A Bright Flash in the Neighborhood


Comparable in size to the Milky Way, our host galaxy, the Andromeda galaxy is the most distant object easily visible (in dark skies) to the naked eye; it lies 2.5 million light-years away.  About 2.5 million years ago, something in this distant star city went “boom”.  And in doing so it flashed, brightly, in high-energy photons — particles of light (or, more precisely, particles of electromagnetic radiation, of which visible light is just an example) — photons that carry many thousands of times more energy than do the photons that our eyes are designed to see.

File:Andromeda Galaxy (with h-alpha).jpg

The Andromeda Galaxy (photo from Creative Commons), which contains perhaps 100 billion stars or more. Something in here exploded a while back, and we just found out about it.

Some of these photons, after traveling for millions of years across space, arrived at Earth this afternoon.  They showed up in the Swift satellite’s telescopes, which are designed precisely to notice these things.  And Swift’s telescopes identified these photons as arriving from a location somewhere within Andromeda… within a globular cluster of stars, a tightly-knit neighborhood within the city that is Andromeda.  NOTE ADDED: Actually, a combination of low-probability events caused

  • a false alarm, of a sort that’s rare but not unexpected: a known object in Andromeda that emits X-rays appeared to brighten, as a result of electronic noise in Swift’s instruments (such noise is always present, in all scientific instruments, and it is normal to occasionally get a strong burst of it)
  • followed (due perhaps to a poorly-timed computer problem at Swift’s data center, which slowed the arrival of more complete information the Swift people know why but haven’t explained it in detail) by a delay in identifying this apparent brightening as a false alarm;

all of which is explained here.  The apparent brightening, which was rather mild, would in fact have been completely disregarded if it hadn’t occurred in Andromeda; for relatively nearby objects like Andromeda, the Swift team sets a low threshold for false alarms, because something real would be so amazingly important and exciting that we can’t afford to miss it. 

What caused this colossal explosion, perhaps the nearest of its type ever observed by modern astronomers?  That is the burning question that astronomers, and their friends in gravitational physics and particle physics, are aching to know.  It is likely that by tomorrow morning, and certainly within the next couple of days, we’ll know much more… perhaps we’ll even learn something of great importance.  NOTE ADDED: And indeed, we know.

For the moment, though, there’s lots of guessing, most all of which will turned out to be wrong.  (Maybe, some are speculating, this is a gamma-ray burst, perhaps caused by a merger of two neutron stars, with consequent bursts of neutrinos and gravitational waves that we might detect; but right now there’s no evidence for this, so don’t get your hopes up.)  You can read many breathless articles by following the Twitter hashtag #GRBm31.  Admittedly you might be better off without it.  NOTE ADDED: Yep.

But do stay tuned as the facts emerge.  The opportunity to observe such a nearby explosion is rare.  So this is certainly going to be interesting… and maybe, if we’re very lucky, it will be more than merely interesting…

NOTE ADDED: Actually, we were very unlucky, and it was completely uninteresting —except as an illustration that it can be very difficult, in the heat of a moment when data is sparse, to distinguish between something scientifically fascinating and a weird fluke.  Scientists do expect these things to happen sometimes.  Fortunately, science is self-correcting.  Even if Swift’s team hadn’t identified this signal as a fluke in their data, other telescopes would have been unable to find the object they’d identified, and doubts would quickly have emerged as a result.  If something’s real, everyone will see it.  

The lesson, in my view, is that when new scientific results are announced, be patient.  Give the experts a little time to check things, and don’t do science the way Twitter does.

And finally: if you are inclined to criticize the Swift team, you’re making a big mistake.  On the contrary, they did exactly what they were supposed to do, as quickly as they could.  Gamma-ray bursts [GRBs] are extremely rare and extremely valuable and extremely brief; Swift’s job is to let the scientific community know, as quickly as possible, that one may have been seen, so that others may look at it.  Inevitably, someone with such a job will occasionally give a false alarm.  Swift has discovered so many GRB’s, and made so many direct and indirect contributions to our knowledge about them and about other objects in the sky, that scientists, while disappointed that this was a false alarm, will certainly not view Swift as irresponsible.  

A week ago, regarding BICEP2’s results coming into question, Seth Zenz wrote a nice, short article on Why, in Science, it’s OK to be Wrong.  I recommend it.

23 responses to “A Bright Flash in the Neighborhood

  1. This is super exciting indeed! If it wasn’t a large enough star or neutron stars… maybe the Great Filter in action? http://www.toebi.com/blog/theory-of-everything-by-illusion/great-filter/

  2. Marshall Eubanks

    Within 24 hours, we should know a lot more (from the light curve). In the meantime, here is some info on the host globular cluster http://www.pa.msu.edu/~strader/b045.html

  3. themodernidiot

    Granted I don’t know squat about how it all really works, but it would be neat to find out dark matter was fuel for the explosions.

  4. Whatever this becomes it will indeed be interesting.

  5. fredinspain

    Perhaps it was the merger of two quark stars, although little knowledge is known if them.

  6. Marshall Eubanks

    We had bad weather (strong thunderstorms) in the DC area last night, and I heard the Swift computer system at the Goddard Space Flight Center lost power because of it. This is just speculation and reverse engineering on my part, but it sure does sound like this happened at just the right (i.e., wrong) time to cause the “problems with the normal data products” which meant “only low-quality data were available.” Maybe they can use this to get the money to buy an UPS.

  7. I thought the Swift detailed explanation by Phil Evans was a good read.

    When it comes to GRBs, check out Friedwardt Winterberg’s firewall that dates from 2001. It sounds unusual, but think about dropping a 511keV electron into a black hole from a “very great” distance. The black hole mass increases by 511keV/c². no more. But just before it gets to the event horizon the electron is said to be going at nearly the speed of light. And the electron’s kinetic energy came from the electron’s potential energy, its mass-energy. And the electron falls faster and faster and faster, but the coordinate speed of light is getting lower and lower and lower. IMHO something’s got to give. And the only thing that can, is the electron.

  8. Marshall Eubanks

    Yep, Robert Rutledge at McGill U. ( @rerutled ) posted a long series of tweets on the false alarm, and it looks like it was related to the storm. Here are the last three.

    (13/15) Usu. other scientists would get the data and look too! BUT last night, a storm took out @NASAGoddard Internet #GRBM31 #DoesNotExist

    14/15) With @NASAGoddard internet disrupted nobody else could analyse the #GRBM31 Data! We all relied on the @NASASwift GCN #DoesNotExist

    (15/15) Analysis mistake->wrong result+ @NASAGoddard Internet down->no ‘second eyes’ to double check->wrong conclusion #GRBm31 #DoesNotExist
    I have to commend the SWIFT team for being on top of this, and being so quick to issue a retraction. This, in a very real sense, is how these things are supposed to be done. They were doing their job in a professional manner throughout, both last night in issuing the alert, and today for retracting it.

  9. Hi Professor Matt.
    While technically not being easy to see with the unaided eye, M33 (Triangulum Spiral) at 2.9 million light years distant can be seen with the nocturnal hawk-eyed younger astronomical generation. Also, M81 (Bode’s Galaxy) at a very dim 6.9 magnitude has also been viewed by some. Keep up the good work always a pleasure to read your blog! 🙂

  10. Your final note is appreciated. Indeed if this had been a GRB in Andromeda it would have been an overwhelmingly important find and every second spent wondering if it was a false alarm before sending word out could have cost untold amounts of science.

    The thought that when they have found real events, that telescopes around the world and circling it all turning to aim at the new sight, the cooperation and coordination it takes and the science that results, it just lifts my heart. If every so often we turn our collective eye for naught, trivial price to pay I say.

  11. The Swift team has my deepest appreciation of the work they do, for me these recent events are proof they’re doing their job right. There’s no way to prevent false alarms from time to time, the important part is setting thigs right when it becomes apparent it was indeed false alarm. I so wish this approach was common in other sciences, not just in astronomy and particle physics.

  12. “The Eyes of the Overworld” (Jack Vance, 1916-2013) make everything look flashy.

  13. They even make the women from Smolod and Grodz look like stars 🙂