Tag Archives: extraterrestrial life

As long as we have known that the sun is just another star, we have dreamed of other worlds. Thanks to the exoplanet hunter's toolkit, we can now do more than dream.

The Exoplanet Hunter’s Toolkit: the science of searching for other worlds

We have all, at some point, stared at the stars and dreamed lazily of other worlds, but, fortunately, for many of us, dreaming alone was not enough. These people set about building a toolkit stocked with instruments and techniques to find planets outside our solar system — exoplanets. In turn, these tools help us better understand our place in the Universe. 

An artist’s impression of 51 Pegasi b — not the first exoplanet to be discovered, but the most important (ESO/L. Benassi)

In October the Nobel Committee awarded the 2019 Nobel Prize in Physics to Michel Mayor, Professor at the Observatory of the Faculty of Science of the University of Geneva (UNIGE), Switzerland, and his doctoral student Didier Queloz for their discovery of 51 Pegasi b in 1995 — which marked the first discovery of an exoplanet orbiting a Sun-like star. The award marked the first time that exoplanet research has scooped what is, arguably, the most prestigious prize in science. Quite fitting as even though 51 Pegasi b was not the first exoplanet to be discovered — that honour goes to Astronomers Aleksander Wolszczan and Dale Frail who discovered an exoplanet around a neutron star in 1992 — it was Mayor and Queloz’s breakthrough that really spurred on the science of exoplanet investigation. 

As extraordinary as it sounds, before the 1990s, it wasn’t entirely certain that other stars actually possessed planets of their own. Whilst there was technically no reason to suspect that the solar system was unique, the 1980s had proved a frustrating time for exoplanet hunters. By the turn of that decade, many potential candidates had come and gone evading positive confirmation. 

Despite early setbacks, since 1995, the catalogue of exoplanets has soared, with over 4,000 examples now in NASA’s catalogue. And with technology only improving, that collection is set to soar. This animation and sonification from SystemSounds is a stunning representation of how the field has exploded since the 1990s. Created by SYSTEM Sounds (Matt Russo, Andrew Santaguida)

Created by SYSTEM Sounds (Matt Russo, Andrew Santaguida)

We are becoming so confident in the discovery of exoplanets, that we are now turning our attention to much more detailed examinations of previously discovered examples. For example, many researchers are now focusing on the investigation of exoplanet atmospheres, attempting to discover if they contain traces of chemicals such as carbon monoxide and other organic and complex molecules, and, of course, water. Should these elements be observed it constitutes a clue, a tiny hint, that life may not be unique to our planet. 

Thus far, searches for exoplanets have been more effective in finding gas giants, planets similar to Jupiter. But new advances such as the James Webb Space Telescope and the Extremely Large Telescope have researchers salivating at the idea of finding and examining smaller, rocky planets. Planets just like Earth. And of course, the discovery of the Trappist-1 system — containing seven Earth-like rocky planets, three in the so-called ‘habitable zone’ capable of harbouring liquid water — has shown that these planets are definitely out there waiting for us to find them. 

An artist’s impression of the Trappist-1 system — 7 Earth-like planets orbiting a red dwarf star (NASA)

As such, exoplanet research stands on the cusp of providing an answer to the question we have all pondered at some point whilst staring at the stars, are we alone in the universe?

Of course, the fact that it took so many years of fruitless searching to begin to successfully spot exoplanets illustrates, these blighters are extremely difficult to observe. This means that astronomers have had to develop extremely precise and sensitive methods of exoplanet detection. These techniques are numerous, each with its own strengths and weaknesses. 

Wobbly Stars

It goes without saying that before we spotted the first exoplanet, our experience of observing other planets was restricted to our neighbours in the solar system. This was done exclusively through direct imaging, but this technique becomes much more difficult as the distance to an object increases. 

Spotting planets in our solar system is possible with direct imaging techniques, for exoplanets, much craftier methods are required (NASA)

The hindrances imposed on direct imaging increase exponentially when we consider the effect of attempting to spot a dim object next to a much bright one — exactly the scenario faced when attempting to spot a distant planet orbiting its parent star. But, this proximity to an extremely bright object is not always a hindrance to exoplanet detection. In fact, many methods of spotting these planets absolutely depend on it. If a dim object can have an effect of the extremely bright object — then the ability to observe this bright object is a benefit.

This interference arises from the fact that stars with planets orbiting them demonstrate a ‘wobble’ in their motion. This arises from the fact, that despite common belief, planets don’t actually orbit stars. In fact, planets and stars orbit a mutual centre of mass— or barycentre —its location based on the masses of the planets and stars involved. As the usual set-up of a planetary system involves a star that is tremendously more massive than its planets, this mutual point of orbit is usually closer to the star centre of mass — often within the star’s surface.

This huge disparity in mass means that this ‘wobble’ is tiny. As an example, consider our own solar system. As the Sun constitutes more than 99.9% of the total mass of the solar system, the barycentre for our planetary system is located very close to our star’s centre of mass. The most significant gravitational influence on the Sun arises as a result of the solar system’s most mass planet — Jupiter. 

Rather than orbiting the Sun, both Jupiter and the Sun orbit a mutual centre of mass. This centre of mass is closer to the surface of the Sun and thus results in a slight ‘wobble’ in the star’s motion. This wobble can be used by astronomers to infer the presence of a planet. (Robert Lea) 

Let’s imagine, for simplicity’s sake, that Jupiter is the only planet orbiting the Sun. An observer viewing this reduced solar system and Jupiter’s 12-year orbit from the nearest planetary system — Alpha Centauri, 4.4 light-years away — would see the Sun as a mere point of light. The shift in its position caused by Jupiter would be just 3.7 milliarcseconds. To put this shift into perspective, consider that one pixel in an image from the Advanced Camera for Surveys aboard the Hubble Space Telescope represents 50 milliarcseconds — one pixel! Thus you can see, this ‘wobble’ caused by Jupiter is a tiny, barely perceptible amount of movement, less than 1/10 of a pixel from the nearest star!

Two further things to consider in this hypothetical situation, Jupiter is the most massive planet in the solar system, the wobble caused by Earth viewed from the same position would be smaller by a factor of at least 300. Also, many of the exoplanets that we are attempting to spot are much further afield than 4.4 light-years. That means that any method using this wobble must be incredibly sensitive and precise. Incredibly, despite this tiny effect, the wobble has spawned several methods of exoplanet detection. 

The astrometry method depends on measuring the ‘wobble’ of a star caused by a planet in orbit around it. (ESA)

One of these methods is astrometry — very effective for detailing high-mass planets in wide orbits around relatively low-mass stars, and thus not well suited to tracking down Earth-like, rocky planets. For an indirect observation method, astrometry is pretty good at pinning down characteristics like mass, and orbital period, shape and width. Unfortunately, it isn’t great at actually identifying planets. 

Thankfully there are other indirect techniques that have helped astronomers help find exoplanets — one of which combines a star’s ‘wobble’ with a phenomenon familiar to drivers and pedestrians everywhere.  

Sirens, soundwaves and stars. The Doppler Wobble

I’m sure everyone reading this has been in a situation in which an ambulance with sirens blaring has raced towards them, passed their position and continued on its journey. You’ll have likely noticed that as the vehicle approaches the sound of its siren is higher pitched, switching to a lower pitch as it moves away.

This is because as the soundwaves are emitted by the approaching ambulance they are compressed and shorter wavelength sound waves mean a higher-pitched sound. As the siren recedes, the soundwaves are stretched out — resulting in a lower pitch. 

The Doppler effect as it applies to soundwaves. The soundwaves from the approaching ambulance are compressed — resulting in a higher pitch. The soundwaves as the ambulance recedes are expanded, and thus lower-pitched. (Robert Lea)

This is the Doppler effect, and the key thing for astronomers is, it applies to any kind of wave emitted by a moving object — even light which propagates as a wave. Just as the wavelengths of soundwaves correspond to different pitches, the wavelengths of light correspond to different colours. Longer wavelengths producing a reddening, shorter wavelengths produce bluer light. This is referred to as redshift and blueshift— a crucial phenomenon in astronomy. 

Instead of an ambulance, let’s think about a star moving towards us, as the light waves emitted are compressed — causing the light signature of the star to be shifted towards the blue end of the spectrum. As the star moves away, the light is stretched out again — shifting the light signature towards the red end of the electromagnetic spectrum. 

The Doppler Effect as it would appear for light-waves emitted by a star. I shouldn’t have to say, but nothing is to scale in this image! (Robert Lea)

If this is the case, why do the lights atop the ambulance as it recedes not appear redder than they were on their approach? This is because the amount of red and blue shift is determined by an object’s speed divided by the speed of light c. As c is so large, an object would have to be moving at tremendous speeds to result in a significant enough change in colour for us to notice. 

You might be wondering how exactly scientists can tell that a star’s signature has shifted towards either end of the electromagnetic spectrum. This is because stars don’t emit light in a constant ‘smear’ across the spectrum. There are notable dark bars where light is not emitted — referred to as the absorption spectrum. It is by tracing the shift of these bars that researchers can see if a star is wobbling and by how much, thus inferring the presence of exoplanets. 

The light signature of a star contains dark absorption lines. These lines not only tell us what elements the star is composed of but also, by tracking the shift in these lines we can infer the presence of an orbiting planet. (Lund Observatory)

Of course, you may well have noticed a flaw with this technique. It’s only useful in detecting exoplanets that are causing their star to wobble towards and away from Earth. This gives rise to the method’s alternative name — the radial-velocity method. In addition to this blind-spot in glimpsing planets moving perpendicular to Earth, the Doppler-wobble technique can also only tell us what a planet’s minimum mass is. 

But, knowledge of the light signature of a star gives rise to another tool in the exoplanet hunter’s arsenal, one which depends on planets crossing — or transiting — their parent star. The photometry technique. 

Don’t cross me!

The photometry technique measures the dip in brightness of a star caused as a planet crosses in front of it, thus allowing us to infer the presence of an exoplanet and even collect details about a few of its characteristics. The method clearly requires searching for rare eclipse events where a planet blocks some of its parent star’s light. 

An illustration of the photometry technique which relies on a planet crossing its parent star, blocking some of the light it emits (NASA)

You may be unsurprised to learn that like the other methods detailed above, the photometry technique has to be incredibly sensitive. In this case, that is because the disparity in size between a star and a planet orbiting it is so huge in the star’s favour that the light obscured by this transit is minuscule. 

To illustrate this, take a look at this image of Mercury transiting the Sun seen from within the solar system. 

This speck, highlighted below, is Mercury. Now imagining the tiny fraction of light this would have obscured. When you’ve done that, imagine viewing this scene from millions of light-years away!

Returning to the example of Jupiter, the largest planet in our solar system, when it transits the Sun it blocks just 1% of the star’s light — making the Sun appear 1% fainter for a period of 12 hours. As small as it is, in comparison to the phenomena exploited by the two methods above this effect is massive.

And again, like its fellow methods of exoplanet detection, the photometric technique has significant limitations that define the situations in which it can be employed. Many planets don’t transit their parent stars and those that do have to be orientated ‘just right’ for the photometry method to work. Also, transits that do occur are incredibly brief, so it takes a lot of good fortune to catch one. That means that the vast majority of exoplanets that we believe exist out there in the depths of space can’t be spotted by this method. 

The Earth’s atmosphere and the ‘twinkling effect’ it has on stars is also a major hindrance to the photometry method. This results in its reliance on space-based telescopes. By taking the atmosphere out of the equation, it is possible to not just improve the precision of our measurements but also allows for the continuous monitoring of a star’s brightness without the agony of something as mundane as a rainy-day ruining data.

The future of exoplanet research is extremely bright

With all the limits and drawbacks I’ve listed it may seem like searching for exoplanets is something of a hopeless task, like searching for a needle in a haystack. Except there are 100 billion ‘haystacks’ or stars outside of our analogy in each galaxy. Clearly its a tribute to our advances in science that we have found 4000 or so ‘needles’ thus far.

The astrometry technique, the first tool we examined in the exoplanet hunter’s toolkit isn’t particularly useful, but the second, the doppler technique has been a real boon. It kickstarted exoplanet-hunting as a viable scientific field in the ’90s and provided the majority of discoveries right up into the 2000s. Despite this, its the transit technique — photometry — the last piece of equipment that we turned over, that holds the most promise for the future.

It was a slow starter for sure, reaching maturity much later than the previous two methods mentioned. But, as the use of automated and space-based telescopes has become more prevalent, the ability to keep thousands of stars under constant observation is making the photometry technique the exoplanet-hunting tool that promises to push the boundaries of our understanding of planets elsewhere in the universe. 

As our catalogue of exoplanets expands, researchers also now begin to look beyond just spotting these other worlds. The CHEOPS telescope will launch this week (17/12/19) with its mission to spot exoplanets close-by that warrant further investigation. And it is the James Webb Space Telescope, launching in 2021, that will really delve into these selected planets.

The future of exoplanet hunting. Clockwise from top: The James Webb Space Telescope, the Extremely Large Telescope and the CHEOPS telescope.

Researchers will then use some of the methods I’ve listed above to examine the atmospheres of these planets, a ‘deep-dive’ that would have seemed like little more than a pipe-dream in 1995 when Michel Mayor and Didier Queloz spotted 51 Pegasi b. 

Exoplanet research, in many ways, represents one of the ultimate expressions of the drive to perform science. For its pioneers, the men and women that stocked our toolkit, it simply wasn’t enough to lie back staring at the stars, dreaming of other worlds. 

Illustration by Wendy Kenigsberg/Matt Fondeur/Cornell University

Biofluorescence shining light on the search for alien life

The use of ultraviolet flares from red suns and biofluorescence may provide astronomers with vital life signs in the universe

Illustration by Wendy Kenigsberg/Matt Fondeur/Cornell University
Illustration by Wendy Kenigsberg/Matt Fondeur/Cornell University

A new method of searching for life in the cosmos has been pioneered by astronomers from Cornell University.

The team propose that astronomers could utilise harsh ultraviolet radiation flares from red suns — once thought to destroy surface life on planets — to assist in the discovery of hidden biospheres. The team’s study — published in the journal Monthly Notices of the Royal Astronomical Society — suggests that ultraviolet radiation could trigger biofluorescence — a protective glow — from life on exoplanets.

Jack O’Malley-James, a researcher at Cornell’s Carl Sagan Institute and the study’s lead author, says: “This is a completely novel way to search for life in the universe.

“Just imagine an alien world glowing softly in a powerful telescope.”

Biofluorescence, similar to that found in coral, could be used by astronomers to search for life (S.E.A. Aquarium)

Some undersea coral on Earth use a similar form of biofluorescence that the team intend to utilise in the search for life. The coral does this in order to render the sun’s harmful ultraviolet radiation into harmless visible wavelengths, in the process, creating a beautiful radiance.

“Maybe such life forms can exist on other worlds too, leaving us a telltale sign to spot them,” points out Lisa Kaltenegger, associate professor of astronomy and director of the Carl Sagan Institute.

She points out that in our search for exoplanets, we have searched for ones which look like our own planet. This research plays off the idea the biofluorescence may not have evolved on Earth exclusively.

In fact, as this is a form of defence from harsh UV radiation, logic suggests that its usefulness — and thus, the chance of development — would be increased around stars where UV flares are commonplace.

A large fraction of exoplanets — planets beyond our solar system — reside in the habitable zone of M-type stars. This type of star — the most commonly found in the universe — frequently flare, and when those ultraviolet flares strike their planets, biofluorescence could paint these worlds in beautiful colours.

The next generation of Earth- or space-based telescopes can detect the glowing exoplanets — should they exist.

Ultraviolet rays are transformed into less-energetic and therefore less harmful wavelengths through a process called “photoprotective biofluorescence.” This should leave a very specific signal which astronomers can search for.

Kaltnegger continues: “Such bio fluorescence could expose hidden biospheres on new worlds through their temporary glow when a flare from a star hits the planet.”

The astronomers used emission characteristics of common coral fluorescent pigments from Earth to create model spectra and colours for planets orbiting active M stars to mimic the strength of the signal and whether it could be detected for life.

Proxima b — a potentially habitable world found orbiting the active M star Proxima Centauri in 2016 could qualify as a target for such a search. The rocky exoplanet has been one of the most optimal space travel destinations due to the proximity of the star it orbits — although such jaunts are a concern for the far-future.

Jack O’Malley-James, continues: “These biotic kinds of exoplanets are very good targets in our search for exoplanets, and these luminescent wonders are among our best bets for finding life on exoplanets.”

Large, land-based telescopes that are being developed now for 10 to 20 years into the future may be able to spot this glow.

Kaltenegger concludes: “It is a great target for the next generation of big telescopes, which can catch enough light from small planets to analyze it for signs of life, like the Extremely Large Telescope in Chile.”


Original research: Biofluorescent Worlds II: Biological Fluorescence Induced by Stellar UV Flares, a New Temporal Biosignature. Jack T O’Malley-James, Lisa Kaltenegger.


TRAPPIST-1, the dwarf star with seven Earth-sized planets, is older than our solar system

The solar system with seven potentially habitable planets is much older than our own.

This illustration shows what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right).
Credits: NASA/JPL-Caltech

TRAPPIST-1, with the much less attractive technical name 2MASS J23062928-0502285, is an ultra-cool brown dwarf just slightly larger than Jupiter. Despite its small size and low temperature, it’s one of the most interesting stars we’ve discovered out there. In February this year, NASA announced the discovery of seven Earth-sized planets around the star, all in the habitable zone — the so-called Goldilocks area where it’s just the right temperature for liquid water to exist. To make things even more exciting, this solar system is a ‘mere’ 40 light years away. It’s far enough to be inaccessible for the foreseeable future, but given the sheer immensity of our galaxy, 40 light years is just peanuts.

But having an Earth-like figure and being located in the habitable zone isn’t nearly enough to support life. That’s why astronomers at NASA have been studying the system assiduously, trying to learn more about it and establish its conditions. Now, for the first time, they’ve put an age on it — or rather, an age range. TRAPPIST-1 is between 5.4 and 9.8 billion years old. This makes it a very old system compared to our own, which is ‘just’ 4.5 billion years old.

It’s indeed a very broad range, but at least it enables us to say that the system is old, though we’re not yet sure how old. Also, while it’s a broad constraint, it’s still a constraint. When it was first discovered, we only knew that the star had to be older than 0.5 billion years, since that’s how long it takes for these stars to contract. It could have been almost as old as the universe itself.

“Our results really help constrain the evolution of the TRAPPIST-1 system, because the system has to have persisted for billions of years. This means the planets had to evolve together, otherwise the system would have fallen apart long ago,” said Adam Burgasser, an astronomer at the University of California, San Diego, and the paper’s first author.

The system overlaid over the habitable zone.
Image credits: NASA/JPL.

It’s not clear exactly what this means for the habitability of the planet. It’s known that older stars tend to flare less than younger stars, thus having less of a chance of wiping out potential life. But this also means that the planets have absorbed billions of years of high-energy radiation, which might imply that their atmospheres have boiled off. A decent analogy here is Mars, which once hosted an atmosphere which has since been wiped off by radiation.

But there are more aspects to consider. TRAPPIST-1 planets have lower densities than Earth, which makes it more likely for them to hold vast reservoirs of volatile molecules, which could generate thick atmospheres, strong enough to protect the planets from radiation. Especially the two outer planets, planet and planet h might have been lucky enough to escape with an atmosphere.

But if any life exists on these planets, it’s almost certainly way more hardy than that on Earth.

“If there is life on these planets, I would speculate that it has to be hardy life, because it has to be able to survive some potentially dire scenarios for billions of years,” Burgasser said.

TRAPPIST-1 is an ultra-cool dwarf star in the constellation Aquarius, and its seven planets orbit very close to it, which puts them in the Goldilocks area.
Credits: NASA/JPL-Caltech

Future observations will focus on identifying potential atmospheres around these planets. If such an atmosphere exists, then it likely existed for billions of years, which makes the possibility of extraterrestrial life significantly more likely. The observations will also help astronomers better understand other similar systems form and develop.

“These new results provide useful context for future observations of the TRAPPIST-1 planets, which could give us great insight into how planetary atmospheres form and evolve, and persist or not,” said Tiffany Kataria, exoplanet scientist at JPL, who was not involved in the study.

 

Electron micrographs of Bacillus pumilus SAFR-032 spores on aluminum before and after exposure to space conditions. [Reproduced with permission from P. Vaishampayan et al., Survival of Bacillus pumilus Spores for a Prolonged Period of Time in Real Space Conditions. Astrobiology Vol 12, No 5, 2012.] Image Credit: P. Vaishampayan, et al./Astrobiology

Mars could become colonized by stowaway Earthling tiny space travelers

The European Technology Exposure Facility (EuTEF) attached to the Columbus module of the International Space Station during orbital flight. Image Credit:  DLR, Institute of Aerospace Medicine/Dr. Gerda Horneck

The European Technology Exposure Facility (EuTEF) attached to the Columbus module of the International Space Station during orbital flight.
Image Credit:
DLR, Institute of Aerospace Medicine/Dr. Gerda Horneck

Whenever alien invasions are concerned, most people tend to image extraterrestrial spaceships landing on Earth, not the other way around. In reality, this alien invasion most likely will happen or already has happen in reverse, as Earth-based life forms could reach distant asteroids or planets, like Mars, hitching rides on human spaceship. To assess this possibility, NASA researchers published three studies that looked at the survival capability of microorganisms, particularly adapted to extreme conditions like those found in deep space travel.

Surviving in space

Contamination with Earth-based organisms is a huge concern for NASA and other space  programs investigating life harboring conditions on other worlds. The Curiosity rover, the most advanced mobile laboratory to have landed on Mars yet, is charged with the task of confirming whtether or not the planet is or ever was capable of sustaining life. Imagine the dismay everyone would feel to find life on Mars, but only later to realize that it came from Earth hitching a ride with the rover in the first place. These concerns are very much real and special measures are in place to ensure that any spacecraft that goes into space leaves sterilized. Some life forms are more persistent than others, however, and while chances are low, the risk of contamination is still there.

[READ] Tardigrades – the microscopic water bears that defy all odds

Currently, spacecraft landing on Mars or other planets where life might exist must meet requirements for a maximum allowable level of microbial life, or bioburden. These acceptable levels were based on studies of how various life forms survive exposure to the rigors associated with space travel.

“If you are able to reduce the numbers to acceptable levels, a proxy for cleanliness, the assumption is that the life forms will not survive under harsh space conditions,” explains Kasthuri J. Venkateswaran, a researcher with the Biotechnology and Planetary Protection Group at NASA’s Jet Propulsion Laboratory and a co-author on all three papers.

This assumption may not hold true, according to these three most recent studies published by NASA scientists, which took place in space, outside the International Space Station. One such study, for instance, showed that spores of Bacillus pumilus SAFR-032 were able to withstand extremely harsh conditions. When researchers exposed this hardy organism to a simulated Mars environment that kills standard spores in 30 seconds, it survived 30 minutes. For one of the recent experiments, Bacillus pumilus SAFR-032 spores were exposed for 18 months on the European Technology Exposure Facility (EuTEF), a test facility mounted outside the space station.

“After testing exposure to the simulated Mars environment, we wanted to see what would happen in real space, and EuTEF gave us the chance,” says Venkateswaran. “To our surprise, some of the spores survived for 18 months.” These surviving spores had higher concentrations of proteins associated with UV radiation resistance and, in fact, showed elevated UV resistance when revived and re-exposed on Earth.

Cover of darkness may help spread contamination

In another investigation, spores of Bacillus pumilus SAFR-032 and another spore-forming bacteria, Bacillus subtilis 168, were dried on pieces of spacecraft-quality aluminum and subjected for 1.5 years to the vacuum of space, cosmic and extraterrestrial solar radiation and temperature fluctuations on EuTEF. These samples were also subjected to the same extreme Martin simulated atmospheres. Most spores didn’t survive when exposed to solar UV radiation in space, as well as the Martin light spectrum, but when samples were kept in the dark about 50% survived. This suggests that spores could survive a trip to Mars if these are tucked away in a dark hatch or layered underneath other spores.

Electron micrographs of Bacillus pumilus SAFR-032 spores on aluminum before and after exposure to space conditions. [Reproduced with permission from P. Vaishampayan et al., Survival of Bacillus pumilus Spores for a Prolonged Period of Time in Real Space Conditions. Astrobiology Vol 12, No 5, 2012.] Image Credit:  P. Vaishampayan, et al./Astrobiology

Electron micrographs of Bacillus pumilus SAFR-032 spores on aluminum before and after exposure to space conditions. [Reproduced with permission from P. Vaishampayan et al., Survival of Bacillus pumilus Spores for a Prolonged Period of Time in Real Space Conditions. Astrobiology Vol 12, No 5, 2012.]
Image Credit:
P. Vaishampayan, et al./Astrobiology

The third study placed rock-colonizing cellular organisms in the EuTEF facility for 1.5 years, further testing a theory of how organisms might move from one planet to another, known as lithopanspermia. In this scenario, rocks ejected from a planet by impact with, say, a meteor, carried organisms on their surface through space and then landed on another planet, bringing that life with them. Strong evidence for lithopanspermia is found within the rocks themselves. Of the over 53,000 meteorites found on Earth, 105 have been identified as Martian in origin. In other words an impact on Mars ejected rock fragments that then hit the Earth.

NASA researchers selected organisms able to cope with some of the most extreme environments on Earth. Much to their surprise, the scientists discovered these organisms were able to survive in even more hostile environment of space.  Lithopanspermia would require thousands or even millions of years, much longer than the experiment’s duration, but results provide the first evidence of the hardiness of these organisms in space and suggest the possibility that space-traveling rocks could carry life between planets.

All three studies, Survival of Rock-Colonizing Organisms After 1.5 Years in Outer Space, Resistance of Bacterial Endospores to Outer Space for Planetary Protection Purposes and Survival of Bacillus Pumilus Spores for a Prolonged Period of Time in Real Space Conditions, have appeared in Astrobiology Journal.

This 3D-printed model of the plant habitat will include cameras, sensors, micro fluidics system, and a seed module needed to sustain life on another world. Photo credit: Hemil Modi.

To boldly go where no plant has gone before – NASA to grow plants on the moon in 2015

  • If astronauts are ever to live on the moon or in deep space outposts, a sustainable living plan in which they would grow their own food (plants) in greenhouses is required.
  • NASA is taking the first steps in this direction by developing a project which aims to germinate plants on the moon’s surface.
  • Thousands of students from high schools and universities will also be involved in the project.

Arabidopsis plant seeds will be germinated on the moon's surface in habitat containers. (c) scienceillustrated.com.au

Arabidopsis plant seeds will be germinated on the moon’s surface in habitat containers. (c) scienceillustrated.com.au

While we may still be many years away from the moment when another human being sets foot on the moon, this doesn’t necessarily mean that other life forms need to miss out as well. For now, the next biological entities set to touch soil with the moon will be plants, according to NASA. To be more precise, plant seeds will be sent to the moon where an automatic system will deploy the necessary steps to commence germination and plant growth. The project is set to be low cost and of high educational value since thousands of university and high school students will participate as citizen scientists.

Before any talks of a permanent moon base or outer space outposts can be seriously discussed, it’s important to conceive a solid sustainable living plan for the men and women staged in such a facility. Although plants have been grown successfully in space, notably on board the International Space Station, the moon’s surface is the closest we can get momentarily to deep space conditions – partial gravity and higher radiation exposure. There’s a fairly accepted consenssous that growing plants on the moon is possible, but not much is know about the feassability of such an endeavour.

A first step in long term presence on the moon or deep space is to send plants; seeding plants, to be more precise. Seedlings are extremely sensitive to their growth environments, and radiation can severely alter their genetic mark-up – so far, the same applies to humans. With this in mind, by thoroughly studying what happens to plants as they mature and grow over a longer time frame, you can make some assumptions regarding what this means for humans as well. If plants prosper, humans prosper and vice-versa.

It’s well known, however, that NASA is on an ever thinning budget. Luckly, modern technology and private space ventures have eased space flight tremendously and NASA’s project to grow plants on the moon will take advantage of this. According to Dr. Chris McKay, a well-renowned planetary scientist, this project would have cost $300 million two decades ago, but now the team is confident they can pull it off with under $2 million. The key is small-scale, translating in small payload, and … hitchhiking.

Interplanetary plants

You might have heard of Google’s LunarX Prize, a contest where a $20 million prize will be awarded to the first private space venture team that manages to deploy a robotic spacecraft on the moon’s surface, at least travel for a bit and transmit back two “Mooncasts” by December 31, 2015. There’s no need to send the seeds on a launch of its own – that would raise the costs of the project to unfeasible lengths – and since teams competing in the LunarX Prize will be the first in the world to attempt a landing on the moon any time soon, the NASA scientists plan on piggybacking a small payload.

This 3D-printed model of the plant habitat will include cameras, sensors, micro fluidics system, and a seed module needed to sustain life on another world. Photo credit: Hemil Modi.

This 3D-printed model of the plant habitat will include cameras, sensors, micro fluidics system, and a seed module needed to sustain life on another world. Photo credit: Hemil Modi.

The payload is comprised of lightweight cyllinders resembling coffee cans in which 10 turnip seeds, 10 basil seeds, and 100 arabidopsis seeds will be germinated. Obviously, the plants won’t be seeded on the moon’s soil itself, which is unsuitable to bear plant life, instead the coffee can-like containers will act as high-tech habitats where soil, nutrients, water and 5-days worth of air will be provided for germination, all while multiple sensors detect and transmit all kinds of valuable information back on Earth. Natural sunlight of the moon will be used. According to NASA, the researchers aim to follow three main parameters:

  • Germination Shows that minimum environmental factors for Earth-normal growth are available; sensitive to hazards, temperature, moisture and light.
  • Phototropism Shows that plants on the Moon responds normally to external environmental cues
  • Circumnutation Shows that Earth-normal endogenous growth patterns and growth rates are expressed in lunar conditions

Citizen science!

Meanwhile on Earth, the second part of the project would be underway – one which would involve thousands of citizen scientists, mostly in high schools and universities. To see how the plants’ germination fairs on the moon, you need to compare the evolution to the same plants back on Earth and the more data you have, the more you statistically become relevant. So NASA will send schools all over the country the same lunar plant habitats which will be investigated in hundreds or thousands of different points. Basically, instead of spending a tonne of money on replicating your experiment, you crowdsource it! At the same time, you provide an incredibly rich educational experience, not to mention you involve thousands of young minds in a project that is well beyond the barriers of our own planet. That’s something you don’t see every day.

After LPX-0 demonstrates germination and initial growth in lunar gravity and radiation, NASA will launch subsequent missions which will test : 1) long term, over-lunar-night experiments, 2) multi-generation experiments, 3) Diverse plants. The implications are clear: you can prove or disprove whether or not the astronauts can sustainably live on the moon, but the findings could also help scientists studying plant growth back on Earth too.

Earth is a paradise for life, still it is riddled here and there with all sorts of  inhospitable areas. Dr. Robert Bowman, the team’s chief biologist, described how plants constantly have to cope with harsh environments and threats: “Simply knowing how plants deal with stress on the moon can really tell us a lot about how they deal with stress right here on Earth.” In the face of climate change, the moon could tell us a great deal.

Neil Armstrong’s iconic first steps and words as he touched down on the moon’s surface still echo to this day and have become a symbol of mankind reaching for the stars. What kind of mark would a plant make?

The first picture of a plant growing on another world – that picture will live forever.  It will be as iconic as the first footprint on the moon,” Dr. Pete Worden, Director of NASA’s Ames Research Center said.

 

 

Has NASA found alien life ?

NASA has excited pretty much everybody’s mind when they announced a press conference for today on the topic of extraterrestrial life and their recent findings in the field.

“NASA will hold a news conference at 11 a.m. PST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life,” NASA said in a Wednesday statement. “Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe.”

The fact that they were extremely vague about the whole thing but did provide some information only managed to make people even more curious about the whole thing; however, we probably shouldn’t expect any major announcements. However, in the unlikely but possible even that they found some decently advanced life forms, they are probably from Mars, considering the Exploration Rover Spirit has been sitting idle on the red planet after getting trapped in sand about a year ago. The time that has passed would allow it to detect chemical signals for life. Another possibility was speculated by blogger Jason Kottke, who makes a point that it could also be about Titan or Rhea, two of Saturn’s moons.

The findings will be published in a journal, but until the conference today they are kept a secret, so at the moment all we can do is make more or less educated guesses. We will keep you posted as the conference develops.