For months, astronomers have been keeping a close eye on the mysterious interstellar object 3I/ATLAS, which is hurtling through the solar system at breakneck speeds.
The object – which is generally believed to be a comet, although we’ll get to other theories later – is expected to make its closest approach to Earth in just over a week, at a distance of just 167 million miles, before it finally leaves us forever. While that’s still about 1.5 times the distance from Earth to the sun, nearby spacecraft have taken full advantage of the opportunity.
NASA’s Hubble Space Telescope captured the image of the unusual visitor on November 30, when it was only 178 million miles away, as a follow-up observation after the telescope discovered the object in July. Hubble used its Wide Field Camera 3 instrument to reveal 3I/ATLAS’s coma, the fuzzy atmosphere of ice and dust surrounding its core, appearing as an ominous blue glow.
“3I/ATLAS will pass closest to Earth on December 19, 2025,” explained Avi Loeb, a Harvard University astronomer who has long supported the far-fetched theory that the object could be an alien spacecraft, explained on his blog . “Fortunately, this date coincides with a new moon and the view of the sky is not polluted by moonlight, making it an ideal night for Earth-based telescope observations.”
He added: “My hope is that with data from hundreds of observatories, including the Hubble and Webb Space Telescopes, we can gain new insights into the nature of 3I/ATLAS at that time.”
Even after its closest approach to Earth, astronomers will continue to observe this unusual visitor.
“Observations are expected to continue for several months as 3I/ATLAS exits the solar system,” NASA noted on its website.
Separate observations last month by the European Space Agency’s Jupiter Ice Moon Explorer (JUICE) also revealed surprising activity in Jupiter’s icy moons as they are heated by the sun, losing mass in the form of sublimating ice.
ESA scientists expect the bulk of the data collected by its spacecraft’s science instruments to arrive in late February.
In addition to its closest approach to Earth, 3I/ATLAS is expected to fly past Jupiter next spring, another tantalizing opportunity to examine the third interstellar object ever discovered crossing the solar system using NASA’s Asteroid Terrestrial Impact Final Alert System (ATLAS), a network of ground-based telescopes.
Another interesting theory: Objects like 3I/ATLAS may have brought life to Earth billions of years ago, a theory known as “originism.”
Recent observations by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile have discovered large amounts of gaseous methanol and hydrogen cyanide, important precursors to the formation of life.
Scientists also believe it could have come from a planetary system much older than our own, a possibility that “quite frankly gives me goosebumps just thinking about it,” as Tom Statler, NASA’s chief scientist for small solar system objects, told reporters at a press conference last month.
More information about 3I/ATLAS: NASA discovers 3I/ATLAS carries ingredients for life