The video discusses the concept of human size and its limitations, including physical, vocal, and fragrant size. It starts with the speaker, Michael, discussing the average height increase in humans over the past 150 years, which is about 10 centimeters or 4 inches. The speaker mentions that better nutrition and medical care have allowed humans to better take advantage of the genetic blueprints that carry plans for human health given an optimal environment.
The speaker then discusses the concept of the maximum biological human size. He mentions that the average human height today is probably quite near the genetic limit. He also talks about the square-cube law, which states that as a shape grows, its volume increases at a greater rate. This means that to grow significantly taller, a human would need a skeleton made out of something stronger than bone or bones that were monstrously thick. There would also be other issues, like the heart not being able to scale up fast enough to keep blood pumping throughout a larger body.
The speaker also talks about the concept of light and electromagnetic radiation. He explains that the human body emits light, and this light doesn't need a medium to travel through. It can keep going out into and through space. This means that the human body's light can continue past the observable universe.
The speaker concludes by saying that the physical size of a human is limited by geometry, biology, and gravity. However, the vocal and fragrant size can be bigger but is still limited by the size of Earth. But the light, or personal glow, emitted by a human isn't really bounded by anything, and the photons that are not absorbed by anything have no reason to stop, making the human, in a way, completely huge and kind of immortal.
Here are the key facts extracted from the text:
1. On average, people today are 10 centimeters (about 4 inches) taller than they were 150 years ago.
2. Better nutrition and medical care have allowed people to better take advantage of their genetic potential for growth.
3. The maximum height for a healthy human being is rarely more than 7 feet 6 inches.
4. Igor Vovkovinskiy, a man with an endocrine disorder, is 7 foot 8 inches tall and is the tallest man currently living in America.
5. Sultan Kösen, who has a condition that affects his pituitary gland, is 8 foot 3 inches tall and holds the Guinness world record for largest hands and feet.
6. Robert Wadlow, the tallest person ever recorded, was 8 foot 11 inches tall and was the size of an average adult male at the age of 5.
7. The square-cube law states that as a shape grows, its volume increases at a greater rate than its surface area.
8. This means that if a person were to grow to 10 times their current size, their weight would increase by a factor of 1000, but their cross-sectional area would only increase by a factor of 100.
9. To support their weight, a giant person would need bones made of a stronger material or bones that are monstrously thick.
10. Even if a giant person had strong enough bones, their heart would not be able to pump blood efficiently enough to supply their body.
11. The maximum height for a person with the same proportions as a current human is around 7 feet tall.
12. A person who is more than 9 feet tall would struggle to move around, and at 12-15 feet tall, it would be difficult to live for very long.
13. The farthest a person can see is the horizon, which is about 5 kilometers (3 miles) away.
14. In outer space, an object's angular size decreases as it moves farther away, but its actual size remains the same.
15. The smallest angular size that can be seen with the naked eye is about one arc minute, which is a sixtieth of a degree.
16. The farthest a person can be seen with the naked eye is about 10-15 kilometers (6-9 miles) away in perfect conditions.
17. A Bloodhound can pick up and trace a scent trail that is days old, making a person's scent imprint on the earth about as large as they can move in a couple of days.
18. The Silvertip grizzly has a sense of smell that is seven times stronger than a Bloodhound and can smell things from 18 miles (30 kilometers) away.
19. The human body emits light, most of which is infrared light, but some of which is visible light, although it is about 1,000 times dimmer than the dimmest light the eye can see.
20. The visible light emitted by the human body is tied to a person's circadian rhythms, with the brightest time being around 4 pm every day.
21. Electromagnetic radiation, such as light, can travel through space without a medium.
22. The photons emitted by the human body can continue to travel through space, making a person's light, or personal glow, unbounded by anything.
23. The photons can conceivably travel past the observable universe, making a person, in a way, completely huge and kind of immortal.