Comet 3I/ATLAS represents just the third object in history to be known to have entered our solar system from outside.

Interstellar comet 3I/ATLAS will fly by our planet at a safe distance of 1.8 astronomical units (roughly 167 million miles or 270 million kilometers) at 1 a.m. ET on Friday, December 19, according to calculations by NASA’s Jet Propulsion Laboratory. That’s about twice the average difference between Earth and the Sun.

While NASA's James Webb Telescope and other instruments have already spotted abundant water vapor, carbon monoxide and carbon dioxide in 3I/ATLAS's coma, X-ray observations are uniquely sensitive to lighter gases such as hydrogen and nitrogen that are otherwise hard to detect.

I've taken incredible photos of this interstellar comet for more than a month using two tiny iPad-connected scopes in my windowsill. You can catch it too, if you act quickly.

The Southwest Research Institute-led Ultraviolet Spectrograph (UVS) aboard NASA's Europa Clipper spacecraft has made valuable observations of the interstellar comet 3I/ATLAS, which in July became the third officially recognized interstellar object to cross into our solar system.