14 DAY TRIAL // According to the results of a new scientific investigation, it would appear that the Sun may have stolen a large number of comets from nearby stars. It is now estimated that around 5 percent of the bodies in the Oort Cloud did not form in the solar system.
Though very difficult to confirm with standard observations methods, the Oort Cloud is believed to be a spherical agglomeration of comets surrounding the solar system, at a distance of less than one light-year away from the Sun.
That is the equivalent of 50,000 astronomical units. An AU is the mean distance between the Sun and the Earth, or about 93 million miles (150 million kilometers). Astronomers estimate that trillions of comets may exist within this structure.
Proportionally speaking, the Cloud lies about 25 percent of the distance to Proxima Centauri, which is the nearest star to the Sun. The two are separated by about 4 light-years. Many astronomers believe that the outer edges of the Cloud also mark the outer edges of the solar system.
In other words, its boundaries show where the gravitational dominance of the Sun ends, and other gravitational forces begin to carry more weight. But the new analysis suggests that around 5 percent of all objects in the Oort Cloud did not originate in the Sun's protoplanetary disk.
One possible explanation for this could be that the Sun passed very close to a small number of stars over the past 4 billion years. These flybys may have been close enough to allow for our star's gravitational pull to snatch some comets away, Space reports.
The new investigation was carried out by a team at the Lowell Observatory in Flagstaff, Arizona, which was led by astronomer Stephen Levine. The expert carried out the research with Indiana University undergraduate student Catherine Gosmeyer.
They basically created a computer simulation capable of showing how stars steal comets from each other during close encounters. “It turns out it's much more frequent than in fact even I would have guessed,” Levine explains.
Throughout its long life, the Sun may have experienced anywhere from 10,000 to 50,000 encounters with other stars, giving it ample time and opportunities to augment the Oort Cloud with stolen comets.
Details of the investigation were presented at the 219th meeting of the American Astronomical Society, which was held in Austin, Texas, in January.