How long would it take for a radio signal from alpha centauri to reach earth?


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MrGray
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Message 549423 - Posted: 20 Apr 2007, 6:17:56 UTC

How long would it take for a sound signal from Alpha Centauri to reach earth?

If frequency is a variable please explain time differentials.

What spectrum of sound frequencies does SETI search through?

I will be trying to calculate this myself but someone may know off-hand.


Thanks in advance.




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Message 549430 - Posted: 20 Apr 2007, 6:46:57 UTC - in response to Message 549423.
Last modified: 20 Apr 2007, 6:58:59 UTC

How long would it take for a sound signal from Alpha Centauri to reach earth?

If frequency is a variable please explain time differentials.

What spectrum of sound frequencies does SETI search through?

I will be trying to calculate this myself but someone may know off-hand.


Thanks in advance.




.

I think it's about 4 years (Because it's roughly 4 light years away from our sun?)

Alpha Centauri
Alpha Centauri is the closest star system to our own solar system at 4.37 light-years distant (about 41.5 trillion km, 25.8 trillion miles or 277,600 AU). Proxima Centauri, often regarded as part of the system, is 4.22 light-years distant.



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Message 549438 - Posted: 20 Apr 2007, 7:14:20 UTC - in response to Message 549423.

How long would it take for a sound signal from Alpha Centauri to reach earth?

If frequency is a variable please explain time differentials.

What spectrum of sound frequencies does SETI search through?

I will be trying to calculate this myself but someone may know off-hand.


Thanks in advance.




.


It would never reach earth. Sound requires a medium, air, water etc. to travel through.

SETI is "listening" to electromagnetic radiation, or if you prefer, radio waves.

Hope this helps.
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Message 549457 - Posted: 20 Apr 2007, 8:03:50 UTC
Last modified: 20 Apr 2007, 8:21:53 UTC

Woops,

Sorry for the terminology error. I knew what I meant, but said what I didn't mean, lol. Thanks Graeme.

So let me Google the speed of radio signals...


Ok.

Thanks guys!




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Message 549658 - Posted: 20 Apr 2007, 16:47:26 UTC

I think this thread needs expanding. So new question:
How long would it take for a typical NASA rocket to reach Alpha Centuri?

And:
What's so great about alpha Centuri anyways?

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Message 549693 - Posted: 20 Apr 2007, 18:11:54 UTC - in response to Message 549658.

I think this thread needs expanding. So new question:
How long would it take for a typical NASA rocket to reach Alpha Centuri?

And:
What's so great about alpha Centuri anyways?

I think the nearest star is not Alpha Centauri but Proxima Centauri, about four and a half light years away. Could not be reached by a chemical rocket even in a thousand years but only by ion propelled systems with nobody aboard.
Tullio
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Message 549705 - Posted: 20 Apr 2007, 18:49:15 UTC

Alpha Centauri is about 25,000,000,000,000 miles away. Sound at sea level travels about 760 miles per hour (under standard conditions). So it would take sound about 3,750,000 years to get there if standard air extended all the way to the star. I guess that would be absolutely impossible-maybe that would coalesce into a big globular cluster or something(?). If a NASA rocket were traveling at Earths escape velocity (about 25,000 mph which is about 40 percent or so more than nearby satellite velocity) it would take 1,000,000,000 hours or about 114,000 years to get there.
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Message 549737 - Posted: 20 Apr 2007, 20:12:38 UTC
Last modified: 20 Apr 2007, 20:13:04 UTC

Amazing how small we really are!

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Message 549868 - Posted: 21 Apr 2007, 0:59:52 UTC - in response to Message 549693.
Last modified: 21 Apr 2007, 1:00:23 UTC

with nobody aboard.

I'll start up a collEction.
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Message 549964 - Posted: 21 Apr 2007, 3:35:04 UTC

I know this is off topic but i cant post in some forums. How do i create a little graphic that others have showing my stats?
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Message 549970 - Posted: 21 Apr 2007, 3:49:02 UTC - in response to Message 549457.
Last modified: 21 Apr 2007, 3:49:22 UTC



So let me Google the speed of radio signals...


Radio waves travel as fast as light waves because they are light waves. Gamma rays, x-rays, microwaves and radio waves they are all light waves.
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Message 549999 - Posted: 21 Apr 2007, 4:55:05 UTC

Yep,

Google was faster.


:)




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Message 550096 - Posted: 21 Apr 2007, 10:25:36 UTC - in response to Message 549693.

I think this thread needs expanding. So new question:
How long would it take for a typical NASA rocket to reach Alpha Centuri?

And:
What's so great about alpha Centuri anyways?

I think the nearest star is not Alpha Centauri but Proxima Centauri, about four and a half light years away. Could not be reached by a chemical rocket even in a thousand years but only by ion propelled systems with nobody aboard.
Tullio


Proxima Centauri. Interesting.

This data look correct too you guys?

http://en.wikipedia.org/wiki/Proxima_Centauri
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Message 550101 - Posted: 21 Apr 2007, 10:51:31 UTC - in response to Message 549964.

I know this is off topic but i cant post in some forums. How do i create a little graphic that others have showing my stats?



Go to Your account / Profile /Edit profile.

Down near the bottom of the page is what you need.

Hope this helps.

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Message 550217 - Posted: 21 Apr 2007, 14:48:17 UTC

What's so great about Alpha Centuri?

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Message 550247 - Posted: 21 Apr 2007, 15:17:35 UTC - in response to Message 550217.

What's so great about Alpha Centuri?


Apart from the Sun, it's the closest star system to us. The whole system consists of three stars, Alpha, Beta and Proxima Centauri. If we ever developed technology to travel between stars, it would be the logical first place to visit.

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Message 550613 - Posted: 22 Apr 2007, 1:21:46 UTC - in response to Message 550247.

We must remember that radio frequecies traveling long distances will degrade as the time from the initial point of transmission to receiver increases.

In space there are many obstacles that radio frequencies must pass through like interstellar gases, UV radiation from sun's and even asteroid fields that would hinder this transmission.


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Message 550787 - Posted: 22 Apr 2007, 8:23:17 UTC

True!

And a bunch of other variables too I bet.
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Message 550856 - Posted: 22 Apr 2007, 11:43:11 UTC - in response to Message 550787.

True!

And a bunch of other variables too I bet.


How about radio signals sent through wormholes, Could easily be mistaken for a natural phenomenon.
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Message 551152 - Posted: 22 Apr 2007, 19:58:45 UTC

True!

But, maybe there is some noticeable effect on things traversing through the holes.
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