Recently, astronomers announced the results of a study using data collected with NASA’s Chandra X-ray Observatory of two comets — C/2012 S1 (also known as “Comet ISON”) and C/2011 S4 (“Comet PanSTARRS ...

An interstellar comet can glow in X-rays even while remaining hundreds of millions of kilometers away. That is what makes 3I/ATLAS unusually valuable to astronomers. The object, only the third known ...