Questionable Science - Redshift
The expanding universe stretches the light

In astronomy, the speed of stars and galaxies can be determined using the redshift. Basically, this is based on the theory that light is a wave and that the observed frequency of that light is changed based on the relative speed of the source with respect to us.

When you hear a siren coming toward you, the perceived frequency is increased. After the source passes you, the perceived frequency gets noticeably lower. This change in frequency based on relative speed is the Doppler shift. The size of the frequency change is related to the speed that the source is moving with respect to the listener.

In a similar manner, when we look at light, the apparent frequency will change based on the relative speed of the light source and the observer. This Doppler shift is calibrated by looking at the absorption lines in the spectra. When we measure the redshift, we are really measuring how far the absorption lines have moved with respect to a reference spectrum.

However, there is another theory that explains the observed redshift - as the universe continues to expand, it stretches the light traveling through it, making it appear redder than what it originally was.

Sunday comics | The NASA Reference | The NASA Source | New Physics

Sunday comics

In the Sunday comics, I like to read whatever science "facts" get printed. It is always fun to see what crap is being taught kids.

On Sunday June 3, 2012, Brewster Rockit tried to describe how the redshift is used to determine how old a galaxy is.

Expanding space stretches light waves with it, shifting them toward the red
To quote Maybe I missed something, but I remember Doppler shift as the explanation for redshift, not “expanding space stretches light”.

I think this is important because millions of people read this stuff.

The NASA Reference

The comic even provided a NASA reference – - which clearly says

The following is copied from the NASA page

How old do I look? :: NASA's The Space Place
Granted, this page is directed at kids .. and Doppler shift is a bit complex .. but lies like this are not acceptable.

The NASA Source

The comic also references "Dr. Marc Rayman of NASA", but I was not able to find an email address to ask a question of him.

I realize that there may be more than one "Dr. Marc Rayman" with NASA, but the most likely candidate a Propulsion Engineer at JPL and is referred to as Dr. Marc at

Dr. Marc answers questions about space.

New Physics

Well - we all know that comics don't lie .. and NASA can't be wrong.

So I did a bit more research .. apparently, there is new physics since I went to school.

In 1937, Edwin Hubble wrote.

According to Wikipedia, some of the observed redshifts were so high that the objects were moving faster than the speed of light. Since we "know" that that is impossible, the physics was modified so that

Describing the cosmological expansion origin of redshift To be clear, the observed redshift is a combination of the Doppler effect and the cosmological effect.

So .. who would have believed it. I learned something new from the Sunday funnies!

On the other hand, I am bothered by the idea that a photon (basically, a particle with wave properties) can be changed by a change in space itself.

Author: Robert Clemenzi
URL: http:// / Redshift_Stretch.html