This post’s subject will be the radiotelescopes, I will explain how they work and why are used.
Was discovered that electromagnetic waves with wavelength bigger than the visible light come from space and are emitted by galaxies, stars and other celestial bodies. The microwave background radiation is a microwave radiation from space and one of the Big Bang remnants.
Some radio wave sources come from quasars, which are supermassive black holes with a gas disk with millions of degrees Celsius and send a great quantity of radiation.
Radio pulses in regular range from space come from pulsars, which are rotating neutron stars and are highly magnetized. One supermassive star which depleted your hydrogen fuel become a supernova and them a neutron star.
Can have a greater understanding of the universe, it`s evolution and it`s phenomena by observing the sky with lights of different wavelength beyond the visible light. The figure below shows a galaxy saw by light in various wavelength.
Many space objects stay so far that only can be visible by radio waves.
How they work?
Every radiotelescope have: parabolic antenna with subreflector, signal receiver, recorder to save content and tuner to choose the frequency of the captured signals. The antenna receives signal from space. The signal is received, amplified and saved in a computer to be analyzed.
The radiotelescopes deal with bigger wavelength. For that they have a lower resolution than optical telescopes with same size. To increase the resolution the parabolic antenna must be bigger. However a parabolic diameter bigger than 100 meters make it difficult to control. The solution is to implement antennas arrays.
Many telescopes appointed in the same direction have the same resolution of a radiotelescope with the the sum of the antennas diameter. For example, 5 radiotelescopes of 10 meters can operate like only one 50 meters telescope. One disadvantages of the arrays is the delay caused by the cable`s length and the antenna`s position.
A correlator is used in the arrays to compensate the delays.