Meteorites that formed in the early days of the solar system may contain liquid water, according to new research, lending credence to the theory that meteorites brought water and other precursors to life to our planet billions of years ago.
Carbon chondrites are a special group of meteorites that trace their origins back to the formation of the Solar System. When bits of them are found on Earth, they contain bewildering bits of information, such as minerals that only appear in the presence of water and organic compounds like amino acids – some of the building blocks of life.
As a result, carbonate chondrites became a major candidate for how water got into the ground. There is a great way to find out if chondrites – which, although rare amongst its meteorite-fallen citizens, still affect Earth regularly – got to Earth with water on it, and we were lucky enough to discover the rock and recover it on it.
This is a long request. The asteroid Ryugu was recently It was found that it was dry with water Long before Japan arrived there with its Hayabusa2 spacecraft. Until now, scientists were aware that the fluid flow happened on carbonate chondrites at some point, but they didn’t know how recently this flow happened. Previous dating methods showed the presence of water on these rocks early – about 4.5 billion years ago, shortly after Earth formed.
„All this leads to the assumption that any change and any presence of water was very old. So our test was to say, Was there a small change?“ Simon Turner, a isotopic geochemist at Macquarie University in Sydney, Australia, said in a video call. „That is, there is still ice on these meteorites.“ Turner is the lead author of a new paper describing the fluid flow in carbonic chondrite, Published This week in Scientific Reports.
A team of researchers from Macquarie University, Florida State University, and the Natural History Museum in Paris found that these carbonaceous chondrites have contained an amount of fluid in the past hundreds of thousands of years – recently, in terms of space and geological time scales.
All meteorites fall, but only those that do fall are called „falls“ afterward. Turner’s team only used carbonic chondrites in their research, because those new rocks from space have a clear time stamp upon their arrival and the context of what they came into contact with on Earth (i.e. what they might have been contaminated with). The meteorites included in the study came from all over the world: one was from Sutter’s Mill, where the California Gold Rush set off, and another fell on a frozen lake in Russia, among many other locations around the world.
The research team took samples from these space rocks and dated the flow of water in them using uranium and thorium dating, in which the isotopes of the two elements can be measured to distinguish age. In this case, the question was not the age of these meteorites themselves, but rather the age at which the liquid moved within the rock. Uranium is very mobile in liquids, while thorium is not, so by seeing when uranium moves inside the meteorite with respect to thorium, the team can deduce when the water around it was washed away.
Turner said, „If there is ice on objects, if there is a reason for the ice to melt and move, and that has happened over the past million years, then you should expect a different behavior of uranium and thorium.“
In other words, when a liquid flows, either on a space rock or along a riverbed, it moves isotopes around, leaving a short-term record of the flow. This signature disappears if a long time has passed. If the isotopes move in precisely a million years, the team will discover the disturbance.
The novelty of the fluid The movement in some of the team’s samples is exciting – this means that the carbonic chondrites may still contain ice, if they have flow Liquid until a few hundred thousand years old.
Edward Young, a geochemist at the University of California, Los Angeles, who was not affiliated with the recent paper, said in an email that the new research was „very interesting“ and „neat“. Other noted Scientists recently learned about the large-scale flow of water on the asteroid Bennu, thanks to NASA processing Mission Osiris Rex.
The next step will be to test space rocks that haven’t fallen as a fireball through Earth’s atmosphere, a violent process that obscures exactly how ice melts on these asteroids (samples brought by a spacecraft would be useful). Meanwhile, researchers will roam the fallen space rocks and monitor the skies for new clues that may collapse.
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