False alarm from Andromeda reveals the exciting and challenging life of astronomers
Tuesday night, social media lit up with the hashtag #GRBm31, as excited astronomers and astrophysicists took to Twitter to discuss a potential new detection - which could turn out to be the closest Gamma Ray Burst (GRB) ever seen. However, by morning, the mood had calmed considerably, after further analysis showed that it was a false alarm. For other fields of science, revealing that kind of information, especially before it was confirmed, could cause a terrible backlash against the scientists, and damage the public's opinion about science. However, for astronomers what happened last night was a necessary, and actually quite challenging part of their job.
When NASA's Swift telescope detected what looked to be a high-energy emission yesterday, coming from the Andromeda Galaxy (also called M31), the spacecraft did exactly as it was designed to, it swiftly reoriented its detectors to examine the event properly, and it issued an alert to astronomers on the ground that something was up. If any other telescope, even another one orbiting in space, had sent such an alert, the scientists probably could have taken their time, finished off whatever other observing they happened to be doing at the time, and eventually got around to checking out this new detection. However, Swift was put into orbit with the primary mission to look for Gamma Ray Bursts. These intense beams of radiation are blasted out by some of the most powerful explosive events in our universe, such as when a supermassive star collapses in on itself, producing a supernova explosion, or perhaps when two stellar remnants - called neutron stars - collide to form a black hole. They can be long-lived in the former case, but the latter are notoriously short-lived.
Plenty of astronomical observing involves pointing a telescope at one part of space for hours at a time. This can, understandably, lead to the impression that astronomy is a fairly sedate science. However, to delay in this particular case, especially if it was a short GRB, could have meant losing precious data. What was even more special about this particular potential GRB was that, coming from the Andromeda Galaxy, it would have been the closest one ever detected, which would have allowed astronomers and astrophysicists to study one of these in unprecedented detail.
So, the rush to get online and tell as many colleagues as possible wasn't due to these scientists bursting with excitement to get the news out (although that was surely a part of it), it was mostly to get everyone who could point a telescope at Andromeda to do so, so that they could gather as much data, from as many locations, as possible. One scientist in particular, Katherine Mack, an astrophysicist at the University of Melbourne, described it well in her Twitter feed:
Remember scene in Contact where they got a weird signal & called up astronomers all over the world to look? That happens for GRBs. #GRBm31— Katie Mack (@AstroKatie) May 27, 2014
Now, unfortunately, it turned out that this wasn't an actual Gamma Ray Burst. According to Phil Evans, who works with the data from the Swift telescope at the University of Leicester, what actually happened was that Swift's Burst Alert Telescope (BAT) spotted something in its field of view, which may have just been a bit of noise in the data. When it turned its attention on that something, it focused on an X-ray source that they already knew about from previous observations. The telescope sent its alert to astronomers on the ground, and normally the full dataset would have shown up very shortly thereafter, giving them more information to work from, but apparently a power failure at the Swift Data Center in the U.S. prevented that from happening. It was only after that dataset finally arrived that he was able to clean up the analysis and show that there was no outburst. The known X-ray source was, as he put it, "puttering along at the same brightness it had been seen at before."
Does the fact that this was a false alarm, and a rather public one, damage the reputation of the science? It might for some, but it really shouldn't.
First of all, interspersed amongst all the discussion, some rather hyped-up tweets that made it seem like this was a lot more certain than it was, and even a few that seemed to imply that we were very lucky we didn't die from this (even though it was much, much too far away to be a danger to us), there were plenty of scientists pointing out that this was all preliminary, and nothing had been finalized. You can never be sure how many people read those particular messages, mixed in with all the others going by, but it was very reasonable and responsible of them to point that out. Getting the news out to the community was necessary and important, but they were also careful to play down the hype at the same time.
This all comes with the territory, according to Evans. As he states in his blog entry:
"This is the challenge that we, as time-domain astronomers, face on a daily basis. Most of this is normally hidden from the world at large because of course we only publish and announce the final results from the cases where the correct decisions were made. In this case, thanks to the power of social media, one of those cases where what proved to be the wrong decision has been brought into the public eye. You've been given a brief insight into the decisions and challenges we have to face daily. So while it's a bit embarrassing to have to show you one of the times where we got it wrong, it's also good to show you the reality of science. For every exciting news-worthy discovery, there's a lot of hard slog, effort, false alarms, mistakes, excitement and disappointment. It's what we live off. It's science."