What are radio telescopes and what do they give us?
Discovering water on another planet, perhaps signs of life, out-of-the-ordinary activities in outer space, tracking teams sent to explore the vast universe, are the multiple and hostel aspirations shared by astronomers around the world. A complicated challenge, but not impossible if you have the necessary technology like radio telescopes, which has taken leaps and bounds in recent times.
Which is a radio telescope?
The radio telescope is a device used to capture radio waves from celestial bodies. Many of these bodies, such as active galaxies, emit radiofrequency radiation. Such radiations are more detectable in the radio region of the electromagnetic spectrum than in the visible light region by captured by police optical telescopes.
The study of all these radiations is called radio astronomy. Thanks to this branch of astronomy, it is possible to see bodies and situations that are not possible to detect with optical astronomy.
In radio astronomy, to capture good signals, large antennas or groups of antennas should be used working in parallel. Most radio telescopes use a satellite dish to amplify the waves. This allows astronomers to observe the radius spectrum of a region of the sky.
Two or more radio telescopes can be used together and the signals they receive from the same source can be combined. This allows astronomers to discern the source of radiation in detail and precision. Radio interference occurs when two or more radio telescopes are combined to form a large radio telescope, this is a widely used technique.
So the portion of radiation we are able to capture is a measure part of the surface of that and will also be affected by the distance, inversely squared. This is why telescopes are cooked and, if possible, the larger the collection area, the better. If an optical telescope has a target with an area 100 times mayor than the pupil of our eyes, be collecting 100 more radiation.
The origin of the radio telescope is due to Grote Reber, an American engineer, the place the pioneer of radio astronomy, who reaches a 9 meter antenna that he had for this purpose.
In the early 1950s, a technique called “interferometry” was used. This is based on the physical principle that if two light waves are crossed that match in phase, the wave as amplified. However, if the waves are in phase opposition, both waves are canceled.
This combination of Provencal light from different telescopes or radio antennas is used to obtain higher resolution images. In those years, with the Cambridge Interferometer, which is a mile away between its antennae, an analysis of the sky was carried out that gave the part the famous 2C and 3C maps of radio sources.
In 1957, at the Jodrell Bank Observatory (University of Manchester, England) it was placed on the radio telescope of a larger antenna window in the world in those years: 76 meters, it has played an important role in the search for quasars and pulsars.
In 1979, Einstein’s theory of general relativity was confirmed, when Jodrell Bank scientists announced the first gravitational detection
What is electromagnetic radiation?
Electromagnetic radiation is the product of a variation in the electrical and magnetic fields. A field is a region of space in which matter is subjected to some kind of force. In the case of electromagnetic radiation, the fields are produced by moving charged particles. Static electrical loads produce electric fields, while moving electrical charges produce, in addition to electric fields, magnetic fields. Changes regularly remain in these loads produced in these fields what we know as electromagnetic radiation. Electromagnetic radiation, by propagating the effects of these changes, carries energy from one point to another within the field. The propagation rate through space is 299,792 km/s. This is known as light speed. In fact, light is just one of these electromagnetic radiations. Examples of electromagnetic radiation include x-rays, microwaves, infrared radiation, AM or FM radio waves, or ultraviolet radiation
The only electromagnetic radiations that achieve the change of the communication unit and reach the observation instruments on the Earth’s surface are the range of visible light, with some expansion into infrared and the wavelengths in radiofrequency radio wave windows.
How does a radio telescope work?
The basic operating principles of a radio telescope are very similar to optical reflectors in telescopes. The most common types of radio telescopes are composed of a large plate that acts as a reflector of radio waves, focalizing them at a point that cone radio frequency detectors. The small current produced by radiation concentrated in the focus is amplified in a radio receiver, so that it can be measured and recorded. Electronic filters are then used to selectively amplify frequency limits commonly referred to as bands. Data processing techniques can even be used simultaneously for thousands of frequency bands. This shows the spectral distribution of radiation.
Importance of Radio astronomy
Radio astronomy has been the main protagonist of the evolution of astronomical knowledge over the course of the last thirty years. Let us remember, for example, the revelation of the spiral arms of the Milky Way to the observation of 21 cm hydrogen radiation or the discovery of quasars and pulsars. As they are not personal because of dust diffused in interstellar space, radio waves have perceived observing the central region of the Milky Way, which hides optical observation.
Radio astronomy has perished, so, begin to penetrate the secrets of the large, cold molecular clouds that populate the galaxy’s spiral arms, revealing the presence of numerous organic molecules that, at such a low temperature, only emit millimeter and centimeter radiation. The entry into recent years of telescopes for millimeter waves has complained to discover in the interstellar medium molecules of carbon oxide, hydrocyanic acid, methylamine, methyl alcohol, ethyl alcohol and many more.