SPACE STRAW - Summary

Summary

The video by Michael from Vsauce discusses the properties and behaviors of the Earth's atmosphere. The speaker explains that while the atmosphere is thin and almost invisible, it plays a crucial role in supporting life on Earth. He also discusses the concept of atmospheric pressure and how it works. He uses the analogy of a vacuum cleaner to explain that a vacuum cleaner or a space straw doesn't suck matter, it simply allows a flow from a region of higher pressure to a region of lower pressure.

The speaker then delves into the concept of buoyancy, explaining how a helium balloon floats because the air down here pushes a tiny bit more strongly than the air up there. He emphasizes that the buoyancy of air isn't enough to cause humans to float away or be lifted. However, he does mention that in a perfect vacuum, you would weigh about a fifth of a pound more than you do right now.

The speaker then discusses the Earth's relationship with space dust and meteorite fragments, and how they contribute to the Earth's mass. He also addresses the concept of "recycling", stating that everything on Earth is recycled, and the Earth doesn't gain or lose mass. However, he mentions that the Earth does lose some light elements like hydrogen and helium due to Earth's gravity, and gains mass from the space dust and meteorite fragments that fall to Earth every year.

Finally, the speaker delves into the concept of carbon dioxide, stating that it doesn't just breathe in and then right back out again. He explains that it takes about one year for a breath of carbon dioxide to thoroughly mix throughout the Earth's hemispheres and about 10 years to thoroughly mix within the troposphere and stratosphere. He concludes by asserting that every breath contains at least a few molecules that were once inside your brain.

Facts

1. Our atmosphere is a thin layer of air held to Earth's surface by gravity.
2. If Earth were the size of an apple, our atmosphere from the ground all the way to outer space would be as thick as the skin of an apple.
3. The atmosphere gets thinner, exponentially, as you go up.
4. 90 percent of our atmosphere's mass could fit within a space as thin as just a third of an apple's skin.
5. Our atmosphere is not heavy or strong enough to push water into orbit.
6. The buoyancy of air isn't enough to cause humans to float away or be lifted on Earth.
7. Earth does lose some stuff. For instance, hydrogen and helium are a bit too light to stick around because of Earth's gravity. They eventually fly out into space or get picked off by solar wind at the edge of our atmosphere.
8. Earth gains mass in some ways as well. For instance, every year it's been estimated that 10 to 20 million kilograms of space dust and meteorite fragments fall to Earth, making it heavier.
9. It has been calculated that every year, Earth becomes 50 million kilograms lighter. However, this is only 0.00 0000 0000 0001 percent of Earth's total mass.
10. The atoms and molecules in our bodies, the food that we eat, the water that we drink, our best friends, has all been here since the early days of Earth, including the air that you are breathing right now.
11. Every breath we take contains about 10 sextillion molecules. In a poetic twist of symmetry, Earth's entire atmosphere contains a volume of air equal to about 10 sextillion breaths.
12. Given that only 5 percent of what we exhale is carbon dioxide and only 20 percent of that came from metabolism within our brain, it is still mathematically certain, even if you were in a brand new place you've never breathed in before, that every breath you take contains at least a few molecules that were once inside your brain.
13. As always, thanks for watching.