Can the Arecibo Radio Telescope Eavesdrop on the Entire Galaxy?

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Discussion Overview

The discussion revolves around the capabilities of the Arecibo Radio Telescope in terms of its ability to eavesdrop on signals from the entire galaxy. Participants explore the telescope's power, resolution, and comparison with other radio telescopes, particularly in the context of SETI (Search for Extraterrestrial Intelligence) and astronomical observations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question whether Arecibo can truly eavesdrop on the entire galaxy, suggesting that its ability depends on signal intensity.
  • One participant notes that Arecibo can pick up a 1 MW signal from about 1000 light years away, prompting questions about the significance of this power.
  • There is a discussion about the factors that contribute to the power of a radio telescope, including antenna size, amplification, filtering systems, and processing power.
  • Some participants argue that while Arecibo is powerful, its resolution decreases with distance, and smaller telescopes in collaboration can outperform it in certain aspects.
  • One participant asserts that Arecibo is unique in its ability to operate from a single location, contrasting it with arrays of smaller telescopes that require data synchronization.
  • Concerns are raised about Arecibo's suitability for SETI purposes due to its non-steerable nature, with suggestions that other telescopes may be better suited for this task.

Areas of Agreement / Disagreement

Participants express differing views on Arecibo's capabilities, with some highlighting its power and uniqueness, while others argue that it is not as effective as collaborative smaller telescopes or that its non-steerable nature limits its utility for SETI.

Contextual Notes

Participants mention various technical aspects and limitations of Arecibo, such as its resolution and the need for synchronization in multi-telescope arrays, but do not resolve these points definitively.

Gold Barz
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Is it true that it can eavesdrop the entire galaxy?, like it has the ability to scan the whole galaxy?
 
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Depends mostly on signal intensity. It would pick up a 1 MW signal out to about 1000 light years.
 
So...I don't know anything about this stuff, is that "powerful"?
 
It's a very powerful radio telescope*...which makes it great for SETI's purposes (and many other astronomy purposes)...but like any other telescope it's resolution decreases with distance.

* The most powerful currently available? Someone remind me.
 
Gold Barz said:
So...I don't know anything about this stuff, is that "powerful"?
Extremely. Keep in mind that several factors determine this. One is the size of the antenna array, another is the amplification and filtering system, and another is the processing power available for presenting the data in a useable format. An antenna the size of the Earth would be useless if you couldn't extract information from it, and the most powerful amplifier on the planet wouldn't do much good hooked up to a Bell ExpressVu satellite dish.
 
Phobos said:
It's a very powerful radio telescope*...which makes it great for SETI's purposes (and many other astronomy purposes)...but like any other telescope it's resolution decreases with distance.

* The most powerful currently available? Someone remind me.
The power of a telescope is usually defined as a function of its resolving power. With very clean amplification, accurate data-handling and a long baseline, small radio telescopes can be combined to trump Aricibo. As a single telescope, Aricebo is a monster, but it cannot probe shorter wavelengths with the resolution of a long-baseline collaboration pair.

http://www.brightsurf.com/EDU_news_093002_b.html
 
So the arecibo is not really a unique radio telescope with what it could do? since a lot of smaller telescopes together could do better.
 
Gold Barz said:
So the arecibo is not really a unique radio telescope with what it could do?
It's unique in doing it all from one location. Multiple receiving dishes spread over a very wide area act like one huge one for radio detection. You just have to keep the data synchronized to give a coherent picture.
 
Arecibo, while sensitive, is not well suited for SETI purposes - it's not 'steerable'. This is, IMO, what you really need to do a bang up job:
http://www.space.com/scienceastronomy/astronomy/greenbank_observatory_000826.html
 
Last edited by a moderator:
  • #10
Chronos said:
This is, IMO, what you really need to do a bang up job:
http://www.space.com/scienceastronomy/astronomy/greenbank_observatory_000826.html
In a way, Aricibo is 'steerable' in that it sweeps the sky at Earth's rotation rate. This thing that you linked to is pretty impressive, I must say, although I only scanned the first page of the site (my time is very limited, but I'll check it out in more depth later).
 
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