The Universe gives us extraordinary celestial bodies that trap us, like the cometa 81P/Wild discovered by Swiss astronomer Paul Wild in 1978. However, until January 2, 2004 it was not studied thanks to the stardust space probewho took photos and collected particle samples of the comet that were returned to Earth along with the interstellar dust that he collected during the trip.
Much has been studied about this celestial body and, currently, it is said that the comet 81P/Wild is at perihelion, but… what exactly does this mean? We explain it to you!
What is comet 81P/Wild like?
A comet is a celestial body made up of dust, rocks and ice particles that orbits the Sun following different elliptical trajectories. According to studies, the so-called 81P/Wild or just Wild 2, has a 5 kilometer surface riddled with flat-bottomed depressions, with steep walls and other features that are very small or vary up to 2 kilometers wide. These features are believed to be caused by impact craters or gas vents.
A team of the NASA analyzed the cells capturing individual particles and grains extracted from comet and interstellar dust, and then sent them to about 150 scientists around the world. The composition of the powder contained a wide range of organic compoundsincluding two that contain biologically usable nitrogen.
In April 2011, scientists at the University of Arizona discovered evidence of the presence of liquid water on comet 81P/Wild. They found copper iron sulfide ores which must have formed in the presence of water. The discovery conflicts with the belief that comets never get hot enough to melt their icy mass.
81P/Wild: What does it mean to be at perihelion?
The perihelion is the closest point in the orbit of a celestial body around the Sun. In the case of the comet 81P/Wild, its perihelion is now about one astronomical unit (the one used mainly to express the distances between celestial objects in the solar system), that is, the equivalent of 150 million kilometers.
What are the best-known comets in history?
Besides of cometa 81P/WildThere are also other known comets that have been studied by various scientists throughout history. Probably the most famous is the cometa Halley, discovered by the English astronomer Edmund Halley. However, there are many kites that have been very popular. Let’s see some of them:
comet caesar: It was the most mythical of antiquity. It was visible for seven days and interpreted as the deification of the Roman dictator Julius Caesar, assassinated four months earlier. It is said that it may have been the brightest comet for which there are historical records.
Great Comet of 1882: It is part of the Kreutz Sungrazers, a family of comets that passed very close to the Sun’s surface during perihelion. It was also very luminous, in fact, its brightness was such that, at perihelion, it could be observed next to the Sun even during the day.
Cometa West 1976: It was discovered in 1975 by the Danish astronomer Richard West and passed 29.5 million kilometers from the Sun on February 25 of that same year.
Comet Hale-Bopp: It was discovered on July 23, 1995 and was seen for 18 months at a great distance from the Sun. Thanks to this brightness, it was called the Great Comet. Some people were terrified of him, since it was said then that a large alien ship would be following his path…