Science Questions

Do telescopes only see back in time?

Sat, 25th Aug 2012

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Question

Muhammad Al-Hakeem asked:

Is it real that all what we see in the sky happened in the far past, even millions of years, depending on how far the object is? And can the present universe be very different from real?

 

Is it possible to make a telescope or some sort of radio detector, that can see the real present universe?

 

Is the rate of the expansion of the universe higher than the speed of light? If so, does this explain why the visible universe is just a portion of the entire universe?

 

Sorry for the multiple questions. Many thanks.

 

Regards.

 

 

Answer

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Or Billions of years in the past.

Everything we see is dependent on the speed of light.  And so far, there are no particles (nutrinos, radio waves, x-rays, gamma-rays, etc) that exceed the speed of light. 

So,  NO, a bigger telescope will not make any difference.  What we see is what we get.

As far as the limit of the distance we can see.  There are at least 3 limitations.
Enough light arriving at earth.  The further an object is, the fainter the object will be.  There may in fact be a distance where incoming light will be too faint to view.
Red Shifting.  Telescopes for deep space often are specialized to see infra-red, due to red shifting.  I'm not sure how far the red-shifting is, but presumably one could view either microwaves, or even radio wave spectra.  Although the longer the wavelength, the larger the pixels.
Age of the universe.  Most estimates put the age of the universe at close to the distance of light that is visible.  We may, in fact, reach a limit in which distinct stars would no longer be visible. CliffordK, Thu, 2nd Aug 2012

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