Comets visit the inner Solar System, and leave without saying goodbye. Maybe they leave a trail of dust behind, and when the Earth passes through it, we get a pretty light show in the night sky, in the form of a meteor shower. Likewise, asteroids frequently go whizzing by, though they don’t leave us with a pyrotechnic display.
Sometimes these rocky interlopers head straight for Earth. And when they do, the results can be cataclysmic, like when an asteroid struck Earth about 66 million years ago, wiping out the dinosaurs and 75% of life on Earth. Other times, it’s not quite as cataclysmic, but still devastating, like in about 2350 BC, when debris from a disintegrating comet may have caused the collapse of an ancient empire.
But regardless of the severity of any of these individual events, the conclusion is crystal clear: Earth’s history is intertwined with the coming and going of space rocks. The evidence is all around us, sort of.
Continue reading “Ancient Meteorites Can be Found Embedded in Rocks, Like Fossils”
What are your chances of getting smacked – and killed — by a meteorite? One astronomer put the odds of death by space rock at 1 in 700,000 in a lifetime, while others say it’s more like 1 in 1,600,000.
Computing the probability for such an untimely death is difficult because this type of event is so rare. In fact, even though thousands of meteorites are thought to hit the ground each year, in looking through the annals of meteorite history, there seemed to be no evidence that anyone had ever been killed by a meteorite. Until now.
Continue reading “Terrible Luck. The Only Person Ever Killed by a Meteorite – Back in 1888”
There are around 61,000 meteorites on Earth, or at least that’s how many have been found. Out of those, about 200 of them are very special: they came from Mars. And those 200 meteorites have been important clues to how Mars formed in the early Solar System.
Continue reading “Mars Was Hit By a Lot of Protoplanets Early in its History, Taking Longer to Form than Previously Thought.”
We’ve all heard this one: when you drink a glass of water, that water has already been through a bunch of other people’s digestive tracts. Maybe Attila the Hun’s or Vlad the Impaler’s; maybe even a Tyrannosaurus Rex’s.
Well, the same thing is true of stars and matter. All the matter we see around us here on Earth, even our own bodies, has gone through at least one cycle of stellar birth and death, maybe more. But which type of star?
That’s what a team of researchers at ETH Zurich (Ecole polytechnique federale de Zurich) wanted to know.
Continue reading “We Know We’re Made of Stardust. But Did it Come From Red Giants?”
From the study of meteorite fragments that have fallen to Earth, scientists have confirmed that bacteria can not only survive the harsh conditions of space but can transport biological material between planets. Because of how common meteorite impacts were when life emerged on Earth (ca. 4 billion years ago), scientists have been pondering whether they may have delivered the necessary ingredients for life to thrive.
In a recent study, an international team led by astrobiologist Tetyana Milojevic from the University of Vienna examined a specific type of ancient bacteria that are known to thrive on extraterrestrial meteorites. By examining a meteorite that contained traces of this bacteria, the team determined that these bacteria prefer to feed on meteors – a find which could provide insight into how life emerged on Earth.
Continue reading “A Microorganism With a Taste for Meteorites Could Help us Understand the Formation of Life on Earth”
Remember the asteroid Psyche? It’s the largest known asteroid in the asteroid belt between Mars and Jupiter. It’s been in the news because of its unusual properties, and because NASA plans to launch a mission to Psyche in 2022.
Psyche, aka 16 Psyche, is unusual because it’s quite different from other asteroids. Psyche appears to be the remnant, exposed nickel-iron core of an early planet. Because of that, Psyche is a building block left over from the early Solar System, when planets were still forming. It’s like a planet without a crust.
Continue reading “Metallic Asteroids Might Have Had Volcanoes Erupting Molten Iron. That’s So Metal”
When Japan’s Hayabusa 2 spacecraft arrived at asteroid Ryugu in June 2018, it carried four small rovers with it. Hayabusa 2 is primarily a sample-return mission, but JAXA (Japan Aerospace Exploration Agency) sent rovers along to explore the asteroid’s surface and learn as much as they could from their visit. There’s also no guarantee that the sample return will be successful.
They chose Ryugu because the asteroid is classified as a primitive carbonaceous asteroid. This type of asteroid is a desirable target because it represents the primordial matter that formed the bodies in our Solar System. It’s also pretty close to Earth.
The sample from Ryugu, which will make it to Earth in December 2020, is the big science prize from this mission. Analyzing it in Earth-based laboratories will tell us a lot more than spacecraft instruments can. But the rovers that landed on Ryugu’s surface have already revealed a lot about Ryugu.
Continue reading “Asteroid Ryugu is a “Fragile Rubble Pile””
On Wednesday, July 24th, the people of the Great Lakes region were treated to a spectacular sight when a meteor streaked across the sky. The resulting fireball was observed by many onlookers, as well as the University of Western Ontario’s All-Sky Camera Network. This array runs across southern Ontario and Quebec and is maintained in collaboration with NASA’s Meteoroid Environment Office (MEO) at the Marshall Space Flight Center.
What is especially exciting about this event is the possibility that fragments of this meteorite fell to Earth and could be retrieved. This was the conclusion reached by Steven Ehlert at the MEO after he analyzed the video of the meteorite erupting like a fireball in the night sky. Examination of these fragments could tell astronomers a great deal about the formation and evolution of the Solar System.
Continue reading “Bright Fireball Explodes Over Ontario, Meteorite Fragments Might Have Reached the Ground”
Since it first formed roughly 4.5 billion years ago, planet Earth has been subject to impacts by asteroids and plenty of meteors. These impacts have played a significant role in the geological history of our planet and even played a role in species evolution. And while meteors come in many shapes and sizes, scientists have found that many become cone-shaped once they enter our atmosphere.
The reason for this has remained a mystery for some time. But thanks to a recent study conducted by a team of researchers from New York University’s Applied Mathematics Lab have figured out the physics that leads to this transformation. In essence, the process involves melting and erosion that ultimately turns meteorities into the ideal shape as they hurl through the atmosphere.
Continue reading “As Meteorites Slice Through the Atmosphere, They’re Sculpted Into Cones”
When an extraterrestrial object slams into the Earth, it sends molten rock high into the atmosphere. That debris cools and re-crystallizes and falls back down to Earth. Tiny glass beads that form in this process are called microtektites, and researchers in Florida have found microtektites inside fossilized clams.
Continue reading “Fossilized Clams Had Evidence of a Meteorite Impact Inside Them”