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Writer looking for help in space

  1. Oct 8, 2012 #1
    I'm a fiction writer working on a short story. I have a few questions about space and other things that I haven't been able to find the answers to.

    Here are a few of my questions:

    1). Will the rotation of Mercury speed up over time?
    2). What effect does synchrotron radiation have on humans?
    3). When a star that is 1.4 times the mass of the sun collapses what does it look like during the explosion? After the explosion?
    4). Is there current research on hypersleep?
    5). Where is the best place to look for information on new technologies for space craft (here I"m looking mainly for speed)?

    I have more, but I"m going to start with these.
  2. jcsd
  3. Oct 9, 2012 #2
    Perhaps, but not by much, would be my tentative answer, based on the wikipedia article.

    Mercury's rotation is tied to its orbit by tidal resonance effects, specifically in such a way that the Sun will always be more or less stationary in the sky when the planet is close to perihelion. At present, the orbit has an eccentricity of about 20%, which results in the well-known 3:2 resonance (3 rotations per 2 orbits -> each solar Mercury-day lasts two Mercury-years) due to this stationary-at-perihelion condition.

    The article states that "imulations indicate that the orbital eccentricity of Mercury varies chaotically from nearly zero (circular) to more than 0.45 over millions of years". In phases of near-zero eccentricity, the preferred resonance would be ordinary tidal locking (1 rotation per 1 orbit -> the solar Mercury-day lasts forever).

    The general relation is, I think, that the ratio of the orbital period to the rotational period is approximately equal to (1+e)/(1-e), where e is the eccentricity. That works for the present values, at any rate. In phases of maximum eccentricity, this value would increase to 29/11, and this would then constitute the upper limit on the resonance factor. Simpler fractions are generally preferred in such cases, so my leading candidates would be either 2:1 (2 days per 2 years) or 5:2 (3 days per 2 years).

    So, if this is more on less true, then Mercury will indeed have slightly shorter days again at some point in the, in astronomical terms, relatively near future.

    There is nothing special about synchrotron radiation. The term simply tells you where it comes from, not anything about its properties, really. Again, if you look at the wikipedia article, it points out that the radiation has a "road Spectrum (which covers from microwaves to hard X-rays): the users can select the wavelength required for their experiment." The effect on humans will simply depend on that selection.

    What do you mean by "the sun collapses"? Ordinarily, it wouldn't, "tars with initial masses less than about eight times the sun, never develop a core large enough to collapse and they eventually lose their atmospheres to become white dwarfs." There can be instability of some degree during the red giant phase in which most of the atmosphere is expelled, but nothing that could be termed an "explosion", as far as I'm aware. There might be some sort of external influence in your story that forces an explosion, though?

    "Hypersleep" is a science fiction term, surely. The only kind of real phenomenon that resembles it, that I can think of, has to do with low temperatures - see e.g. hibernation and cryonics. I know that there are similar effects in non-mammalian species which are initiated and maintained by low moisture (desiccation) instead, but I can't see that working for us. Beyond that, I come up blank.

    Have a look at the rocketry link in the "Sci-Fi Writing Resources" thread on this board.
  4. Oct 10, 2012 #3
    These are great! Thanks for the answers.
    I've been doing research on collapsing stars and had another question. When a supernova explodes does it emit radiation as well as dust? If it does emit dust, is there the possibility for that dust to interfere with any functions of a space craft?

    I've also been trying to find what a supernova looks like as it is exploding - do you know any website that would explain it?

  5. Oct 10, 2012 #4
    The thing that causes a supernova is a runaway nuclear reaction in the stellar core. Think atomic bomb with a mass of, well, the Sun. That reaction produces large amounts of both radiation and subatomic particles. The first and foremost effect of the reaction is to "blow up" the stellar envelope, i.e. everything that's not the core itself. That envelope is almost exclusively made up of hydrogen and helium, so the "supernova remnant" which can be observed for a long time afterwards is an expanding cloud composed of those gases.

    The question what a supernova looks like is largely theoretical, I expect. If you are close enough to see the star as anything but a point-source of light, the energy density of the radiation and particle streams will be enough to vaporize anything that's not already "vapor", pretty much. If you are far enough away to see it as a point, all you'll see at first is that the point is rapidly getting brighter and then somewhat less rapidly dimmer again. Long after that, the remnant as described above will have grown sufficiently to become visible.

    If I were to speculate, the appearance of the supernova itself might be something like a combination of the flash of a nuclear explosion, falling into the Sun (except that it's actually the stellar surface that's expanding towards you and not you going towards the stellar surface), and a bad case of blue-shift because the initial expansion proceeds at an appreciable fraction of the speed of light, and because the envelope is being heated by the energy pumped into it from the core, which makes it ever hotter (bluer). There might well be lots more interesting details, but my guess would be that you'd have to go to primary sources (academic publications) for those, none of which are likely to tell you about visual appearances directly, because that is not their primary concern. Sorry. :frown:
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