What do astronomers mean when they refer to "gaps" in the asteroid belt between mars and jupiter?

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.

Name the river that forms a natural border between new york and new jersey and is the site where a passenger jet made a miraculous landing on january 15

What causes heat transfer in fluids