Results 1 to 21 of 21
  1. #1
    Thailand Expat
    bsnub's Avatar
    Join Date
    Jun 2009
    Last Online
    @
    Posts
    18,745

    The Hubble Ultra Deep Field in 3D

    Please take the time to watch this.



  2. #2
    Days Work Done! Norton's Avatar
    Join Date
    Oct 2007
    Last Online
    @
    Location
    Roiet
    Posts
    30,310
    Great vid. One comment by the narrator is puzzling to me.

    Galaxies, some of which are "traveling at greater than the speed of light". Thought this was not possible?

  3. #3
    Thailand Expat
    bsnub's Avatar
    Join Date
    Jun 2009
    Last Online
    @
    Posts
    18,745

  4. #4
    Thailand Expat
    bsnub's Avatar
    Join Date
    Jun 2009
    Last Online
    @
    Posts
    18,745
    Quote Originally Posted by Norton View Post
    Great vid. One comment by the narrator is puzzling to me.

    Galaxies, some of which are "traveling at greater than the speed of light". Thought this was not possible?
    I am not sure Norton. Yet I am no expert.

  5. #5
    Days Work Done! Norton's Avatar
    Join Date
    Oct 2007
    Last Online
    @
    Location
    Roiet
    Posts
    30,310
    Quote Originally Posted by bsnub
    Yet I am no expert.
    Nor am I so I defer to Einstein.

  6. #6
    Pronce. PH said so AGAIN!
    slackula's Avatar
    Join Date
    Jul 2009
    Last Online
    @
    Location
    Behind a slipping mask of sanity in Phuket.
    Posts
    9,093
    From the first vid:

    "Photons that have been traveling for over 13 billion years"

    Amazing stuff, thanks for posting.

  7. #7
    Days Work Done! Norton's Avatar
    Join Date
    Oct 2007
    Last Online
    @
    Location
    Roiet
    Posts
    30,310
    Just did some checking and sure enough, the narrative is likely correct. Other galaxies may be observed to be moving at greater than light speed because telescopes measure speed relative to the speed of the observation point and the observed point. So, closing or opening speed is the sum of the speed of both and could well be greater than the speed of light.
    Whenever you find yourself on the side of the majority, it is time to pause and reflect.

  8. #8
    Thailand Expat
    Stinky's Avatar
    Join Date
    Sep 2009
    Last Online
    @
    Location
    Next door to digit
    Posts
    11,170
    Good OP bsnub, very interesting stuff mate

  9. #9
    Thailand Expat
    Join Date
    Jan 2006
    Last Online
    @
    Posts
    60,017
    Well done norton. Nice find bsn00b

  10. #10
    Not a Mod.
    Begbie's Avatar
    Join Date
    Mar 2006
    Last Online
    @
    Location
    Lagrangian Point
    Posts
    11,369
    Quote Originally Posted by Norton View Post
    Just did some checking and sure enough, the narrative is likely correct. Other galaxies may be observed to be moving at greater than light speed because telescopes measure speed relative to the speed of the observation point and the observed point. So, closing or opening speed is the sum of the speed of both and could well be greater than the speed of light.

    Don't think that can be correct as the observation point is basically fixed. A sattelite orbiting the earth will still be moving at a reltive snails pace around earth in terms of light.

    The speed that a galaxy is moving away is measured by the shift in wavelength. If a galaxy was moving faster than the speed of light the light would never reach the observer and thus the wavelength of the light could not be measured.

  11. #11
    Thailand Expat
    bsnub's Avatar
    Join Date
    Jun 2009
    Last Online
    @
    Posts
    18,745
    I would advise all to read a great book by the late Carl Sagan titled "Cosmos". Humbling stuff.

  12. #12
    Out there...
    StrontiumDog's Avatar
    Join Date
    Jul 2009
    Last Online
    @
    Location
    BKK
    Posts
    40,030
    Quote Originally Posted by Begbie View Post
    Quote Originally Posted by Norton View Post
    Just did some checking and sure enough, the narrative is likely correct. Other galaxies may be observed to be moving at greater than light speed because telescopes measure speed relative to the speed of the observation point and the observed point. So, closing or opening speed is the sum of the speed of both and could well be greater than the speed of light.

    Don't think that can be correct as the observation point is basically fixed. A sattelite orbiting the earth will still be moving at a reltive snails pace around earth in terms of light.

    The speed that a galaxy is moving away is measured by the shift in wavelength. If a galaxy was moving faster than the speed of light the light would never reach the observer and thus the wavelength of the light could not be measured.
    A useful link on this subject

    Apparent Superluminal Velocity of Galaxies

    Apparent Superluminal Velocity of Galaxies

    A distant object can appear to travel faster than the speed of light across our line of sight, provided that it has some component of motion towards us as well as perpendicular to our line of sight. Say that on January 1st you make a position measurement of galaxy X. One month later, you measure it again. Assuming you know its distance from us by some independent measurement, you derive its linear speed, and conclude that it is moving faster than the speed of light.

    What have you forgotten? Let's say that on January 1st, the object is Dkm from us, and that between January 1st and February 1st, the object (which is actually moving at 45 degrees to the line of sight) has moved dkm closer to us. You have assumed that the light you measured on January 1st and February 1st were emitted exactly one month apart. Not so. The first light beam had farther to travel, and was actually emitted (1 + d/c) months before the second measurement, if we measure c in km/month. The object has travelled the given angular distance in more time than you thought. Indeed, we can calculate that if its real velocity is v, then its apparent velocity in this case is v/[sqrt(2)-(v/c)] which could be higher than twice the speed of light without v being greater than c. For galaxies moving at more acute angles to the line of sight the apparent velocity can be much higher. Similarly, if the object is moving away from us, the apparent angular velocity will be too slow, if you do not correct for this effect, which becomes significant when the object is moving along a line close to our line of sight.

    The effect has been observed in the radio emissions from jets of quasars which are thought to travel close to the speed of light in a direction near to our line of sight.
    "Slavery is the daughter of darkness; an ignorant people is the blind instrument of its own destruction; ambition and intrigue take advantage of the credulity and inexperience of men who have no political, economic or civil knowledge. They mistake pure illusion for reality, license for freedom, treason for patriotism, vengeance for justice."-Simón Bolívar

  13. #13
    Out there...
    StrontiumDog's Avatar
    Join Date
    Jul 2009
    Last Online
    @
    Location
    BKK
    Posts
    40,030
    A useful link on faster than light phenomena...

    Faster Than Light

    I find this all very fascinating.

  14. #14
    Thailand Expat
    teddy's Avatar
    Join Date
    May 2009
    Last Online
    08-03-2015 @ 08:12 PM
    Posts
    1,927
    If you look inside yourself, you'll understand the universe

  15. #15
    Thailand Expat
    bsnub's Avatar
    Join Date
    Jun 2009
    Last Online
    @
    Posts
    18,745
    Quote Originally Posted by StrontiumDog View Post
    Quote Originally Posted by Begbie View Post
    Quote Originally Posted by Norton View Post
    Just did some checking and sure enough, the narrative is likely correct. Other galaxies may be observed to be moving at greater than light speed because telescopes measure speed relative to the speed of the observation point and the observed point. So, closing or opening speed is the sum of the speed of both and could well be greater than the speed of light.

    Don't think that can be correct as the observation point is basically fixed. A sattelite orbiting the earth will still be moving at a reltive snails pace around earth in terms of light.

    The speed that a galaxy is moving away is measured by the shift in wavelength. If a galaxy was moving faster than the speed of light the light would never reach the observer and thus the wavelength of the light could not be measured.
    A useful link on this subject

    Apparent Superluminal Velocity of Galaxies

    Apparent Superluminal Velocity of Galaxies

    A distant object can appear to travel faster than the speed of light across our line of sight, provided that it has some component of motion towards us as well as perpendicular to our line of sight. Say that on January 1st you make a position measurement of galaxy X. One month later, you measure it again. Assuming you know its distance from us by some independent measurement, you derive its linear speed, and conclude that it is moving faster than the speed of light.

    What have you forgotten? Let's say that on January 1st, the object is Dkm from us, and that between January 1st and February 1st, the object (which is actually moving at 45 degrees to the line of sight) has moved dkm closer to us. You have assumed that the light you measured on January 1st and February 1st were emitted exactly one month apart. Not so. The first light beam had farther to travel, and was actually emitted (1 + d/c) months before the second measurement, if we measure c in km/month. The object has travelled the given angular distance in more time than you thought. Indeed, we can calculate that if its real velocity is v, then its apparent velocity in this case is v/[sqrt(2)-(v/c)] which could be higher than twice the speed of light without v being greater than c. For galaxies moving at more acute angles to the line of sight the apparent velocity can be much higher. Similarly, if the object is moving away from us, the apparent angular velocity will be too slow, if you do not correct for this effect, which becomes significant when the object is moving along a line close to our line of sight.

    The effect has been observed in the radio emissions from jets of quasars which are thought to travel close to the speed of light in a direction near to our line of sight.
    Awesome! We are on to something here. Here is another great one;


  16. #16
    DaffyDuck
    Guest
    Quote Originally Posted by Norton View Post
    Great vid. One comment by the narrator is puzzling to me.

    Galaxies, some of which are "traveling at greater than the speed of light". Thought this was not possible?
    Relativity.

    If I move away from you at 2/3 the speed of light, and you move away from me at 2/3 the speed of light, either of us appear to be moving away at greater than the speed of light, yet without ever individually surpassing the speed of light.

    Additionally, the narrator explains in the sequence following that the expansion of the universe additionally contributes to this perception (which is why it is possible for some objects appear to move at greater than 2x the speed of light).

  17. #17
    DaffyDuck
    Guest
    Quote Originally Posted by Begbie View Post
    The speed that a galaxy is moving away is measured by the shift in wavelength. If a galaxy was moving faster than the speed of light the light would never reach the observer and thus the wavelength of the light could not be measured.
    Wrong - a galaxy moving at faster than the speed of light would still generate photons that are left behind, and that leave it at the speed of light. Just because the galaxy moves at speeds beyond c does not mean it 'captures' its own light - only black holes are known to do that, and that's not the case here.

    Quote Originally Posted by teddy View Post
    If you look inside yourself, you'll understand the universe
    Useless, as always.

  18. #18
    In transit to Valhalla

    Join Date
    Oct 2008
    Last Online
    @
    Posts
    5,036
    Anyway if that was the position 13 billion years ago it's fair to say they are long gone by now, that's what really freaks me out, we are looking at things who have been gone for a very long time, and our sky if we could get an instant photo of real time positions, would look vastly different. That is to me a real strange thing to come to terms with when everything else we look at is more or less where we see it.

    When you lie down and look up at the night sky most of what you see is the distant light of things as they once was, very strange


  19. #19
    Thailand Expat
    bsnub's Avatar
    Join Date
    Jun 2009
    Last Online
    @
    Posts
    18,745

  20. #20
    DaffyDuck
    Guest
    Quote Originally Posted by larvidchr View Post
    Anyway if that was the position 13 billion years ago it's fair to say they are long gone by now, that's what really freaks me out, we are looking at things who have been gone for a very long time
    Essentially, what we consider 'present day', whenever we are looking up, is actually ancient (VERY ancient) history.

    We are always living in the past, ever second of our lives -- just in the case of our 'reality', the time lag is short enough to allow us to fool ourselves.

    Now, try to align that awareness with the illusion of 'free will'.

  21. #21
    Thailand Expat
    Takeovers's Avatar
    Join Date
    Nov 2008
    Last Online
    Today @ 12:47 AM
    Location
    Berlin Germany
    Posts
    5,755
    Tanks for the OP and the Video

    Quote Originally Posted by StrontiumDog
    Apparent Superluminal Velocity of Galaxies
    Very interesting read.

    One point the author seems to have gone wrong though IMHO.

    Shadow and Light spots

    Shadow and light spots are described like objects that move. They are not objects and the observed speed therefore is not the speed of an object. He makes clear at the same time that both are not methods of transferring information so it is really ok.

    Very interesting the
    Quantum tunnneling effect.

    The scientists who performed the experiment even claimed that they transferred information faster than light. But this description explaines why that is not worth much and is probably wrong.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •