Astronomers view light coming from distant galaxies moving away from the Earth at speeds greater than 10% the speed of light. How fast does this light meet the telescopes of the astronomers?
2007-05-31 20:17:48 · 5 answers · asked by Anniepannie06 2 in Science & Mathematics ➔ Physics
Speed of light is 3x10^8 m/s.
10% of this speed is 10% x 3x10^8 = 0.3 x 10 ^8 m/s.
Or we can say 0.1 C where C is the velocity of light.
In the problem it is given that the galaxies are moving away from the earth with speed greater than 0.1 C.
The “Light rays” are coming at the speed of C from the galaxies.
Whether the galaxies are moving away from earth or toward the earth and whether the speed of the galaxies is less or more, the astronomers in the earth will measure the speed of light as C only.
The light rays once emitted from the galaxies will travel with a speed of C only and it is not affected by the speed of the galaxies.
2007-05-31 22:13:51 · answer #1 · answered by Pearlsawme 7 · 0⤊ 0⤋
Your question "How fast does this light meet the telescopes of the astronomers?"
To me, this means - at what speed is this light traveling when it reaches the telescope?
There is nothing to calculate. The speed of light in vacuum is absolute, not relative. The speed of light therefore remains unchanged regardless of how fast the distant galaxy is moving.
Speed of light = c = 3 x 10^8 m/s.
2007-05-31 22:02:25 · answer #2 · answered by CC 2 · 0⤊ 0⤋
Since the speed of light does not vary, what happens is that the color of the light is shifted (toward red if going away) in a way that indicates the speed of the star. We "know" what the color of the star "should" be because of rules for various types of stars and because when we can make out a spectrum, the markers for hydrogen, helium, etc., are also shifted.
The light reaching us from the stars is traveling at the same speed as the light from the sun, so it gets here in a few billion years.
2007-05-31 20:26:35 · answer #3 · answered by Mike1942f 7 · 0⤊ 1⤋
Light always travels at velocity c = 10^8 m/sec, regardless of the motion of the source or the observer.
2007-05-31 20:22:46 · answer #4 · answered by gp4rts 7 · 0⤊ 0⤋
Speed of light in vacuum is constant and is not affected by the relative motion of the observer and the object, unlike the change in relative velocity of objects at normal day to day levels.
2007-05-31 20:36:01 · answer #5 · answered by Swamy 7 · 0⤊ 0⤋