doppler effect

What is the doppler effect?

The Doppler Effect is the perceived change in frequency/wavelength of waves due to the relative motion between the object emitting the waves and the observer. When an object emitting waves is moving the waves in front of it get bunched up, so an observer will perceive a higher than actual frequency. For light, this means the light will appear to be blue-shifted, or higher frequency than the actual light. The waves behind a moving object will get stretched, causing them to appear to be lower frequency than they actually are. For light, this means a shift toward the red end of the spectrum.

Explain why the spectral lines of almost all visible galaxies/stars appear to be red-shifted.

The fact that all spectral lines from nearly all visible galaxies are red-shifted is evidence that all objects in the universe are spreading apart (the universe is expanding).

What would it mean if the spectral lines from a star or galaxy were blue-shifted?

If the spectral lines of a star or galaxy were blue-shifted it would mean that the body is moving toward Earth rather than away from Earth.

Construct an argument to support the claim that our solar system formed long after the Big Bang.

the solar system formed from a cloud of gas and dust called the solar nebula. A shock wave from a nearby supernova explosion probably initiated the collapse of the solar nebula.