Asteroid effects have a poor reputation on earth – it is the dinosaurs & # 39; signature public representativeness – but it is the month that & # 39; t really learn from & # 39; brings life into a nasty neighborhood.
This is because the earth's arsenal of forces has left the craters behind it. And that's frustrating scientists wanting to understand the dirt over our solar system. So a new study uses the pockmarked liner surface to taste the history of things in our moon and earth, found signs that we received a lot of messier over 290 million years ago.
"It is a cool study that speaks of our dynamic solar system and it is good that there is," Nicolle Zellner, a physiologist in Albion College Michigan, who was not involved in the new study, said Space.com. "It will think and test people, so that's exciting." [How the Moon Formed: 5 Wild Lunar Theories]
The earth and the month are close enough to the total system scale that regions asteroids should at least come to about the same frequency. (The earth may have some extra with its strong heaviness, and the earth probably believes more hits because it is larger in area – but in consequence of impact on square miles, it must be the same.)
Science has only identified 180 impact craters at the Earth, as opposed to hundreds of thousands of moon-craters. The earth turns them with winds and slumps, oceans and plate tectonics. "The month is perfect for studying craters", Sara Mazrouei, a planetary scientist who led the new study under her doctoral degree at a University of Toronto, Space.com said. "Everything remained there."
But to track down the history of consequences, scientists were not just identifying craters, but I estimated their lifetime. And that is much harder at & # 39; the month than at & # 39; Earth, for geologists cannot directly attempt to run craters.
Thus, the team after the new study determined what can be a surprising measurement: how well the nuts save bikes warm in a long, cold month night. This can be a great random measurement. But when a large stretcher strikes the month, it shakes a crater and leaves the surrounding landscape with fielders out of the material. In & # 39; run from & # 39; In time, these stones are wound by smaller impactors which remove them into smaller and smaller feelings, which are ultimately regenerated, so that the team determined that older craters were covered by finer stones and younger craters of larger ones.
Then, if that landscape of a 14-day day after a 14-day month goes out, the temperature changes to different rates. "The idea is that big hills can keep warm all night, while that regolit or seven fades away," Mazrouei said. "As craters grow older, they become less sensitive." At last they get faster.
So Mazrouei and her colleague are looking at thermal image data of an instrument called the Divine on board NASA's Lunar Reconnaissance Orbiter, which has been the month since 2009. The team identified 111 individual craters that they knew were less than 1 billion years old, analyzed their heat notations and, by a model of how quickly lunare boulders ignite, estimate their lifetime.
The result showed an intriguing pattern: a spike in implementations of about 290 million years ago, when the criterias appeared to be more than double. That would make something important around our solar system around – often, the team sets, breaking a large spacecraft into one's asteroid belt and getting closer to the earth and the moon. And it compares the craters that we know on earth about their results, the team sees some patterns, suggesting that scientists have found a beautiful representative, like small, crater collecting.
Not everyone is convinced. "The results are intrusive, but I think the real support for these conclusions is very poor," said Jay Melosh, a planetary scientist at Purdue University who was not involved in the new study, said Space.com. In particular, he has not been sold to the boulder integration model, which they used – he thinks it does not properly account for how & # 39; t that process slows down when fevering decreases. And he does not see enough earthquakes to support fixed statistical analyzes; He causes them to work too small a problem. [The Moon: 10 Surprising Lunar Facts]
"That doesn't mean it's wrong, but it doesn't mean it's right either – we just don't find it," said Melosh. "This is a noble visit to just go a little further than the data type."
Zellner understands how brave learning months can be crater: they worked with the drops of glass that were switched by finding and retrieving on earth in collections that were collected by the Apollo astronauts. But the date of this glass is still a laboratory challenge, and the samples are all coming from a small patch of one month of & # 39; month. Orbiter data put scientists at a distance, but treatment over the whole month – no method is perfect.
"We do the best we can with what we have now," said Zellner. "That's science, right? We put ideas out there, and then we find ways to test these ideas, and the idea is the test of time or it's not."
And all three scientists offer reasoned reasons why the work is done to find out the month's impact history. First, of course, is the self-interested approach: Earth craters can come with some unfavorable side effects.
"Everyone is interested in the crater voyage on Earth, because we don't want to, like the dinosaurs," said Melosh. The catastrophic background of & # 39; the consequences flipped in & # 39; e between a heavy three of four types of life, although the expiratory room left enough room for our own mammals ancestors. "We have to thank our happy meteorite, but it was bad for everyone on a planet." Nice enough about the impact, the theory goes on, and we can save our own shine the next time.
For Zellner, there is also an exotic call: Learn more about our own solar system can help help carriers just do not run our own, but also the processes that form the single-sun systems that detect the scientists .
Mazrouei looks at the work as an example of how different solar system bodies can shine together. One of her co-authors has already seen how the BepiColombo mission to Mercury, with an instrument instrument, much like a month, added another dimension to crater study. can.
The earth is great for living, but scientists cannot finish it from home in the past. It calls for the month and its previously cratered surface to understand what our planet has done, Mazrouei said. "We also get a lot of the earliest history."
The new study is written in a current paper (January 17) in a & quot; magazine & quot; Science.