Show how orbital speed depends on distance from the galactic center for a galaxy with constant mass density within 20,000 light-years of its center, and zero density beyond
that distance.

object 2 because all the other ones are wrong

k2s for potassium sulphide

the aurora is formed when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. these collisions result in countless little bursts of light, called photons, which make up the aurora.

auroras are generated by charged solar particles hitting molecules in earth's atmosphere. this usually happens in high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles. that’s why it can be experienced in northern ohio.