8 ms·
"Dying" is a bit of an under-statement. A white dwarf is to all intents and purposes dead. It has no source of energy, and radiates only because of stored heat.
by denton-scratch 5y ago
"Dying" is a bit of an under-statement. A white dwarf is to all intents and purposes dead. It has no source of energy, and radiates only because of stored heat.
That heat dissipates so slowly that (AIUI) no white dwarf in the universe has yet had time to cool down enough to stop radiating (i.e. the universe does not yet contain any black dwarves).
So a star that is in the process of collapsing into a white dwarf could reasonably be said to be "dying". Once it's collapsed, it's dead.
- sailingparrot 5y ago"Dying" is not referring to the state of the star today, but to the process of death: the planet survived while it's star was dying, which is the interesting bit of the story.
- denton-scratch 5y agoAgreed. To survive in orbit around a WD is not a remarkable achievement - you just carry on orbiting forever (roughly). Orbiting a red giant would be pretty interesting, though - the RG has an indistinct surface, its diameter and luminosity varies, and it emits a lot of material as wind. To survive in orbit around a neutron star would be another thing again. Neutron stars have intense magnetic fields, and spin rather quickly, resulting in a rotating field that is wrapped around on itself. That in effect creates a particle accelerator, driving electron flows (the electrons were all expelled when the NS collapsed) with extreme energies. Short of hanging around near an exploding supernova, I can't imagine a more hostile environment.
- hinkley 5y agoWould the magnetic fields of a neutron star create a tidal locking effect through eddy currents in the planet’s core, boosting it into a larger orbit and slowing the spin of the star? Seems like a giant inside out induction motor. I wonder what the band of survival is, where the planet doesn’t get turned to Swiss cheese first.
- denton-scratch 5y agoI have no idea what the neighbourhood of a neutron star is like, nor what the effects of such intense fields might be. This is theoretical physics and cosmology. I'm not competent even to speculate. Yes, I get the "induction motor" idea. With fields and voltages that intense, I guess just about anything becomes conductive. [Edit] I don't know whether those field strengths are consistent with atoms continuing to be atoms - I guess there must be some range beyond which a thing like a planet could maintain its integrity. But (guessing wildly) I would expect there to be a region around a neutron star within which it is impossible for atoms to exist.
- justshowpost 5y agoNewly discovered Click-Bayitt type stars
- rapsey 5y agoHow would we see black dwarves?
- Ericson2314 5y agoIf there were bright things behind them The universe is young, a lot of stuff hasn't happened yet. It wouldn't be surprising if we are about the earliest life of this sort that could exist.
- vlovich123 5y agoI thought the cosmological expansion theory of the standard model was falling apart calling into question the Big Bang theory. If that’s the case, then are we sure we have a good handle on the age of the universe?
- garblegarble 5y agoDo you have any links where I can read more about that? That's fascinating and I wasn't aware, and I evidently am not using the right search terms to find out more
- Taek 5y agoMaybe unrelated but YouTube has been throwing a lot of faux science and astronomy at me lately. Youtubers reading controversial papers presented as indisputable even when there's no scientific consensus at all on the results.
- whatshisface 5y agoIt's depressing to think about, but for many intents and purposes fake space facts are just as good as true space facts.
- 6502nerdface 5y ago
- JohnJamesRambo 5y agohttps://www.scientificamerican.com/article/living-near-a-white-dwarf/ https://www.scientificamerican.com/article/living-near-a-whi... I’ve always found this idea neat.
- uyaij 5y ago> By damping trash onto the surface of the white dwarf, one could harvest its gravitational binding energy from the emitted electromagnetic radiation at nearly the yield of nuclear fuel. This sounds interesting, how would such a method of power generation work?
- jerf 5y agoWell, that very nearly is the method of power generation. It would presumably be paired with some sort of Dyson sphere around the white dwarf. (Remember that a "Dyson sphere" isn't necessarily a solid shell, but just some configuration of matter where no matter which direction the energy goes it is intercepted by something.) You may also enjoy: https://www.youtube.com/watch?v=t-O-Qdh7VvQ https://www.youtube.com/watch?v=t-O-Qdh7VvQ which is a minutephysics on black hole power using much the same principles but attaining yet higher efficiencies.
- FredPret 5y agoSo we would decelerate the trash, it hits the white dwarf, gets crushed, and then undergoes various nuclear transformations resulting in energy output we would then capture with our Dyson swarm?
- justshowpost 5y agoSorry, but it has to be rigid to be a sphere. Angular momentum is a bitch! PS: Dyson Spheres is misnomer, Olaf Stapledon should be credited for this idea (Star Maker 1937)
- subroutine 5y agoI've read somewhere that we now have a ton of junk satellites orbiting earth, and if they happen to crash into each other it could set off a chain reaction that creates a satellite-debris shell around the entire earth, roughly resembling a non-rigid sphere. Is that true?
- deleted 5y ago[deleted]
- postalrat 5y agoNext you are going to say that a phone is dead unless it's being charged.
- denton-scratch 5y agoPlease explain how a "charger" for a white dwarf might work! I mean, you could just chuck a huge ball of hydrogen at it; that might work, but it'd be easier to just bundle together two balls of hydrogen and make a new star. I think I'd expect a charger to restore a phone to something like its as-new functionality. I've never heard of any mechanism that could change a white dwarf into not a white dwarf, other than extreme age, or being merged with another object.
- postalrat 5y agoThe star gets charged up then gets to live a much longer life as a white dwarf. You haven't been as-new since the day you were born and we both agree you are still in your life.