Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 01/12/2015 08:50:02

Title: Do big objects block or distort radiation?
Post by: thedoc on 01/12/2015 08:50:02

Philip Bartle asked the Naked Scientists:
   What is the effect of all the massive objects in between us and the cosmic background radiation, would some kind of distortion be expected on the map?
What do you think?

Title: Re: Do big objects block or distort radiation?
Post by: evan_au on 01/12/2015 11:36:12

The nearest big object is the Sun, and I imagine that the satellite controllers were careful not to point their sensitive detectors at the Sun!

The next nearest big thing is the galaxy. When you look at the raw data picked up by the Planck spacecraft, you can see a very strong signal from stars in the plane of the galaxy (the red horizontal band). This would have to be carefully subtracted by looking at the spectrum expected from stars, and removing it from the background radiation.

See: http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2009/09/planck_first_light_survey/10198835-2-eng-GB/Planck_first_light_survey_fullwidth.jpg