On Thursday (Dec. 4), NASA shared the latest image of 3I/ATLAS taken by the Hubble Space Telescope. The glowing white dot at the center of the image shows the comet's nucleus (its main body) and coma, the bright atmosphere of gas and dust that wraps around the comet before getting funneled into its tail. In the background, stars are stretched into long streaks as Hubble's camera stays fixed on the fast-moving comet.
Comets typically brighten as they approach the sun, when the ice within them heats up and sublimates. Solar radiation pushes this gas into a tail that stretches away from the sun. Meanwhile, the warmest, sun-facing side of the comet may erupt with jets of gas and dust angled toward our star. Both of these features are faintly visible in the new Hubble image.
NASA snapped this image on Nov. 30, when Hubble was about 178 million miles (286 million km) from the comet. This is considerably closer than when Hubble first imaged the comet in late July. Although that first view showed little more than a blue blur, it nevertheless allowed scientists to constrain 3I/ATLAS' size to somewhere between 1,400 feet (440 meters) and 3.5 miles (5.6 km) wide — likely the largest interstellar object seen to date.
New data from this image, including details of the coma's composition, has yet to be released but is likely on the way.
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