21–30 of 35 posts
Hours, and 21 million years, after it happened.
Earlier quoted context omitted.
I always have to point this out at the risk of downvotes: it doesn't make sense to say that an event you're currently seeing on Earth "happened 21 million years ago." Both space and time are relative, so if you're choosing Earth as your reference point, the supernova is happening right when you're seeing it.
No, you are confusing relative time, with transit time (i.e. the time it takes for the information to reach you). Relative time is a real thing, certainly and messes with the idea of simultaneous. But transit time is not that. We and the supernova are more or less in the same frame of reference (we are not accelerating relative to one another, and there isn't much relative velocity difference either). And because of…
Earlier quoted context omitted.
No, you are confusing relative time, with transit time (i.e. the time it takes for the information to reach you). Relative time is a real thing, certainly and messes with the idea of simultaneous. But transit time is not that. We and the supernova are more or less in the same frame of reference (we are not accelerating relative to one another, and there isn't much relative velocity difference either). And because of…
Is that correct? Let's say Bill was born here on Earth on August 26, 2011, "at the same time" astronomers first detected this supernova. On Earth, we observe Bill's birth and the beginning of the supernova to be simultaneous events. However, isn't it true that an observer at the supernova (presuming he could survive) wouldn't agree that Bill's birth and the supernova were simultaneous, would he?
Earlier quoted context omitted.
No, you are confusing relative time, with transit time (i.e. the time it takes for the information to reach you). Relative time is a real thing, certainly and messes with the idea of simultaneous. But transit time is not that. We and the supernova are more or less in the same frame of reference (we are not accelerating relative to one another, and there isn't much relative velocity difference either). And because of…
Is that correct? Let's say Bill was born here on Earth on August 26, 2011, "at the same time" astronomers first detected this supernova. On Earth, we observe Bill's birth and the beginning of the supernova to be simultaneous events. However, isn't it true that an observer at the supernova (presuming he could survive) wouldn't agree that Bill's birth and the supernova were simultaneous, would he?
No, that is incorrect. We observe that the light from the supernova reached us now, yes. But we are well aware that it actually happened long ago.
Both us and the distant observer agree about the order and relative timing of the events.
It's only when we are not in the same frame of reference that we would disagree, and that is not the case here.
Earlier quoted context omitted.
I don't think it's nonsensical. There is a meaningful way in which it is in the past. Even if you turn yourself into photons, match positions with the supernova remnants, then return to physical form, the supernova is going to evolve though time for quite a ways beyond the current state we observe it in before your physical form has its rendezvous, even if the trip has zero duration for you. Putting a specific time s…
If you set a reference point, then I think it's perfectly sensical to say two events happen simultaneously or "now," but without a set reference point those notions are completely nonsensical. Most educated people understand the principle of relativity (which states that the laws of physics behave consistent in all frames of reference) and the fact that the speed of light is constant regardless of your frame of refer…
Please keep in mind that we and the supernova are more or less in the same frame of reference. So all the ambiguity of simultaneity does not apply here.
Hours, and 21 million years, after it happened.
Not particularly exciting in the sense of being compared with Hollywood special effects. But I'm excited to look at it through my telescope and know that thing I'm looking at is a star exploding in a distant galaxy . And photons from that exploding star that have crossed 21 million light-years of intergalactic void are entering my eyeballs.
Earlier quoted context omitted.
Not particularly exciting in the sense of being compared with Hollywood special effects. But I'm excited to look at it through my telescope and know that thing I'm looking at is a star exploding in a distant galaxy . And photons from that exploding star that have crossed 21 million light-years of intergalactic void are entering my eyeballs.
I hope you don't take offense to this but I laughed when I saw you're an attorney, because that is so poetic.
One major factor in this change has been the advent of wide-angle surveys, that repeat often enough to find variable sources like SN's, blazars, asteroids, lensing events, etc., while they're still interesting. The Palomar Transient Factory (http://www.astro.caltech.edu/ptf/) is the one mentioned in the article, but there are many others. They automatically detect and post events in a standard XML format for anyone (including robotic telescopes) to scoop up (e.g., http://www.skyalert.org/events/all/2/).
One of the largest, LSST, is now being designed, and its data volume will prove to be a huge engineering/computer science challenge (http://www.lsst.org/lsst/science/petascale).
There's a sophisticated and multifaceted image processing pipeline to detect the changes in sources, to automatically extract photometric parameters, and to pass these parameters on to a classifier to separate the events into types of interest to various communities (the SN folks could care less about asteroids).