Redshift / Blue Shift

These examples are gross generalizations but it’s a wobbly step in the right direction.

When a wave of light is crunched up (high frequency), zipping TOWARD us, we see the color BLUE.

When a wave of light is stretched out (low frequency), zipping AWAY from us, we see the color RED.

The image below (Redshift and Blue shift of light/Doppler Effect by Ales Tosovsky from the Czech Republic) does a good job of illustrating redshift.

File:Redshift blueshift.svg

Okay, you’re busy and on the fly. Check out this 30 second video with the 1950s made-for-radio voice. It’s nothing fancy, but gets the point across.

This 2.5 minute video is a little Mr. Rogerish from NASA’s Infrared Processing and Analysis Center (IPAC), but it is informative.

Okay, you’re not on the fly and you like this stuff. This 8.5 minute video from the University of Nottingham (with a nice tangent about the Milky Way and Andromeda passing through one another in a few billion years) drives the point home.

One response to “Redshift / Blue Shift”

  1. Li Kong says:

    The following are the explanations why the discovery of Edwin Hubble does not provide a good evidence that our universe would be expanding currently:

    a)Despite many red shifts through telescope from astronomers, it does not provide the proof that this universe could be expanding for the following reasons:

    1) The possibility that our universe could be very huge that it would take more than trillion of years to reach the opposite end of the unverse (sphere). The assumption is based upon the following factors: This universe is assumed to be as a shape of sphere with external boundary and all galaxies are assumed to move within the boundary of this universe.

    Let’s imagine you stand at one end of the sphere (the universe) to have a full view of all the surrounding movement of galaxies. As all the galaxies were advancing at a high speed from your end to the edge of the sphere that is right opposite from you that form a half complete round, you certainly would visualize that all the galaxies are advancing as if that they are leaving away from you since their movement in speed is a few time faster than your galaxy. As this universe is very huge so much so that it would take a very long time, let’s say, more than a trillion years to reach the point that is right opposite to the point so as to make a half complete turn of this universe. Despite many galaxies have been moving towards the point that is right opposite to the point where you are viewing through telescope, the result would turn up to be many red shifts to have appeared in the universe. As universe is too huge for galaxies to travel from one end to another and only a few have completed a half turn to move than to the starting point of the sphere where you are to the edge of the sphere that is right opposite from you, it turns up that they are many red shifts than blue shifts.

    2) The second possibility is that many galaxies might have advanced faster than us and yet many galaxies might have made a complete half turn within the sphere (the universe) and yet the galaxies might not as what we think that they would keep on rotating themselves in a circle. Instead, they might not return to the previous track where they have passed through. These could result that they do not turn back to us.

    3) The third possibility is that all the clusters of galaxies could be advancing in the same place and same direction just that most of the galaxies are advancing faster than us as if that their galaxies are moving further away from us. As we are in this tiny world and cannot have the full sight of this universe, we could not reject this possibility since it might be so without our full view of this universe since the astronomers just looked at the sky with a telescope that comes to their conclusion without viewing the universe as a whole. No matter how advance is the technology, it could never be possible to build an advice that could capture the whole view of universe from one end (the earth).

    4) The fourth possibility is that majoirty of the galaxies might have made a full complete turn in this universe within the boundary of the universe in many years ago, such as, more than a few thousand years ago. Or in other words, there might be a time in the past in which there were many blue shifts than red. What the astonomers that have seen right now with many red shifts do not reflect the universe might be expanding since there might be a period of times in many years ago that almost all the galaxies have made a complete full turn and it turns up that many galaxies have turned up to be red shifts currently. Or in other words, it would take many years later, such as more than a few thousand years later, in order to have many blue shifts instead of red shifts at that time.

    5) The fifth possibility is that universe was created in infinity and that all galaxies are advancing ever since the past. If that is so, it is erroneous to use many red shifts as discovered by astronomers to conclude that the universe is expanding.

    There might be other possibilities that you could think of why there are more red shifts than blue shifts and yet it does not come to the conclusion that the universe is expanding. As there are many alternative possibilities, to jump into conclusion that the universe is expanding through many red shifts being discovered is rather a little speculation.

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