Earth’s gravity could destroy ‘killer’ asteroids, study says

A theory long held by planetary scientists is Earth and other terrestrial planets can use their gravitational forces Destroying or deflecting “killer” asteroids was first demonstrated in a recent study and accepted for publication. Astrophysics Journal Letterscurrently hosted in the preprint repository arXiv.

Using population-level evidence from so-called “near-Earth asteroids” (NEAs), two researchers found that our planet’s gravitational pull can break even large asteroids apart, creating families of smaller, more manageable celestial bodies during close encounters with Earth. Venus.

For nearly a decade, the new study’s first author, Mikael Granvik, a planetary scientist at Luleå University of Technology in Sweden, had been looking for “NEA families” that might form in such tidal disturbances, but we found nothing. ” , told Live Science by e-mail. This is because possible fragments formed in this way blend with the background and quickly become undetectable..

Counting asteroids between Earth and Venus

In 1994, Earth scientists obtained a practical demonstration of the incredible destructive power of tides. Comet Shoemaker-Levy 9 broke apart during close encounter with gas giant Jupiter. But astronomers have not been able to prove that the same thing could happen on terrestrial planets, including ours.

Granvik had the insight in 2016 and helped create a model that calculated the orbits of asteroids of different sizes to determine their number at different distances from the Sun. The model was tested with seven years of observations obtained by the Catalina Sky Survey, a Catalina Sky Survey. Program based on NASA-funded Arizona telescopes.

At first, the team was disappointed that these missing asteroids were very small and also traveled in circular orbits around the Sun, in roughly the same plane as the orbits of Earth and Venus. That’s when Granvik experienced his “eureka moment”: He realized that these objects might actually be fragments of larger asteroids that had been torn apart by tidal forces during close contact with terrestrial planets.

Calculating the masses of large and small asteroids

A partnership with co-author Kevin Walsh, a researcher at the Southwest Research Institute in Boulder, US, allowed Granvik to test his new theory. To do this, they started from the principle that asteroids hitting rocky planets lose 50% to 90% of their mass, creating a stream of fragments.

They managed to “close the account” with this model. Previously unexplained asteroids were fragments of asteroids torn apart by tidal movements.

According to Gravink, “While individual families may be difficult to find, combining multiple families will produce a signature that we can identify.” In additional simulations, the researchers found that these fragments wandered intact through space for an average of nine million years until they hit the Sun or a planet or were “ejected” from the Solar System.

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