Could life rise on interstellar visitors like 'Oumuamua?

Oumuamua, the first known interstellar visitor to the solar system, points out that life could also be spread between stars and perhaps even across the galaxy, according to two new studies.

In 2017, astronomers detected a cigar-shaped asteroid named "Oumuamua" or "A / 2017 U1", a chaotic object that culminated in a 400-meter (400-meter) length whose trajectory suggests that it might come from another star, or even two. The researchers have since learned that "Oumuamua is unlike anything in the solar system, its color varies over its entire surface so that no scientist can at first explain.

Previous research has estimated that about one billion interstellar objects are comparable in size to Oumuamua by 35 light-years cube, which is much higher than some previous estimates. This has led scientists to explore the implications that such astronomical numbers of 'Oumuamua' type bodies have. could have on the prospect of lithopanspermia – the idea that life could have spread in space by hitchhiking on rocks. [‘Oumuamua: The Solar System’s First Interstellar Visitor in Photos]

"Interstellar objects could potentially be the life of another planetary system in the solar system," Space Researcher Avi Loeb, an astrophysicist at Harvard University and lead author of the two new studies, told Space.com.

The group calculated the speed at which the sun and Jupiter together could gravitatively capture interstellar objects such as 'Oumuamua' and discovered that the largest body they could trap had a width of a few dozen kilometers. They performed similar calculations for the Alpha Centauri A and B binary systems and discovered that it could capture interstellar objects the size of the Earth.

The researchers also estimated that an interstellar object of about one kilometer wide could hit the Earth every 10 million to 100 million years. Such collisions could have contributed to the delivery of organic compounds or even microbes to Earth, they said.

"Life can extend over great distances," Manasvi Lingam, principal author of the study, mathematician applied at Harvard University, told Space.com. Lingam and Loeb have detailed their findings from the first online study published Oct. 12 in Astronomical Journal.

Scientists then explored how rocky asteroids or icy comets ejected from one planetary system can be trapped by another across the entire Milky Way. They explained the number of stars that an interstellar object could encounter, the number of stars in the Milky Way, the distances between the stars, the time it could take for an interstellar object to move from one star to another and the amount of time life could stay alive.

"Bacteria can survive for millions of years, that's for sure," Idan Ginsburg, astrophysicist at Harvard University and lead author of the second study, told Space.com. "If the rocky body were large enough, the bacteria would be protected from most radiation and, when they would enter the atmosphere, while the surface of the object would be burned, microbes would Inside could survive. "

The researchers estimated that "if life can survive for a million years, there could be more than a million objects of the size of Oumuamua that are captured by another system and can transfer life between the stars, "said Loeb.

Overall, "Panspermia could spread throughout the galaxy," said Ginsburg. In principle, galactic panspermia could not only bring life to lifeless planets, but also extend a life form to a planet with a different life form, he added.

In addition, "in principle, life could even be transferred between galaxies, some stars escaping from the Milky Way," Loeb said. "These stars could potentially transfer life across the universe."

Ginsburg, Lingam and Loeb detailed their findings from the second online study, online Oct. 10, in a study submitted to Astrophysical Journal Letters.

Follow Charles Q. Choi on Twitter @cqchoi. follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.