Timeline for How can the stars be wrong, so that an observer realises they're not in our world anymore?
Current License: CC BY-SA 4.0
24 events
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| Jun 22 at 8:54 | comment | added | Gray Sheep | P.P.P.S: We are very complex things depending on millionth or billionth precision of the law of the Universe. Most physical laws, or physical constants, should change only a very, very little bit and the result would be that our body explodes like a nuclear bomb. | |
| Mar 27 at 20:44 | comment | added | Gray Sheep | @Tom a) Is right, but it is not too far away from it. Previously I have already mentioned the known reddish Mars, unfortunately you did not read it or it was deleted, which is not much more lighter as the stars in general. I think, the strongest stars are only yellow on the sky because they are really yellow. My direct experience that yes there is some color of some stars if there is a good sky, but I admit maybe it was some illusion. b) The question does not mention the early XXth centaury. Mentioning Lovecraft things is not an explicit statement. | |
| Mar 27 at 17:59 | comment | added | Tom | I have two problems with this answer. a) with the naked eye you can't make out the color of stars. b) was the black body color temperature something known well enough in the early 20th century so that an author would use it knowing that his audience would make the connection? I doubt that. | |
| Mar 27 at 7:47 | vote | accept | Olegiwe | ||
| Mar 26 at 14:14 | comment | added | Nosajimiki | Then I would assume the planet is in a stellar nursery. A lot of recently exploded stars will create a nebula of different, unevenly mixed gasses. | |
| Mar 25 at 21:15 | comment | added | Gray Sheep | @Nosajimiki Right :-) But what if the stars are of random color, from which most of them is impossible. I am thinking on RGB(RND(),RND(),RND()). | |
| Mar 25 at 19:18 | comment | added | Nosajimiki | If your planet itself is in an oxygen nebula, won't many if not all stars look green? | |
| Mar 25 at 16:49 | comment | added | David McKee | There are also regions in space that have relatively uniformly coloured stars. Whether that's intense star-formation regions like the Pleiades which have nearby, bright blue stars, or the old, cold red stars of a globular cluster. | |
| Mar 25 at 12:30 | comment | added | Christopher Bennett | The other problem with the relativistic scenario is that the planet would probably be rendered uninhabitable from a variety of factors. The star's magnetosphere would probably be compressed by friction with the interstellar medium, exposing the planets to intense cosmic radiation, which would be lethally blueshifted from the oncoming direction. The medium itself might strip away the planet's atmosphere, and any collision with a relativistic meteoroid or asteroid would be devastating. Any mechanism that launched the star that fast would probably have destroyed its planets already anyway. | |
| Mar 25 at 11:55 | comment | added | Gray Sheep | @Philipp Note also, naked eye-visible stars are close to us even in our own galaxy. Their relative speed from us is far below where it would have any visible effect due to doppler or spec relativity (compare some 10 km/s to the 300000 km/s speed of light). | |
| S Mar 25 at 11:54 | history | suggested | phoog | CC BY-SA 4.0 |
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| Mar 25 at 11:49 | comment | added | Gray Sheep | @Philipp That has also the side effect, that having only a black body spectrum, you have no way to know, if it is a colder thing nearing you, a warmer thing going away, or what. We know it from the stars (galaxies) only because their spectrum is not exactly black body spectrum, there are various lines in that and these are so characteristic like a fingerprint. | |
| Mar 25 at 11:48 | comment | added | phoog | @Philipp red shifting of stars doesn't make them appear red to us because, while blue light is shifted to red, red light is shifted to invisible infrared, and invisible ultraviolet is shifted to visible blue, leaving the distribution of energy across the visible spectrum more or less even, namely, white. | |
| Mar 25 at 11:47 | comment | added | Gray Sheep | @phoog And what would you think if you would see a star with random colors (most of them impossible)? | |
| Mar 25 at 11:47 | comment | added | Gray Sheep | @Philipp :-) You have spot a very nice and very surprising point of the physics :-) Fun is that normally doppler makes a red or blue shift. But, the black body spectrum has a very funny feature: if you doppler shift it in any direction, you get yet another black body spectrum, only warmer or colder one! It happens only with the black body spectrum, it has a deep mathematical reason and it has very nice consequences (for example, the cosmic microwave background does not really cool, it is doppler shifting). | |
| Mar 25 at 11:46 | comment | added | phoog | @ChristopherBennett if I saw a sky full of green stars (or of any other color), my first thought would be that there is some glass or gas cloud or any other transparent substance between me and the stars filtering the light. | |
| Mar 25 at 11:44 | review | Suggested edits | |||
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| Mar 25 at 11:43 | comment | added | Gray Sheep | @ChristopherBennett If I watch the sky and there is a good sky, I see some color difference between them. (There is also Mars with its known reddish look, ok it is planet, but its light is not much stronger as of a star). Not much. Maybe if the stars are enough strong? | |
| S Mar 25 at 11:13 | history | suggested | Judith Jones | CC BY-SA 4.0 |
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| Mar 25 at 10:58 | review | Suggested edits | |||
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| Mar 25 at 10:46 | comment | added | Philipp | When the observer is on a rogue planet that travels through a galaxy at relativistic speed, then they would see the stars in one direction red-shifted and those in the other direction blue-shifted. That could reduce in unusual star colors without requiring to be in an entirely different universe. | |
| Mar 24 at 23:16 | comment | added | Topcode | @ChristopherBennett to be honest, I don't think its possible to have an answer to this that isn't more or less a fantasy scenario. Stars do follow general rules but, to a naked eye observer, most of those cannot be accurately evaluated. So, you kinda have to make something super obvious and super impossible. | |
| Mar 24 at 22:31 | comment | added | Christopher Bennett | Most stars look white to the naked eye, since only a very few are bright enough to activate the color-sensitive cones in the eye. And an inexperienced stargazer like the one in the question might not know that green or purple stars don't exist. Maybe if they were all a sickly green, say, that would be eerie enough, but that seems like a fantasy scenario rather than something with a scientific explanation. | |
| Mar 24 at 20:47 | history | answered | Gray Sheep | CC BY-SA 4.0 |