when an asteroid Hit a planet, and it can have a powerful impact — just as bad for them as dinosaurs discovered 66 million years ago. But what if two asteroids hit the same spot at the same time?
First-of-its-kind research published in journals Icarus Investigate this phenomenon on Mars. Looking at the planet, the researchers found hundreds of craters that may have been created by the impact of a binary star system in which one asteroid orbits the other, much like the moon orbits Earth.
“They’re really hard to find,” said the study’s lead author Dmitrii Vavilov of the University of the Côte d’Azur in France. But he said the findings suggest that these binary craters do exist.
Binary asteroids were first discovered in 1993 by NASA’s Galileo spacecraft on a trip to Jupiter. While taking images of an asteroid called Ida en route, mission scientists were shocked to find a second asteroid orbiting nearby. “They were very confused,” said University of Maryland astronomer Harrison Agrusha, who was not involved in the new study. “People are debating whether there is something wrong with the camera.”
no. Instead, Ida is the first to confirm that asteroids can orbit in pairs, and in some cases even more. Ada’s companions, later named Dactyl, were very small but attested to their existence. “It sent a huge shockwave through the community,” Agrusha said.
Based on observations of millions of other asteroids in the solar system, scientists today estimate that about 1 in 6 asteroids, or about 16 percent, are part of a binary star system. We can see them orbiting the solar system, especially in the asteroid belt between Mars and Jupiter, with the most famous pair – Didymos and its little pal Dimorphos – NASA and the European Space Agency (ESA) Asteroid Defense The goal of the mission later this year.
Asteroids frequently strike planets and moons, so binary asteroids are expected to do the same. Finding binary craters can be difficult, though, especially among the myriad other craters in places like our moon. It’s harder on Earth, because geological processes quickly remove evidence of an impact.
The best candidate for a binary crater on Earth today is Sweden’s Locken crater and a smaller nearby crater called Mullingen. “We dated these structures very accurately and found that they formed at exactly the same age,” says Jens Ormö of the Spanish Centre for Astrobiology, who led the 2014 study Crater analysis. Another promising candidate pair is well known, the Kamensk and Gusev craters, but their location — on the border between Russia and Ukraine — makes them difficult to study in the current global climate.
On Mars, craters can persist for billions of years. So, using high-resolution images taken by the Mars Orbiter, Vavilov and his colleagues examined nearly 32,000 craters over 4 kilometers in diameter, looking for pairs of craters.
Their results showed that 150 pairs appeared to be the result of binary impacts, for a total of 300 individual craters. These estimates come from looking for paired crater shapes expected after binary asteroid collisions. These include Teardrop Crater, where two craters overlap; Peanut Crater, where their edges meet; and Double Crater, where there is a gap between the two. The orientation of the two craters depends on where the two asteroids were at the time of impact.
