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"What it's like to walk on a dead star"
Here's an astronomy question (I'm a newcomer here) which never seems to be answered anywhere. I've tried books, various online resources and 'Ask Alan' etc. in Astronomy Now but never got a response. I wonder if this is because my question is of no use in understanding how the universe got to be as it is today, and because it also deals with a scenario that probably won't exist for a _very_ long time into the future. Let's limit this query to an average star like our Sun. It'll eventually become a White Dwarf. But what then? We then hear talk of "it will fade" or "become a cinder" and nothing more is said. My question. What is a cold white dwarf like? After 10s/100s of billions of years, when this planet-sized 'cinder' eventually cools down, what will it be made of ? Will there be shells of different elements? Presumably its surface gravity will be very high.... does this mean it will be a perfect sphere - billiard-ball smooth even on millimetre scale? Or will mountains and stress cracks be possible on such a structure? If you shone a torch on it, what would be the reflective albedo, or even the 'colour' of such cold degenerate matter? Will it be a 'slippery' surface (what about its friction characteristic) or rough? Will loose material be possible on its surface Pointless knowledge no doubt...please excuse me if I have just asked about one of the 'unmentionables' of astronomy. I may be the only person who is fascinated by what it would be like to walk on the surface of what was once a star and admire its landscape - assuming I wasn't squashed flat of course!!. Here's hoping I won't be squashed flat here... :-) Is anything known about this? Many thanks. Steve |
#2
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Hi Steve
This is a question that really fires the imagination - a gold star to you! Even more extreme than a dead white dwarf would be a dead neutron star - but things are probably on something of a continuum. First thoughts are that the gravitational force would be extreme - stellar mass, planet-sized object, definitely a squash-flat recipe. Also, being totally degenerate, "metallic" and so probably brilliantly reflective. Spinning rapidly too, probably, so ellipsoidal. However, this thing would almost certainly be the core of a huge pile of other debris - rock etc, with extensive gas atmosphere - so we're probably dealing with something more like an outsized gas giant planet (Jupiter's core is thought to be degenerate too.) I suppose that, like Russian dolls, the ultimate "Omega Hades" object (hypothesised by Fritz Zwicky many years ago to get a foot in the door of pre-recognition) would be a black-hole-cored neutron star with outer shells of dead white dwarf, rock etc and gas... not a good place to take an inquisitive stroll, except in the mind... Best wishes: Roxof 8-) |
#3
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In message , .
writes Hi Steve This is a question that really fires the imagination - a gold star to you! Even more extreme than a dead white dwarf would be a dead neutron star - but things are probably on something of a continuum. First thoughts are that the gravitational force would be extreme - stellar mass, planet-sized object, definitely a squash-flat recipe. Also, being totally degenerate, "metallic" and so probably brilliantly reflective. Spinning rapidly too, probably, so ellipsoidal. I doubt if anything but a millisecond pulsar would be spinning fast enough to be markedly ellipsoidal. IIRC, an "ordinary" pulsar is the most accurately spherical object known, though as it is also the most accurate natural clock a tiny deviation from perfection can be detected - there was a recent paper about this. I'll have to think about the dead white dwarf (black dwarf) landscape, but a neutron star has been the setting for at least three novels ('Dragon's Egg' and 'Starquake' by Robert Forward, and 'Flux' by Stephen Baxter), and a section of Poul Anderson's novel 'The Avatar' is set on a pulsar. Among many strange features, the enormous magnetic field distorts atoms on the surface. -- Remove spam and invalid from address to reply. |
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I'll have to think about the dead white dwarf (black dwarf) landscape, but a neutron star has been the setting for at least three novels ('Dragon's Egg' and 'Starquake' by Robert Forward, and 'Flux' by Stephen Baxter), and a section of Poul Anderson's novel 'The Avatar' is set on a pulsar. Among many strange features, the enormous magnetic field distorts atoms on the surface. Thanks so far chaps. Asking this question does generally seem to meet with a sphinx-like silence, as if somehow it's unproductive and of no concern to decent astronomers. . And any answers that are forthcoming seem to rapidly sidestep into matters pertaining to back holes and the like. I simply want to walk on our Sun's surface in 100 billion years. That's not so much to ask is it ? S |
#5
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In message , Skycloud
writes I'll have to think about the dead white dwarf (black dwarf) landscape, but a neutron star has been the setting for at least three novels ('Dragon's Egg' and 'Starquake' by Robert Forward, and 'Flux' by Stephen Baxter), and a section of Poul Anderson's novel 'The Avatar' is set on a pulsar. Among many strange features, the enormous magnetic field distorts atoms on the surface. Thanks so far chaps. Asking this question does generally seem to meet with a sphinx-like silence, as if somehow it's unproductive and of no concern to decent astronomers. . And any answers that are forthcoming seem to rapidly sidestep into matters pertaining to back holes and the like. I simply want to walk on our Sun's surface in 100 billion years. That's not so much to ask is it ? Unless you mean a British billion I suspect that isn't long enough, and you need several more zeroes. I should look it up, but I think a white dwarf will still be respectably hot by then. Which prompts a question I thought of after posting my first response. Will electron degeneracy still maintain the black dwarf if it is near room temperature, or will it be in danger of collapsing to form a neutron star? The surface gravity of a white dwarf is apparently about 200,000G, which is about the same as a laboratory ultracentrifuge, so I would think the surface will have small features if it is solid. And yet another question. Could an instrument be built to withstand that force? What's the deceleration on the penetrator probes the Japanese plan to drop onto the Moon, for instance? I doubt you'll get a sphinx-like silence round here! |
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#7
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WOW!! A quick web search produced a link to the Beckman XL 90 which can
produce forces of 802,400g. I can't fathom how such a machine could be built without it tearing itself apart. Wow, that is some spin dryer. http://www.gmi-inc.com/Genlab/beckman%20XL90.jpg Can it dry my knickers in less than a minute? Martin -- M.A.Poyser Tel.: 07967 110890 Manchester, U.K. http://www.livejournal.com/userinfo.bml?user=fleetie |
#8
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Why not a British billion? It's primarily a British newsgroup (hence the uk
in the name), and multiplying by a million at a time is more logical in that the prefix indicates the power of a million involved (an American billion isn't ANY rational number squared). Just to show that this isn't blind jingoism I do acknowledge that Americans use the phrase "public school" more sensibly. "Jonathan Silverlight" wrote in message ... In message , Skycloud writes Thanks so far chaps. Asking this question does generally seem to meet with a sphinx-like silence, as if somehow it's unproductive and of no concern to decent astronomers. . And any answers that are forthcoming seem to rapidly sidestep into matters pertaining to back holes and the like. I simply want to walk on our Sun's surface in 100 billion years. That's not so much to ask is it ? Unless you mean a British billion I suspect that isn't long enough, and you need several more zeroes. I should look it up, but I think a white dwarf will still be respectably hot by then. Which prompts a question I thought of after posting my first response. Will electron degeneracy still maintain the black dwarf if it is near room temperature, or will it be in danger of collapsing to form a neutron star? The surface gravity of a white dwarf is apparently about 200,000G, which is about the same as a laboratory ultracentrifuge, so I would think the surface will have small features if it is solid. And yet another question. Could an instrument be built to withstand that force? What's the deceleration on the penetrator probes the Japanese plan to drop onto the Moon, for instance? I doubt you'll get a sphinx-like silence round here! |
#9
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In message , Charles Gilman
writes "Jonathan Silverlight" wrote in message ... In message , Skycloud writes Thanks so far chaps. Asking this question does generally seem to meet with a sphinx-like silence, as if somehow it's unproductive and of no concern to decent astronomers. . And any answers that are forthcoming seem to rapidly sidestep into matters pertaining to back holes and the like. I simply want to walk on our Sun's surface in 100 billion years. That's not so much to ask is it ? Unless you mean a British billion I suspect that isn't long enough, and you need several more zeroes. I should look it up, but I think a white dwarf will still be respectably hot by then. Why not a British billion? It's primarily a British newsgroup (hence the uk in the name), and multiplying by a million at a time is more logical in that the prefix indicates the power of a million involved (an American billion isn't ANY rational number squared). Just to show that this isn't blind jingoism I do acknowledge that Americans use the phrase "public school" more sensibly. I have absolutely no problem with the British billion and I wish it had prevailed, but the US has an obsession with being biggest, best, and first which occasionally becomes absurd. But I had my doubts that Skycloud was using it, and bigger doubts that a star will have cooled substantially in 100 thousand million years. That's only about 10 x the current age of the universe. |
#10
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"Jonathan Silverlight" wrote in message ... In message , Charles Gilman writes I have absolutely no problem with the British billion and I wish it had prevailed, but the US has an obsession with being biggest, best, and first which occasionally becomes absurd. But I had my doubts that Skycloud was using it, and bigger doubts that a star will have cooled substantially in 100 thousand million years. That's only about 10 x the current age of the universe. You're right. I've fallen into the habit of using the US billion rather than the British. I must say I think it's much more convenient to have the billion come up after on the next thousand-multiple than the million-multiple. I was attempting to not step too far outside accepted cosmological time frames or put people right off, by citing the mere 100 x 10(9) yrs. As has been pointed out though, this 'room temperature star' though could well need a full British billion years to get 'comfortable'. But really, has no serious work been done on this? Steve |
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