Comets: Crash Course Astronomy

Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into gas, forming the long tail, and also releases dust that forms a different tail. We’ve visited comets up close and found them to be lumpy, with vents in the surface that release the gas as ice sublimates. Eons ago, comets (and asteroids) may have brought a lot of water to Earth — as well as the ingredients for life.

Table of Contents:

Comets Are Chunks of Rock and Ice That Orbit the Sun 1:26
When They Get Near the Sun They Turn Into Gas 2:08
Comets Release Gas Via Vents As Ice Sublimates 2:15
Comets May Have Brought Water and Ingredients for Life to Earth 9:30

GRE Issue Task Pool


По приведённой ниже ссылке дан список официальных заданий GRE Issue, предложенных ETS, официальным создателем теста GRE. Работа с этими заданиями поможет подготовиться к сдаче теста GRE, если вы находитесь в Астане или другом городе.

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