P2

Heavey-weight star:

Star - Red supergiant - Supernova - Neutron star or Black hole

Medium-weight star:

Star - Reg giant - Planetary nebula - White drawf

Red shift is the shifting of the wavelengths of light towards teh red end of the spectrum. It can be observed in the light we recieve from galaies. The further away the galaxy is, the greater the red shift. This means that galaxies further away from us are travelling faster than those closer to us.

Measuring red shift provides evidence for the expansion of the Universe.

• Craters can be found all over the planet
• There are layes of unuual elements found in rocks
• There are sudden changes in the number of fossils found in adjacent rock layers, which could be due to the sudden death of animals

The moon may be the remains of a planet which collided with the Earth billions of years ago. A ollision between two plaets couls result in an Earth-moon system in this way:

• The planets collide.
• The iron cores of each planet merge to form the core of the Earth.
• Less dense material becomes the moon and begins to orbit the Earth.