Headings The Earth
and Beyond Universe
Search Questions
gcsescience.com 39 gcsescience.com
The Universe - Big Bang - Red-Shift.
The
big bang theory developed as an attempt to explain the observation
that light in line spectra from
other galaxies is red-shifted.
This means that light from
other galaxies
appears to be at a longer wavelength than it is
on Earth.
It is
called a red-shift because the colour red is at the longer
wavelength end
of the visible
light spectrum.
If light appeared to be at a
shorter wavelength, it would be called a blue-shift.
It is
accepted by scientists as a fact
that light from other galaxies has a red-shift.
The further away the galaxy, the greater
the red-shift.
The fact that this light is at a longer
wavelength than expected
requires an explanation.
The most popular explanation is that
other galaxies are moving away from
us
(see next
page).
Headings The Earth
and Beyond Universe
Search Questions
gcsescience.com Contents Index Quizzes gcsescience.com
Copyright © 2008 Dr. Colin France. All Rights Reserved.