Cold comets — both natives and the interstellar Comet Borisov — have nickel and iron vapor in their atmospheres, and scientists want to know why.
New analysis shows that Comet 2I/Borisov, which zipped nearest the Sun in late 2019, was unlike any comet we’ve seen before.
A new study estimates the number of interstellar objects that fly through the inner solar system every year, and it could be quite a lot.
The solar system's newest interstellar visitor, Comet 2I/Borisov, bears a striking resemblance to the icy population of the outer solar system.
Only the second object thus far to visit the solar system from interstellar space, Comet Borisov is expected to reach perihelion in December. What can we see now?