According to a new study, the earliest meteorites formed in the solar system may contain liquid water, which provides a basis for the theory that meteorites brought water and other precursors to our life billions of years ago.
Carbonaceous chondrites are a special group of meteorites whose origin can be traced back to the formation of the solar system. When they were discovered on the earth, they were found to contain tantalizing information fragments. For example, minerals and minerals only appeared in the presence of organic compounds (some basic components of life) such as water and amino acids.
As a result, carbonaceous chondrites have become the main candidates for how water eventually reaches the earth. A good way to know with certainty is that although chondrites are rare in their fellow meteorites, they still have a regular effect on the earth, but it is covered with water, and we are lucky to find the rock and recover it.
This is a very high requirement.Asteroid Ryugu (Ryugu) recently Was found to be dry It has been a long time before I got there on the Hayabusa2 spacecraft in Japan. So far, scientists have always known that carbonaceous chondrites had a fluid flow at some point, but they did not know that this flow happened recently. Previous dating methods indicate that there was water on these rocks about 4.5 billion years ago, shortly after the formation of the earth.
“All of this leads to the assumption that any change and the existence of water are very old. So our test is that young changes are possible?” Simon Turner, an isotope geochemist at Macquarie University in Sydney, Australia, said in a video call. “That is to say, there is still ice on these meteorites.” Turner is the lead author of a new paper describing the flow of liquid in carbonaceous chondrites. Published Published this week in the journal “Science Reports”.
A team of researchers from Macquarie University, Florida State University, and the Paris Museum of Natural History found that in the past hundreds of thousands of years, these carbonaceous chondrites contained a certain amount of fluid in terms of space and geological time scales.
All meteorites fall, but only those who witness the fall are called “drops.” Turner’s team used only carbonaceous chondrites in the study, because these fresh rocks from space have clear time stamps on the time of arrival and the content of contact with the earth (that is, things that may be contaminated). The meteorites in this study came from all over the world: one came from Sutter’s Mill, where the gold rush in California started, and the other landed on a frozen lake in Russia and many other parts of the world.
The research team took samples from these space rocks and used uranium-water dating to determine their currents, in which the isotopes of these two elements can be measured to distinguish their age. In this case, the problem is not the age of the meteorites themselves, but the age of the liquid moving in the rock. Uranium is very fluid in fluids, and or is very fluid in fluids. Therefore, by observing the movement time of uranium relative to or in meteorites, the research team can infer when the water is washed away.
Turner said: “If there is ice on the body and there is some reason for the ice to melt and move, and it happened within the last million years, then you should expect uranium and th to behave differently.”
In other words, when a liquid flows, whether on space rocks or along a riverbed, it will transfer isotopes around it, leaving a short-term flow record. If too much time passes, the signature will disappear. Specifically, if the isotope moves within a million years, the research team will discover this destruction.
The latest in liquids The movements found in some of the team’s samples are exciting-this means that carbonaceous chondrites are likely to still contain ice (if they are flowing) It didn’t start flowing until hundreds of thousands of years ago.
Edward Young, a geochemist at the University of California, Los Angeles, has nothing to do with the latest paper. He said in an email that the new research is “very interesting” and “elegant.”He pointed out that other Thanks to NASA’s help, scientists have only recently learned about the widespread currents on the asteroid Bennu processing OSIRIS-REx mission.
The next step will be to test space rocks that will not fall through the Earth’s atmosphere like a fireball. This is a violent process that covers exactly the way the ice on these asteroids melt (samples brought by spacecraft will be useful ). At the same time, researchers will look around on the falling space rocks, paying close attention to the sky, looking for new evidence of possible fall.