New images show an interstellar comet that will soon make its closest approach to Earth

The Hubble Space Telescope and the Jupiter Icy Moons Explorer have captured new images of an interstellar comet as the object makes its closest approach to Earth later this month.

Comet 3I/ATLAS has intrigued astronomers because it originated outside our solar system and was discovered in July in our celestial neighborhood.

Since it is only the third interstellar object ever observed passing through our solar system, astronomers have directed numerous missions to focus on the comet. The observations were key in helping scientists determine the object’s trajectory and even provided clues about its composition, thanks to gases that sublimated from the comet during its closest pass in front of the sun in October.

Hubble was one of the first to observe 3I/ATLAS in July, shortly after its discovery, providing the most detailed view of the comet’s teardrop shape at the time.

Astronomers spotted 3I/ATLAS again with Hubble on November 30, when it was 178 million miles (286 million kilometers) from Earth, and using the telescope’s Wide Field Camera 3 instrument, they captured an even sharper photo.

Meanwhile, an image taken by the European Space Agency’s Jupiter Icy Moons Explorer, or Juice, mission, en route to study Jupiter and its icy moons, shows intriguing activity around the comet.

Spot two tails

The Juice mission will study the potential habitability of Jupiter’s three largest moons, Ganymede, Calliston and Europa. The moons likely harbor subterranean oceans beneath their icy crusts that could support life.

But first, Juice must reach Jupiter. The mission was launched in April 2023 and is expected to arrive at its destination in July 2031.

And in early November, Juice was in a prime position to observe 3I/ATLAS about 41 million miles (66 million kilometers) from the comet.

The spacecraft used five of its science instruments, as well as its onboard navigation camera, or NavCam, to glimpse the comet.

Most of Juice’s data won’t arrive on Earth until February because the spacecraft uses its main antenna as a heat shield to protect it from the sun during its long journey to Jupiter. A smaller antenna sends data back at a fraction of the rate.

Juice’s team didn’t want to wait that long, so they uploaded a quarter of a single image taken by NavCam. The image shows the thermal activity of the comet during its close passage in front of the sun.

The newly released image shows a coma, or bright halo of gas surrounding the comet, as well as two tails: a plasma tail composed of electrically charged gas, as well as a faint dust tail of released solid particles.

Comets originating in our solar system typically have these two tails, as well as a hazy coma surrounding a solid core composed of rock, gas, dust, and ice from the formation of the sun, planets, or other celestial bodies. As comets approach stars like our sun, they heat up, forming tails of sublimating material that extend behind them.

Comet 3I/ATLAS will approach within 270 million kilometers of Earth on December 19, but it will be on the far side of the sun and will not pose any risk to our planet. For reference, Earth is about 93 million miles (150 million kilometers) from the sun. The comet is expected to remain visible to telescopes and space missions for a few more months before leaving our solar system, according to NASA.

The remainder of the Juice data from the comet flyby, expected between February 18 and 20, is expected to include images from the spacecraft’s high-resolution optical camera, as well as compositional and particle data that could provide more clues about the interstellar object’s origin.

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with information on fascinating discoveries, scientific advances and much more.

For more CNN news and newsletters, create an account at CNN.com