The red shift of a star means that?

Answer 1

ones moving away from us

Above is the typical Doppler Explanation. Of course, the star could be even still relative to us, when you consider the gravity hole (as an explanation for the red shift).

Answer 2

The speed with a star is moving at, or most probably away, from us can be calculated using the Doppler effect. The Doppler effect is the apparent shift in frequency of a wave due to relative motion between the source and the observer. Let's look at this a moment. You're standing in the middle of the straightaway at a race course. If an F1 car is headed your way at you full blast, it sounds like a large, angry insect. It has a characteristic "whine" as it comes at you. But as it passes you, the whine changes pitch downward. You've just experienced Doppler effect. The frequency of the sound as the machine was approaching was higher than it was from the point of view of the driver. And the sound pitched down after the machine passed you and headed away. To the driver, the pitch of the engine was pretty constant. Not so for you as the observer. When a star is moving away from the observer, receeding, the frequency of the light "shifts downward" so we see lower frequency light than what the star is actually emitting. As red is the color at the lower end of the visible spectrum, we call a shift toward the lower end of that visible spectrum a red shift, or redshift. (We removed the space.) Here's the deal. We look at the color we see and the color the star "should" be emitting. Then we do the math to see how much of a shift from its real color to the color we see, and that shift in frequency corresponds directly to a receeding velocity. We've applied what we know about Doppler shift or redshift to solve a problem! Note that this won't work for stars moving "across" our field of view, but only moving toward or away from us. It's quite simple, really. Piece of cake. Links can be found below.

Answer 3

Either you or the star are moving away from one another, or both.

It is when the light is stretched because you are moving away from each other so the light goes red- red shift!

Or the light is exiting a gravity hole (star).

Answer 4

Yes; in stars or galaxies that move away from us, the spectrum would shift towards lower energies; this is called "redshift"; if the star or galaxy comes towards us, the spectrum would shift towards higher energies, known as "blueshift".

Answer 5

We can determine the direction of travel of a distant star using the spectrum of light because of phenomena called the Doppler effect.

We have all experience a police car speeding past us. When is is coming towards us we hear a higher pitched siren. When it passes us and moves away from us there is a perseived shift in the tone of the siren the pitch of the sound goes down.

This is because sound at any given density has a constant speed. So when the source is moving towards us the sound waves are compressed. When the source is moving away from us the sound waves are stretched. The more stretched the sound wave the lower the tone we hear.

This is also true of light. Light speed is a universal constant. When objects are coming towards us the light from that object is compressed towards the blue end of the spectrum, it is said to be blue shifted. When it is moving away it is red shifted.

All elements absorb certain frequencies of light. These are called absorption lines. For the most common elements such as Hydrogen we know with a high degree of certainty what the absorption light should be. When we look at distant galaxies we see a distinct shift in these frequencies towards the red end of the spectrum. The further we look the more the light is red shifted. This allowed Edwin hubble to prove that the universe is expanding.

To a much finer degree astronomers have worked out that the absorption lines of certain stars are in constant flux. They seem to move from red shift to blue shift as if they were some how wobbling. This leads them to calculate that they may have planets orbiting them. January 20th, 2010 there are believed to be 334 stars with known planets orbiting and some 394 planets found using this method.

Answer 6

There is an effect called the Doppler effect. When a star is moving away from you, the frequency you "see" is lower than the frequency emitted by it. Because of that shift to lower frequencies and because red has the lowest frequency in the visible spectrum we call it a Redshift.

Answer 7

The redshift tells us how fast a star or galaxy is moving away from us (or a blue shift if it is moving towards us).

This is caused because of the limit of light speed and special relativity. It doesn't matter how fast you go, light always appears to travel at the speed of light. Even if you are going just a few miles per hour slower then the speed of light, it will appear that light zips on by you at it's normal speed. because of this, as galaxies travel away from us, the light has to stretch to maintain this principle, as the light stretches, it shifts its wavelenght a bit, making it appear redder.

Answer 8

Shifting is this context refers to the Doppler shifting of emitted light. Objects moving towards us will undergo blueshift while light moving away will undergo red shifting. If a star previously known to have a blueshifted emission spectrum changes to red shiffted then the stars relative velocity to us has changed. This could mean its orbit is no longer carrying towards Earth but is now carrying it away or that Earth is now moving away from the star in its orbit when previously it had been moving towards it.

If the star is in a distant galaxy then the former applies. Earth's orbit is of no relevance at large distances.

Answer 9

when a star moves away from us, the frequency and wavelength of the rays coming towards us changes, so if it is red then we know it is moving away, if it is blue it is coming towards

Answer 10

This is the Doppler Effect.

Astronomers use "spectroscopy" to analyse redshifts.