Look at this mess...
... would cleaning up your solar system once in a while be too much to ask...?
Astroboffins using the ALMA telescope in Chile have snapped new images of a supernova dust factory, which could help them figure out how galaxies are formed. Artist's illustration of Supernova 1987A Nova and out ... artist's illustration of Supernova 1987A. Credit: Alexandra Angelich The pictures from the Atacama Large …
Voice One, nagging: "Did you see the dust?"
Voice Two: "Yes (?!)"
Voice One, more nagging: "And did you think it looks good?"
Voice Two: "Well, no, not particularly. Actually, I didn't think anything about it at all"
Voice One, even mor... (you get the picture): "Yes, you never think! It's always me who's got to do the chores! And you just be there and do nothing. All eternity long."
Voice Two, getting up, thinking "why don't you STFU" and walking to the shed...
Voice One, yelling after, fading: "That is typical! Every time I ask you something....."
Voice Two ...and inventing gravity.
Mephistopheles, much later: "God Damn! What's all this sudden order all around?! I need to do something about it. - I need supernovae!"
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quote: "Supernova 1987A [2], which is in the dwarf galaxy known as the Large Magellanic Cloud orbiting the Milky Way around 160,000 light years from Earth"
"The new ALMA results, which are the first of their kind, reveal a supernova remnant chock full of material that simply did not exist a few decades ago."
I'm pretty sure that, given the distance of the supernova and the methods being used to observe it, that the material may not have existed around 159,980 years ago. Although taking that pedantry further, the material existed as part of the stellar object prior to the supernova anyway, so "did not exist a few decades ago" could be claimed inaccurate in either case, it should really be "was not observable a few decades ago".
Yeah, I'll go get my coat ^^;
"I'm pretty sure that"
Your surety will have to take the proper dent once you realize that depending on your local movement (e.g. shuttling towards and from the khazi), the actual date of the supernovation does suffer serious adjustments due to the effects of Special Relativity and large leverage (i.e. distance to the boomcentre), although I cannot be bothered to compute the actual amounts of delta-t involved.
quote: "Your surety will have to take the proper dent once you realize that depending on your local movement (e.g. shuttling towards and from the khazi), the actual date of the supernovation does suffer serious adjustments due to the effects of Special Relativity and large leverage (i.e. distance to the boomcentre), although I cannot be bothered to compute the actual amounts of delta-t involved."
A good point, and well made. I think I might need to go drown my sorrows in the pub... ^^;
"Galaxies can be quite the dust-gatherers and astronomers already think that supernovae could be a primary source of that dust, especially in the early life of the Universe"
My guitar, r/c helicopter, Arduino, Raspberry Pi and many other short-lived ventures could well be similar sources.
Out of curiosity, what stops all that new founded dust coalescing into another Star on the same spot? Stars are formed from large quantites of matter coalescing together under gravity until they get so large they can ignite fusion reactions in there core. If 2/3 of a Red Giant Star is sitting around as dust after the Supernova, I would have thought that would be a fair amount of matter to get the Star formation process going again, maybe it would only create a dwarf star, but still.
What am I missing here?
That's exactly what does happen, the "metallicity" of first-generation stars is zero - there are no elements heavier than Helium (astronomers consider oxygen and carbon to be metals).
The cinders from the first stars and a fresh supply of interstellar hydrogen make the second generation - and make more of them (there needs to be gain..) - and so on...
If you go several generations down this path then you get enough "metal"-rich junk to form planets etc.
I can see why the fundamentalists prefer their version of things... :-)
Out of curiosity, what stops all that new founded dust coalescing into another Star on the same spot?
In a word, fusion. IIRC, the reason the sun went nova in the first place is that it ran out of hydrogen and (?) then helium. Then it reached a point where neutron pressure from the core (a byproduct of fusion) became insufficient to stop the sun from collapsing on itself, which in turn triggered the nova.
So even if you gathered up all the relatively heavy elements that the nova produced, there wouldn't be enough hydrogen left to trigger star formation again.
Also, consider that a lot of the mass that the nova sheds will be traveling at a significant fraction of c and will have been spread over distances measured in light years in short order (in the cosmological time scale) and it should be pretty clear that gravity (the weakest force) will probably not be enough to cause the matter to coalesce again before the death of the universe anyway...
So even if you gathered up all the relatively heavy elements that the nova produced, there wouldn't be enough hydrogen left to trigger star formation again.
Actually, the outer layers of the old ball should yield a a solar mass of perfectly good hydrogen.
Yes, what is that dust, the same stuff under my sofa, perhaps. Perhaps this will help, although it does not help me much.
"Explanation: Our universe is a very dusty place. Dust usually shows its presence by blocking out light emitted from stars or nebulae behind it, sometimes creating the illusion of a horse's head or a sombrero hat. But nobody really knows what a typical interstellar dust grain looks like. By studying how dust absorbs, emits, and reflects light, astronomers do know that interstellar dust is much different than the cell and lint based dust found around a typical house. Interstellar dust grains are composed mostly of carbon, silicon, and oxygen and are usually less than about 1/1000 of a millimeter across. Recent work indicates that most dust grains are not spherical. The above picture shows the result of a fractal adhesion model for dust grains involving random conglomerates of spherical compounds of different properties, here artificially highlighted by different colors.
http://apod.nasa.gov/apod/ap030706.html
... my favourite ever supernova. Because I volunteered to be sent up a hill in the south island to help (very slightly, and in a not very critical role, as an MSc student) with the building of the JANZOS cosmic ray observatory. I think I might have moved some thingies from here to there, or possibly put one sort of thingy on top of another sort of thingy, or joined thingies together, in somewhat chilly weather.
I wasn't aware that any red giant had the mass to collapse into a supernova! I wonder if the media are doing their homework? From what I remember, a red giant is just a star close to our Sol in original mass, but expanding as the fuel runs out, then collapsing into a smaller object, although I don't remember what. The stellar shell, or what is left of the outer gasses is blown off, but not in any way as exciting as a "supernova". :/
It depends on the mass of the star. Ones like our sun swell and cool (hence red) at the surface then slowly contract.. Bigger ones swell (to a larger size) and cool but as the outward pressure from the fusion drops suddenly the greater gravity and mass involved will make more dramatic things happen.
A rather weak analogy is it you move a match across a matchbox slowly not much will happen. But move it fast enough wil enough pressure and there'll be an explosion.