Hubble Captures Stunning Image of Rapidly Moving Interstellar Comet 3I/ATLAS, Potentially Revealing Secrets from Beyond Our Solar System
An unprecedented image captured by the Hubble Telescope offers the clearest view yet of an interstellar comet, designated as 3I/ATLAS, speeding through our solar system. On July 21, when the object was approximately 277 million miles (445 million kilometers) away from Earth, the Wide Field Camera 3 recorded a remarkable sight of the comet, which originated beyond our solar system.
The image reveals a teardrop-shaped dust cocoon streaking from the comet’s icy nucleus. A comet’s nucleus is its solid core, composed of ice, dust, and rocks. As comets approach stars such as the sun, heat causes them to release gas and dust, forming their distinctive tails.
Several telescopes, including Hubble, are being utilized to track 3I/ATLAS as it hurtles at a staggering speed of 130,000 miles (209,000 kilometers) per hour. This velocity makes the comet the fastest known object from outside our solar system ever observed passing through it.
New observations are providing insights into the comet’s size, with its small nucleus estimated to measure anywhere between 3.5 miles (5.6 kilometers) in diameter and 1,000 feet (305 meters) across, as detailed in a recent paper accepted by The Astrophysical Journal Letters.
Additional space-based telescopes like the James Webb Space Telescope, Transiting Exoplanet Survey Satellite, and Neil Gehrels Swift Observatory, along with ground-based observations from the W.M. Keck Observatory in Hawaii, will help reveal more about the comet’s chemical composition. 3I/ATLAS is expected to remain visible to ground-based telescopes until September before it gets too close to the sun for observation until its reappearance on the other side of our star in early December.
However, much remains unknown about 3I/ATLAS, such as its origin point. “No one knows where the comet came from,” stated lead study author David Jewitt, professor of astronomy at the University of California, Los Angeles. “It’s like glimpsing a rifle bullet for a thousandth of a second. You can’t project that back with any accuracy to figure out where it started on its path.”
Despite behaving similarly to comets originating within our solar system, the high speed of 3I/ATLAS suggests it is an interstellar visitor. Scientists believe it has been traveling through interstellar space for billions of years, gaining momentum from gravitational slingshots caused by whizzing past stars and stellar nurseries.
3I/ATLAS is the third known interstellar object observed in our solar system after ‘Oumuamua (2017) and 2I/Borisov (2019). The discovery of 3I/ATLAS was fortuitous for Matthew Hopkins, a recent doctoral student in the department of physics at the University of Oxford, who authored a separate study about the object. Hopkins will continue researching 3I/ATLAS during his postdoctoral research fellowship at the University of Canterbury in New Zealand.
Determining the age of interstellar objects is challenging, but Hopkins and his colleagues estimate that 3I/ATLAS has about a 67% chance of being more than 7.6 billion years old, while our solar system, sun, and comets are only 4.5 billion years old.
The interstellar comet’s entry into our solar system was purely accidental, but it is not exceptionally rare, Hopkins explained. Small, undetectable interstellar objects pass through the orbit of Jupiter every year. However, astronomers are hopeful that the Vera C. Rubin Observatory will aid in detecting more interstellar objects as it scans the skies for small, faint, and distant objects. With its massive primary mirror spanning 28 feet (8.4 meters) across, the observatory can spot such objects better than previous telescopes. Hopkins’ coauthors estimate that the Rubin Observatory could identify between five and 50 interstellar objects over the next ten years.