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3D meteorite level.

What’s the difference between an asteroid and a meteorite?

On June 30th, 1908, the boreal forests of Tunguska, Siberia, were shaken (and subsequently flattened) by a massive explosion. It wasn’t man-made — an asteroid pierced our planet’s atmosphere and exploded before hitting the surface.

3D meteorite level.

Artistic rendering of a meteorite.
Image via Pixabay.

This explosion, known as the Tunguska event, would make history. It was the largest impact event humanity has ever witnessed first-hand and would lead the UN to declare June 30th the International Asteroid Day.

While definitely awe-inspiring, the event didn’t lead to the massive loss of life that, say, the Chixulub Impactor caused (that’s the pebble that killed the dinosaurs). So why did one space-rock kill off the largest beasts to ever roam the Earth, while another merely flattened 2,000 square kilometres (770 square miles) of forest without causing a single human death? Well, the secret is all in the definition. Today, we’ll take a look at that simple yet oh so important distinction between an asteroid and a meteorite.

What is an asteroid?

The word itself gives us a glimpse into the nature of asteroids. “Aster” is the ancient Greek word for ‘star’, and the suffix “-oid” is used to show an incomplete or imperfect resemblance to the root word. “Asteroid”, therefore, means ‘star-like’ or, taken more literally, ‘star-like, but not quite’.

Keep in mind that for the ancient Greeks looking up into the night sky, planets and stars all looked the same; ‘aster’, therefore, can be understood as both ‘star’ and ‘planet’.

Vega asteroids.

Artist’s concept of an asteroid belt around the star Vega. Oumuamua, the first object to pass through our solar system that was confirmed to come from outside it — originates from this system.
Image credits NASA / JPL-Caltech.

Asteroids are chunks of space rock ranging from one meter to almost a thousand kilometers in diameter. The larger ones may rightfully be considered minor planets (or dwarf planets/planetoids). Ceres is a good example of this latter category, and the largest known asteroid. These large ones closely resemble planets: they’re roughly spherical and have at least partly-differentiated core structures. They’re generally considered baby planets that didn’t quite make it to adult status.

Most asteroids, however, are quite petite. They also don’t seem to prefer a particular shape. To the extent of our knowledge, they either formed from the primordial matter of a stellar system or via subsequent impacts between its first rocky bodies. Most asteroids in our neighborhood today make a home in the asteroid belt (surprising, I know).

So, to recap: asteroids are chunks of rock or metal (or both) in space. They’re mostly made up of telluric elements (such as carbon, metals, and silica), which tend to be quite resilient. They’re either planets that couldn’t grow large enough or their shattered remnants. Most known ones hang out in the asteroid belt between Mars and Jupiter, but they can take on all sorts of orbits (or none at all!)

What is a meteorite?

Hoba meteorite.

The Hoba meteorite in Grootfontein, Namibia, is the largest meteorite known to have landed on Earth. Estimated to weigh around 60 tonnes, it has never been moved from the spot it was discovered in. Hoba is currently a very visited touristic attraction.
Image credits Sergio Conti / Wikimedia.

A meteorite is any space-borne body that enters a planet’s or moon’s atmosphere, survives the violent trek through it, impacts the surface, and leaves behind solid pieces of material. The name comes from the ancient Greek words “meta” and “aerio”, which put together roughly translate to ‘something hanging up in the air’.

Meteorites start their life as meteoroids (small meteors) or asteroids. On contact with an atmosphere, meteorites experience immense friction, causing them to spontaneously combust (at up to 3,000 degrees Fahrenheit, or 1,649 degrees Celsius). These fireballs — colloquially called shooting or falling stars — are meteors.

The life of a meteor is short — and hellish. The friction they experience is enough to raise surface temperatures beyond the material’s boiling point, vaporizing it layer by layer. In fact, it’s enough to break apart its (and the atmosphere’s) constituent molecules into ionized particles (basically plasma), which then recombine, releasing energy as light. This is the tail you see on a shooting star.

Meteor over Sardinia.

Meteor over Sardinia, seen on the 8th of May 2016.
Image credits Migebuff / Wikimedia.

The extreme violence of the final impact generally shaves off much of a meteor’s mass — the remaining kernel is our meteorite. Keep in mind that geologists generally call impactors large enough to create a crater ‘bolides’, while astronomers tend to prefer ‘meteorite’.

Depending on chemical composition, angle and speed of atmospheric entry, as well as sheer happenstance (whether it breaks apart or not), a meteor needs to range in size between a marble and a basketball for even a tiny portion of it to reach our planet’s surface.

Meteorites under 2mm (0.07in) in diameter are called micrometeorites. Meteorites that impact celestial bodies apart from Earth (and thus don’t necessarily pass through an atmospheric layer, such as those hitting the Moon) are called extraterrestrial meteorites.

As a side note, these burning chunks also spawned the associated term ‘meteorology’, or ‘the knowledge of things happening up in the air’, the branch of atmospheric sciences involved heavily in the study and forecasting of weather events.

So… what’s the difference between them?

As a general guideline, most meteorites are asteroids — but very few asteroids are meteorites.

Ceres.

Ceres, for example, is a moon and an asteroid. We do NOT want it to be a meteorite, too!
Image credits NASA / JPL-Caltech / UCLA/ MPS / DLR / IDA.

The definitions tend to overlap a little. Let’s take size, for example. An astronomer will call any of these space projectiles ranging between a molecule and a chunk several hundred feet wide (usually up to 100m / 330ft in diameter) a meteoroid. Anything larger than that, generally, is considered an asteroid.

However, that leaves out chemistry, which is also a hard delineator for what is (and isn’t) an asteroid. Comets are globs of ice and dust formed in the freezing corners of the cosmos (i.e. outside of solar systems). They also have a little pocket of atmosphere around them (a distinctive feature for comets), generated by evaporation from this ice. Their interaction with heat and particles generated by stars is what creates those long, elegant plumes that are quintessentially comet-y.

Comets can and do fly towards planets and moons. The beefier ones also generally make it through any atmospheric layer and impact the surface. What makes comets generally fall short of being termed ‘meteorites’ is that they’re made up of volatile materials that don’t survive post-impact. However, some do — and also leave behind traces of their impact in the form of impact glass or diamonds. While definitely traces of impact, it can be seen as a technicality to consider such elements remnants of the impacting body itself. I personally do. So, following the impact-and-debris definition, I’d consider comets impacting the surface to be meteors as well.

And herein lies the difference. To be a meteorite, one needs to impact a planet or moon and leave behind solid debris. To paraphrase Iain Banks (my favorite author) the meteorite only lives as it is falling. For asteroids, it’s sufficient to be. Have the right chemical make-up, don’t be too tiny, don’t sublime too much when around stars, and voila! You’re an asteroid.

Most asteroids are nice and never impact any planets or moons. The overwhelming majority of them, actually, are content to orbit around in their asteroid belts or on whatever path they’re set on. But we should never take their absence for granted; it only takes one to come visiting for humanity to become a thing of the past.

Just ask the dinosaurs.

A Japanese company wants to sell on-demand fake meteor showers — but scientists aren’t happy

Artist impression of what an artificial meteor shower would look like. Credit: ALE.

The latest venture in the burgeoning field of private aerospace might be fake meteor showers. A Japanese company wants to revamp the whole fireworks experience by offering on-demand shooting stars that light up the sky at a precise location and timing. Some people, however, are concerned that the firey debris might spell trouble for satellites in the same orbit, which happens to be preferred by intelligence agencies.

Artificial shooting stars

Astro Live Experiences, or ALE, plans on firing its first shooting star show in the summer of 2019. If all goes well, a buyer — which can be anyone from a city looking to offer its citizens something different to a wealthy rancher who wants to surprise his daughter — will be treated to a meteor shower lasting a couple of seconds. At the right moment, a spacecraft would eject 15 to 20 small metallic pebbles on command, each less than half an inch wide. The pebbles are made from the same heat shield material that lines the bottom of space capsules, which chars rather than burns upon atmospheric re-entry.

The company is the brainchild of University of Tokyo astronomer Lena Okajima. Initially, it was supposed to be an unconventional opening light show for the 2020 Tokyo Olympics but the researchers found they could turn the project into a demand service around the world. While some private ventures, such as SpaceX or Blue Origin, are in the business of sending astronauts, cargo, and even tourists into space, ALE is in the business of entertainment.

In December, ALE plans on launching two microsatellites below an altitude of 220 miles. Each $3-million microsatellite weighs 150 pounds (68kg) and carries 300 to 400 shooting star particles, along with enough propellant for 27 months of operation in orbit. When the fuel runs out, the microsatellite will be burned in Earth’s atmosphere. The ultimate plan is to set up a constellation of six such satellites capable of serving light shows round the clock, almost anywhere on Earth.

But not everyone is following ALE with 4th of July enthusiasm.

“I salute them for cleverness and for their technical expertise, but from an orbital debris standpoint, it’s not a great idea,” University of Michigan astronomer Patrick Seitzer told BuzzFeed News. “I’m concerned space will be getting crowded in low-earth orbit in the next 10 years.”

In their defense, ALE claims it has run simulations releasing particles for every hour a year against the US Strategic Command’s satellite trajectory catalog, finding there was no risk of collision. What’s more, the particles are supposed to fire for only 4-5 seconds before rapidly falling to 37 miles above Earth, which is too low for low-Earth-orbit satellites and too high for experimental balloons.

There are currently only 40 or so official satellites traveling in low orbit below 220 miles above Earth’s surface. There are, however, some orbiting bodies that aren’t listed in the catalog, such as spy satellites. But in the future, this sparse orbit is expected to get crowded — and fast. For instance, Elon Musk’s SpaceX plans to put 7,500 new broadband internet satellites in orbits about 210 miles high, just below ALE’s satellites.

The first ALE launch has already been approved by the Japan Aerospace Exploration Agency. If all goes well, the world should get a test of the first artificial meteor shower in 2019.

Geoscience Australia confirms — last night’s tremor caused by asteroid impact

Geoscience Australia confirmed that the tremor which shook Gladstone last night has been caused by a meteor, not an earthquake.

A Nasa image showing a meteor streaking across the sky in the United States. Image credits NASA / EPA.

A Nasa image showing a meteor streaking across the sky in the United States.
Image credits NASA / EPA.

Queensland residents have reported bright lights and a loud booming noise in the night sky on Monday. Local radio stations and police have received numerous phone calls from locals reporting a fireball in the sky and tremors, but so far no damage or victims have been reported.

A spokesperson for Geosciences Australia confirmed today that a tremor had been recorded around Gladstone, Central Queensland, around 8:30pm on Monday night but that it wasn’t caused by an earthquake. Harvard astrophysicist Johnathan Powell told the Gladstone Observer that it all “sounds like a big [meteor], first in several years that has been that big.”

“I’m guessing about a rock about a metre across which would have been big enough perhaps to leave fragments,” he added.

Catching pebbles

Here’s a thought to keep you up at night: meteorites hit the Earth all the time. The Universe is chock full of particles zipping about, and planets are really good at catching them. Just look at Mars’ or the Moon’s surface and you’ll see records of these events captured as craters — lots and lots of craters. Thankfully, we have a hefty atmosphere to burn up space rocks before impact, so technically most of these bodies are classified as meteoroids because they don’t collide with the surface.

Estimates for how many fall on Earth vary quite a lot, though, depending on size and because estimates are intrinsically plagued by assumption errors. Studies found that anywhere between 37,000-78,000 tons of material falls on our planet each year. Most of this matter comes in the dust-sized variety, and really is harmless.

“The Earth gets hit by 100 tonnes of meteorite activity every day. While you are and I are driving around doing our shopping, going outside, socialising, we’re getting hit by debris,” said Astro Space News editor and publisher Dave Reneke.

But a small part of this total does fall on Earth; a 1996 study (P.A. Bland et al, Geosciences) found that averaged over the last 50.000 years, 900-7300 kilograms of matter in the 10 gram to 1 kilogram range (0.02 to 2.20 pounds), hits the ground every year.

Yesterday night, one such daring rock made a bee-line for Queensland’s coast, putting on quite a display. People took to social media to describe loud “bangs”, and a “bright flash” lighting up the the sky as houses “shook.”

“[It] looked like a big as hell shooting star and lit up the beach then about a minute later a big bang and a shockwave came over the water and shook my car little bit was a pritty (sic) awesome experience,” posted Boyne beach local Jacques Reimers on the Higgins Storm Chasing Facebook page.

The Higgins Storm Chasing group said the meteorite most likely hit somewhere offshore as there have been no reports of damage on land as of yet. A 3.8 magnitude earthquake struck off the coast of Airlie Beach at around 10.15pm, though there is nothing to suggest it was as a result of the apparent meteor strike.

japan meteor shower

Artificial meteor shower might open the Japan 2020 Olympic Games

japan meteor shower

One Japanese startup is planning one hell of a fireworks show for the official opening of the Tokyo 2020 Olympic Games. The company, called Star-ALE, wants to launch a satellite in space which just at the right moment will release pellet particles. Once they re-enter the atmosphere, these should ignite and glow by the hundreds like a meteor shower.

For the Sky Canvas project, microsatellite will carry 500 to 1,000 pieces of these pellets in the second part of 2017. At the opening of the games in 2020, a command will be sent to the now orbiting satellites to discharge the particles. These will travel one-third of the way around the planet, and then enter the atmosphere where they will become shooting stars.

To make things even more interesting, the pellets will be made from various chemicals that will burn in different colours. In the lab, Star-ALE demoed how this should work. Researchers shot the particles in a vacuum chamber at supersonic speeds to simulate atmospheric re-entry. The graphic below shows the colours of the shooting stars varied according to their composition.

shooting stars particles

Credit: : Star-ALE

Once the particles burn, the fireworks should be visible over a 100 kilometres radius. That’s wide enough to entertain 30 million people in the greater Tokyo metropolitan area.

This ought to be pretty expensive, though. Each pellet costs $8,000 while one single microsatellite is priced at $100,000.

Skydiver nearly struck by meteor, catches it all on film

Anders Helstrup and several other members of Oslo Parachute Club were expecting a good time, and no major events when they went skydiving in Hedmark, Norway. They most certainly weren’t expecting a meteor swooping by past them.

This is the first time in history that a meteorite has been filmed in the air after its light goes out. Thankfully, no one was hurt, even though it was a little too close for comfort. Also, Helstrup had two cameras fixed to his helmet, which allowed him to see the meteor on film, even though he didn’t realize it at the moment.

“I got the feeling that there was something, but I didn’t register what was happening,” Helstrup explained to NRK.no.

Immediately after landing, he watched the film and saw the culprit: a meteor. The adventurers that they are, he and his friends organized a search party, but were unable to find the meteorite. Eventually, he contacted the Natural History Museum in Oslo.

“The film caused a sensation in the meteorite community. They seemed convinced that this was a meteorite, perhaps I was the one who was the most sceptical.”

meteorite

Suddenly, more people got involved, and some triangulated the possible positions of the meteorite and started looking for it. The area has now been limited to 100 x 100 meters, but that’s big enough, especially considering that people don’t exactly know how the meteor looks like.

A slice through a fragment of the meteorite shows numerous veins from a long-ago impact shock that weakened the original object. (Qing-zhu Yin/UC Davis photo)

Meteoroid that caused massive damage in Russia fully described

At the beginning of the year the most powerful meteoroid strike since the infamous Tunguska event took place in Russia, over Chelyabinsk. The meteor exploded many kilometers above ground, however the event released so much energy that it appeared much brighter than the sun and the ensuing shock wave caused billions of rubles worth of damage and sent over 1,200 people to hospitals in the Chelyabinsk Oblast area that day. Was this bad luck or were we actually fortunate nothing more damaging occurred? Well, it’s best if we consider this a wake-up call.

“If humanity does not want to go the way of the dinosaurs, we need to study an event like this in detail,” said Qing-zhu Yin, professor in the Department of Earth and Planetary Sciences at UC Davis.

Now, many months after the event an international team of scientists report their final findings. Apparently, the Chelyabinsk meteorite was made out of  “ordinary chondrite”, or the most common material such cosmic bodies are made of. It entered Earth’s atmosphere at a whooping velocity of 19 kilometers per second and eventually the 20-meter sized alien rock eventually exploded at 30 km altitude from the high stress energies it was subjected.

The explosion was equivalent to about 600 thousand tons of TNT, 150 times bigger than the 2012 Sutter’s Mill meteorite in California. Its brightness peaked at an altitude of 29.7 km (18.5 miles) and was so intense that it appeared brighter than the sun. In fact, there had been reports of people hospitalized for severe sunburns. As for the shock wave itself that actually caused 99% of the damage it traveled  90 kilometers (50 miles) on either side of the trajectory.

Meteor impact – a reality

A slice through a fragment of the meteorite shows numerous veins from a long-ago impact shock that weakened the original object. (Qing-zhu Yin/UC Davis photo)

A slice through a fragment of the meteorite shows numerous veins from a long-ago impact shock that weakened the original object. (Qing-zhu Yin/UC Davis photo)

At the moment of explosion, some three quarters of the meteoroid (a meteoroid is the rock still in space or air; a meteorite is the rock that impacts the ground) evaporated instantly. The rest (4,000 to 6,000 kilograms, or less than 0.05 percent of the original mass)were fragmented into tiny pieces and dispersed over a wide area – the biggest chunk weighed about 650 kilograms and was recovered from the bed of Lake Chebarkul.

Most of these facts so far have already been determined shortly following the meteoroid event, greatly thanks to a lot of footage citizen science provided. This analysis only serves to paint a more detailed picture. The study does however provide some valuable new insights. Following isotopic analysis, magnetic properties determination and X-ray computed tomography scanning of the meteorites, the researchers learned a great deal about the history of the rock.

According to their findings, the Chelyabinsk meteoroid was  4,452 million years old and most likely originated from the Flora asteroid family in the asteroid belt, but the chunk that hit the Chelyabinsk area was apparently not broken up in the asteroid belt itself. Interestingly enough, the rock wasn’t at its first collision event. Previously, the researchers estimate, the meteoroid  went through a significant shock event about 115 million years after the formation of the solar system 4,567 million years ago.

“Chelyabinsk serves as unique calibration point for high energy meteorite impact events for our future studies,” he said. Technology for early detection of these objects is needed, Yin said — such as the Large Synoptic Survey Telescope, currently being developed by an international team headed by UC Davis physics professor J. Anthony Tyson.

The team was led by Olga Popova of the Russian Academy of Sciences in Moscow, and by NASA Ames and SETI Institute meteor astronomer Peter Jenniskens, and included 57 other researchers from nine countries. The findings were reported in the journal Science.

The high temperatures of the meteorite impact 12,900 years ago produced mm-sized spherules of melted glass with the mullite and corundum crystal structure shown here Photographed by: Mukul Sharma

Meteor impact in Canada may have triggered the Big Freeze that caused mass extinction and forced humans into agriculture

The high temperatures of the meteorite impact 12,900 years ago produced mm-sized spherules of melted glass with the mullite and corundum crystal structure shown here Photographed by: Mukul Sharma

The high temperatures of the meteorite impact 12,900 years ago produced mm-sized spherules of melted glass with the mullite and corundum crystal structure shown here
Photographed by: Mukul Sharma

A recent study has revived an older controversy, after  Dartmouth Professor Mukul Sharma and his team reported what they claim is the first conclusive evidence that links an extraterrestrial impact in Canada with the beginning of the Younger Dryas, a period of abrupt climate change that caused major cooling through the Earth. During this time, a number of species became extinct and the human hunger-gatherer population transitioned to an agricultural based lifestyle.

In the 1.5-billion-year-old Quebecia terrane in northeastern Canada, near the Gulf of Saint Lawrence and modern day Quebec, researchers believe a comet or meteor impact took place, after at they analyzed the chemical composition of spherules discovered at the location (droplets of solidified molten rock expelled by the impact of a comet or meteor). The chemical composition matched those of spherules  deposited in Pennsylvania and New Jersey at the start of the Younger Dryas period.

The Younger Dryas or the Big Freeze as its also been called began some 12,900 years ago and enveloped the world in a short lasting (in geological terms – some 1,000 years) glacial period. During this time, a number of species became extinct, including saber-toothed cats, giant sloths, and mastodons. The same event marked the end of the Clovis hunter-gatherer culture in favor of the adoption of farming and animal husbandry, as supported by evidence dated from the time collected from the Near East – coincidentally or not the region was also home to the earliest city settlements we know of (Ur, Uruk).

“The Younger Dryas cooling impacted human history in a profound manner,” says Dartmouth Professor Mukul Sharma, a co-author of the study. “Environmental stresses may also have caused Natufians in the Near East to settle down for the first time and pursue agriculture.”

The newly discovered spherules do not originate from the 4km-wide Corossal crater – a known impact crater in Quebec. This fact leads the researchers to conclude that a series of comet or meteor impacts caused the beginning of the Younger Dryas 12,900 years ago. The meteor/compact impact theory sparking the Younger Dryas isn’t new and has for a long time been contested. The current accept theory is that an ice dam rupture released huge amounts of freshwater into the Atlantic. This in turn was thought to have shut down ocean currents moving warm tropical water, resulting in colder conditions.

“It may well have taken multiple concurrent impacts to bring about the extensive environmental changes of the Younger Dryas,” says Sharma. “However, to date no impact craters have been found and our research will help track one of them down.”

Worth noting is that ZME Science reported earlier of a newly discovered meteor impact site in Mexico dating from 13,000 years ago, where an eclectic geological mix of materials, including nanodiamonds, impact spherules, and more, which, according to the researchers, are the result of a cosmic body impacting Earth.  Apart from the Mexican site, the researchers also identified sediment layers of the same age, dating back 13,000 years ago,  in Canada, the United States, Russia, Syria and various sites in Europe.

Findings appeared in the journal PNAS.

Severed trees in the wake of the Tunguska alleged meteor impact. Photo circa 1908. (c) UNIVERSAL HISTORY ARCHIVE/GETTY IMAGES

Tunguska event was caused by meteor strike, rock sample analysis finds

You may have heard about the Tunguska event – a huge blast of energy which occurred in 1908 over Russia and flattened more than 2,000 square kilometres of forest. More than a century since, its remarkable that scientists have yet to confirm the source of what undoubtedly is the biggest Earth impact in recorded history. The leading theory is that a meteor exploding in the atmosphere caused the huge blast, however up until now this has been difficult to confirm despite being the likeliest option.

Severed trees in the wake of the Tunguska alleged meteor impact. Photo circa 1908. (c) UNIVERSAL HISTORY ARCHIVE/GETTY IMAGES

Severed trees in the wake of the Tunguska alleged meteor impact. Photo circa 1908. (c) UNIVERSAL HISTORY ARCHIVE/GETTY IMAGES

A recent study by scientists at the Institute of Geochemistry, Mineralogy and Ore Formation of the National Academy of Science of Ukraine in Kiev might settle the origin of the Tunguska event once and for all, after rock samples collected from a peat bog close to the epicentre of the blast bear uncanny physical characteristics found in other meteorites.

It’s quite curious how the source of such an important event, in which an equivalent energy of 3 to 5 megatonnes of TNT was discharged,  has been so difficult to confirm. In all likelihood, something that most geoscientists seem to agree upon, the even was triggered by a meteor impact, however some have proposed more extreme theories like antimatter and blackholes (yeah, blackholes…). This is because the impact was so powerful that no fragments could be retrieved.

Of course, the Soviets made a number of scientific expeditions in the area, but the best they could come up with were microscopic metallic spheres found in Tunguska soil samples, thought to be remnants of a vaporized meteorite, but these too are up for debate. Now, researchers in Ukrain led by Victor Kvasnytsya think they have finally sealed Tunguska.

In 1978  Mykola Kovalyukh, an Ukranian scientist, collected fragments of rocks, less than one millimeter wide, from the epicenter of the impact site. Subsequent research by Kovalykh at the time revealed that the fragments contained a form of carbon called lonsdaleite, which has a crystal structure somewhere between graphite and diamond, and forms under extreme heat and pressure. The grains also contained less of the dense metal iridium than is typically found in meteorites, so the scientific community concluded that Kovalykh’s samples weren’t actually from the meteor. Instead, what he had were terrestrial rocks altered by the high energy of the impact.

Luckily, technology has evolved a great deal since then, and after taking a second, more thorough look, Ukranian researchers found that Kovalykh may have actually been right. The scientists probed the sample samples using transmission electron microscopy and discovered carbon grains that were finely veined with iron-based minerals including troilite, schreibersite and the iron–nickel alloy taenite,  very similar to that in other iron-rich meteorites. “The samples have almost the entire set of characteristic minerals of diamond-bearing meteorites,” says Kvasnytsya.

Moreover, previous studies that modeled the impact found that an  iron-rich, stony asteroid was the only culprit that could have produced the effects reported on the ground, which conveniently fits the present findings.

Other researchers aren’t that convinced, however, citing inconclusive proof. The low levels of iridium and osmium in the samples are “a red flag” that raises doubts that the fragments originated in an asteroid, according to Phil Bland, a meteorite expert at Curtin University in Perth, Australia. Moreover, the peat sediment in which the samples were found has not been convincingly dated to 1908.

“We get a lot of meteorite material raining down on us all the time,” adds Bland. Without samples of adjacent peat layers for comparison, “it’s hard to be 100% sure that you’re not looking at that background”.

More tests by Kovalykh and his team, as well as those by other scientists, will be required to fully confirm the findings, which can be read in a paper published in the journal Planetary and Space Science

via Nature

Hundreds of meteor sites have been recorded by NASA during the past few years alone. (c) NASA

Meteor crash on the moon causes biggest explosion since monitoring

In March, a medium sized meteorite slammed into the moon’s surface causing the greatest explosion observed thus far, ever since the moon’s surface was first monitored by NASA looking for such events eight years ago.  The meteorite collided with the moon at a mind-boggling 56,000 mph (90,000 kph), creating a new crater 65 feet wide (20 meters).

Unlike Earth, the moon doesn’t have a thick atmosphere to safeguard it from the never-ending cosmic onslaught. As such, it regularly gets hit by meteorites with as many as 300 collisions having been recorded thus far since NASA first launched its monitoring program. No impact, however, has been as powerful as a most recent one, when on March 17 a roughly 1-foot-wide (between 0.3 to 0.4 meters) meteorite , weighing 88 lbs (40 kg), slammed into the moon releasing an important amount of energy, as powerful as a 5 tons of TNT explosion.

Hundreds of meteor sites have been recorded by NASA during the past few years alone. (c) NASA

Hundreds of meteor sites have been recorded by NASA during the past few years alone. (c) NASA

The flash unleashed by the collision could have been seen with the naked eye by those fixing their gazes at the moon, according to NASA, though the event lasted for a mere second. Below, you can find embedded a NASA-produced 4 minute video reporting the meteorite crash, where you can also footage of the actual collision (skip to the 00:47 mark).

NASA scientists aren’t monitoring the lunar surface for meteor crashes just out of pure curiosity. The agency still has plans of sending astronauts or expensive equipment like rovers back on the moon – having a meteorite crashing right near the landing site or even in the vicinity of a manned outpost could spell disaster. By studying just how frequent meteorite crashes with the moon are and during which period, scientists can infer the safest spots and best timings for such maneuvers to be carried out.

2012 DA14 radar observation

NASA radar observation shows asteroid 2012 DA14 flyby [VIDEO]

I realize we’re maybe bugging some of you with these constant asteroid/meteor pieces here on ZME Science, but for what’s it worth we found this recently released NASA video comprised of radar images during 2012 DA14’s recent flyby very interesting.

2012 DA14 radar observationThe movie, which combines 73 radar-images  captured over the course of eight hours on the night of Feb. 15-16, was compiled by NASA’s Jet Propulsion Laboratory. Now, if you’ve already pressed play and seen the movie, you might have felt a bit disappointed. But even though the asteroid might look like something off of Space Invaders, the image resolution is still a whooping 13 feet (4 meters) per pixel.

That goes a bit to show how massive DA14 really is and how devastating an eventual collision of the asteroid with our planet might have caused. These radar observations provide the most accurate measurement of DA14,  40 meters along its long axis. Also, the radar imaging also help better fine-tune calculations of 2012 DA14’s future orbit by getting a better fix on its size, shape, rotation, surface features and surface roughness. Next time it comes by Earth again, we’ll be ready.

If you’re interested, we’ve also posted some live video footage of 2012 DA14 captured by optical cameras and telescopes.

meteor-map

A map of every meteor strike since 2300 BC

The recent historical flyby of 2012 D14 – the largest asteroid ever to pass this close to Earth in recorded space observational history –  as well as the modest in size, but monumental in punch meteorite that exploded over Russia caused an whole frenzy around them on the web.

meteor-map

Thing is, meteorites and asteroids have been flying by and colliding with Earth long before the internet was invented, to the surprise of some folks. Javier de la Torre, cofounder of geo software companies Vizzuality and CartoDB, showcases this idea perfectly with his interactive map of every meteor strike on Earth, those found at least, since 2300 BC.

Actual impact data collected from the Meteoritical Society was used and you can click on specific impact sites in order to see the size, location and year that the meteorite strike occurred. If you’re more interested to find out how the map was created, check out de la Torre’s  blog post on the subject.

Check out the map here.

As you can see, North America and Europe have been simply bombarded along the years more than every other area on Earth. However, that’s not to say that other regions of the world have been spared; simply put, not enough data was available.

Orionids

Don’t miss this weekend’s Orionids meteor shower peak

Orionids

Since last Sunday, Halley’s comet offspring have been swirling through the night sky delighting star gazers all around the world. This coming weekend, however, the Orionids will be at their peak and full splendor – your definitely don’t want to miss it!

This time of year, the moon sets at about midnight, which offers more time for catching shooting stars in the darkness. This couldn’t come at a better time for the Orionid meteor shower, which will reach its peak activity in the post-midnight hours of October 21 and 22. Predicting the moment or even the hour where the highest density of meteor debris will enter Earth’s atmosphere is an extremely difficult feat for astronomers, but all the better. It’s the perfect pretext for you and your friends or family to lean back and enjoy the spectacle all night long. Enthusiasm is a great fuel for burning the midnight oil in expectation of the night sky climax.

The shower originates from the Halley comet, and has its name from the constellation in the sky where it’s easiest to spot –  Orion the Hunter. The meteors are particularly fast – swirling at up to 66 kilometres per second – and can be spotted in a yellow or green color, depending on atmospheric conditions. Anyway, be sure to leave the city and head from a spot where the skyline is clear – you don’t need any telescope to enjoy this awesome astronomical event. Just a fine dispositions and great company.

 

Lunar rock

Biggest moon rock auctioned so far set to fetch $380,000

Lunar rock

This four pound geological marvel, captioned above, is what’s commonly reffered to as a lunar meteorite. And like all things of rarity, it’s been recently listed for auction – the biggest chunk of moon rock yet. Experts believe it should sell around the $380,000 mark.

Lunar meteorites are a special class of moon rocks. During meteorite collisions with the moon’s surface, which happen quite often given its  cheesy aesthetic, inevitably some chunks of rocks get blown off and enter Earth’s atmosphere due to the weak gravity on our natural satellite. The rocks big enough to survive atmospheric entry end up on Earth’s surface.

So far, a mere 100 pounds of lunar meteorites have been found, most of which in Antarctica and North Africa. Concerning the slab-shape moon rock in question, dubbed Dar al Gani 1058, experts believe it originated as a piece of lunar highland breccias from the moon’s far side. It was discovered in Libya in 1998, according to the Meteoritical Society, and was put up for auction by an anonymous collector.

The auction is set to end on October 14, and opening bids start $170,000. That may seem like much, but collectors have paid far more for far less. It’s worth considering however, that lunar rocks which end up on Earth due to natural conditions, pale in worth to those gathered during lunar missions. In fact, the 800 pounds or so of lunar rocks gathered so far from the moon from missions like the Appollo are considered invaluable and national treasures by the world’s governments.

Hand-picked moon rocks have never been awarded to individuals, and are considered completely off limits to civilians. Actually, I remember writing last year about a granny who was seized by armed government officials after auctioning a spec of lunar dust the size of a grain of rice for $1.7 million; aside from the fact that officials were a bit overzealous and the uncertainty of how exactly a 74-year-old got ahold of such an artefact, it gives to show that lunar meteorites are virtually your single best shot at owning a piece of the lunar pie.

Lyrid meteor shower

The Lyrid Meteor Shower – not to be missed this weekend

Lyrid meteor shower

A moonless night might offer the best setting for the best view of the upcoming Lyrid meteor shower in years this very weekend. The best time to catch it on display will be on Saturday night, although the skyline fireball display is set to rage on well into the following morning.

The Lyrids are somewhat modest in display compared to other meteor showers like the Perseids or the Orionids, but if you’ll be patient enough you’ll be certain to catch some veritable gems.

“Typical hourly rates for the Lyrids can run between 10 and 20 meteors. However, rates as high as a hundred meteors per hour are not uncommon,” said Raminder Singh Samra, a resident astronomer at the H.R. MacMillan Space Centre in Vancouver, Canada.

“On rare occasions there may even be fireballs”—especially bright meteors—”streaking across the sky, too, making it quite a spectacular sight for observers.”

Meteor showers occur when the Earth passes through the trail of dust left behind by a comet; these particles, most no bigger than grains of sand, get caught in the atmosphere and ignite, creating the wonderful spectacle watched by sky gazers all over the world. The Lyrids are thought to originate from comet Thatcher, whose 416-year orbit is nearly perpendicular to the plane of the solar system.

“Like clockwork every year in April, the Earth passes through the particle stream of this long-periodic comet, which last approached the sun in 1861,” Samra said.

“These particles hit our atmosphere while traveling at high speeds and burn up, leaving behind streaks of light”—what we see as meteors.

Look towards the meteor shower’s namesake constellation, Lyra, near the bright star known as Vega for the best chance of gazing shooting stars. As always, if you happen to shoot some footage of event, please feel free to send some over to andrei@zmescience.com – hopefully, we’ll be able to gain enough to publish a photo post, where each individual author will be credited accordingly.

Here’s a video about the Lyrid meteor shower and the April sky.

Photo of a comet plummeting towards Earth's atmosphere taken from on-board the International Space Station by NASA astronaut Ron Garan. (c) NASA/Ron Garan

Stunning photos of the Perseid meteor shower

I was lucky enough this weekend to be away from the city and at an altitude of about 1800m, deep in the mountain side. The rare, clean atmosphere allowed for an uncanny view of the night sky, at least for an urbanite as myself, filled with the most distinguishable stellar bodies I’ve ever been granted to see. The whole experience was turn to gold as I found myself right in the middle of the annual Perseid meteor shower, which covered the firmament with shooting stars every few minutes or so. Actually, the International Meteor Organization recorded an average of 30 shooting stars an hour Friday morning, rising to 45 to 60 by Friday night and Saturday morning. And on top of everything, one had a bright full moon performing on the skyline stage as well.

Now, like I said, I had an incredible view which I’d love to re-edit as many times as possible, but can you imagine how the show must have been like from above the meteor shower, instead of beneath it. Well, astronaut Ron Garan surprised a shooting star with his camera in all its splendor as it was passing below the International Space Station, and like expected it’s nothing short of breathtaking.

Photo of a comet plummeting towards Earth's atmosphere taken from on-board the International Space Station by NASA astronaut Ron Garan. (c) NASA/Ron Garan

Photo of a comet plummeting towards Earth’s atmosphere taken from on-board the International Space Station by NASA astronaut Ron Garan. Click on photo for larger zoom. (NASA)

Wow, eh? My reaction exactly!

“What a ‘Shooting Star’ looks like #FromSpace Taken yesterday during Perseids Meteor Shower…” Garan tweeted from his Twitter account on Sunday, who is at the end of his six months tour on-board the ISS. Quite the finale it must have been for the American astronaut.

The Perseid meteor shower hits Earth every August, as a result of a myriad of debris filled with dust particles left over from the Swift-Tuttle comet. The meteors originate from the constellation Perseus, hence the name. The ice and dust particles, most sized like a grain of sand, while others comparable to peas or marbles, enter Earth’s atmosphere at 133,200 mph, plummeting in flames – none reach the ground.

Although, the Perseid meteor shower peaked on August 12, those of you who missed it due to weather or whatever other reasons shouldn’t fret since Perseids will be active till August 24, where you can glimpse at least 5-10 meteors per hour.

It’s time to dust off that telescope from the attic. What was your experience with the Perseids? Did any of you manage to take some photos? If so, please share – impressions and photos are welcome in the comment section below or on our facebook page.

Here’s some more stunning photos of the Perseids, this time taken from the ground.

 

Macon comet

[VIDEO] Man-sized meteor over Georgia sky

Macon comet

In a relevant display of  NASA’s fireball-observing network capabilities, a set of automatic robotic cameras caught a man-sized meteor as it blasted though Earth’s atmosphere causing a fireball spectacle.

The event took place on May 20, when the 6-foot-wide (1.8-meter) space rock entered the atmosphere at about 66 miles (106 kilometers) above the city of Macon, Ga, traveling at about 86,000 mph (138,404 kph) – possessing the striking power somewhere between 500 and 1,000 tons of TNT.

Burning down in flames

Thankfully, the meteor was too small and never got a chance to touch ground, since it blazed to smithereens at 38 miles (61 km) above the town of Villa Rica, Ga., before subsequently four distinct flares emanated from the comet as the chunk broke apart multiple times.

Although fireballs like the Macon meteor are a splendor, they’re not all that rare. Objects the size of washing machines are reported to enter the Earth atmosphere every month or so, but most of the time they burn out before reaching Earth’s surface. This one is special, however, since it was all caught on tape, the video of which you can see right below.

More videos like the Macon comet soon enough, NASA promises

This was all captured by NASA’s fireball-observing network, which has open operational for only three years now. The network comprises of  a set of “smart” cameras linked into a computer system that automatically analyzes their video, then calculates relevant information about incoming space rocks’ trajectories and orbits.

Currently, there are the two in Georgia, one in Huntsville, and one in southern Tennessee and NASA officials say the hope to increase the number to 15 such cameras in various locations throughout the eastern United States

[Story via MNM]

Shorties: 4.5 billion meteorite shows new mineral

A recently analyzed 4.5 billion years old meteorite yields one of the oldest minerals known in our solar system: krotite. The mineral is not actually new, in that it was thought to be only a man-made constituent of some high-temperature concrete, according to study researcher Anthony Kampf, curator of Mineral Sciences at the Natural History Museum of Los Angeles County (NHM).

“This is one that simply was not known in nature until we found it here,” Kampf told LiveScience. “That’s pretty dramatic.”

The mineral is a compound of calcium, aluminum and oxygen, and it needs an estimated temperature of 1500 degrees Celsius to form, which supports the idea that it was created in the early solar system, as the solar nebula condensed and planets started to form.

“This meteorite likely came from an asteroid in the asteroid belt,” leader researcher Chi Ma of Caltech stated.

(c) NASA/JPL/University of Arizona

New craters sighted on Mars [PICS]

(c) NASA/JPL/University of Arizona

Last year, the Mars Reconnaissance Orbiter’s low-res, grayscale Context camera cought a patch of new dark spots on the martian surface which weren’t there just two years before. Further, detailed investigations soon followed as MRO’s more sharp-eyed HiRISE camera went in for a closer look – its capable of spotting even beach ball sized objects on Mars’ surface.

What scientist found were four distinct craters, each ringed with a dark blanket where soil was blasted out in the impact. Scientists believe the craters were actually caused by a single meteorite which broke as multiple pieces as it entered the martian atmosphere.

The MRO helps researchers determine how often Mars gets hit by interplanetary debris by watching the Martian terrain change beneath it. Based on the number of craters, planetary scientists gauge the age of a planet’s surface features.

(c) NASA/JPL/University of Arizona

(c) NASA/JPL/University of Arizona

Geminids to offer another thrilling night for stargazers

The strangest meteor shower one can observe every year is almost upon us. Geminids is the only meteor shower that isn’t caused by a passing comet, but rather by an asteroid; the meteors are slow moving and pretty bright, making them a perfect target not only for astronomy afficionados, but for everybody who want’s to see a stellar show.

From this point of view, December is indeed a great month – not only can you see Geminids under weather conditions that promise to be good, but you can also witness the only full moon eclipse of the year. The night of December 13 is probably the best one for watching the ‘shooting stars’ (it’s estimated that then the intensity will be at maximum levels) and it promises to be quite a remarkable show, but you should definitely dress way more warmly than usual, and grab a blanket or two. The good thing is that the meteor shower will be so close that no binoculars or telescopes are necessary, but since it will last for a while, perhaps another good idea would be to grab a lawn chair or a sleeping bag (or a girlfriend) – something to keep you comfortable and warm for the 72 minutes when you will be enjoying the show in the sky.

Also, on the night of 20 (and/or 21, depends where you live) is a great one, and if you live in North America, you can go out and see the best lunar eclipse until April 2014. I will get back to you with more details a few days before the eclipse, but for now, you really should prepare for a dazzling display offered by the Geminids.

Photo credits 1 2

Dramatic fireball flies above Arizona

I’m really sorry I didn’t find out about this earlier, but better late than never. So, on June 23, several observers from Tucson, Arizona reported they noticed a bright fireball on the sky.

As it turns out, it was rock from outer space that broke apart and took a dive in our planet’s atmosphere, a ‘shooting star’, and a pretty big one too. Events such as these one are not really uncommon, but in the vast majority of the cases, they take place above the ocean, so it’s pretty hard to see one of them.

Observers compared it to a famous local event, the Peekskill Fireball in 1992, and one eve wrote about it.

Here’s the recent fireball:

Here’s the one in ’92