How astronomers work?

5.Radio Astronomy
 
Radio Telescopes
The Very Large Array is a collection of parabolic dish antennas, located near Socorro, New Mexico. The 27 antennas are attached to a system of Y-shaped tracks; each track is 21 km (13 mi) in length. The individual signals from each telescope are combined into one high-resolution image, making the array the world's largest radio telescope.

Radio waves have the longest wavelengths. Radio astronomers use giant dish antennas to collect and focus signals in the radio part of the spectrum (see Radio Astronomy). These celestial radio signals, often from hot bodies in space or from objects with strong magnetic fields, come through Earth's atmosphere to the ground. Radio waves penetrate dust clouds, allowing astronomers to see into the center of our galaxy and into the cocoons of dust that surround forming stars.

6.Study of Other Emissions
Sometimes astronomers study emissions from space that are not electromagnetic radiation. Some of the particles of interest to astronomers are neutrinos, cosmic rays, and gravitational waves. Neutrinos are tiny particles with no electric charge and very little or no mass. All stars emit neutrinos, but neutrino detectors on [[KW]] Earth [[/KW]] receive neutrinos only from the Sun and supernovas. Most neutrino telescopes consist of huge underground [[KW]] tanks [[/KW]] of liquid. These tanks capture a few of the many neutrinos that strike them, while the vast majority of neutrinos pass right through the tanks.
Cosmic rays are electrically charged particles that come to Earth from outer space at almost the speed of light. They are made up of negatively charged particles called electrons and positively charged nuclei of atoms. Astronomers do not know where most cosmic rays come from, but they use cosmic-ray detectors to study the particles. Cosmic-ray detectors are usually grids of wires that produce an electrical signal when a cosmic ray passes close to them.
Gravitational waves are a predicted consequence of the general theory of relativity developed by German-born American physicist Albert Einstein. Since the 1960s astronomers have been building detectors for gravitational waves. Older gravitational-wave detectors were huge instruments that surrounded a carefully measured and positioned massive object suspended from the top of the instrument. Lasers trained on the object were designed to measure the object’s movement, which theoretically would occur when a gravitational wave hit the object. No gravitational waves have yet been detected. Gravitational waves should be very weak, and the instruments are probably not yet sensitive enough to register them. In the 1970s and 1980s American physicists Joseph Taylor and Russell Hulse observed indirect evidence of gravitational waves by studying systems of double pulsars. A new generation of gravitational-wave detectors, developed in the 1990s, uses interferometers to measure distortions of space that would be caused by passing gravitational waves.
Some objects emit radiation more strongly in one wavelength than in another, but a set of data across the entire spectrum of electromagnetic radiation is much more useful than observations in any one wavelength. For example, the supernova remnant known as the Crab Nebula has been observed in every part of the spectrum, and astronomers have used all the discoveries together to make a complete picture of how the Crab Nebula is evolving.