We've watched it speed through the solar system using the most powerful telescopes in human history. We've studied its light with probes whipping around the sun and robots marooned on Mars. Countless eyes watched it make its closest approach to Earth on Dec. 19 — and yet, for all of this, the interstellar comet 3I/ATLAS remains little more than a blur of gas, shrouded in mystery.
Since its discovery in early July, 3I/ATLAS has been studied more enthusiastically than practically any other celestial object in recent memory. Still, for all its fame, much remains unknown about it. The comet’s origins, from somewhere far across our galaxy, may never be known. Its true age, size, composition, and shape are also poorly constrained.
