Comments by "Tony Wilson" (@tonywilson4713) on "Why we should teach astronomy" video.

  1. AEROSPACE ENGINEER HERE: And for a coincidence I grew up in Warragul down the road from Traralgon. The simple answer is NO. In fact most people cannot even grasp the scale of the planet we live on. A while back I heard the claim that the Earth is so smooth that if you had a scale model of the Earth the size of a Billiard Ball you would not be able to feel Mt Everest. So I did the math. The Earth has a mean radius of 6371km (or 12742km average diameter). So if you had a scale model of the Earth with a 1m diameter it would be a 1:12,742,000 model. Everest is 8,848.86m high and on that 1m scale Earth it would be 0.00069m or less than 1mm high. The standard snooker ball is 52.5 mm (2+1⁄16 in) And on that ball Everest would be about 1/19th of that or close to 0.000036 0R 0.036 mm. So Yeah you might have trouble feeling for Mt Everest on a scale model of the Earth that's the size of a Snooker ball. Sorry if the rest of this is lengthy but this issue with people understanding the size of the Earth isn't new to me. I did my degree in America (U. of Illinois) and in my final year (1987) we used to have guest lectures. One of them was an alum who'd worked at NASA and had just completed a study of what it would take to terraform Mars. Considering that at the stage (despite the Challenger accident) we all expected to build Space Station Freedom and then go to the Moon by 2001 we also expected to go onto Mars after that. We were excited to hear this. His opening was "Sorry but its impossible and here's why!" He then introduced us to what I know call "Planetary Mechanics" and "Planetary Dynamics." Planetary Mechanics are the straight forward calculations of what's needed. These are things like how much Earth standard air would we need to terraform Mars (and its a lot). Then considering Mars is about -60C what it would take to heat that much air from -60C to say +20C. These are all things we can calculate. Its just they are big numbers. Planetary Dynamics are things like water cycles, oxygen, nitrogen, carbon dioxide and other gas cycles. That's the stuff that we know exists but we have NO IDEA how we could begin to make them work. Plus there's that whole issue of Mars having only 1/3rd of Earths gravity and no magnetic field to prevent the Sun from just stripping away that atmosphere. Then there's the thermodynamics of retaining enough heat from the Sun to keep mars warm enough. Yeah BOTH Planetary Mechanics and Planetary Dynamics are subjects we aren't even beginning to discuss and its mainly because the numbers are so huge that it confuses the hell out of people. If you just look at the first 1km of air above the worlds surface. Going back to our 1m scale model of the Earth that's less than the thickness of a sheet of paper (0.1mm) It represents about 500,000,000 cubic kilometers of air and its where about where about 87% of humanity lives or about 7 Billion people. The other billion people mostly live in the next 600m. Only about 6% of the worlds population lives above 1 mile (1,600m) and only about 2-3% above 2,000m So we (the bulk of humanity) lives in a volume of about 1 Billion cubic kilometers, which sounds like a lot. But on that 1m scale model of the Earth its less thick than the thickness of 2 sheets of paper. Going back to Mars and trying to terraform it. If you calculate how much air you'd need just to cover Mars in a layer of Earth Standard Air that's 1km thick at the same pressure you'd need 178 Trillion tons of air. The scariest number is how much energy does it take to to raise 500,000,000 cubic kilometers of air from 20C to 21C because that gives you an idea of what we have done to the planet. Its a bad number to discuss because most people cannot grasp just how big the planet is. Derek - If you'd like to do a video where we go over some of these things let me know.
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