A team of scientists studied and found out that Earth’s water did not come from melted meteorites. Woods Hole Oceanographic Institution was part of this study, which uncovered new information about where our lakes, rivers, and oceans initially came from. We don’t know exactly how a lot of water got here on Earth, since it makes up 71% of the planet’s surface.
Recent research published in Nature helps scientists better understand why Earth became a livable planet. The study looked at some very old meteorites from the time our solar system was first created, around 4.5 billion years ago. The special thing about these meteorites is that they have almost no water inside of them – making them some of the driest materials ever measured from space.
This means that these rocks cannot be the source of all the water found on Earth and makes it even harder to find other planets with possible signs of life outside our own solar system. With this new knowledge, researchers now know more about how unique our planet is and how rare conditions had to line up for humans to exist here today!
Megan Newcombe from the University of Maryland, with help from other scientists from the Carnegie Institution of Science, was trying to figure out how our planet got water. Even though it’s close to the sun, having oceans on such a small planet is quite challenging.
A group of researchers studied seven meteorites that landed on Earth many years ago. They found that the meteorites come from at least five objects called planetesimals, which combined to create our planets. The planetesimals were heated up long time ago when radioactive elements decayed, which caused them to splinter into pieces with a core, mantle, and crust.
This experiment was something new, because no one had ever measured what is inside of meteorites from earth before. Liam Peterson, a student in geology at the University of Maryland, studied the amounts of magnesium, iron, calcium and silicon in these meteorites using an electron microprobe. He then worked with Newcombe at the Carnegie Institute for Science’s Earth and Planets Laboratory to measure how much water was inside them with a special instrument called a secondary ion mass spectrometry.
Conel Alexander, a scientist at the Carnegie Institution for Science, said that it’s very hard to analyse water levels in dry materials. This is because any water that is on the sample or in the instrument used to measure can easily be found and mess up the results.
In order to prevent contamination, the researchers first heated their samples in a low-temperature oven to get rid of surface water. Then, they had to dry them again before they could be analyzed by the secondary ion mass spectrometer. To make sure that there isn’t any terrestrial water left on the samples, Newcombe had to put the samples under a special vacuum for over a month.
Scientists got some of their meteorite samples from inside the solar system, around Earth’s area. This area is mostly hot and has no water. But they also got rarer samples from further away in the solar system, where it’s cold and icy. It was thought that this part supplied water to Earth, but nobody knows what kind of things may have brought it here.
Scientists from the WHOI (Woods Hole Oceanographic Institute) had already figured out that some objects from the outer Solar System are made differently than others. But they thought these objects would have a lot of water in them. This new research shows us that once these objects get too hot, almost all of their water disappears.
Scientists studied some meteorite samples and found out that they contain extremely little water. To be exact, the amount of water in the analyzed meteorite samples was only two-millionths of their total weight. In comparison to those meteorite sample studied by researchers, the wettest ones – known as carbonaceous chondrites – have up to 100,000 times more water.
Scientists recently learned that melting of planetesimals (space rocks) caused a lot of the water in our solar system to disappear. It turns out, not all space rocks are filled with lots of water, meaning it is likely Earth once received some of its water from meteorites (really big shooting stars).
Newcombe said that the results of their research can help a lot beyond just geology. In fact, scientists from all sorts of fields (especially exoplanet researchers) are interested in discovering where Earth’s water came from because it plays an important role in having life on our planet.
Water is very important in allowing life to exist. So, as we look out into space and find planets outside of our solar system, scientists want to figure out which of those planets could potentially come with life too. To do that, they must first understand more about our own solar system.
A new research article published in Nature on 15 March 2023 details how the gas released by early planetesimals likely limited the amount of water available to be delivered to our planet Earth. The authors of this research paper were M. E. Newcombe, S. G. Nielsen, L. D. Peterson, J. Wang, C. M. O’D. Alexander, A. R. Sarafian, K. Shimizu, L. R. Nittler and A. J J Irving and its DOI is 10:1038/s41586-023-05721-5
This is research done by NASA (Award Nos. 80NSSC20K0336 and 80NSSC22K0043) as well as a Carnegie Institution for Science postdoctoral fellowship but their views may not necessarily be the same as those expressed in this story.
