If the asthenosphere was made of rigid rock, like the lithosphere, do you think tectonic plates would move the same way? Would we still have landforms like mountains, volcanoes, and rift valleys?

Explain the cause for movement river valley civilization to early industrial centers

Which continents lie only in the northern hemisphere

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.