In the Previous Section, the focus was on telescopes observing the visible spectrum. Obviously, this is a very small section of a much larger spectrum - the Electromagnetic spectrum.
In order to gain a true understanding of the wider Universe, all sections of the EM spectrum must be observed. To do this, scientists have developed a range of telescopes that can view different sections of the EM spectrum.
The image below shows the Crab Nebula (Messier object 1), imaged in different parts of the EM spectrum:-
Visible Light
These telescopes have been covered extensively in the previous section (Optical Telescopes). The image below shows the Crab Nebula in the visible spectrum as imaged by the Hubble Space telescope, to be used as a reference image for other sections of the EM Spectrum:-
Radio Telescopes
The image below show the Crab Nebula as seen in Radio Waves:-
The lowest Energy section of the EM Spectrum gives a unique view of the wider Universe. By observing the Radio part of the Spectrum, it is possible to view some of the most energetic processes in the Universe.
Radio Astronomy has allowed scientists to observe Pulsars, a type of very dense star left over after a supernova. These Pulsars rotate very quickly (several times a second) , emitting a beam of radio waves, like a lighthouse. These signals were originally mistaken for Alien transmissions!
Radio Astronomy has also given scientists strong evidence for the Big Bang, by showing the 'afterglow' of the Big Bang in the form of the 'Cosmic Microwave Background'.
Radio telescopes can also be linked together to form a Radio telescope array, where many telescopes can act together to create highly detailed images in a process called Radio Interferometry.
Radio telescopes are the some of the biggest telescopes on Earth, with the Arecibo array in Puerto Rico (image below) being the largest at 300 m in diameter.
The video below show that the Arecibo array can have uses other than Astronomy...
Infrared Astronomy
The image below show the Crab Nebula as seen in Infrared waves:-
Infrared Astronomy allows the detection and observation of some of the coldest material in the Universe. Stars and other hot object appear very faint in the far Infrared spectrum, but cold dust and gas glows brightly.
Very little Infrared astronomy can be done on the Earth's surface as the water vapour in the atmosphere absorbs the incoming Infrared radiation. Most is accomplished using space telescopes, such as the Spitzer Space Telescope.
X Ray Astronomy
The image below show the Crab Nebula as seen in X-Ray radiation:-
X Ray astronomy allows the detection of the Hottest Objects in the Universe. X-Ray astronomy can be used to image the infalling dust and gas around a Black Hole event horizon due to the heating caused by the intense Gravitational Forces.
Very little X Ray astronomy can be done on the Earth's surface as the atmosphere absorbs the incoming X Ray radiation. Most is accomplished using space telescopes, such as the Chandra X-Ray Observatory.
