This animation shows the observations of comet 3I/ATLAS when it was discovered on July 1.ATLAS / University of Hawaii / NASA
Interstellar comet 3I/ATLAS.David Rankin / Saguaro ObservatoryAt the time, the comet was about 290 million miles away from the sun. The SPHEREx observations revealed the comet’s coma, a hazy cloud of gas and dust akin to an atmosphere that surrounds its nucleus. Researchers determined that the coma contained an abundance of ice water and carbon dioxide, similar to the chemistry of comets formed in our solar system.
The European Space Agency's ExoMars Trace Gas Orbiter image of 3I/ATLAS as it passed close to Mars. The European Space Agency
The European Space Agency released new images of the comet in October, which were taken by a spacecraft in orbit around Mars. The ExoMars Trace Gas Orbiter, jointly operated by ESA and Russia’s Federal Space Agency, observed the comet for about a week beginning on Oct. 1.
3I/ATLAS as it moves. The European Space Agency
The photos show a fuzzy white dot — the center of the comet — moving against a dark and starry expanse. When the images were taken, 3I/ATLAS was roughly 18.6 million miles from the orbiter.
3I/ATLAS, circled in the center, as seen by NASA’s Lucy spacecraft. This image was made by stacking a series of images taken Sept. 16 as the comet was zooming toward Mars. NASA / Goddard / SwRI / JHU-APL
After weeks of delays because of the government shutdown, NASA released a trove of 3I/ATLAS photos taken by various spacecraft from late September through mid-October.
The comet mostly appeared as an illuminated dot, but some images were detailed enough to pick up its tail as a faint, elongated smudge.
Observations of 3I/ATLAS from Sept. 28 to Oct. 10 from the PUNCH satellites in low-Earth orbit, when the comet was 231 million to 235 million miles away. NASA / Southwest Research Institute
Among the NASA missions that observed the comet relatively up-close were the sun-watching PUNCH satellites, the Solar and Heliospheric Observatory, the Lucy space probe, the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission and the Perseverance Rover on the surface of Mars.
NASA’s Hubble Space Telescope reobserved 3I/ATLAS on Nov. 30 with its Wide Field Camera 3 instrument.NASA, ESA, STScI, D. Jewitt (UCLA) / M.-T. Hui (SAO) / J. DePasquale (STScI)
Late last month, NASA’s Hubble Space Telescope tracked 3I/ATLAS when it was approximately 178 million miles away from Earth. Hubble’s instruments recorded the moving comet as a luminous point while the background stars appeared as streaks of light. NASA released the images on Thursday and said it intends to gather more data on 3I/ATLAS in the coming months as the comet moves out of the solar system.
