New scans of the interstellar visitor known as 3I/ATLAS have found that it is likely an unusual comet that's much smaller than it previously appeared and is unexpectedly releasing loads of carbon dioxide gas (CO2). The large amount of CO2 pouring out, about 940 trillion molecules per second, is a major finding, suggesting 3I/ATLAS formed in a star system that doesn't look anything like ours, where comets are much different than the ones we see orbiting our sun.