In what ways do astronomers depend on electromagnetic radiation to provide information about objects?
99849
Light is one form of electromagnetic radiation, I think it is pretty obvious how light is important to astronomers.\n\nBut sometimes just seeing the object isnt enough, we want to know more.\nFor example, if we wanted to know the chemical composition of a far-off star we can do this by analysing the emmision spectrum of the star.  When electrons around the nucleus of particular atoms get excited they jump up to higher energy levels.  When the electrons fall back to the ground state, the give off a photon of light (not necesarily in the visible spectrum) of a specific wavelength.  We can analyse that light given off by a star and compare it to the ligh given off by known elemetns, from this we can figure out what stars are made out of.\n\nThe electromagnetic spectrum is so broad, there are so many things we can learn by studying the EM waves coming in from outer space.
75779
This is intuitive if you remember that light is an example of an electromagnetic wave.  \n\nA lens can focus electromagnetic waves, and mirrors can divert them.  They can be 'stopped' by being absorbed into something, and many materials will absorb electromagnetic waves (like skin, that absorbs light, and therefore warms up and gets tan in sunlight).
24075
Radio SETI (Search for Extraterrestrial Intelligence) is the effort to detect narrow-band radio signals. Nothing known other than technology (i.e., a radio station) can make narrow-band signals—that is, signals that you can tune into and out of with just a turn or two of the radio dial. Optical SETI uses the same reasoning, but here again apparently only technology can produce light pulses that last a billionth (nano) of a second (although stars can collapse to make a millisecond pulsar that can pulse a thousand times per second). Since PlanetQuest will be using only the red part of the star’s light to detect the transits of planets across their stars, we plan to "beam-split" (divide off) the blue light and send it to our nano-second diode detectors to see at the same time if any of those stars are sending billionth-of-a-second pulses toward us, as well. Thus you, the PlanetQuester, will be looking for planets and extraterrestrial technology at the same time!
382985
Light and radio signals are all the same thing, electromagnetic radiation. Radio waves are just very low frequency light and light is just very high frequency radio signals. All objects that are hotter than absolute zero give off some electromagnetic radiation. The really hot objects give off visible light. Cooler ones give off infra red light. Cooler still and you get radio emissions. The Earth's surface gives off radio waves because it is warm. In fact, it gives off so much that it is an interference for communication satellites trying to hear signals from the ground.\n\nModern radio astronomy uses giant antennas to focus radio waves, just like optical telescopes focus visible light. Computers are used to construct images of what the sky would look like if your eyes could see radio waves.
489848
They study the science of objects and matter beyond the earth's atmosphere and their interactions in space.
326233
They can basically find out the composition of the sun ie.., what material it is made up of, which is because different elements have unique spectral characteristics.And they can estimate its surface temperature.
955715
There is an awful lot of info. You are talking about a field to which tens of thousands of people have each dedicated a lifetime of study!  If you are studying for a test, you need to focus on the contents of that particular test.  \n\nA nice site I like that has cursory information on many thing astronomical and space related written for the lay person is the Astronomy Picture of the Day.\n\nhttp://apod.gsfc.nasa.gov\n\nThe archives go back to 1994, with few repeats.
1035641
if you mean spectroscopy and related fields here's something.\n\nspectrum:  variation of intensity with frequency or wavelength.\n\nstudy of intensity of the radiation. Basically\nyou have an unkown source of light. You tell what frequencies\n(or colours) are how much intense.\nUsually it's of the following types\n\nOptical spectroscopy (visible light)\nX -ray spectroscopy\ninfrared spectroscopy\nneutron spectroscopy\nthomson spectroscopy\nradio\n\nspectra can be absorption or emmision. \n\natomic specroscopy\nmolecular spectroscopy\n\nall this info can be used to study known materials\nand find composition of un-known materials.\nhealth purposes too
565906
Electromagnetic radiation travels (propagates) by means of oscillating electromagnetic fields that pass through the air and the vacuum of space equally well, and does not require a medium of transport (such as the aether). When radio waves pass an electrical conductor, the oscillating electric or magnetic field (depending on the shape of the conductor) induces an alternating current and voltage in the conductor. This can be transformed into audio or other signals that carry information. The word 'radio' is used to describe this phenomenon, and television, radio, radar, and cell phone transmissions are all classed as radio frequency emissions.
132650
There are many instruments used by astronomers:\n1. optical telescopes\n2. radio telescopes\n3. computers\n4. space craft\n5. magnetometers\n6. cameras\n7. photomultiplier tubes\n8. CCD arrays\n9. clocks\n10. photometers\n11. thermocouples\n12. comparators (blink microscope)\n13. spectrohelioscope/spectroheliograph\n14. coronagraph\n\nThere have been a large number of instruments that have been used historically. Many are listed in some of the references below. Many more can be found with a few simple web searches.
24533
If you have ever wondered how you get to see and hear. how stuff like cell phones, microwave and remote-controled toys work, you need to learn Electromagnetic Spectrum, Wavelength And Frequency to understand.\nIf you are not curious, they are not important.
121596
You don't send radio or x-ray, you measure them coming from the objects in the sky. The telescope is the instrument to collect this waves and concentrate them. Just as a common telescope receives light, this instruments receive other wavelenghts such as the mentioned above, which are produced and send by the objects.
604233
By using spectra. Each element has characteristic frequencies of light that it emits or absorbs. If light from the star is spread out into a spectrum (like a rainbow), there will be dark lines for absorbtion and bright lines for emission. By identifying the chemicals that correspond to those lines, we deduce the composition of the star.
945555
One of the four forces in nature is the electromagnetic force.  A sub-aspect of this is the qualities of electromagnetic radiation.  What is electromagnetic radiation?  It's every form of energy radiation on the electromagnetic spectrum such as:\nmicrowaves -- get a quick meal, transmit information using microwaves as a carrier wave like cell phones and satellites do.\nradio waves -- pretty much everyone knows what a radio is and has one.\nX-rays -- medical diagnosis would be lost without them.\nUse of the magnetic force also allows for things in the medical industry such as MRI and CT scans....that whole nuclear medicine field.\nThe flow or movement of particles called electrons is studied by physicists.  The flow or current of electrons is also known as electricity.  Lots of people use that for various things.\nIn a fundamental sense, everything is made up of atoms.  \nThe atomic and sub atomic world is the purview of the field of study called quantum physics.  So, EVERYTHING is influenced by physics in a sense.
34105
The electromagnetic radiation from electrical devices COULD be used to induce a tiny current in a conductor, and used for some purpose. However, energy efficient devices experience very little leakage of radiation at these frequencies, or else they would violate FCC rules and interfere with a lot of other things. The biggest source of electromagnetic radiation from these devices is probably infrared radiation, or heat, which you could use to heat your home or for other purposes.
360176
Just singular? Sceintist or professor? Maybe you meant scientists or professors. Not that the professors are the leading authority on celestial discoveries. They more of just train others to go outside and look straight up in the air. Usually they use a telescope. In some cases, they consult the spheres. In your case, I'm surprised you even know what the word discover means.
1103962
Analyzing light can tell you almost anything about the universe.  You can calculate just how excited every photon is, what color or what "brand" of light is emitted from any given star in the entire visible universe.  Photons behave certain ways when they interact with certain substances, so how light bounces or reflects or refracts or in other ways interacts with planets and their atmospheres can give us an idea as to what makes it up.  By combining what we can determine from gravitational influence and the amount of energy and type of light emitted from a star, we can find out how massive a star is and what makes it up.  Light is really the only data we have about the universe--luckily, light is qualitative and quantitative and we can learn a heck of a lot from it.  Every single reaction that takes place on an astronomical scale has a tag associated with it--something it gives off 999,999 times out of a million, where if astronomers see it, they know what's going on.  By seeing light--which is more than visible light, but radio waves, UV rays, and gamma rays--they can postulate anything that's going on, even billion of light years away.