00:00Space dust rains on Earth constantly, but because of its microscopic size, we never knew exactly
00:10how much. These micrometeorites are a fraction of a millimeter and are shed like dander from
00:16passing comets and asteroids. Earth's atmosphere is filled with all kinds of dust. In fact,
00:23according to Science Alert, there is about 17 million metric tons of dust blowing around our
00:29planet at any given time. To minimize the background dust, researchers went to Antarctica and
00:36spent 20 years collecting samples there and found that there are about 5,200 tons of micrometeorites
00:44smaller than 0.7 millimeters coming from outer space every year. The team also wanted to know
00:50the origin of the dust coming in and found that 80% of the samples they collected were from comets
00:56that passed nearby. The total mass of cosmic dust before entering our atmosphere is around 15,000
01:03tons. While they aren't sure why these numbers don't add up, they think it may be due to the fact
01:09that we aren't able to detect all of the dust coming in and dust may be removed during entry.
01:15The third option is that there may be significantly less dust in space than we think. Researchers believe
01:22if they can figure out the reason why they may be able to detect how water molecules and carbon
01:28entered Earth, which would provide clues about life itself.
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