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. 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. 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'. The researchers predicted where the object should be in each of TESS's images, and stacked up multiple photographs of the sky so that the interstellar object became bright enough to detect. By pushing back the start of the 'observation window' by almost two months, this 'precovery' allows for a better estimate of 3I/ATLAS's orbit that confirms it came from outside the solar system. Additionally, this early observation indicates that 3I/ATLAS underwent a sudden and rapid increase in brightness when it reached a distance six times greater than the Earth's distance from the Sun. The researchers found that 3I/ATLAS became around five times brighter in under a month, far more than would have been expected from a normal comet. Professor Michael Garrett, an astronomer from the University of Manchester who was not involved in the study, told Daily Mail: 'The observed brightening cannot be explained by geometry alone. 'If a comet is not symmetrical, then as the comet rotates, we see different parts of the surface; the bigger the comet looks, the brighter it will be.

'But a factor of six seems to be too big to be explained by geometry, so it must be due to activity on the comet.' Previously, 3I/ATLAS's abnormal brightness has been taken by some as evidence that it could be non-natural in origin. Professor Avi Loeb of Harvard University has argued that the object might be producing its own light through mechanical means. According to Professor Loeb, this has added yet another potential clue that 3I/ATLAS might be artificial, containing a powerful source of energy that's capable of generating light we see from millions of miles away . However, most scientists have dismissed Professor Loeb's theory, with Chris Lintott, of the University of Oxford, branding the idea 'nonsense on stilts' and calling it 'an insult to the exciting work going on to understand this object.'

According to this latest research, the sudden increase in brightness is likely to be caused by the release of 'hypervolatile' ices made up of carbon monoxide and carbon dioxide. These ices are so volatile that they evaporate into gas at a much greater distance from the sun than ice made from water. These gases gather around the comet in a bubble known as a coma as the comet approaches the sun, reflecting more light and producing the spike in brightness picked up by TESS. Comets from inside our solar system have already lost all their carbon monoxide and carbon dioxide, so telescopes don't detect this same behaviour. Interestingly, this suggests that objects from different solar systems might have very different chemical compositions from those found in our stellar neighbourhood. Professor Garrett says: '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.' Want more stories like this from the Daily Mail? Visit our profile page here and hit the follow button above for more of the news you need.