gee-whiz mini-post
The Sun is usually associated with mind-wobbling huge numbers. It's 109 times the diameter of the Earth and a third of a million times more massive. Almost all of the energy from fusion is produced in its core. A relatively small region that only extends to about a quarter of the Sun's radius. The average density of the core is about 150 times that of water and it's approximately hot. Hot enough that fusion can proceed. Six hundred million tonnes of hydrogen are turned into helium every second. Even as far away as we are, the amount of solar energy striking the Earth is about 10,000 times the world's current energy use.
Big numbers, but it gets curious when you take a deeper look.
It turns out fusion in the Sun is very slow. That's not a bad thing as the leisurely pace allows the Sun to last a long time. Long enough to get intelligent life started. While 600 million tons of hydrogen a second may sound like a lot, the Sun is mind boggling big. Trying to recreate the the Sun's fusion in an Earth-bound reactor would be a fool's errand. The process is so slow you'd never get enough power out to make it practical. Fusion reactors need much greater temperatures and somewhat different fusion processes to be practical. That turns out to be a non-trivial problem.
The power density (the power per cubic meter inside the core turns out to be astonishingly small - about 275 watts per cubic meter. That's about the same as a lizard's metabolism! Being warm blooded and active, ours is higher. The average metabolic power density of an adult human is about 1400 watts per cubic meter.
One of you is competing in Tokyo in about a week. When Sarah's running around in the sand during a beach volleyball match her metabolic power density is six to eight times greater than average. Even at the lower figure her power density is thirty times that of the Sun's core!
We all knew that, Steve!!!
If you can tell us by what margin they will win the gold - against all odds - now that would be something !!!!
Best of fortune…and some luck too, to the Olympians!!!
Charlie Hess
Posted by: Charles Hess | 07/17/2021 at 06:06 PM