Famous comet 3I/ATLAS shows itself from our solar system forever – but not before space paparazzi from Earth's space agencies take some of the clearest photographs of the place yet.
Discovered at the end of June and confirmed as third known interstellar object In July, 3I/ATLAS has spent the last few months traveling through the inner solar system at approximately 130,000 mph (210,000 km/h). Massive, snowball spewing streams made its closest approach to Mars and the Sun in October. Its closest approach to Earth is expected on December 19, when it will be at a distance of about 170 million miles (270 million kilometers) – almost twice the distance between our planet and the Sun.
Hubble doubles down
Thursday (December 4) NASA shared last 3I/ATLAS image taken Hubble Space Telescope. The glowing white dot at the center of the image shows the comet's nucleus (its main body) and the coma, the bright atmosphere of gas and dust that envelops the comet before being caught in its tail. In the background, stars stretch out into long stripes as Hubble's camera zooms away from the fast-moving comet.
Comets typically become brighter as they approach the Sun as the ice inside them heats up and sublimates. Solar radiation pushes this gas into a tail extending from the Sun. Meanwhile, the warmest side of the comet, facing the Sun, can spew out jets of gas and dust directed towards our star. Both of these features are faintly visible in the new Hubble image.
NASA took this image on November 30, when Hubble was about 178 million miles (286 million km) from the comet. It's much closer than when Hubble first photographed the comet in late July.. Although this first image showed little more than a blue blob, it nevertheless allowed scientists to place 3I/ATLAS's size at somewhere between 1,400 feet (440 meters) and 3.5 miles (5.6 km) wide—likely the largest interstellar object observed to date.
New data from this image, including details about the composition of the coma, have not yet been published, but are likely on the way.
ESA is gaining momentum
Also on Thursday ESA shared last photo of the comet taken Explorer of Jupiter's icy moons (Juice) The orbiter is on its way to studying Jupiter's moons for signs of life. Juice took the image on November 2, just days after 3I/ATLAS's close approach to the Sun.
Located even closer to its target than Hubble (just 41 million miles or 66 million km), Juice shows us a comet full of activity.
“Not only do we clearly see the glowing halo of gas surrounding the comet, known as its coma, we also see a hint of two tails,” an ESA spokesman said. wrote in a statement. The comet's “plasma tail,” made of electrically charged gas, extends toward the top of the frame. We may also be able to see a fainter 'dust tail' of tiny particulate matter extending towards the bottom left edge of the frame.”
The earth is getting ready
Juice observed 3I/ATLAS with five scientific instruments over two days. But beyond this teaser image, we don't know what these instruments have seen yet; The full data set will not reach Earth until the end of February 2026, according to ESA. That's because Juice currently uses its main antenna as a heat shield to protect it during a close solar transit, and relies on its smaller, less efficient antenna to relay its observations to us.
While we can learn little from the new NASA and ESA images without a full set of scientific data, it is a good reminder that human space exploration is paying off in unexpected ways. Hubble and Juice are among a dozen spacecraft that have observed 3I/ATLAS from across the solar system, including Mars rovers, solar orbiters, asteroid trackers and space telescopes which were never designed to track comets.
And that's not all: as 3I/ATLAS approaches Earth The James Webb Space Telescope will take another look at itand countless scientific observatories and amateur astronomers will also have the opportunity to observe it. When you're dealing with mysterious guest from unknown placesevery observation matters.
