Which way's up?

Q:

Do we know which direction the Milky way "pancake" is spreading out relative to the position of Earth?
In other words: Does our North pole point toward the "top" of the pancake, the south pole toward the "bottom" of the pancake and East and West toward the edges of the pancake?

I find it most common for us to think of North as up, South as down and East and West as left and right. How are we actually situated in our Galaxy even if the rest of space is isotropic

A:

Within the solar system, most of the planets are rotating fairly close-ish in line with their orbit around the sun. The Earth's north pole isn't exactly at right angles with our orbit though - it's out by about 23°. The north pole always points in the same direction, even though we are orbiting around the sun. So half the the north pole is pointing slightly towards the sun, and half the time it's pointing away - that's actually what causes the seasons.

The plane that the sun, the moon and all the planets are on is called the "ecliptic". From Earth it looks like a great big arc. If you can see the moon and a couple of planets at night or the sun and the moon at day you can actually trace vaguely where it goes. Also, all of the signs of the zodiac are along this curved line - so if you find a starchart and look up a few of those constellations (Scorpius, Libra, Gemini, Taurus etc) then you at night you can find where the ecliptic is.

The galactic plane isn't the same as the ecliptic though. But that's actually easier to see at nigh (if it's dark enough): it's the Milky Way, the faint stripe of stars going across the sky.

See if you can find both the galactic plane (the Milky Way) and the ecliptic in the same night: it really helps to see our place in the universe.

But if you like angles: The plane of the solar system is about 23° from the Earth's equator, and the plane of the galaxy is about 63° from the Earth's equator.

Do stars spin?

Q:

Do stars spin?

A:

Yes.

You can see an animation of the sun rotating here. It rotates every 25 days or so. This rotation comes from angular momentum left-over from the gas cloud that collapsed to form the solar system. Actually, this initial gas cloud had too much angular momentum - the sun had to get rid of it by firing out huge jets of gas before settling into its present state.

Other stars rotate too - some of them are so fast that they are "oblate" - the centrifugal force pulls them out in the middle, so they're a bit fatter and a bit shorter than a slower rotating stars.