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Posers and Puzzles

Posers and Puzzles

  1. 11 Feb '08 07:34
    Hey Everyone.

    I'm new to the site (introduced by some friends for a chess tourney were having) and I saw a lot of people posting "hypothetical"questions. I have no formal schooling but I have two questions I always wanted to hear an attempted answer to.

    1. Your travelling at the speed of light towards Earth with a telescope fixed on a populated location. Even though time is relative, would the images in the telescope appear to be moving faster?

    2. Since an object that is moving faster experiences less time, is it possible to assume that Jupiter is younger then Earth (assuming both were created at the same time) because of how much faster it spins? And if thats the case, how can we accurately estimate the age of the universe if at the instant of the big bang when the singularity expanded close to the speed of light, virtually no relative time would have passed for all matter?

    Interested in hearing your answers...
  2. 11 Feb '08 11:28
    Originally posted by KevinMWHM
    1. Your travelling at the speed of light ...
    No, you don't. You cannot ever travel in the speed of sound if you have mass.

    When you start with a false assumption, you can never get an anwser that has anything to do with science.
  3. 11 Feb '08 11:43
    Ok, you're moving at a rate of speed unbearably faster then ever thought humanly possible. A rate of speed that causes windows to shatter and babies to cry. It's not light speed, but damnit, it'll take more than a squadran X-Wing fighters and the Enterprise to catch you.

    How about at that speed?

  4. 11 Feb '08 12:18
    Originally posted by KevinMWHM
    Ok, you're moving at a rate of speed unbearably faster then ever thought humanly possible. A rate of speed that causes windows to shatter and babies to cry. It's not light speed, but damnit, it'll take more than a squadran X-Wing fighters and the Enterprise to catch you.

    How about at that speed?

    With a speed nearly at the speed of light the question is valid.

    The answser is, yes, the images in the telescope would appear faster. But you won't see anything because the light is blue-shifted in an extent to appear in ultra-violet and further. Only the infra-red and longer wavelength of light will be visible.
  5. Subscriber sonhouse
    Fast and Curious
    12 Feb '08 02:39
    Originally posted by FabianFnas
    With a speed nearly at the speed of light the question is valid.

    The answser is, yes, the images in the telescope would appear faster. But you won't see anything because the light is blue-shifted in an extent to appear in ultra-violet and further. Only the infra-red and longer wavelength of light will be visible.
    But telescope cameras can be built sensitive to just about ANY wavelength, UV, Xray, Visible, IR, any of them can be used to generate images.
    Serious telescopes don't even have provisions for eyeball viewing.
    Those sensors can be by themselves thousands of times more sensitive than human eyes so that would be how any self-respecting rocket scientist would design it, especially for space. What would you do to look through a telescope on a spacecraft? Have it staring out a port window? The window would distort the image probably to uselessness anyway.
  6. 12 Feb '08 05:34
    Originally posted by sonhouse
    But telescope cameras can be built sensitive to just about ANY wavelength, UV, Xray, Visible, IR, any of them can be used to generate images.
    Serious telescopes don't even have provisions for eyeball viewing.
    Those sensors can be by themselves thousands of times more sensitive than human eyes so that would be how any self-respecting rocket scientist woul ...[text shortened]... t staring out a port window? The window would distort the image probably to uselessness anyway.
    We are talking about velocities near to that of light.

    Then what will the reddening, due to Doppler, be? At what wavelength should we have emitting from the source to be visible at the space craft? And what will the images be like?

    Or, supposing that we want to see the ordinary light, now in the gamma side of the spectrum, what kind of device would we use to record this as images? Does electromagnetic radiation behaves so you can see it in a telescope??

    I think everyone agrees to that we can't just use telescope to see events as we re used to. The original question was "would the images in the telescope appear to be moving faster?" and the answer is "yes", but what would the images be like in reality?
  7. 12 Feb '08 08:52
    If you travel in your spacecraft in high velocities (still under the velocity of light) you will experience some visual pecularities:

    If you see at 90 degrees from your travel direction you see the stars as usual. No shifting there, neither blue or red shifted.

    If you see ahead you will se stars in blue shift. And if it is blueshifted enough you see their infrared, but now in visible light. It means that even interstellar clouds will be visible. The stars with ordinary light will be ultraviolet and for that reason perhaps not visible for your eyes at all.

    If you see backwards you don't see anything but the most hot stars that shines in ultraviolet. Ordinary stars will only be seen in infraread, but not with your eyes.

    So your perception of the space around you will be very different, depending of the direction you look at.
  8. Standard member agryson
    AGW Hitman
    13 Feb '08 22:53
    Originally posted by KevinMWHM
    Hey Everyone.

    I'm new to the site (introduced by some friends for a chess tourney were having) and I saw a lot of people posting "hypothetical"questions. I have no formal schooling but I have two questions I always wanted to hear an attempted answer to.

    1. Your travelling at the speed of light towards Earth with a telescope fixed on a populated locat ...[text shortened]... y no relative time would have passed for all matter?

    Interested in hearing your answers...
    Look, to give you a straight answer, it is technically true that you cannot travel at the speed of light by conventional means, but let's assume that you meant as close as possible before it's physically impossible...
    1: Since relative time for you is much much slower than relative time for those being observed, yes, everyone would be zipping around like the bejaysus to use a colloquialism.
    2: Yes, one could argue that Jupiter is objectively younger; as for the age of the universe, guaging it by the emission of light (background microwave radiation) which always travels at the same velocity, accurate measurements can be made.
    I have to admit that I'm not an astrophysicist, but as a physicist who has done a little bit of that stuff, that's my initial interpretation. But then, I failed a few exams in my time too...
    The problem for both you and I is the difference between relative and objective time... what is objective time, does it really exist? How does one measure time without some object/particle etc. which would be experiencing a relative timeframe?
  9. 14 Feb '08 21:19 / 1 edit
    Originally posted by agryson
    2: Yes, one could argue that Jupiter is objectively younger;
    The time for Jupter compared with Earth relativistically is different by three reasons:
    (1) Because of its higher gravitation,
    (2) Because of its lower velocity around the Sun, and
    (3) Because of its higher rotation and therefore its tangential speed at its 'surface'.
    Does the three add up?, or are they counteractive in any way, or a mix?
    But how much are we talking about? Seconds per year? No, probably much less than that...