Study: comets visit the sun’s vicinity more frequently than scientists think

A new study has found that comets from other star systems, like 2019 Borisov , you visit the vicinity of the sun more often than scientists think.

The study, based on data collected during Borisov’s extraction from Earth at a distance of about 300 million kilometers (185 million miles) in late 2019, suggests that the comet’s frame of reference in the outer solar system remote known as the Oort Cloud could be filled with objects. In fact, the study’s authors suggest that the Oort cloud may contain more interstellar matter than household matter..

It is named after the famous Dutch astronomer Jan Oort, who first proved its existence in the fifties of the last century, and the Oort Cloud is a spherical envelope of small objects – asteroids, comets and distant fragments of the orbit of Neptune, and it is believed that the inner edge of the cloud begins with around 2,000 astronomical units (TO) of the sun, and its outer edge is about 200,000 astronomical units, a TO It is the average distance between the Earth and the Sun, approximately 93 million miles, or 150 million kilometers.

No spacecraft has ever visited the Oort Cloud, and it will take 300 years for NASA’s distant Voyager 1 probe to see the closest part of the cloud.

Astronomers have very limited tools to study this interesting world, as the objects in the Oort Cloud do not produce their own light and, at the same time, these objects are too far away to reflect much sunlight..

So how exactly did scientists find out that there must be so many interstellar objects in the Oort Cloud, and what does Borisov have to do with it?

Amir Siraj, a graduate student in the Harvard Astronomy Department and lead author of the study, said DeepSpace.org In an email, he said he could calculate the likelihood of alien comets visiting the solar system based on the fact that Borisov’s comet has been discovered.

“Based on the distance at which Borisov was discovered, we estimated the implicit local abundance of interstellar comets, as well as the abundance of ‘Oumuamua-type objects calibrated with the discovery of Oumuamua,” Siraj said. .“.

The mysterious “Oumuamua”, first spotted by astronomers in Hawaii in October 2017, was the first interstellar object to be discovered in our solar system. The object passed Earth at a distance of 15 million miles (24 million kilometers), about a sixth of the distance between our planet and the Sun, and a heated debate ensued over the nature of ‘Oumuamua, because it was not initially clear whether the object was a comet or an asteroid..

Even the detection of a single object can be used for statistical analysis, Siraj said. The so-called Poisson method, used by astronomers, calculates the probability of an event occurring in a fixed time and space since the last event.

Taking into account the gravitational force of the Sun, Siraj and his co-author Avi Loeb, an astronomer at Harvard University, were able to estimate the probability of an interstellar comet heading towards the vicinity of Earth, and they discovered that the number of interstellar comets passing through the solar system increases with distance from the Sun.