text | Li Muzi
"Dragon Palace" asteroid. Image source: JAXA
Recently, researchers analyzed the primitive gas from an asteroid for the first time. The gases were obtained from rock samples collected and returned by the Japanese Hayabusa 2 probe, which visited the asteroid "Ryugu" from 2018 to 2019, providing scientists with clues about how and where the asteroid and other celestial bodies in the solar system formed. The relevant paper was published in "Science Progress" on October 20.
"Dragon Palace" is most likely formed at the edge of the solar system before it is thrown to Earth as the giant planet moves. A new analysis of iron in the sample suggests that it may come from near Uranus and Neptune , farther away than researchers imagined. Therefore, these samples may help elucidate the history of in the outer solar system of .
"Basically, our understanding of how the solar system is formed and the matter in the outer solar system is based on meteorites , but these meteorites have one drawback: that they will be polluted by air, weather and humans when they land on Earth." Henner Busemann, a member of the Hayabusa 2 sample research team and an ETH Zurich, Switzerland. "In this case, we know exactly where the sample comes from, and it has never touched the ground or touched rain."
This means that scientists can use these samples to learn more about asteroids and the outer solar system in more detail. The researchers did this by examining the gases released from rock samples but remained in the sealed sample container during their return to Earth and determining how these gases reached the Dragon Palace.
Some of these gases come directly from space radiation, which allows researchers to measure the age of the asteroid's surface.
"If you walk on an asteroid, you'll be exposed to cosmic rays and solar wind and you'll die from cancer soon," Busemann said. "Of course, these rocks won't die, but they will have nuclear reaction , which can tell us how long the rocks have been exposed."
Although the "Dragon Palace" itself, or at least the parent body that separated it a long time ago, is expected to be about 4.5 billion years old, the rocks in the sample have only existed on the surface of the asteroid for about 5 million years. This age is consistent with the rocks on the surface of the asteroids near the Earth, and is different from the asteroids in the outer solar system, so the Dragon Palace migrated from its birthplace to the solar system millions of years ago.
Related paper information:
http://doi.org/10.1126/sciadv.add8141
