Scientists capture death star in violent explosion Astroboffins have confirmed for the first time that Wolf-Rayet supermassive stars can die in a violent explosion known as a Type IIb supernova, using a global rapid response protocol to capture the moment. Wolf-Rayet star explodes in a Type IIb supernova The life and death of stars is an endlessly fascinating subject for …
"We are gradually determining which kinds of stars explode, and why, and what kinds of elements they produce," I can't think of any 'practical' use for the research but for some reason I am delighted to hear of their fantastic boffinery.
Maybe a mug of Horlicks is what they crave after their all-nighters but a beer is what they get from me.
Betelgeuse will go bang any time in the next million years. About 620 years later, neutrino detectors will warn us something is going on. For about a month, Betelgeuse will be as bright as the full moon. 100,000 years later, 21ˢᵗ century space ships will be grounded because of the high proton radiation.
IK Pegasi is only 150 light years away, but by the time it goes bang it will be too far away to cause fear an panic on Earth.
For a 'practical' supernova, we are looking for a star within 30 light years when it goes bang. There could be some we haven't noticed yet, but you might have to wait anything up to 250 million years for supernova research to be practical for Earthlings. Humans would only be affected if someone makes a few to inhabit the future equivalent of Jurassic Park.
That is possibly the most inaccurate description of how gravitational collapse works I have read.
Firstly, not only Wolf-Rayet stars fuse heavier elements; all stars do it as they approach the end of their lives.
This has nothing to do with "wielding more gravity" but is a consequence of the energy output from hydrogen fusion no longer being sufficient to overcome the gravitation attraction of the matter in the star, at which point, it can contract sufficiently for helium fusion to begin, until the helium is all gone, etc., all the way up to iron. Once you get to iron, nuclear fusion no longer releases more energy than it takes, and fusion stops. Gravitational attraction takes over.
Therefore, stars end their lives in one of two ways; they do not have enough mass to continue fusion of heavier elements, and they essentially 'go out', or they collapse in on themselves and explode in a supernova.
Secondly, The Pauli Exclusion Principle applies not only to electrons but to all particles. This is, however, a moot point, as this paragraph appears to be describing how black holes form (which may or may not happen in a supernova), not the mechanism by which supernovae occur, which is essentially a collapse and rebound, with a not insignificant part played by the shock-wave generated, which is thought to be the mechanism responsible for the nucleosynthesis of all elements heavier than iron.
wrist slap accepted; I couldn't be bothered to google it (lazy me), I was referring to 'particles' in the sense of electrons, protons, neutrons, etc., rather than things like photons, which in the strict sense are particles too and to which it obviously does not apply. I should learn to be clearer...
I had thought that the collapse part was widely accepted as the force counteracting gravity rapidly drops off. But I had thought that the 'rebound' part was one of several theories, and had become unfashionable. Surely for most of the outer layers of a star to go from being part of the star to going outward at a rate of knots would need energy added. Even a perfect bounce only gets you back to where you started.
I think this was addressed in "The Star" by Arthur C. Clarke
And somewhere out there in the stars
A keen-eyed look-out
Spied a flickering light
Our last hurrah
And when they found our shadows
Groups 'round the TV sets
They ran down every lead
They repeated every test
They checked out all the data in their lists
And then the alien anthropologists
Admitted they were still perplexed
But on eliminating every other reason
For our sad demise
They logged the only explanation left
This species has amused itself to death
No tears to cry
No feelings left
This species has amused itself to death
Arthur C Clarke ($Deity rest his soul) commented that "Supernovae are industrial accidents".
In some cases this may be possible, but only if the star was already on the edge of the "Chandraseker limit" ie about to collapse anyway.
It appears that this puts an upper limit on energy usage of hypothetical Type 2 civilizations as it would appear harnessing energy directly from a star is either not possible or very very hard.
Corollary to this, it is theoretically possible to move a gigantic solar array near an about-to-nova star to act as a trans galactic beacon which sends a pulse flash via coherent neutrinos to the nearby systems.
(scientific paper pending)
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2024
