Since we are not able to travel to a star or take samples from a faraway galaxy, we must depend on electromagnetic radiation — light — to carry information to us from distant objects in space.
The Hubble Space Telescope can view objects in more than just visible light, including ultraviolet, visible and infrared light. These observations enable astronomers to determine certain physical characteristics of objects, such as their temperature, composition and velocity. The electromagnetic spectrum describes all of the kinds of light, including those the human eye cannot see.
In fact, most of the light in the universe is invisible to our eyes. The light we can see, made up of the individual colors of the rainbow, represents only a very small portion of the electromagnetic spectrum. Other types of light include radio waves, microwaves, infrared radiation, ultraviolet rays, X-rays and gamma rays — all of which are imperceptible to human eyes.
All light, or electromagnetic radiation, travels through space at , miles , kilometers per second — the speed of light. Light travels in waves, much like the waves you find in the ocean. As a wave, light has several basic properties that describe it.
One is frequency, which counts the number of waves that pass by a given point in one second. Another is wavelength, the distance from the peak of one wave to the peak of the next. These properties are closely and inversely related: The larger the frequency, the smaller the wavelength — and vice versa. A third is energy, which is similar to frequency in that the higher the frequency of the light wave, the more energy it carries.
Your eyes detect electromagnetic waves that are roughly the size of a virus. Your brain interprets the various energies of visible light as different colors, ranging from red to violet.
Red has the lowest energy and violet the highest. On one end of the electromagnetic spectrum are radio waves, which have wavelengths billions of times longer than those of visible light. The Visible Spectrum Visible light is the light that we can see, and thus is the only light detectable by the human eye.
White light is visible light, and it contains all the colors of the rainbow, from red to violet. The range of visible wavelengths is to nanometers. Ultraviolet light is the radiation from the sun that causes a sunburn when you have been outside too long on a sunny day. But, watch out! You can't see ultra-violet light, so you can still get sunburned on a cloudy day.
The range for ultraviolet light is 10 -8 to 10 meters. X-rays are very energetic, and are used in X-ray machines to take pictures of your bones. The range for X-rays is 10 to 10 meters. Gamma rays are the most energetic light waves found on the electromagnetic spectrum. We can find Gamma rays released in nuclear reactions and particle collisions. The range for a gamma ray is in picometers 10 meters.
Energy whose wavelength is too long to see is "redder than red". Light with such long wavelengths is called "Infrared" light. The term "Infra-" means "lower than". How do we know this kind of light exists? One way is that we can feel energy with these wavelengths such as when we sit in front of a campfire or when we get close to a stove burner. Scientists like Samuel Pierpont Langley passed light through a prism and discovered that the infrared light the scientists could not see beyond red could make other things hot.
Very long wavelengths of infrared light radiate heat to outer space. This radiation is important to the Earth's energy budget. If this energy did not escape to space, the solar energy that the Earth absorbs would continue to heat the Earth. About this capture. Organization: Alexa Crawls. Collection: Alexa Crawls. Learn more: Violet light. Indigo light. Blue light. Green light. Yellow light. Orange light. Red light.
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