What do we mean when we say that the rotation curve for the milky way galaxy is "flat"?

One of the brightest comets of the 20th century was comet hyakutake, which passed close to the sun in early 1996. the orbital period of this comet is estimated to be about 30,000 years. find the semi-major axis of this comet’s orbit. compare it to the average sun-pluto distance and to the distance to alpha centauri, the nearest star to the sun, which is 4.3 light-years distant.

The ethnic conflicts in darfur have led to an attempt to destroy a whole people known as

Ocean crust is a. made from submerged continents b. magnetically produced crust c. produced at mid-ocean ridge d. produced at all plate boundaries