4

I saw this video at Space.com and I noticed that at 00:05 the animation illustrates waves propagating from space into The Dish at Parks Observatory, but at 00:50 the direction of propagation is reversed! Would there be some reason for transmitting - for example to create an artificial "star" for wavefront correction analogous to adaptive optics at visible wavelengths, or could it be simply a mistake in the animation?

Here are some GIFs from screenshots. You can check the video at the indicated times.

circa 00:05

at 00:05

circa 00:50

enter image description here

uhoh
  • 31,151
  • 9
  • 89
  • 293
  • 1
    Its just a slightly dodgy graphic. No astronomical meaning. – James K Feb 26 '16 at 19:14
  • If you are sure @JamesKilfiger , can you add some supporting information and post it as an answer so I can accept it? – uhoh Feb 28 '16 at 09:47
  • There's a lesson to be learned here: Youtube (along with other websites that dish out videos, pun intended) is not the place to learn science. – David Hammen Feb 29 '16 at 08:53
  • 1
    Maybe the lesson is really "consider the source." YouTube is just a library - you can browse the "tabloids", or go to the "bookshelves" for the good stuff. Plenty of top notch stuff available there. Note @DavidHammen - the source for the link in this question is a private, advertisement-laden site. – uhoh Feb 29 '16 at 11:55
  • Consider the source -- That is exactly right. Any decent layperson's site that publishes a key scientific discovery will inevitably provide links to the underlying scientific journal papers in which those discoveries were first announced. space.com rarely, if ever, does this. It is not a good source. – David Hammen Feb 29 '16 at 15:45
  • 1
    screen shot of what I mean by "advertisement-laden" – uhoh Mar 01 '16 at 02:14

1 Answers1

2

I guess it's a mistake in the animation. At radio wavelengths turbulence doesn't affect the measurments anymore and above 200 MHz the ionosphere doesn't play a role yet, so I guess the notion of a guide star is unnecessary here.

AtmosphericPrisonEscape
  • 9,840
  • 1
  • 31
  • 42