Although meteorites are known to fall all over the world, the environment and unique processes in Antarctica make them somewhat easier to find on the pristine, snowy landscape. Still, collecting meteorites in Antarctica is physically grueling and hazardous work.
But what if there was a “treasure map” which showed the most probable places to find meteorites in Antarctica, directing researchers where to look?
Mars is still quite mysterious, despite all we’ve learned about the planet in recent years. We still have a lot to learn about its interior and surface evolution and how changes affected the planet’s history and habitability. Fortunately, an impact on the red planet sent clues to Earth in the form of meteorites.
The geological information contained in these meteorites would be even more valuable if we knew exactly where they came from. A team of researchers say they’ve figured it out.
When Carl Sagan said, “We are all made of star stuff,” he didn’t just mean we were made up of parts of our own star. Other stars contributed to the material that built our solar system, and some of that “presolar” material is still present in a pristine form inside meteorites. Now, a team led by Dr. Nan Liu at Washington University in St. Louis took a close look at some of the parts of meteorites that formed before the Sun. They held some exciting surprises and answers.
OK, all you meteorites that are falling to Earth … You are being watched!
The ever-expanding use of security cameras, doorbell cams and vehicle dashcams have increased the number of fireballs that have been spotted streaking across the skies. And sometimes, all that visual data provides the side benefit of allowing rocks from space to be tracked and found.
Planetary scientists estimate that each year, about 500 meteorites survive the fiery trip through Earth’s atmosphere and fall to our planet’s surface. Most are quite small, and less than 2% of them are ever recovered. While the majority of rocks from space may not be recoverable due to ending up in oceans or remote, inaccessible areas, other meteorite falls are just not witnessed or known about.
But new technology has upped the number known falls in recent years. Doppler radar has detected meteorite falls, as well as all-sky camera networks specifically on the lookout for meteors. Additionally, increased use of dashcams and security cameras have allowed for more serendipitous sightings and data on fireballs and potential meteorite falls.
A team of researchers is now taking advantage of additional technology advances by testing out drones and machine learning for automated searches for small meteorites. The drones are programmed to fly a grid search pattern in a projected ‘strewn field’ for a recent meteorite fall, taking systematic pictures of the ground over a large survey area. Artificial intelligence is then used to search through the pictures to identify potential meteorites.
Since they were formed in the early solar system, many meteorites offer an unadulterated view into what that solar system was made out of, or what happened to it as we reported before. Recently a team of researchers led by Maggie Thompson at University of California Santa Cruz (UCSC) took a look at the chemical composition of three different chondritic meteorites, which have largely been untouched since before the planets were formed. Their composition was different than current models predicted, and could lead to a better understanding of early planetary atmospheres.
The effects of ancient asteroid impacts on Earth are still evident from the variety of impact craters across our planet. And from the Chelyabinsk event back in 2013, where an asteroid exploded in the air above a Russian town, we know how devastating an “airburst” event can be.
Now, researchers in Antarctica have discovered evidence of a strange intermediate-type event – a combination of an impact and an airburst. The event was so devastating, its effects are still apparent even though it took place 430,000 years ago.
Meteorites are excellent windows into early solar system formation. Many were formed in the those early days, and unlike rocks on the Earth, most are not affected by billions of years of tectonic activity that wipes away any of their original structure. Recently a team led by Nicolas Dauphas and Justin Hu at the University of Chicago (UC) found that the formation process for many of these meteorites was much more violent than previously thought.
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.