I'm just starting to look into amateur radio astronomy, and a thought crossed my mind. I was hoping someone here could answer this question for me.

I've been doing some reading, and it seems that "noise storms" eminating from Jupiter are a favorite target for amateur radio astronomers. According to the things I've read, these storms are the result of a reaction between Jupiter and it's moon, Io.

My question is thus - would it be possible to aim an existing (or planned) radio telescope in the direction of one of the confirmed extrasolar planets, and see if we can detect a similar "storm", or would:

a) Interference from the parent star make this a silly thing to do
b) There's no way that a radio telescope would be sensitive enough to pick up such a thing at that sort of distance.

Because it would be interesting to not only be able to confirm the existence of other planets, but of moons surrounding them as well. Based on observations of our own solar system, it's probably safe to assume that these gigantic planets elsewhere in the galazy probably have a good number of moons around them as well, some of which might be capable of supporting life.

Anybody know enough about this to comment?

Welcome to the board!

I think that (b) is the likely explanation of why this is not done. Extrasolar planets can not ever be observed directly, let alone characteristics of the planets that happen on a smaller scale. It would be interesting to see, however, once we get the tech necessary to do this.

I think I know enough to say that the parent star interference would be overwhelming. But I also think that certain frequencies could be receivable, though it would surely need highly sensitive devices. Anyway it looks like a good idea.

I should remark that Earth is a very bright body in certain radio frequencies (the artificial ones). I believe that in a radius of 1000 thousand light years it would be possible to detect clearly the artificial radio signals output by us, using devices as sensitive as ours.

<font size=-1>[ This Message was edited by: Argos on 2002-11-06 06:50 ]</font>

Isn't there a big radio telescope due to be shot into space at some point (or is it there already?) That would be really cool, I can't imagine all the things it would find.

As I thought about this more, the SETI program is designed to find artificial signals eminating from extrasolar planets, and I don't know what their relative strength would have to be compared to the noise storms on jupiter, but I'm guessing that those storms would be fairly intense if they're a favorite starting point for amateur radio astronomers with comparatively weak equipment, so aside from interference from the parent star, it logically doesn't seem like quite such an insurmountable task.

It would have less to do with strength than frequency. There is a natural microwave window that SETI seems to have a preference to look into. I also think their searches are looking for minute signals in all of the background noise. They take all of the signal in and then pick it apart looking for a coherent stream.

I suspect you mean 100 light years? We have only been producing any significant artificial RF broadcasts for about 100 years.

^Actually it is more like 60, watch Contact, it gets it pretty much right. [img]/phpBB/images/smiles/icon_smile.gif[/img]

A might cause B if you think about it. -Colt

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I think he means that the signals we are currently transmitting are strong enough to be detected as far away as 1000 LY. Of course we would have to wait 1000 years for the signals to travel that far. And then another 1000 years for the reply?

One proposed NASA project that is similar to your proposal is the Terrestrial Planet Finder. Although optically based, it will have to overcome the same problem that segfault is talking about.

"One great challenge is how to detect planets against the blinding glare of their parent star, an effort that has been compared to trying to find a firefly in the glare of a searchlight. Terrestrial Planet Finder will reduce the glare of parent stars to see planetary systems up to 50 light-years away."

Maybe a similar approach could be done with radio telescopes or even incorporated into the TPF concept.

<font size=-1>[ This Message was edited by: RafaelAustin on 2002-11-06 17:56 ]</font>

Exactly. But the signals of Earth could be detected very far away if someone wanted to, using state-of-the-art receivers. In certain frequencies Earth is even brighter than the Sun. If you were located at the other side of the galaxy, and could receive VHF, for instance, the Sun would be a dwarf compared to Earth.

<font size=-1>[ This Message was edited by: Argos on 2002-11-07 06:40 ]</font>

Atmposphere is pretty transparent to radio. So, putting a radio telescope in space would be quite a luxury.

I really don't know if such a project is being carried out. Perhaps someone here knows more than I do.

Talking bout amateur radioastronomy, take a look at this:

http://www.geocities.com/Area51/Dime...9/extracom.htm

Í've been trying to find more about those folks, without success. Maybe thay're only hoaxers. But the idea is feasible, in principle.

The detractors have their word too:

http://www.setileague.org/editor/extracom.htm

http://seti.sentry.net/archive/publi...9/00000010.htm

We've already strung up the entire planet with radio telescopes, networking them to effectively create radioscopes the size of the Earth. There'd be little benefit to putting a scope in orbit.

There is one possible place where an off-Earth telescope would be useful though. If we could put one on the far side of the Moon, we'd be able to shield it from the continual radio noise our busy modern society.

I'm also reminded of the A.C. Clarke novel Imperial Earth. In it he advocates creating very big radio telescopes in the outer solar system to investigate signals in extremely long (as in kilometers long) wavelengths.

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I'd say it wouldn't make much sense to put a radio telescope into LEO, but bringing it away as far as possible would give a pretty long baseline for interferometry.

Yes , David. That would add quality to radioastronomy.

And this would be awsome, too.

In the near(I hope) future we'll have antennas on Mars. The baseline Earth-Mars will constitute a helluva interferometer.

I could very well be wrong here, but I recall something about the Earth's atmosphere cutting off everything below 15mhz (or was it khz... I can't remember). Is that frequency range even significant?

And wouldn't shooting a radio telescope into space considerably lessen interference woes?
I suppose all the really big radio telescopes have this pretty much under control, but you could stick a really gigantic dish out in space and not have to worry about a hurricane destroying it and such. Although meteorites could be quite a problem I imagine.

To my knowledge, after the visual, and some bands in the IR, the main transparent region is in the radio spectrum. Of course there'll be some absorption in certain frequencies. Things may vary depending on cloud cover and water vapor concentration.

here's an interesting site for you to peruse.

The problem here is the cost/benefit ratio.

<font size=-1>[ This Message was edited by: Argos on 2002-11-07 11:49 ]</font>

That is precisely the type of site I've been looking for, thanks a mil for the link!

Yes, the ideas are great indeed, what if..? The links are good, but who is to say that an alien lifeform will be anything like our own.

One indication of distances over which radio transmissions might be detected here-
http://www.faqs.org/faqs/astronomy/f...ection-12.html

note- these distances are much smaller than some distances suggested earlier in this thread; so a critical look at this link might well be in order.

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