RADIO ASTRONOMY One Earth Foundation

Electromagnetic spectrum Whenever an electric charge changes speed or direction it gives off an electromagnetic (EM) wave. How fast the wave ‘wiggles’ determines what kind of EM radiation is created. Lowest energy to highest energy as follows: Radio, Infrared, Visible Light, Ultraviolet, X-Rays, and Gamma Rays.

What are Radio Waves? Form of electromagnetic radiation. Travel at the speed of light Frequencies from 3kHz to 300GHz Wavelengths from 1mm to 100km. Used by radio, mobile phone, TV. Any electromagnetic with a wavelength greater than 1 mm is a radio wave.

Difference between radio waves and light energy RADIO WAVESLIGHT ENERGY Long wavelengthShort wavelength Low frequencyHigh frequency Low energyHigh energy

What is radio astronomy? In simple words, radio astronomy is the study of the invisible universe. It is the study of celestial objects that emit radio waves. With radio astronomy, scientists can study astronomical phenomena that are often invisible in other portions of the electromagnetic spectrum. Radio astronomers make images using the radio waves emitted by objects, as well as by gas, dust and very energetic particles in the space.

History of radio astronomy First detected in space in around the 1930’s After WWII scientists used radars to investigate radio signals from space. Australia was at the leading front of radio astronomy.

Advantages and Disadvantages Advantages: Can see part of electromagnetic spectrum other instruments cannot see. Can see through dust Can see ionized hydrogen and thus map the galaxy Work day and night Relatively simple technology Disadvantages: Poor resolution per aperture Expensive to build and maintain Need to be supercooled to maintain precision

Radio Telescope Designed to detect radio waves from space. Has 3 components:  One or more antennas to collect the incoming radio waves.  A receiver and amplifier to boost the very weak radio signal to a measurable level.  A recorder to keep a record of the signal.

What do we learn from Radio Astronomy? Radio astronomy has been a major factor in revolutionizing concepts of the universe and how it works. They have revealed exciting objects such as pulsars and quasars that had been completely unexpected. Remnants of the big bang have been revealed. Shows afterglows of the supervenergetic gamma ray bursters. Of ten nobel prize laureates, six of them used radio telescopes for their works.

Random fact Cassiopeia A is the remnant of a supernova explosion that occurred over 300 years ago in our Galaxy, at a distance of about 11,000 light years from us. Cassiopeia A is one of the brightest radio sources in the sky, and has been a popular target of study for radio astronomers for decades.

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