Do photons travel in straight paths or curved paths in the most distant "outer" parts of the cosmos?

It seems to me that photons, as part of a field, can only exist where gravity exists, however small the gravity field. Notice we see light from stars, though they are so far away, and photons bend in their path when traveling around massive objects such as the sun; so photons and gravitons interact, and it seems the g fields are much finer.

But I don't think photons can travel away from the cosmos. It doesn't make sense.

So then what is the nature of space at the edge of expansion in the cosmos with respect to fields?

6 Answers

  • Anonymous
    1 decade ago
    Favorite Answer

    Photons follow a geodesic, which is (from the photon's point of view) a straight line. To an outside observer, a geodesic will be curved due to the presence of gravitational fields. Such fields are not necessary for the photon's existence or activity. The universe, though of finite size, does not have an edge: you can go as far as you please, as fast as you please, and won't encounter an edge. A common analogy is to a bug on the surface of a balloon; the bug can explore the balloon as much as it pleases, but never encounters an edge. Now suppose that the balloon is inflating, and you have a plausible model of the universe.

  • 1 decade ago

    First of all, it is very difficult to answer a question when you preach your own theories within the question...

    At this time "nothing" resembling the "edge", "end", or termination of the Universe has been found or located or detected.

    The Universe has been more or less agreed by numerous astronomers to be at least 40 Billion Light Years "seeable" deep in all directions through the use of our most sophisticated optical and radio telescope equipment. Beyond that distance our equipment fails to provide us with any useable information. That is a technical limitation of our equipment and not a wall or end of space. In future years we might have some new technology that pushes that limitation out to maybe 60 Billion Light Years or so. Only time will tell...

    Photons travel in a straight line unless pulled slightly off course by some extremely powerful magnetic (gravitational) force. In those cases, the path of the photons is bent slightly in the vicinity of the powerful source of gravity and then the photons continue onward in a straight line for what must be an endless time. There is nothing that can make photons "curve" as in a semi-circle, or spiral, or circle.

  • Anonymous
    1 decade ago

    Since, as another Answerer said, Gravity exists everywhere, then photons can exist anywhere. and WHAT does your question mean? If photons can't travel outwards, how could a spaceship? that makes no sense. Not sure what you mean by "cosmos". Galaxy? Universe? that's a vague term. If the Hubble space telescope can see stars and galaxies literally BILLIONS of light years away, then the Photons must have reached our solar system from them, over billions of years. So your theory, as it is, makes no sense. Otherwise all we'd see is our own galactic light in the night sky, if that's what you meant by "cosmos", and no other light whatsoever. But since we can see other galaxies ( with telescopes ), then the light must travel between huge expanses of near-nothing to get here.

    "There is nothing that can make photons "curve" as in a semi-circle, or spiral, or circle." - Uh, Mr. Answerer, I beg to differ. I believe a massive black hole CAN make light bend, circle, and curve. Scientists have already stated that some B-holes are so big and powerful, not even light can escape them, as it warps gravity, so it does capture Photons. So, if it comes in near it, I suppose a 90 degree curve is the best you could get, but I don't know if there's a way to track a single photon thru space yet, to see if one comes by a B-hole, gets sucked in, and it curves back to meet it's fate. We won't know in our lifetime, I'm sure. I won't, anyway. Maybe a slight curve is all you'd ever get, but it would still be a curve. maybe if you were falling INTO a black hole, and shining a flashlight out, it might suck the photon back in in a curve, heck I don't know that one. But curving Photons, yes, that is possible.

  • Anonymous
    1 decade ago

    Technically, gravity exists everywhere in the cosmos, but it's flatter (less powerful) in some regions than others. I'm actually referring to the curve of space-time, but gravity is a curvature of space-time.

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  • ZikZak
    Lv 6
    1 decade ago

    There are no "outer" parts of the cosmos.

    The universe has no edge and is uniformly filled with galaxies everywhere.

  • Anonymous
    1 decade ago

    Einstein basically says nothing goes straight and eveything curves a little.

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