# Comet 3I/ATLAS: A Record-breaking Interstellar Visitor
Comet 3I/ATLAS has currently disappeared from astronomers’ instruments. In recent days, it has come closest to the Sun and is now behind it. At the moment, it has taken a direction away from the Solar System again – but it will come closer to the Earth during its departure. In fact, so close that it could be seen in the sky even with ordinary telescopes from mid-November.It approached the Sun at a distance of only 203 million kilometers. When it will be closest to Earth just before Christmas, it will be 270 million kilometers away. “This distance is about 1.8 times the distance between Earth and the Sun. It will be on the other side of the sun during its closest approach to Earth. It poses no danger to our planet or any other planets in the Solar System,” emphasizes the European Space agency (ESA) that the body poses no threat.
A visitor from another star under the microscope
This comet is remarkable, because it is only the third body that is known to have arrived in the Solar System “from outside”, i.e. from interstellar space, i.e. from other stars. It moves through space at a speed of 210 thousand kilometers per hour, so it is the fastest interstellar visitor so far.
This is precisely why it is indeed an exceptionally crucial source of details for astronomers. From her study, they can learn a lot about comets, but also the places where this body was formed, or where it moved.
Scientists assume that 3I/ATLAS has a solid core made up of ice, dust and rocks. This is what it looks like when flying through the cold interstellar space, but when it gets close to a star, its appearance changes. Heat from the Sun causes dust and gas to be released from the comet. And it is indeed these that make up the distinctive tail, which is great to observe.
Astronomers do this not only for an aesthetic experience, but primarily because the released substances, the composition of which can be analyzed from a distance, show what and where the comet was formed. 3I/ATLAS has already been targeted by the most sensitive instruments available to humanity, including the webb and Hubble Space Telescopes, and also others. A key role is played by the SPHEREx instrument, which functions as a spectrometer: it breaks down light into its individual components and obtains physical information from this data.
These investigations are not only of scientific interest. In the past, speculation about comets also led to tragedies. And today, the comet also arouses interest among occultists.science knows of only three bodies that flew into the Solar System from places beyond its borders. The latest so far is a comet that has just come within record-breaking distance of the Sun, which means that now is the time astronomers can learn the most about it.