Announcement

Collapse
No announcement yet.

OT gravity lens solar concentrator?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • OT gravity lens solar concentrator?

    So I have a question. It has been proven that Einstein was right that gravity bends light. So consider the light from our sun going past earth and consider just the rays that are in a thin ring say a mile wide just above our atmosphere. The rays in that ring with a circumference of about 25,000 might be bent by gravity and focused to say a spot a mile across, with a light intensity of 25,000 suns! So does this happen? If it does how far from earth or the sun is the focal point? Obviously the focal point would be sweeping around the sun with the earths orbit. Would every planet be doing this? Jupiter with a huge diameter and heavy gravity might be more intense. Is this a place for spacecraft to avoid? Just wondering.

  • #2
    Is this a place for spacecraft to avoid? Just wondering.
    -No. First, because there's no real "point", like you get with a magnifying lens. The amount the light is "bent" varies by the distance from the center of gravity, so at best you'd have a slightly brighter-than-usual "doughnut" shape to the light.

    Second, even if you did get a single "point" of light, the amount the light is bent is extremely minute, which means the "focal point" would be a huge distance away. I have no idea on the actual math, but I'd wager the "focal point" for earth would be out around the orbit of Neptune, if not further. Keeping in mind we can see extrasolar planets tens or hundreds of light-years away, that we spotted as they occluded a local (to them) star.

    Doc.
    Doc's Machine. (Probably not what you expect.)

    Comment


    • #3
      Light being bent by gravity is a reality. It has been observed when the light of a distant galaxy is bent by another distant galaxy which is less distant than the first and is almost perfectly aligned with it. Or by another massive object, like a black hole, again in almost perfect alignment. What has been observed is some galaxies appear to us as several objects or in an image that is spread out across a greater angle than it should subtend or perhaps a partial ring.

      But this effect is very slight. The mass of the earth or the moon would have such a slight effect that light that passes on opposite sides of either of those bodies would never come to a common point. They just aren't heavy enough. For that to happen you need an object that is as massive as a whole galaxy and you need the distances from here to the distant galaxies for it to happen. In short, it is a very, very slight effect.

      Sorry Doc, it won't happen by the orbit of Neptune or Pluto or even by the next star or the next galaxy. It won't happen even at the furthest reaches of the universe. At least, not if it is the earth or moon that is doing the bending.
      Paul A.
      SE Texas

      Make it fit.
      You can't win and there IS a penalty for trying!

      Comment


      • #4
        Apparently, no light or energy of any kind escapes the universe. That is almost "by definition", since "universe" means "all that there is". The universe might be envisioned as a sphere, although it is actually four dimensional with the inclusion of time. You can aim a sensor (look) in any direction from Earth, and detect cosmic background radiation from the "big bang" that occurred about 13.8 billion years ago. Since it must have started as a singularity or a point with dimensions of 0, 0, 0, 0, that means that it is subject to gravitational lensing that makes it appear to be infinite in size, or as if it is a sphere with a radius of 13.8 billion light years with Earth at the center. Other extremely distant objects also may appear larger than they actually were at the time the light we see was emitted from them. The concept of distance becomes entangled with time. I think it may be possible for multiple images of the same objects to be observed, at different stages of their development, separated by millions of light-years. This would mean that light travels in a spiral orbit around the center of mass of the universe. These are just my own ideas - I don't know if astronomers would agree.
        http://pauleschoen.com/pix/PM08_P76_P54.png
        Paul , P S Technology, Inc. and MrTibbs
        USA Maryland 21030

        Comment


        • #5
          Originally posted by PStechPaul View Post
          Apparently, no light or energy of any kind escapes the universe. That is almost "by definition", since "universe" means "all that there is". The universe might be envisioned as a sphere, although it is actually four dimensional with the inclusion of time. You can aim a sensor (look) in any direction from Earth, and detect cosmic background radiation from the "big bang" that occurred about 13.8 billion years ago. Since it must have started as a singularity or a point with dimensions of 0, 0, 0, 0, that means that it is subject to gravitational lensing that makes it appear to be infinite in size, or as if it is a sphere with a radius of 13.8 billion light years with Earth at the center. Other extremely distant objects also may appear larger than they actually were at the time the light we see was emitted from them. The concept of distance becomes entangled with time. I think it may be possible for multiple images of the same objects to be observed, at different stages of their development, separated by millions of light-years. This would mean that light travels in a spiral orbit around the center of mass of the universe. These are just my own ideas - I don't know if astronomers would agree.
          Sorry, I think you're on your own with this one...

          Comment


          • #6
            Since we have never traveled to the extents of the universe, there is always room for speculation about what happens at such distances. There is speculation among astronomers and, of course, disagreement. Some have speculated that space is curved and closes back in on itself. Others say it just goes on and on. There are many theories.

            I suspect it will be a long, long time before we know even a little for sure.
            Paul A.
            SE Texas

            Make it fit.
            You can't win and there IS a penalty for trying!

            Comment


            • #7
              Disregarding gravity there is a very real and observable bending of the sun's rays when passing through the earth's atmosphere at an oblique angle and you can see this if you take numerous sun shots with a sextant when the sun is rising, or setting, when it will appear to 'jump' somewhat. I dont know if the rays of the sun are being caused to diverge or converge.

              Comment


              • #8
                Originally posted by Paul Alciatore View Post
                Others say it just goes on and on.
                By definition those others do not believe the current best guess at the origins of the universe, the Big Bang theory.
                If you benefit from the Dunning-Kruger Effect you may not even know it ;-)

                Comment


                • #9
                  ok...NOW.... you gave me a headache !!

                  Comment


                  • #10
                    Thats air bending .. not gravity.
                    Change of density, like looking at fish-in-water they are not where they appear to be.

                    Originally posted by The Artful Bodger View Post
                    Disregarding gravity there is a very real and observable bending of the sun's rays when passing through the earth's atmosphere at an oblique angle and you can see this if you take numerous sun shots with a sextant when the sun is rising, or setting, when it will appear to 'jump' somewhat. I dont know if the rays of the sun are being caused to diverge or converge.

                    Comment


                    • #11
                      Originally posted by The Artful Bodger View Post
                      Disregarding gravity there is a very real and observable bending of the sun's rays when passing through the earth's atmosphere at an oblique angle and you can see this if you take numerous sun shots with a sextant when the sun is rising, or setting, when it will appear to 'jump' somewhat. I dont know if the rays of the sun are being caused to diverge or converge.
                      That's refraction caused by the air which makes the sun or moon or stars on the horizon seem to travel faster for the first couple of degrees. It's also responsible for the sun and moon looking a bit larger to the eye when they are right on the horizon. So.... I guess you could say that the shell of air is acting like a lens to some small extent. After all a lens is just something that refracts the light in a controlled manner.
                      Chilliwack BC, Canada

                      Comment


                      • #12
                        I agree with the assertion that the bending of the light will be very slight, meaning that the focal point would be very far away, probably way outside the orbit of all the known planets. We see the light from stars that are thousands of light years away, so the light passing around the earth won't be dissipated much even if the focal point is very far away. Point is probably the wrong word. The light rays would be converging over a great distance. I used the 1 mile diameter just to give an idea of the concentration ratio. So the 'hotspot' might actually be a tapered cylinder millions of miles long, like a laser beam.

                        Comment


                        • #13
                          No, you are not looking at it right. You are talking about a ring that is above our atmosphere and that is one mile wide. The atmosphere does not have a sharp end, but one number is that it extends to about 10,000 km above sea level. So, with the diameter of the earth as 12,742 km your ring would be around 32,742 km. The distance from the sun to the earth is about 149,597,870 km. So we have a half angle where the sine = 32,742 / 2 / 149,597,870. That half angle is 0.00627 degrees (or 22.6 seconds of arc) and that is the amount that the light on opposite sides of your ring would have to be bent just to make it parallel to the light on the other side. To bring it to a common point at some distance, it would have to be bent a bit more than that.

                          Now that may sound like a very small angle, but the effect of gravity in bending that light will be incredibly smaller than that. The amount of gravitational lensing observed by even a galaxy with a mass more than 100 billion times that of the Sun will produce multiple images separated by only a few arc seconds, not tens of them. So the effect of the planet earth will be at least 100 billion times less than that. Actually, the effect will be a lot less than even that because the earth is a lot less massive than the sun. So, for all practical purposes, those light rays on opposite sides of the earth will still be diverging away from each other at the same half angle of 22.6 seconds of arc. Their change in direction will be trillions of times less than that original divergence angle so it has absolutely no chance of overcoming it. The gravitational effect of the earth's mass is totally negligible.

                          In order for an object with the mass of the earth to have a significant gravitational lensing effect where the rays of light from opposite sides of it to converge ever, that mass would have to be reduced in size to less than the diameter of an atom. It would have to be a black hole. Then your ring would also be less than the diameter of a single atom and the original half angles involved would be much, much smaller AND the amount of bending at such a short distance from the mass would be much, much greater. Then there may be the possibility of those rays of light coming together at some real distance past that earth mass black hole. Perhaps even a very short distance past it.

                          But with an earth sized earth, it ain't gonna happen. Period.



                          Originally posted by garyhlucas View Post
                          I agree with the assertion that the bending of the light will be very slight, meaning that the focal point would be very far away, probably way outside the orbit of all the known planets. We see the light from stars that are thousands of light years away, so the light passing around the earth won't be dissipated much even if the focal point is very far away. Point is probably the wrong word. The light rays would be converging over a great distance. I used the 1 mile diameter just to give an idea of the concentration ratio. So the 'hotspot' might actually be a tapered cylinder millions of miles long, like a laser beam.
                          Paul A.
                          SE Texas

                          Make it fit.
                          You can't win and there IS a penalty for trying!

                          Comment


                          • #14
                            Paul is correct.

                            Here's an example of gravitational lensing. We see here the same distant galaxy shaped like a do-nut as its light has been warped by something massive that's directly between it and us.


                            Comment


                            • #15
                              I still have my noggin wrapped in knots over the single particle double split experiment, but do find gravitational lensing interesting. Thanks for the cool pix...
                              I hear and I forget.
                              I see and I remember.
                              I do and I understand.
                              Confucius (孔夫子)

                              Comment

                              Working...
                              X