I think he's bracing himself, not because he's concerned about the recoil, but more because he's worried about being hit by a ricocheting bullet, or flying ice fragments.
Question: which other planet is, on average, closest to planet Earth?
Don't look at the answer till you've thought about it!
Right now, Venus is closest, at 115m km. The sun is at its usual ~ 150m km. Mars is 211m km away and Mercury 212m km away, nearly twice as far away as Venus.
Simplify and assume circular orbits, all in the same plane (this is near enough to reality to not make any difference). Then the sun is, on average, closer than any planet, as it's always just the radius of Earth's orbit away.
If you take the distance of Venus and Mercury parallel to the Earth-Sun line, then the average is the same for both (and the same as the sun), but you also need to consider their distance perpendicular to that line - the true average distance you get by combining the parallel and perpendicular distances using Pythagoras.
Because Venus has more of this perpendicular, "side to side" motion than Mercury, it follows that, on average, Mercury is the closest. In fact Mercury is, on average, the closest planet to each of the other planets and dwarf planets - all the way out to Pluto, Utima Thule, and beyond!
This Sunday (for some meaning of that) there will be a lunar eclipse. It's viewable from the USA Sunday evening, and from much of Europe in the predawn hours of Monday morning. Before and after the eclipse, the moon will be unusually bright, because of the current distances of the sun and the moon from Earth. It's the brightest since 2010 and there won't be brighter one till 2030. However, the brightness doesn't really vary that much, so you won't be able to tell without sensitive measuring equipment.
At the beginning of the video, does he brace himself ... and then release the safety and brace himself again?
He was carrying in the non american style, needing to chamber a bullet to fire the weapon. As this is the safest way to carry the weapon, it's discouraged in america, since you can see it slowed down his reaction time and that's when the immigrants get ya!
(Of note, this is old enough that the Mythbusters tested it and found that it is quite real.)
Watching the eclipse. It's very convenient, I can see it from the front steps and it's at a decent hour. First eclipse experience. It's taking much longer than I imagined. Pretty cold and very windy so vision is pretty blurry. Came in to clear the eyes a bit.
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Chained out, like a sitting duck just waiting for the fall _Cage the Elephant
Started about 22:40 by my reckoning. At first I thought I had missed it, because it was supposed to start at 22:34. It was worth the time and cold. I just hope I don't get a stiff neck. It took very nearly an hour to cover the moon. It really did turn, I would say not red, but more a reddish orange. There were only a few thin clouds, and they added to the experience a bit by filtering the brightness a bit occasionally. I suppose it will take another hour to reappear as normal?
The thing most striking to me is that in the final minutes, I thought I could perceive the moon to be spherical rather than a flat disk. It really seemed to be another world suspended out there, moreso than it ever appeared to be before.
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Chained out, like a sitting duck just waiting for the fall _Cage the Elephant
It was pretty elevated here. Now I know why they put those eyepieces on the top side of a telescope tube.
It was interesting to see the curve of the umbra, penumbra, w/e. I didn't really gauge the relative size, but I was thinking the curve should be close to matching the moon's. I was thinking this because of the similar apparent size of the sun and moon, but it doesn't really apply to earth vs moon, does it.
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Chained out, like a sitting duck just waiting for the fall _Cage the Elephant
Now I'm trying to visualize the geometry of it given the cone shape of the total occlusion, and would it matter to the curvature of the Earth's shadow against the moon. Thinking yes, but it's a bit late to sketch it all out.
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Peering from the top of Mount Stupid
Now I'm trying to visualize the geometry of it given the cone shape of the total occlusion, and would it matter to the curvature of the Earth's shadow against the moon. Thinking yes, but it's a bit late to sketch it all out.
Aristarchus of Samos c. 310 – c. 230 BC figured out the size (relative size to Earth) AND distance of the moon, just by watching lunar eclipses.
He must have been one of those annoyingly clever people, who you probably wouldn't want to invite to your party.
He also figured out the distance to the sun just by watching the moon, but though his method was sound, it relied on judging the exact times of half moons (when the moon looks like a D) and lacking a telescope he couldn't really be expected to resolve those times accurately enough. He did figure out that the sun is much further away than the moon, and much larger: with the aid of a telescope he could have converted that 'much' into 'much much much'.
I left this as a link because it is exactly as it says. But I wanted to post it because I found it fascinating how after listing to it for awhile you start to get a gut feel for what the next prime number will be (I was using it to fall asleep to the other night). The first pattern that becomes obvious is that once out of the gate they will always end 1, 3, 7, 9 and you get a much better feel for how earlier numbers remove huge swaths of bigger numbers.
I found it way more interesting than just looking at a list of prime numbers because as he's reading them out it gives you time to think about both that number and the next.
Latest images received from the Ultima Thule flyby show that it is much flatter than previously thought. Rather than a snowman made from two roughly spherical parts, scientists now think it's more like a lumpy pancake attached to a walnut.
I'm not a scientician (okay maybe I am a little bit), but it's hard to wrap my brain around something remaining as cool as room temperature while under that amount of pressure. I don't remember the exact relationship between pressure and heat (apart from what elevation does to cooking times, and why) but I feel like something under that amount of pressure should heat up. Is that a thing? I'm still just waking up.
Boyle's Law. Given a fixed volume, pressure rises with temperature. It also falls with temperature.
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Sleep - the most beautiful experience in life - except drink.--W.C. Fields
That's really Charles's Law mixed with Boyle's. Charles's Law is normally stated given constant pressure and mass: then the volume varies with (absolute) temperature.
Boyle's Law is about the inverse relationship between pressure and volume given constant temperature and mass.
Re: Drive by science
Linear Mode
