![]() While this has occasionally yielded some promising results-for example, the famous ”Wow!” signal detected in 1977-much of the search has gone pretty much nowhere. "They all might just be unknown variable polarised objects near the centre of the galaxy," Professor Murphy said.One of the many methods that scientists have been using in the search for life on other planets is via the radio-or rather, incredibly powerful and precise radio antennas pointed at the cosmos. So although they are all lumped in the same category, we don't know enough about them to tell if they are related at all. "All of properties are slightly different to all of the ones that are known, but the thing is they are all different to each other," Professor Murphy said. "It could be that we've discovered one of these, so in a way that's exciting, because there are very few of them known, but also frustrating because we don't actually know what galactic centre radio transients actually are," Professor Murphy said.Įvery single galactic centre radio transient that has been discovered is slightly different while some emit regular pulses of radio waves, others don't. The only other possibility is that it belongs to a rag-tag group of rare objects known as galactic centre radio transients, one of which is dubbed the "cosmic burper". "So then we've got this situation where we've ruled out the two most likely explanations." Is it a 'cosmic burper'? "But … we didn't see it at all, it was completely invisible. "This object was so bright that if it was a star, we should be able to see it in visible light," Professor Murphy said. The second possibility the team explored was whether the signal could have come from a massive flare from a star. Space telescopes also found no objects emitting light in the X-ray and infrared ranges in the area that would indicate the source was a pulsar or another type of dead, fast-spinning star known as a magnetar. They saw nothing for three months, but in February this year they detected a single signal that was almost as strong as the original signal, before fading away.Įven though the signal had some of the properties of a pulsar, there were no telltale fast pulses. ![]() ![]() So then they went to the MeerKAT radio telescope in South Africa, which can detect not only pulses, but take images of signals. The team turned to the Parkes Radio Telescope, which is famous for detecting pulsars, but found nothing that could be the source. The first option was a pulsar - the fast-spinning heart of a dead star, which regularly send out very fast pulses of energy like clockwork. "It's a bit like a detective story trying to rule out all these different possibilities," Professor Murphy said. In the months following the initial discovery, the team led by PhD student Ziteng Wang explored a number of options trying to work out what the source was. "That rules out almost all astronomical objects we know of," Professor Murphy said.īut that doesn't mean we've suddenly detected aliens. LoadingĮven more weirdly, the radio waves are aligned in one direction that rotates as the signal travels through the universe towards us. Not only is the timing random, but the signal can vary in strength, becoming 100 times brighter in the radio spectrum. "Sometimes it seems to stay on, detectable for days or weeks at a time, and then other times it can come on and off in a single day, which is extremely fast for an astronomical object," Professor Murphy said. Then the signal from the source dubbed ASKAP J173608.2−321635 disappeared, reappearing a couple of times a few months later. "That's when we were starting to think, 'OK, this is a real thing.'"
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