What makes the sky change colour at different angles and directions?

a: Where does the sky get its colours/gradient come from?

b: Why is the sky blue above and red towards the horizon? Why not the other way around?

Thanks!

If the Moon lost orbit somehow for whatever reason, how would the timeline of the crash look like.

I'm thinking of these ingredients:

- slowly dropping free fall

- at some point it will enter atmosphere, what happens to the Moon?

- tidal waves, will the Moon break up and would cities be flooded during downfall

- say the Moon crashed into solid land, wat kind of crater would it leave, what would it do the the immediate surrounds (shockwave?)

- what happens to the atmosphere if anything at all, and what about the magnetic field?

- will humanity survive or perish, and by what cause?

We assume that life possibly came to Earth through the landing of a relatively large body of mass from somewhere else in the cosmos.  Could the inverse happen?  Could a large volcano (or any other natural means such as storm pressures or atmospheric disruptions), have sufficient energy and force to eject material from our planet (no matter how small a fragment, but sufficient to contain and protect bacteria) to send life onto somewhere else (no matter how improbable)?  Could Earth be a staging post in life's spread further across the universe?

If a camera was placed 1 light year away from Earth with a high enough definition, could it be used to spy on events that took place on Earth one year ago? And, if so, could this technique be used to record our past by sending an array of such cameras to the appropriate distance in order to capture momentous events in Earth's history?

Jon King, Swindon, Wiltshire, UK

My limited understanding of science tells me that

a year is the period taken for the earth to orbit the sun, but

seasons are dictated by the tilt of the earth.

Why should there be a link between these?

I recently read that during a change in earth's climate 70 per cent of the creatures became extinct.  If we can predict this can we predict how many species were alive, for example do we know at what point the most species lived on the earth?

Surely it is not now.