Radio Telescopes Vs Optical Ones

[Zacs-Master]

Prompted by a question posted by the Ed:

I appreciate that due to the speed of light distant galaxies etc are seen as they were millions, if not billions, of years ago bt is the same true of radio and other non light dependant astronomical observations?

[bert_h]

Yes, all of these non-material waves travel at exactly the same speed: light, infra-red, radio, microwave, X-rays, gamma radiation, everything.

[Teddio]

All electromagnetic radiation travels at the same speed in a vacuum. Therefore if an object in a galaxy, say one billion light years away, was emitting radio waves and gamma rays, both types of radiation would reach Earth with the same transit time.

[Jonathan-Joe]

Yes, what call "the speed of light" applies to all forms of electro-magnetic radiation which includes visible light and radio (and infra red, ultra violet, X-ray, microwave radiation etc). All these have the same velocity in a vacuum, so radio astronomy is looking into past in the same way as ordinary, visible light astronomy.
One difference though is in the size of intruments used. The sensitivity to E-M waves receives varies inversely to the wavelength. As radiowaves are much longer than light waves, larger receivers are needed for the same degree of resolution. This is why large arrays of seperate instruments are used for radio astronomy, the signals received being combined.
Some forms of E-M radiation mentioned above are of wavelengths that cannot penetrate tthe earth's atmosphere, so ground based observations are not possible.

[Zacs-Master]

Many thanks. You should never stop learning.