Radio Astronomy

A lot of useful information can be got from studying the radio waves emitted by large scale cosmic objects such as galaxies. The image below is of the galaxy NGC 4261

(Passive radio astronomy, not active as in the use of RADAR)

pic NRAO

Stars do not emit a huge amount of radio waves although there are advantages to studying in this part of the electromagnetic spectrum.

• Radio waves travel through dust and other material that can obscure light and other waves, e.g. from the heart of our own galaxy.
• New radio emitting objects such as pulsars have been discovered
• Patterns in large scale objects, such as nebulae and galaxy clusters, are more easily seen.

Radio waves have the largest of all electromagnetic waves, because of this the resolution (ability to tell things apart) of the images obtained is poor. Very large radio telescopes are needed like those at Jodrell bank. radio telescopes, however, can be linked together with all the information going into the same computer to effectively produce one huge telescope.

The Very Large Array, VLA, in New Mexico consists of 27 telescopes arranged in a Y shape 36km across.

pic NRAO

The American national radio astronomy observatory  www.nrao.edu

The UK national radio observatory is at Jodrell Bank  www.jb.man.ac.uk