<p>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.</p>

CC BY-SA 3.0
2016-02-26T18:05:28.020Z
Thanks! That was a "*for example*" only: "*Would there be some reason for transmitting - for example to create...*". I'd like to find out for sure if there is some transmission of some kind, or if the video is wrong.
uhoh
CC BY-SA 3.0
2016-02-26T19:18:37.013Z
@uhoh: Yeah sorry, I cannot tell about any other transmissions for sure, as I'm not a radio astronomer.
AtmosphericPrisonEscape
CC BY-SA 3.0
2016-02-28T13:15:53.360Z
Now you've [got me thinking!](http://astronomy.stackexchange.com/q/13930/7982) Thanks!
uhoh
CC BY-SA 3.0
2016-02-26T18:02:45.580Z
2016-02-26T18:02:45.580Z
AtmosphericPrisonEscape
<p>I saw this video at <a href="http://www.space.com/32055-mystery-fast-radio-burst-space-explosions-location.html" rel="nofollow noreferrer">Space.com</a> and I noticed that at 00:05 the animation illustrates waves propagating from space into <a href="https://en.wikipedia.org/wiki/Parkes_Observatory" rel="nofollow noreferrer">The Dish</a> 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 <a href="https://en.wikipedia.org/wiki/Laser_guide_star" rel="nofollow noreferrer">artificial</a> "star" for wavefront correction analogous to <a href="https://en.wikipedia.org/wiki/Adaptive_optics" rel="nofollow noreferrer">adaptive optics</a> at visible wavelengths, or could it be simply a mistake in the animation?</p>

<p>Here are some GIFs from screenshots. You can check the <a href="http://www.space.com/32055-mystery-fast-radio-burst-space-explosions-location.html" rel="nofollow noreferrer">video</a> at the indicated times. </p>

<p><strong>circa 00:05</strong></p>

<p><a href="https://i.sstatic.net/NdD8W.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/NdD8W.gif" alt="at 00:05"></a></p>

<p><strong>circa 00:50</strong></p>

<p><a href="https://i.sstatic.net/n8Oon.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/n8Oon.gif" alt="enter image description here"></a></p>

CC BY-SA 3.0
2016-02-26T19:14:50.390Z
Its just a slightly dodgy graphic. No astronomical meaning.
James K
CC BY-SA 3.0
2016-02-28T09:47:42.830Z
If you are sure @JamesKilfiger , can you add some supporting information and post it as an answer so I can accept it?
uhoh
CC BY-SA 3.0
2016-02-29T08:53:00.677Z
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
CC BY-SA 3.0
2016-02-29T11:55:44.263Z
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
CC BY-SA 3.0
2016-02-29T15:45:45.777Z
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
CC BY-SA 3.0
2016-03-01T02:14:42.583Z
screen shot of what I mean by "[advertisement-laden](http://i.imgur.com/3jvBp6O.png)"
uhoh
<radio-astronomy>
Why is this video showing radio waves transmitted from a radio telescope?
uhoh
# Why is this video showing radio waves transmitted from a radio telescope?

(Asked by: username_0 on 2016-02-26)

I saw this video at [Space.com](http://www.space.com/32055-mystery-fast-radio-burst-space-explosions-location.html) and I noticed that at 00:05 the animation illustrates waves propagating from space into [The Dish](https://en.wikipedia.org/wiki/Parkes_Observatory) 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](https://en.wikipedia.org/wiki/Laser_guide_star) "star" for wavefront correction analogous to [adaptive optics](https://en.wikipedia.org/wiki/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](http://www.space.com/32055-mystery-fast-radio-burst-space-explosions-location.html) at the indicated times.

**circa 00:05**

[![at 00:05](https://i.sstatic.net/NdD8W.gif)](https://i.sstatic.net/NdD8W.gif)

**circa 00:50**

[![enter image description here](https://i.sstatic.net/n8Oon.gif)](https://i.sstatic.net/n8Oon.gif)

**Tags:** radio-astronomy
> **Comments:**
> **username_1**: Its just a slightly dodgy graphic. No astronomical meaning.  
> **username_0**: If you are sure @JamesKilfiger , can you add some supporting information and post it as an answer so I can accept it?  
> **username_2**: 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.  
> **username_0**: 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.  
> **username_2**: 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.  
> **username_0**: screen shot of what I mean by "[advertisement-laden](http://i.imgur.com/3jvBp6O.png)"  

---

## 1 answers

### Answer by username_3 on 2016-02-26. Score: 2 | Accepted answer

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.

> **Comments:**
> **username_0**: Thanks! That was a "*for example*" only: "*Would there be some reason for transmitting - for example to create...*". I'd like to find out for sure if there is some transmission of some kind, or if the video is wrong.  
> **username_3**: @uhoh: Yeah sorry, I cannot tell about any other transmissions for sure, as I'm not a radio astronomer.  
> **username_0**: Now you've [got me thinking!](http://astronomy.stackexchange.com/q/13930/7982) Thanks!  

---

