Reason for using infrared for capturing cosmic images Why is infrared used to capture the images of distant galaxies? I came to know that due to its higher wave length, it could penetrate easily through the mighty dust of the cosmos out of which magnificent pictures can be captured. But that confuses me, higher wavelength means lower frequency hence lesser energy from the equation E=hf. 
So how can a light with lesser energy would pass through the mighty cosmic rubble and is able to capture the images. And if that is so, why are radio waves with much higher wavelength are not used to do so?
 A: The main reasons to use infrared light to study distant galaxies are:
(a) Because their light is highly redshifted. The peak wavelength of their light is increased by a factor of $(1+z)$, where $z$ is the cosmological redshift. Distant galaxies may have $z \sim 3$ and perhaps as large as 10.
(b) Because many galaxies in the early universe are highly obscured by dust formed from the metals produced by bursts of supernovae in their early lives.
Radio waves have even longer wavelengths and are even more able to penetrate dust. Radio waves are used to study high redshift galaxies, but the emission that they detect is often "non-thermal" in nature and more usually associated with quasars and other active galactic nuclei. The light produced by "normal stars" in galaxies has "thermal emission" that peaks in the rest-frame UV, visible and near infrared part of the spectrum and this is redshifted into the mid- to far-infrared regions for distant galaxies with $z>3$.
You ask why light of lower energy is more likely to make it to us through the "dust and rubbles of the cosmos"?
First, there is very little (negligible) dust between galaxies, so the problems with absorption arise in light passing through our Galaxy and escaping from the distant galaxy that emitted the light.
Second, there is no "rubble". The cross-sectional area occupied by anything that could be described as such is completely negligible.
The answer is complex, but the simplest way of putting it is that light of lower energy has less chance of interacting with any matter that it encounters. In the case of scattering by interstellar dust, there is a big increase in transparency when the wavelength of light becomes larger than the dust particle size - see for example any article on Rayleigh scattering. In general matter is more transparent to longer wavelengths of light.
