millions of light years away, through a technique called the transit method. Basically, as a planet passes in front of its star in our plane of observation, it affects the incoming light that reaches us. By studying which frequencies get absorbed and how much of the light gets blocked by the exoplanet can infer a number of properties about it, like mass, size and orbital period.

transit_method_exoplanet

Credit: Las Cumbres Observatory Global Telescope Network

The exoplanet is found in the constellation Cygnus, about 124 light-years from Earth. The planet, roughly four times the size of Earth,  it orbits at only one twentieth the distance between Earth and the Sun, making the trip once every five days. Because of its close proximity, the planet’s surface can reach temperatures as high as 1,120 degrees Fahrenheit, making life impossible.

To study the chemical makeup of the exoplanet’s atmosphere, a technique called  transmission spectroscopy is employed. Different molecules, such as water,produce different spectra by absorbing different wavelengths of the star’s light as it passes through the planet’s atmosphere. Observations suggested that indeed the planet’s atmosphere contained water vapor, but to be sure they weren’t actually picking up signals of water in relatively cool starspots on the host star, the researchers used visible-light observations from Kepler and infrared observations from Spitzer. The data suggests the hotspots are too hot to support water and confirmed the finding, making  HAT-P-11b the smallest planet found so far to support water.

“This discovery is a significant milepost on the road to eventually analyzing the atmospheric composition of smaller, rocky planets more like Earth,” said John Grunsfeld, assistant administrator of NASA’s Science Mission Directorate in Washington, D.C.

Water vapor has traditionally been found in larger, gassier giants as large or larger than Jupiter since smaller planets typically contain little hydrogen, suggesting a hazy atmosphere that is very difficult to study. Besides water, HAT-P-11b has plenty of hydrogen in its atmosphere which made observations easier.

“In the long run, if we can detect water, methane, carbon monoxide, carbon dioxide, etc., in dozens to hundreds of exoplanet atmospheres of various bulk properties, then we will be able to paint a much clearer picture of how planets form, and, likewise, how Earth formed,” lead author Jonathan Fraine, a graduate student at the University of Maryland, told Space.com. “This was just one of the beginning brush strokes to painting the full picture of how planets, as well as ourselves, were formed.”

The researchers — a international team consisting of astronomers from Maryland, California and Seattle as well as the United Kingdom, Chile and Switzerland — published their findings in the journal Nature on Wednesday.

Image credit: NASA/JPL-Caltech

First possible evidence of an exomoon

Image credit: NASA/JPL-Caltech

Image credit: NASA/JPL-Caltech

Until just a few decades ago, there wasn’t any proof that there were any planets beyond those in our solar system, although of course everybody expected them to exist somewhere. After the Kepler Space Telescope was deployed, astronomers found not one, but a couple hundred exoplanets (planets orbiting other stars). In fact, our galaxy is supposed to harbor some 50 billion Earth-like planets.  Now, after observational techniques have become more refined, a joint  Japan-New Zealand-American team   spotted the first signs of an “exomoon,” and though they say it’s impossible to confirm its presence, the finding is a tantalizing first step toward locating others.

First moon outside our solar system?

The team used ground-based telescopes in New Zealand and Tasmania and applied a technique called  gravitational microlensing – a sort of natural occurring optical enhancer. Imagine the observer as being the telescopes and in between your target object (a star), lies a massive object (another star) in the foreground. This cushion star acts like a magnifying glass to focus and brighten the light of the more distant one using its gravity. Astronomers have been using this sort of the technique for years with marvelous results – they’ve even been able to peer through billions of light years , otherwise impossible using direct observations.

There’s more to it, however. If the foreground star has a planet orbiting around it, then the said planet has a gravitational effect on the incoming light as well, further dimming or brightening light, by case. By making precise measurements and comparing brightness events, astronomers can tell how massive is a star relative to its planetary companion.

What if the foreground object is a massive planet itself, and not a star? It can happen, we’ve seen that rogue planets – drifting planets through the galaxy – are a reality, so there’s a chance these could affect observations. In our particular case, the joint Japan-New Zealand-American Microlensing Observations in Astrophysics (MOA) and the Probing Lensing Anomalies NETwork (PLANET) programs  found the ratio of the larger body to its smaller companion is 2,000 to 1.

A moon or a planet?

So, we’ve got two cases on our hands: either the object in question is a faint-star circled by a planet about 18 times larger than Earth, or the object is in fact a planet about the size of Jupiter, circled by a moon smaller than Earth. No matter what the reality may be, right now there is no way astronomers can tell which of the two is true.

“One possibility is for the lensing system to be a planet and its moon, which if true, would be a spectacular discovery of a totally new type of system,” said Wes Traub, the chief scientist for NASA’s Exoplanet Exploration Program office at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., who was not involved in the study. “The researchers’ models point to the moon solution, but if you simply look at what scenario is more likely in nature, the star solution wins.”

The Kepler Space Telescope has studied thousands of stars, but it was never equipped to find one or multiple moons orbiting a planet. Discovering an exomoon would be nothing short of amazing, indeed. In the future, however, astronomers might be able to avoid this sort of stalemates by using the parallax-technique. Basically, you need two observing bodies in space, far enough from each other – like Spitzer and Kepler.  The basic principle of parallax can be explained by holding your finger out, closing one eye after the other, and watching your finger jump back and forth. A distant star, when viewed from two telescopes spaced really far apart, will also appear to move. When combined with a lensing event, the parallax effect alters how a telescope will view the resulting magnification of starlight.

Findings were reported in the Astrophysical Journal.

Artist impression of KOI-314c. Credit: C. Pulliam & D. Aguilar (CfA)

Newly found gassy exoplanet has mass similar to Earth’s

Artist impression of KOI-314c. Credit: C. Pulliam & D. Aguilar (CfA)

Artist impression of KOI-314c. Credit: C. Pulliam & D. Aguilar (CfA)

A team of astronomers recently discovered a new exoplanet some 200 light years away whose mass is about the same as Earth’s – the first Earth-mass planet that transits, or crosses in front of, its host star. Although very similar in mass, the planet is 60% larger in diameter suggesting it has a thick atmosphere. Due to its very short orbital period, the planet’s surface is most likely scorching hot and, consequently, unfit to foster life.

Astronomers used data from NASA’s Kepler spacecraft, now defunct, to identify the exoplanet KOI-314c, which orbits a dwarf star. Considering the exoplanet is very far away from Earth and it orbits a very faint star, describing KOI-314c in terms of mass and size was no easy task.

Typically, scientists rely on fairly straightforward method for determining the mass of planets outside our solar system that relies on studying wobbles of the parent star induced by the planet’s gravity. This only works accurately for big planets, at least 1.5 times the size of Earth, that orbit bright stars. For KOI-314c, the researchers used a different technique.

A new method for finding low-mass exoplanets

Known as transit timing variations (TTV), the method, which works only for systems with at least two planets, measures the slight tug planets make on each other, that slightly changes the times that they transit their star.

“Rather than looking for a wobbling star, we essentially look for a wobbling planet,” explains second author David Nesvorny of the Southwest Research Institute (SwRI). “Kepler saw two planets transiting in front of the same star over and over again. By measuring the times at which these transits occurred very carefully, we were able to discover that the two planets are locked in an intricate dance of tiny wobbles giving away their masses.”

Thus, the researchers found KOI-314c is only 30 percent denser than water. This suggests that the planet is enveloped by a significant atmosphere of hydrogen and helium hundreds of miles thick. It might have begun life as a mini-Neptune and lost some of its atmospheric gases over time, boiled off by the intense radiation of its star. The team estimates its temperature is 220 degrees Fahrenheit, too hot for life as we know it.

The second planet, KOI-314b, is about the same size as KOI-314c but much denser, weighing about 4 times as much as Earth. It orbits the star every 13 days, meaning it is in a 5-to-3 resonance with the outer planet.

The TTV method was used for the first time in 2010, and these latest findings show that it can be particularly useful when studying low-mass exoplanets. However, it seems to be effective only when discussing systems with multiple planets. For those of you interested, I invite you read about a new exoplanet hunting technique I wrote about a while ago. Called MassSpec, this method employs transmission spectroscopy – concentrating on measuring light from a star passing through an exoplanet’s atmosphere – and is reportedly accurate for studying the mass of exoplanets that are both low mass and orbit a faint parent star.

Illustration of a exoplanet transiting its parent star in the observational plane. (C) scienceoffice.org

Most Earth-like exoplanet in terms of size and mass discovered

Illustration of a exoplanet transiting its parent star in the observational plane. (C) scienceoffice.org

Illustration of a exoplanet transiting its parent star in the observational plane. (C) scienceoffice.org

Although the Kepler Space Telescope itself is defunct due to a malfunction that rendered it out of operation some months ago, the mission goes on as scientists churn through massive amounts of data gathered by Kepler, enough to keep them busy for years to come. One of the fruits of Kepler is an exoplanet called  Kepler 78b located just 400 light-years away, which apparently is the most Earth-like planet in terms of size and mass discovered thus far. The similarities end here, however. The planet completes a full orbit around its parent star every 8.5 hours compared to Earth’s steady 365-day orbit. This makes Mercury sound like the North Pole in comparison.

Kepler discovers worlds beyond our solar system by studying light. Each time a planet transits between the observational plane Kepler/parent star, a distinct wobble can be measured. Because Kepler 78b has such a short orbital period, scientists were able to gather a whole lot more data than usual, basically collecting enough data to characterize the planet in a few weeks compared to years with other exoplanets.

Each week Kepler 78b circles its star about 20 times, and based on this MIT researchers found the exoplanet is about 1.2 times Earth’s size — making Kepler 78b one of the smallest exoplanets ever measured. The mass was a lot trickier to determine, though. Each planet exerts a gravitational tug on its parent star, and this stellar motion can be detected as a very slight wobble, known as a Doppler shift. Analyzing this effects was daunting to say the least, since the star’s signal was very faint and besides  starspots –   dark patches on the surface of stars – also interfered with measurements.

By tracking the frequency at which certain starspots appeared and devising a set of clever calculations, the MIT researchers found the star completes a full rotation every 12.5 days and d that the star rotates relatively slowly, at 1.5 meters per second — about the speed of a jog, or a brisk walk.

“The star is moving at the same speed as when we walk to school or go grocery shopping,” notes  Roberto Sanchis-Ojeda, an MIT student who was part of the research. “The difference is that this star is 400 light-years away, so imagine how complicated it is to measure such speeds from so far away.”

The most Earth-like exoplanet in terms of size and mass

Knowing the star’s true Dopler Shift, the researchers determined Kepler 78b is  1.7 times more massive than Earth. When considering size as well, this implies that the exoplanet is similar in density to Earth and that it may be primarily made out of iron and rock. So, in many ways, Kepler 78 is pretty similar to Earth, but when considering how close its is to its star, all other similarities end here.

“It’s Earth-like in the sense that it’s about the same size and mass, but of course it’s extremely unlike the Earth in that it’s at least 2,000 degrees hotter,” says team member Josh Winn, an associate professor of physics at MIT and a member of the Kavli Institute for Astrophysics and Space Research. “It’s a step along the way of studying truly Earth-like planets.”

The researchers say they still have a lot to learn about the planet, like its surface and atmospheric composition. Just earlier this month is was reported that a team of NASA scientists made the first cloud map of an exoplanet, Kepler 7b.

Artie Hatzes, a professor of astronomy at the Institute of Thuringer Landessterwarte in Germany, says this is the first Earth-like planet, in terms of mass, size, and composition, that has been fully characterized.

“This is a tricky measurement to make because the star is very active and it has starspots,” says Hatzes, who did not participate in the research. “These create a false Doppler signal often referred to as ‘activity jitter.’ You can use special tricks to disentangle the Doppler wobble due to the planet, and the Doppler velocity variation caused by the spots on the star. If the planet had a much longer orbital period, it would be much more difficult to do so.”

The exoplanet Kepler 78b was characterized in a paper recently published in the journal Nature.

Artist impression of Kepler-76b orbiting around its parent star. The planet was discovered after relativistic effects were observed. The star has a slight elliptical shape that's been exaggerated in this illustration. David A. Aguilar (CfA)

Alien planet spotted using Einstein’s theory of relativity

Artist impression of Kepler-76b orbiting around its parent star. The planet was discovered after relativistic effects were observed. The star has a slight elliptical shape that's been exaggerated in this illustration. David A. Aguilar (CfA)

Artist impression of Kepler-76b orbiting around its parent star. The planet was discovered after relativistic effects were observed. The star has a slight elliptical shape that’s been exaggerated in this illustration. David A. Aguilar (CfA)

A new alien planet has been found by astronomers who have a novel planet hunting method which makes good use of Einstein’s special theory of relativity. The newly found exoplanet is slightly larger than Jupiter and is the first such planet found with this method.

The planet orbits a star in the constellation Cygnus, about 2,000 light-years away from Earth. It’s about 25 percent larger than Jupiter in diameter and twice as massive. In honor of the scientists who first described general relativity, the planet has been nicknamed “Einstein’s planet” by the team of international astronomers that discovered it. Officially, it’s name is Kepler-76b, signifying the ever resourceful Kepler space telescope was used for observations, but on that in just a few moments.

Typically, astronomers make use of the transient method to discover other worlds beyond our solar system, which consists  of looking for faint blips in the brightness of a parent star. If stars dim periodically, it means that in the observational plane between the observer (Kepler) and the star, an object (exoplanet) must be orbiting around the star. Primarily using this method, some 800 planets have discovered, some of which are considered Earth-like, both in terms of size and potential for supporting life.

The new method capitalizes on Einstein’s theory of special relativity to find the planet. The star brightens when the planet moves toward Earth, tugging the star with it because of gravitational tides. Relativistic effects focus the star’s light. This causes it to appear brighter when its wider side faces us, revealing more surface area, and dimmer when it moves away from Earth.  Additionally, the planet reflects starlight off it, contributing further to the discovery.

The method is appealing for wider use since it can be employed to find planets that can’t be observed otherwise using other methods, like the transient or wobbly methods. You don’t need Kepler, Earth and the parent star to be perfectly aligned in order to detect planets and high-precision measurements of a star’s velocity aren’t required anymore. It’s not without shortcomings either. The method requires extremely detailed observations to work and is only reliable for hunting large planets, not Earth-sized. Luckily, exquisite data NASA is collecting with the Kepler spacecraft is detailed enough for the relativistic method to render results.

“We are looking for very subtle effects,” said team member David Latham of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “We needed high quality measurements of stellar brightnesses, accurate to a few parts per million.”

When combined with other methods, however, the new method, whose acronym is BEER (BEaming effect with Ellipsoidal and Reflection/emission modulations), can complement the advantages of different techniques.

Kepler-62-planets

Most promising Earth-like planets found by Kepler

An artist's impression of a sunrise on Kepler 62f. (c) American Association for the Advancement of Science

An artist’s impression of a sunrise on Kepler 62f. (c) American Association for the Advancement of Science

The ever resourceful Kepler mission has recently unveiled several new possible Earth-like planet candidates, two of whom are favored by scientists with the best odds yet of supporting alien life.

The pair actually orbits around the same star, called Kepler 62, after NASA’s Kepler spacecraft, which is smaller and dimmer than our own star. Kepler 62 is some 1,200 light years away, in the constellation Lyra,  and hosts a total of five recognized planets, but only two of them – Kepler-62f, a rocky world just 1.4 times bigger than Earth and  Kepler-62e, which is 1.6 times larger than Earth – are well within the Goldilocks band of habitable planets. This band signifies that any rocky planet in this orbit is within the temperature threshold allowing for liquid water to form and flow on the surface – a must have prerequisite for supporting life.

As such, the two planets circle their star at distances of 37 million and 65 million miles, about as far apart as Mercury and Venus in our solar system. What’s important to note is that both worlds are rocky and in a way resemble our own solar system pair of hospitable planets – Earth and Mars, the latter once being host to liquid water on its surface billions of years ago.

“This is the first planet that ticks both boxes,” Dr. Charbonneau said, speaking of the outermost planet, Kepler 62f. “

Kepler-62-planets

While nobody knows what the two exoplanets look like, a separate modeling study published in the Astrophysical Journal suggests they’re both probably water worlds covered by endless, uninterrupted global oceans. This statement is far from being flawless and should be taken as nothing more than an educated guess, at best.

“There may be life there, but could it be technology-based like ours? Life on these worlds would be under water with no easy access to metals, to electricity, or fire for metallurgy,” lead author Lisa Kaltenegger, of the Max Planck Institute for Astronomy and the Harvard-Smithsonian Center for Astrophysics, said in a statement.

“Nonetheless, these worlds will still be beautiful blue planets circling an orange star — and maybe life’s inventiveness to get to a technology stage will surprise us,” she added.

In another system, Kepler-69, scientists have also found a super-Earth in the habitable zone, announced at the same NASA conference that presented the most viable Earth-like pair to date. The planet, Kepler-69c, is 1.7 times larger than Earth and is regarded as an important find since it orbits a parent star very similar to our own, 2,700 light-years away. So far, it’s the smallest Earth-like planet found to orbit a star of similar mass and brightness to the sun, as other similar findings were made of planets several times the mass of Earth. Researchers believe that a planet with mass closer to that of Earth is more likely to host life.

The team of 60 authors, led by Mr. Borucki, reported the discovery in an article published online in the journal Science.

Embedded below is the full video press conference where the new exoplanets were announced and described. It’s an hour long, but it’s really worth it if you have the time.

An artist's impression of an Earth-like planet with two moons orbiting around a red dwarf star. (c) David A. Aguilar (CfA).

Earth-like planets closer than previously thought. Nearest one might lie 13 light-years away

After researchers surveyed data from the Kepler mission tasked with identifying possibly habitable planets outside our solar system they found that 6% of red dwarfs – the most common type of planets – are within this zone. This new adjustment would mean that the nearest Earth-like planet might lie just 13 light years away.

An artist's impression of an Earth-like planet with two moons orbiting around a red dwarf star. (c) David A. Aguilar (CfA).

An artist’s impression of an Earth-like planet with two moons orbiting around a red dwarf star. (c) David A. Aguilar (CfA).

Astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) first took a look at the entire Kepler catalog of 158,000 target stars to identify all the red dwarfs. Then a more refined method was used to assess the stars’ temperature and size, an analysis that showed that these were generally smaller and cooler than previously thought.

An exoplanet is discovered and has its properties determined based on its transient orbit in plane with its parent star. This implies that the exoplanet’s size and properties are the same time determined based on its host star, since they’re based relative to the star’s properties. Thus, cooler dwarf stars means cooler planets and a tighter habitable zone.

“We thought we would have to search vast distances to find an Earth-like planet. Now we realize another Earth is probably in our own backyard, waiting to be spotted,” said Harvard astronomer and lead author Courtney Dressing (CfA).

A new Earth might be closer to us than thought

Red dwarfs make up three out of every four stars in our galaxy for a total of at least 75 billion. The astronomers involved in the present study identified 95 planetary candidates orbiting such red dwarf stars. Upon closer inspection most of them didn’t fit the right size and temperature requirements needed for them to be considered Earth-like, though. Three candidate planets, however, were considered both warm and Earth-sized. This would statistically imply that some 6% of all red dwarfs should have an Earth-like planet orbiting.

“We now know the rate of occurrence of habitable planets around the most common stars in our galaxy,” said co-author David Charbonneau (CfA). “That rate implies that it will be significantly easier to search for life beyond the solar system than we previously thought.”

It so has it that our solar system is located in a cloud of red dwarfs, which is why more than 75% of all neighboring stars are red dwarfs. With this new analysis in play, this all adds up implying that the nearest Earth-like planet might lie just 13 light years away.

Actually locating an Earth-like planet, with all its perks, would require an analysis of its atmosphere, something not possible with today’s technology. Once with the deployment of massive space telescopes like the James Webb Space Telescope or ground based telescope arrays like the Giant Magellan Telescope probing a distant world’s chemistry will be possible – expect some of humanity’s greatest discoveries to be made once this happens.

The three habitable-zone planetary candidates identified in this study are Kepler Object of Interest (KOI) 1422.02, which is 90 percent the size of Earth in a 20-day orbit; KOI 2626.01, 1.4 times the size of Earth in a 38-day orbit; and KOI 854.01, 1.7 times the size of Earth in a 56-day orbit. All three are located about 300 to 600 light-years away and orbit stars with temperatures between 5,700 and 5,900 degrees Fahrenheit. (For comparison, our Sun’s surface is 10,000 degrees F.)

Dressing presented her findings today in a press conference at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

source: press release

This EPOXI mission image shows what an Earth-like exoplanet might look like from afar. (c) NASA/JPL-Caltech/UMD/GSFC

Technique that allows mapping of distant worlds might allow us to find the next Earth

This EPOXI mission image shows what an Earth-like exoplanet might look like from afar. (c) NASA/JPL-Caltech/UMD/GSFC

EPOXI mission image shows what an Earth-like exoplanet might look like from afar. (c) NASA/JPL-Caltech/UMD/GSFC

The Kepler mission has proven to be invaluable to science today thanks to its formidable discoveries of exoplanets in our galaxy. It’s rather remarkable how scientists can tell so much from so little, like the size, mass, orbit and sometimes even composition of a distant planet all by analyzing light. On other hand, it’s frustrating at times not being able to tell how a potentially life harboring planet might look like.

This might change in the future. Using novel techniques, like the one developed by planetary scientist  Nicolas Cowan, that can feedback the proportion of land, ocean and clouds of a planet by analyzing the reflect light, scientists might be able to map distant worlds and actually visualize how it looks like, albeit far from accurately.

The technique presented this month at a meeting of the American Astronomical Society in Long Beach, Calif works by analyzing specific signals that tell features apart similar to how some military satellites today analyze images and work out whether a feature is a natural surface, like a wooden area, or an unnatural one, like a bunker.

Mapping distant worlds

Cowan’s technique – called “rotational unmixing” – analyzes the changing color of starlight reflecting off a distant, spinning exoplanet to calculate the mix of planetary features – such as land or ocean – that might combine to create a specific hue.

The technique is similar to being in an otherwise dark room with a muted television and analyzing the light reflected on the opposite wall to figure what is playing on the TV.

Cowan’s technique, called “rotational unmixing” picks up startlight reflected off a distant world and analyzes the variation in color. So by analyzing the reflect light of a spinning exoplanet throughout its full rotation, the technique can output calculate the mix of planetary features – such as land or ocean. As an exercise of imagination, Cowan explains the technique works somewhat like when you’re in a dark room with a muted television set facing opposite from it and being able to tell what’s on TV simply but looking at the distorted and blurry reflections on the wall.

“You’re not seeing the picture, but you’re seeing the reflection of the picture and learning something about what’s going on there,” said Eric Ford, an astronomer at the University of Florida in Gainesville, who was not involved in the study.

A new tool for hunting Earth-like planets

Now, there are a number of challenges that make this technique difficult to implement. For one, in order to distinguish to color of reflect light bouncing off very distant worlds you’d need a really powerful optical telescope, the kind which doesn’t exist yet and won’t for quite a while from now on.

If this is the case how do we know the technique works in the first place? Well, Cowan thought of this and used images that capture planet Earth from some of the most distant vantage point photographs have ever been made, like those from NASA’s Deep Impact spacecraft as part of the EPOXI mission.

When the software was used to analyze the EPOXI images, it was able to extract reflectance signatures corresponding to three major surface types – land, ocean and clouds. Sounds familiar right?

The technique is far from being perfect however. Lisa Kaltenegger, an exoplanet researcher at the Max-Planck Institute for Astronomy in Heidelberg, Germany says the targeted he exoplanet must have highly contrasting surfaces, such as ocean and land, or ocean and clouds, for this technique to work well. Distinguishing between clouds and ice is yet another challenge which the technique fails to address.

“Being able to tell whether a planet is simply undergoing significant cloud cover, or is in the midst of a global glaciation is important from the standpoint of habitability,” said o Aomawa Shields, an astrobiologist at the University of Washington in Seattle.

Still, if the right planet is targeted, then the technique could allow for a very rough estimate of how much water to land to clouds the said planet presents. Then again, while the technique is unsuitable to be used for strange planets – the kind we couldn’t even imagine – it does sounds like it’s perfectly tailored for hunting other planets that look very similar to our own. And what better bet of finding extraterrestrial life on a distant planet is there than that on an Earth-like planet?

The resulting picture would not be a map in the traditional sense.  “It’s not like a map that you can use to land a spacecraft on a planet … but it’s better than nothing,” Cowan said. It sure is, since Kepler reports 1 in 6 stars hosts at least an Earth-sized planet in a close orbit, raising the number of such planets in our own galaxy alone to 17 billion.

via Insider Science

 

Kepler telescope – Earth size planets number ’17 billion’

Astronomers working on the Kepler telescope believe that every 1 in 6 stars hosts at least an Earth-sized planet in a close orbit, raising the number of such planets in our galaxy to 17 billion.

Finding planets

kepler planets

Astrophysicists also announced 461 new planet candidates discovered by the telescope; this raises the number of planets discovered by Kepler to 2,740 – quite a remarkable number, especially considering how it was launched just 3 years ago. The findings were announced at the 221st meeting of the American Astronomical Society in California.

Since 2009, Kepler has looked at over 150.000 stars, trying to figure out if there are planets orbiting them. In order to do this, it analyzes what is called a transit – a dip in the star’s luminosity as planets pass in front of it – sort of like a mini-eclipse. However, these luminosity dips are extremely small and hard to measure and put in context, especially considering that not every dip is caused by a planet.

But Francois Fressin of the Harvard-Smithsonian Center for Astrophysics (who discovered several Earth-sized planets) is not only trying to find and characterize planets using this method, but he also wants to find planets that haven’t been visible to Kepler.

“We have to correct for two things – first [the Kepler candidate list] is incomplete,” he told BBC News. “We only see the planets that are transiting their host stars, stars that happen to have a planet that is well-aligned for us to see it, and [for each of those] there are dozens that do not. The second major correction is in the list of candidates – there are some that are not true planets transiting their host star, they are other astrophysical configurations.”

The most notable example here are binary stars – stars that orbit each other, often blocking light and dipping luminosity as one passes in front of the other.

Strength in numbers

“We simulated all the possible configurations we could think of – and we found out that they could only account for 9.5% of Kepler planets, and all the rest are bona fide [good faith] planets,” Dr Fressin explained.

kepler telescopeTheir results suggest that 17% of stars host a planet up to 1.25 times the size of the Earth, in close orbits lasting just 85 days or fewer – pretty much like the planet Mercury. If their results are correct, then our galaxy must have at least 17 billion such planets – much more than previously expected!

But even has he was reporting these numbers, Christopher Burke of the Seti Institute found 461 new candidate planets, a substantial fraction of which were about as big as Earth, or just a little larger.

“What’s particularly interesting is four new planets – less than twice the size of Earth – that are potentially in the habitable zone, the location around a star where it could potentially have liquid water to sustain life,” Dr Burke explained.

The good thing is that not only are they finding more and more planets, but they’re also getting better at it.

“It’s very exciting because we’re really starting to pick up the sensitivity to these things in the habitable zone – we’re just really getting to the frontier of potentially life-bearing planets.”

William Borucki, the main man and driving force behind the Kepler missions was also delighted.

“The most important thing is the statistics – not to find one Earth but to find 100 Earths, that’s what we’ll be seeing as the years go on with the Kepler mission – because it was designed to find many Earths.”

Via BBC

Artist impression of the Kepler-30 solar system, complete with its planets' orbits. (c) Cristina Sanchis Ojeda

Newly discovered solar system is very similar to our own

Artist impression of the Kepler-30 solar system, complete with its planets' orbits. (c)  Cristina Sanchis Ojeda

Artist impression of the Kepler-30 solar system, complete with its planets’ orbits. (c) Cristina Sanchis Ojeda

Researchers at MIT, the University of California at Santa Cruz and other institutions have come across the first exoplanetary system, whose planets exhibit a regularly aligned orbit, after analyzing data from NASA’s Kepler space telescope. So far, other discovered exoplanetary systems had planets, particularly hot-Jupiters, which presented  far more eccentric orbits.

Our solar system is comprised of eight planets, each orbiting their own regular lane and always on the same plane, in contrast to the rest of the other planetary systems discovered thus far. Finally, data from Kepler, an instrument that monitors 150,000 stars for signs of distant planets, has revealed a solar system very much similar to our own, 10,000 light years away and at the center of which lies Kepler-30, a star as bright and massive as the sun. The star has a vertical axis and has three planets which orbit in the same plane.

“In our solar system, the trajectory of the planets is parallel to the rotation of the sun, which shows they probably formed from a spinning disc,” says MIT graduate student Roberto Sanchis-Ojeda. “In this system, we show that the same thing happens.”

Some scientists worried that our solar system’s orbital structure might be extremely rare, if not unique – a fluke of nature. This recent find proves that something one of a kind in the Universe comes at a distant possibility, a cosmic one.

“It’s telling me that the solar system isn’t some fluke,” says Josh Winn, an associate professor of physics at MIT and a co-author on the paper. “The fact that the sun’s rotation is lined up with the planets’ orbits, that’s probably not some freak coincidence.”

The finding seems to support a recent theory which discuss how hot-Jupiters form – giant bodies named after their extremely close proximity to their white-hot stars, completing an orbit in mere hours or days. Kepler-30 provides evidence that only hot Jupiter systems are misaligned, formed as a result of planetary scattering.

“We’ve been hungry for one like this, where it’s not exactly like the solar system, but at least it’s more normal, where the planets and the star are aligned with each other,” Winn says. “It’s the first case where we can say that, besides the solar system.”

Planetary orbits correlated with life?

There could be implications for the study of how life evolved in the universe, as in order to have a stable climate suitable for life, a planet needs to be in a stable orbit.

 “In order to understand how common life is in the universe, ultimately we will need to understand how common stable planetary systems are,” Lloyd says. “We may find clues in extrasolar planetary systems to help understand the puzzles of the solar system, and vice versa.”

Findings were published today in the journal Nature. 

source: MIT newsroom

Artist impression shows a beautiful, purple Kepler-36c dominating the skyline, as seen from the surface of the smaller Kepler-36b. (c) David Aguilar, Harvard-Smithsonian Center for Astrophysics

Two newly discovered alien planets form closest known pair in the Universe

Kepler, a space telescope on a mission to find alien planets by measuring dips in the brightness of more than 150,000 stars, has come across a fantastic discovery. Two planets orbiting a distant star, which are closer to one another than any other two planets discovered thus far. Apparently, from the surface of the smaller planet, its neighbor would appear about the size of a 2.5 full-moon, while from the surface of the bigger planet, its dance partner would be the size of a full-moon. Indeed, this is a REAL SciFi scenario.

Artist impression shows a beautiful, purple Kepler-36c dominating the skyline, as seen from the surface of the smaller Kepler-36b. (c) David Aguilar, Harvard-Smithsonian Center for Astrophysics

Artist impression shows a beautiful, purple Kepler-36c dominating the skyline, as seen from the surface of the smaller Kepler-36b. CLICK for a magnified view. (c) David Aguilar, Harvard-Smithsonian Center for Astrophysics

The newly found planets are located in a system 1,200 light-years from Earth. Kepler-36b is a rocky world measuring 1.5 times the radius and 4.5 times the mass of Earth, while Kepler-36c is a gaseous, Neptune-size world about eight times as massive as Earth. Kepler-36b orbits its star every 13.8 days, and Kepler-36c every 16.2 days, and at their closest, the two planets come just within about 1.2 million miles of each other. That’s only five times the Earth-moon distance and about 20 times closer to one another than any two planets in our solar system.

“These two worlds are having close encounters,” said Josh Carter, a Hubble Fellow at the Harvard-Smithsonian Center for Astrophysics, in a press statement.

“They are the closest to each other of any planetary system we’ve found,” said the report’s co-author Eric Agol of the University of Washington in a press statement. “The bigger planet is pushing the smaller planet around more, so the smaller planet was harder to find.”

Twin planets trapped in an odd dance

Were these planets to house an atmosphere similar to that of the Earth, a view from any of the two’s surface would surely seem divine; especially from the Kepler-36b, where Kepler-36c would appear in the night sky 2.5 times bigger than our full moon. Sadly, the planets are so close to their sun, that nothing could survive, and their atmosphere, especially that of the gaseous Kepler-36c, would most likely obstruct any attempts at peering outside the worlds.

“Planet c would appear roughly 2.5 times the size of the full moon when viewed from the surface of planet b. Conversely, planet b would appear about the size of the full moon on planet c,” Carter said.

“We can speculate on the appearance of planet c: It may appear slightly more purple that Neptune,” he added. “The purple hue owes to absorption of red and yellow by sodium and potassium. There could also be a slight brown tint owing to hazes of photo-disassociated methane.”

The team of researchers from the University of Washington and Harvard University, published their findings in the journal Science.