![]() As all matter has some heat energy stored in it, atoms vibrate, emitting electromagnetic radiation. Thermal emissions are caused by the motion of charged objects such as molecules and atoms. There are two basic forms of radio emission thermal and non-thermal. So what exactly do radio waves tell us? In order to answer this we need to understand how they are produced. By detecting and studying electromagnetic emissions, astronomers can determine the conditions that produced them and so increase our understanding of objects and conditions far out in space. Some forms such as X-rays can only be detected by telescopes in space as our atmosphere absorbs them, preventing them from reaching the Earth's surface. Astronomers can now detect all these types of emissions, sometimes by telescopes on the ground. ![]() The Electromagnetic Spectrum (Credit: NASA)Įach type of electromagnetic radiation is produced by certain conditions. Going up in frequency and energy the electromagnetic spectrum comprises radio and microwaves, infrared waves, visible light, ultraviolet rays, X-rays and γ - or gamma rays. The long wavelength, low frequency hence low energy form is called radio waves. We can detect many forms of electromagnetic radiation that together comprise the electromagnetic spectrum. When charged particles such as electrons and protons accelerate by changing their speed or direction, they emit electromagnetic radiation. Atoms have in turn are made of sub-atomic particles, with electrons orbiting the nucleus comprised of protons and neutrons. How are Radio Waves Produced?Īll the matter around us is made of atoms. Australia was at the forefront of this work with scientists at CSIRO's Radiophysics Laboratory making many important discoveries. After the war many of the scientists involved started to use this equipment to investigate the radio signals coming from space. The development of radar in the Second World War led to improvements in antennas and electronics. Radio waves were first detected from space in the 1930s but few scientists took the discovery seriously. Any electromagnetic with a wavelength greater than 1 mm is a radio wave. Radio waves are far weaker than this so we need electronic amplifiers to help us boost their signal. Visible light is energetic enough to help plants produce their own food through photosynthesis. ![]() The difference in radio waves is that they have a longer wavelength and are lower in frequency than visible light. Radio waves are a form of electromagnetic radiation, just like the visible light you are used to seeing with your eyes. When you listen to your radio, use a mobile phone or watch TV, you are using a device that receives radio waves. Astronomy, perhaps the oldest of Sciences, is the study of celestial objects including the planets, stars, galaxies - even the Universe as a whole. In effect, we see objects as they were in the past as it takes that light time to travel across space. ![]() When astronomers use large telescopes to probe the Universe, the faint light they gather may have come from objects millions or billions of light years away. That light has travelled across space for dozens, hundreds or thousands of years before entering your eye. When you gaze up at the night sky you see light given off by stars. ![]()
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