In the video, the speaker discusses the concept of gravity and its properties. Gravity is a property of matter, including everything from the moon to the sun, and even the human body. If two people were to stand three-quarters of a millimeter apart, every atom in their bodies would draw them together with the same gravitational force that the sun exerts on them. However, this force is so minimal compared to the gravitational influence of the Earth that it's virtually negligible.
The video also explores the hypothetical scenario of the sun disappearing. Although the sun will not disappear in the foreseeable future, the speaker speculates on what would happen if it did. In the first 8 minutes after the sun disappeared, we would not know what was happening. However, once we did, we would lose its gravitational influence, and Earth would fly out in a straight line tangent to wherever it was in its orbit. The Earth would lose its sunlight, and the universe would be our only source of visible light from space.
The speaker calculates that the Milky Way contributes about as much light as 1/300th of a full moon, which would be enough light for us to see around a bit. However, all forms of life on Earth, including plants and animals, would struggle without the sun. The temperature on Earth would drop significantly, and most life would die within days or weeks. Only large plants and trees would be able to survive for a while due to their ability to store energy.
The speaker also discusses the possibility of life continuing on Earth without the sun. Extremophiles, microbes that live around hydrothermal vents deep in the ocean, could survive and even thrive. They obtain energy from chemosynthesis, converting heat and methane into the energy they need. Their food chain is complete, and they are independent of the sun.
Finally, the speaker speculates on the possibility of life on Earth developing to a point where it could potentially uncover and understand the existence of our lives. If the sun were to disappear, Earth would fly out into space, covering about 30 kilometers every second. After a billion years, it would have covered 900 quadrillion kilometers, or about 100,000 light years, potentially leading to a scenario where life could develop on Earth again.
1. Gravity is a property of matter, including the moon, Earth, Jupiter, the sun, and even humans.
2. If you stand three quarters of a millimeter away from someone, every atom in your body and their body will draw you together with the same gravitational force that the sun is exerting on you.
3. We don't feel the gravitational attraction between you and someone you're hugging or your individual body and the sun 150 million kilometers away because it's much less than the gravitational influence of the Earth.
4. The sun will not simply disappear; matter and energy don't vanish. Matter can quantum tunnel to different locations.
5. The sun will die billions of years from now by expanding, boiling off our oceans, and swallowing the Earth whole.
6. It takes light from the sun 8 minutes and 20 seconds to reach Earth, so for a little over 8 minutes after the sun disappeared, we would have no idea what would happen.
7. Even after the sun disappeared, the Earth would continue to orbit and reflect light from a sun that no longer exists.
8. Without the sun, photosynthesis would stop immediately, which is a problem for plants.
9. Even without photosynthesis, and including all the other animals and insects and microorganisms that consume oxygen, it would take us thousands of years to run out of oxygen.
10. Most plants would die within days or weeks without the sun.
11. Without the sun, the average surface temperature across Earth would be freezing 0 degrees Celsius or 32 degrees Fahrenheit in the first week.
12. By the end of the first year without the sun, the average global surface temperature would be negative 73 degrees Celsius or negative 100 degrees Fahrenheit.
13. The best option would be to move to geothermal areas like Yellowstone or Iceland, which would be the few safe havens for human life after the sun disappeared.
14. The Earth produces its own heat, 20 percent of which comes from the fact that when the Earth formed, mass crushed so tightly in the middle that the pressure liquefied rock. The other 80 percent of Earth's internal heat comes from the fact that deep in its core, radioactive elements decay.
15. In a science fiction short story "A Pail of Air" by Fritz Lieber, the Earth was ripped away from the sun, and a family must go outdoors in a special suit and scoop up a pail of oxygen snow, bring it back in, and place it over a fire to warm and allow them to breathe.
16. A year or so after the sun disappeared, Earth's oceans would freeze over ice all the way across.
17. Instead of becoming frozen and lifeless, the Earth would be a spaceship carrying living passengers with enough geothermal heat for billions of years of life.
18. If the sun disappeared, the Earth would fly out in a straight line, covering about 30 kilometers every single second. After just one billion years, it would have covered 900 quadrillion kilometers, or about 100,000 light years.
19. The Earth could potentially fall into orbit around one of the thousands of stars near it, thaw out, and allow its still living extremophiles to proliferate life on Earth all over again.
20. Maybe one day, a life form intelligent enough to uncover whatever is left of our lives could also find this video.
21. The video ends with a thank you to the viewers for watching and a final message about the planet's history and journey.