This is the lovely composite Hubble space telescope picture that is going around, showing the debris of a supernova – a star’s explosion. This is Cassiopeia A, and the explosion happened in 1680 AD, our time. See HST’s website for more on this , and discussion on the Bad Astronomy Blog.
In other supernova news, there’s a lot of news today (Wed) about a new supernova explosion, recorded this year (2006). This particular event is highly significant since astronomers were able to watch most of the entire event in real time. The thing that signalled that something was about to happen was a (relatively mild) gamma ray burst (GRB060218 – it was seen in Feb. 18th) picked up by the Swift telescope. After the burst (really it was an X-ray flash… a GRB’s younger sibling, as it were) faded, the star exploded -essentially on camera.
Quote from an AFP (via Yahoo News) article:
“Usually these events are not detected until after the supernova has brightened substantially in the optical wavelength, many days after the initial explosion,” said Keith Mason, chief executive of Britain’s Particle Physics and Astronomy Research Council (PPARC), which operates an ultra-violet/optical telescope aboard Swift.
“But on this occasion we were able to study the remarkable event in all its glory, from the very beginning.”
Other articles at the BBC (with images of the event – an article is due to appear in Nature tomorrow), and Reuters (via Yahoo).
-cvj
While you understand(?) that I stand on the outside of the scholaristic system, it is with much internal motivation and drive I am ever the student. So while you had patience for your students, I have suffered under a classification?
Anyway I am trying to make sense here of this entry and thought it well to post it here as a connection to your article, to see whether I am on the right track?
If not, continue to blast away. 🙂 I know your a busy man
I can see it’s reasonable that something communicated to us at lightspeed can be said to occur when the light reaches us. I think that way and hope it is correct.
However, what about correlated particles at sublight speed?
If we have an event which causes an electron and an anti-electron to zoom off in opposite directions, their description is a single wavefuntion and, in a sense, the electrons do not yet exist. If one of those electrons smacks into a detector and causes a bleep, then the other electron’s spin direction, say, is now fixed, and it now exists, kindof.
Is it fair to say that the event happens when the wavefunction collapses and we actually observe something?
I had a mad dream you see, where correlated photons were arriving from a shell at the edge of the observable universe. As the photons interact with my detector(head), the other halfs come into existance. A continuous and expanding shell of infrared photons is coming into life beyond the edge of the universe!
All that is probably completely wrong and please accept my apologies in advance.
Glad you picked up on this and posted some links. I saw a reference to it on BBC World News early Wednesday evening and read the BBC story online.
It probably will if this kind of detection becomes more commonplace. One well-studied supernova doesn’t tell you much about the expansion of the universe, but if you start being able to see lots more supernovae much earlier in their evolution, then you can start classifying them more reliably and reducing systematic errors in those distance calculations.
Possibly off the wall question…
I seem to remember that our primary evidence for just barely eternal expansion was due to supernova data. Will viewing a supernova from the beginning help us to fine tune our knowledge on the expansion rate of the universe?