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So, I'm very excited to share this today!
I've been working on this for months, having first had the idea a year ago.
It's a 200-year-old cosmic whodunnit, which could reveal the origins of every planet in the universe.
By me @SciAm + small thread (1/) https://www.scientificamerican.com/article/asteroid-dust-from-hayabusa2-could-solve-a-mystery-of-planet-creation/
I've been working on this for months, having first had the idea a year ago.
It's a 200-year-old cosmic whodunnit, which could reveal the origins of every planet in the universe.
By me @SciAm + small thread (1/) https://www.scientificamerican.com/article/asteroid-dust-from-hayabusa2-could-solve-a-mystery-of-planet-creation/
This story is about chondrules, tiny seed-like rocks found in nearly all Earth's meteorites.
Chondrules have been known about since the early 19th century, but to date no one has been able to definitively explain how they formed. (2/)
Chondrules have been known about since the early 19th century, but to date no one has been able to definitively explain how they formed. (2/)
There have been lots of attempts. Chondrule scientists like to joke there are as many hypotheses about chondrule formation as there are chondrule scientists.
But finding an exact answer is tricky. Because under our models of planet formation, chondrules shouldn't exist. (3/)
But finding an exact answer is tricky. Because under our models of planet formation, chondrules shouldn't exist. (3/)
We know chondrules formed in the first few million years of the Solar System, 4.567 billion years ago.
They must have been heated to temperatures of 2,000C, before rapidly cooling over days or hours and becoming embedded into larger rocks that we call chondrites.
But how? (4/)
They must have been heated to temperatures of 2,000C, before rapidly cooling over days or hours and becoming embedded into larger rocks that we call chondrites.
But how? (4/)
There are two main camps. One, they were some of the first solids to form in the Solar System, directly out of the solar nebula.
If so, they might well be the seeds of planet formation itself, explaining how every planet - including Earth - takes shape. (5/)
If so, they might well be the seeds of planet formation itself, explaining how every planet - including Earth - takes shape. (5/)
The other major camp is they formed after planetary building blocks known as planetesimals, or even after the planets themselves.
Here, they could have formed through planetesimal collisions - making them a secondary (and maybe less important) feature of planet formation. (6/)
Here, they could have formed through planetesimal collisions - making them a secondary (and maybe less important) feature of planet formation. (6/)
Whatever the answer, chondrules would give us a remarkable insight into the early Solar System like nothing else.
But until we understand how they formed, it's not clear exactly what they are telling us. (7/)
But until we understand how they formed, it's not clear exactly what they are telling us. (7/)
Now, however, new research is understanding chondrules like never before.
And two asteroid sample return missions, Japan's Hayabusa2 this weekend, and NASA's OSIRIS-REx in 2023, could well bring fresh chondrules back to Earth. (8/)
And two asteroid sample return missions, Japan's Hayabusa2 this weekend, and NASA's OSIRIS-REx in 2023, could well bring fresh chondrules back to Earth. (8/)
There have been arguments along the way. But if we can understand how chondrules formed, a whole new window into our early Solar System - or any planetary system - will be opened.
Maybe, just maybe, that answer is on the horizon.
Enjoy! (9/) https://www.scientificamerican.com/article/asteroid-dust-from-hayabusa2-could-solve-a-mystery-of-planet-creation/
Maybe, just maybe, that answer is on the horizon.
Enjoy! (9/) https://www.scientificamerican.com/article/asteroid-dust-from-hayabusa2-could-solve-a-mystery-of-planet-creation/
Massive thanks, as always, to @LeeBillings for taking this on and making me write good much better.
And thanks to the many people who spoke to me for this story, especially @vorlon, the don of chondrules, who put up with my incessant emails and calls for most of 2020.
And thanks to the many people who spoke to me for this story, especially @vorlon, the don of chondrules, who put up with my incessant emails and calls for most of 2020.
