An equally important tool is the spectroscope. The light given off by stars usually contains a mixture of several different colors of light. A spectroscope can break up the light from a distant star into its characteristics colors.
When light enters a microscope, the light is first focused into a beam by a lens. The beam of light then passes through a PRISM. A prism separates light into its different colors. The band of colors formd when light passes through a prism is called
This kind of spectrum produced by the light from a star tells astronomers a great deal about the star.
Every single object in the universe is on the move.
The moon, for example, moves around the earth. The earth, in turn, travels around the sun.
The sun moves about the center of the galaxy it is located within.
Astronomers suggest that there may be as many as 100 billion major galaxies. And each galaxy has billion of stars. Like all the other objects in space, each and every galaxy is on the move. By using a spectroscope, astronomers can determine whether a particular galaxy is moving toward the earth or away from earth.
As we all know, spectroscope breaks up light into a spectrum. This happens because each color of light has a different wavelength. When the light strikes the prism in a spectroscope, the prism bends the light according to the wavelength of each color.
Suppose a star is rapidly approaching the earth. The light waves from the star will be compressed, or pushed together. What is the color of light with shorter wavelegnth? So the entire spectrum of an approaching star appears to be shifted slightly toward the blue end of the spectrum. This shifting is called BLUE SHIFT.
Suppose a star is moving away from earth. The light waves from the star will be slightly expanded. What is the color of light with longer wavelength? So the entire spectrum of an approaching star appears to be shifted slightly toward the blue end of the spectrum. This shifting is called RED SHIFT.
an increase (or decrease) in the frequency of sound, light, or other waves as the source and observer move toward (or away from) each other. The effect causes the sudden change in pitch
When astronomers first used the spectroscope to study the light from stars in distant galaxies, they had a big surprise. None of the light from distant galaxies showed blue shift, meaning none of the galaxies were moving towards the earth. Instead the light from distant galaxies showed red shift. Every galaxy in the universe seemed to be moving away from the earth.
After examining the red shifts of distant galaxies, astronomers concluded that the universe is expanding. Galaxies that are far from the center of the universe is moving away at tremendous speed. Galaxies near the center of the universe is also moving but at slower speed.
And scientist have discovered that the background radiation in the entire universe is almost the same everywhere.This constant background radiation is one observation that supports the big bang theory.
After the initial big bang, the force of GRAVITY began to affect the matter racing outward in every direction.
Most astronomers feel that the big bang theory leads to two possible futures for the universe.
-Open Universe and Closed Universe
If the big bang theory is correct, then quasars at the very edge of the universe were among the first objects formed after the big bang. Keep in mind that the light from a quasar 12 billion light-years from the earth.
