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These BBC videos are a bit "for the masses," but they do their job: Feb 6, 2019 - "Why Almost All the Universe Is Utterly Invisible" on bbc.com Just to throw something out there, since black holes are causing everything in each galaxy to swirl around them, why can't they be repelling everything that's outside of their galaxy? Doesn't it seem like galaxies are all pushing themselves away from each other, sort of like (for a visual example) two magnets whose negative poles are facing each other? If black holes have a such a strong attractive force, then why can't they have an equally impressive repulsive force? There. I just solved all the mysteries of the cosmos in two minutes. Only I could have done this. Sincerely, Donald
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These are two really well-written articles: Apr 9 - "A Brief History of Black Holes As We Await the Big Reveal from the Event Horizon Telescope" by Sarah Kaplan and Joel Achenbach on washingtonpost.com Apr 10 - "See a Black Hole for the First Time in a Historic Image from the Event Horizon Telescope" by Sarah Kaplan and Joel Achenbach on washingtonpost.com And here it is, an actual Black Hole - this is one of the most important pictures ever taken:
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On this day in 1781, William Herschel discovered Uranus. Are there any facts about Uranus that you'd like to share?
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"Reminder: Humanity Has Made The Moon into a Garbage Pile, Wants To Keep Doing It" by Tim Herrera on washingtonpost.com The one, three-word question: Does anybody care? If we could take the entirety of human waste (including radioactive waste) generated throughout history, and successfully launch it to the Moon, would it matter? There must come a point where the universe is considered "a bunch of mass," and that both we and our garbage are nothing more than subatomic specks, eventually to be annihilated by the Sun exploding. Does polluting the Moon reach that point, or is there some degree of urgency that I'm not seeing? I suppose that, for people who hope to colonize the Moon in the future, this might be something more than an academic issue, but I'm not in that camp just yet. Bonus! Here is the first picture ever taken of the Earth from the Moon, on Aug 23, 1966, by the Lunar Orbiter I, as the grapes were ripening in the second-most successful Bordeaux vintage of the decade: What makes this seemingly uninteresting picture so philosophically fascinating is that, at the time it was taken, the photograph contained every single known thing ever to have lived. I'm assuming that the actual photo didn't clip off the top part of Earth, and that no skeletons or ashes had previously been shot into space; I'm also discounting any microscopic particles on the orbiter, and noting that most of everything is blocked either by darkness, or by the Earth itself. Am I missing anything, other than, say, sanity, or a brain that's larger than a walnut?
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This is a relatively important event in the course of human history - "Sounds of Mars - NASA's Insight Senses Martian Wind"
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I read Stephen Hawking's (R.I.P.) "A Brief History of Time" not long after it was published in 1988, and even though everyone is saying how simple it is, I'm pretty much in the Charles Krauthammer camp: I found it almost 'incomprehensible' at the time. Granted, I'm much, much more educated now than I was then, so maybe it would be a walk in the park for me now, but it was not easy reading for me at age 28-ish. (I should add that Richard Feynman's book, "Six Easy Pieces," put me in the same boat: They were *not* easy. And then, I was foolish enough to tackle "Six Not-so-Easy Pieces," which I read more as a personal challenge than anything else - I remember nothing about it.) I think the problem might be that, while these are two scientific geniuses, they aren't great authors. Honestly, I question the myriad of five-star reviews, and all the comments saying they were reading "Six Easy Pieces" to their grade-school children. I don't believe it! There are two kinds of people who say they enjoy these books: those with a degree in physics, and those who are trying to impress people - I am neither. Grade-school children, my eye.
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If you're discussing the planet Mercury. Mercury rotates 2 times on its axis (day) for every 3 revolutions around the sun (year).
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From eclipse2017.nasa.gov: Where Can You See It? You can see a partial eclipse, where the moon covers only a part of the sun, anywhere in North America (see “Who can see it?”). To see a total eclipse, where the moon fully covers the sun for a short few minutes, you must be in the path of totality. The path of totality is a relatively thin ribbon, around 70 miles wide, that will cross the U.S. from West to East. The first point of contact will be at Lincoln Beach, Oregon at 9:05 a.m. PDT. Totality begins there at 10:16 a.m. PDT. Over the next hour and a half, it will cross through Oregon, Idaho, Wyoming, Montana, Nebraska, Iowa, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, and North and South Carolina. The total eclipse will end near Charleston, South Carolina at 2:48 p.m. EDT. From there the lunar shadow leaves the United States at 4:09 EDT. Its longest duration will be near Carbondale, Illinois, where the sun will be completely covered for two minutes and 40 seconds.
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Here's a weird one. I can't believe that the science isn't totally settled on this. I always thought that the reason the moon appears larger when it's close to the horizon was because of a magnification effect of the atmosphere. Boy, was I way behind the times. Aristotle thought the same thing, but the moon occupies the same half of an angular degree in the sky regardless of it being on the horizon or straight over your head. Dec 13, 2016 - "Why the Moon Looks Bigger Near the Horizon" by Nadia Drake on news.nationalgeographic.com
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No, I was writing quickly, and just assumed that the two Equinoxes would be when the Earth was exactly 1 AU away from the sun, but now that you mention it, there's no particular reason I should have assumed this. The 12-hour days have to do with tilt, and not distance. I also assumed that the Winter Solstice was when the Earth was at the maximum AUs from the Sun, and the Summer Solstice was when the Earth was at the minimum AUs from the Sun, but again, these were just automatic assumptions I made without even thinking about it (in fact, it's just about the exact opposite). This is, quite literally, something you learn in freshman science class, if not before (yes, I took Astronomy because it was an easy A). Do you think the 1-AU moments are exactly 3 months away from the perihelion and the aphelion? I couldn't find anywhere that says when they occur, although I did find one webpage that said they did occur exactly twice a year.
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Okay, half the people reading have no earthly (pun intended) clue as to what I'm talking about, so let me define some terms: Decuple (pronounced deck-CUP-pull) means "10" just like Triple means "3" or Quadruple means "4." Syzygy is an Astronomical term that's very simple: Anytime three celestial bodies are in a line, you have syzygy (it's nothing more than "a configuration.") The pronunciation is easy too: SIH-zih-gee. For example, anytime you have an eclipse, you have syzygy (three bodies in alignment), but an eclipse is just one of many, many examples. Here's one more term that many of you have probably heard: the "Transit of Venus." We had one of these a few years ago, and it's when Venus passes between the Earth and the Sun - the problem being that Venus is so small that you don't even notice it's happening. If Venus was large enough to block out the sun (it isn't), you'd have an eclipse; what you have instead is a Transit of Venus. And, you also have syzygy, i.e., the Sun, Venus, and Earth are all in alignment: You could draw a hypothetical straight line, and it would touch all three celestial bodies. So, my mind started to drift, and I began to wonder ... On Mar 21, 1894, from the perspective of Saturn (i.e., you're standing on Saturn), there were two simultaneous transits that took place: the Transit of Venus *and* the Transit of Mercury. Now bear in mind, this is from the perspective of Saturn - time for another term defined: An Astronomical Unit is the average distance that the Earth is from the Sun. Since Earth's orbit is elliptical, it's almost always a little more than 1 AU, or a little less than 1 AU. The actual distance is exactly 1 AU at exactly two moments per year: during the vernal and autumnal equinoxes, and even then, it's only for an instant - a period of time so short in duration that it essentially doesn't even exist. Okay, so the Earth is about 1 AU away from the Sun. Saturn, however, is almost 10 AUs away from the Sun, or about ten-times the distance from the Sun as the Earth is. So you can imagine how small the Sun would look if you were standing on Saturn. I don't know if it would be 1/10th the size, because I don't know if it's an exact inverse (I suspect it's more complicated than that, but regardless, the Sun would look pretty damned small). Now, I'm not certain that these simultaneous transits resulted in a quadruple syzygy. For a quadruple syzygy to have happened, you would need to be able to draw a mathematically perfect straight line, and have it touch the Sun, Mercury, Venus, and Saturn. Just because both Mercury and Venus were in transit doesn't necessarily mean they were in a straight line, but given how small the Sun must look from Saturn, they must have been pretty damned close - for a quadruple syzygy to have occurred, there would have had to have been a Venus-Mercury eclipse that took place during the double transit (I'm not even sure there's a term for this): Venus would have needed to eclipse Mercury *while* the two were in transit of the Sun (does that make sense?) In that case, you would have had a quadruple syzygy (again, I don't even know if this is a term); otherwise, you would have instead had two "regular" syzygys that happened to be *really* close together. I'm proposing the possibility of an decuple syzygy: I'm wondering if it is theoretically and physically possible for someone to be (hypothetically) standing on Pluto, and have every single planet in alignment. In other words, you could draw a straight line that would be touching the Sun, Mercury, Venus, Earth, Mars, Neptune, Saturn, Uranus, Neptune, and Pluto - ten celestial bodies that you could draw a line through. Actually, it doesn't matter if someone is standing on Pluto or not; the only thing that matters is the alignment. Assuming time sprawls forward into infinity, and that each planet orbits the sun at a different velocity, it's perfectly logical to hypothesize that, at some point - maybe trillions or quadrillions of years from now (assuming the Sun doesn't explode) - all ten celestial bodies in our solar system will be in alignment. Bear in mind: The planets all orbit the sun in the same plane; otherwise, this might be mathematically impossible; given that they *do* orbit in the same plane, I don't see how it *can't* happen, at some point in the ever-so-distant future. It should not take a very complex computer model to predict the exact moment in time when this would occur. It can actually become even more complicated than the scenario I've proposed: Some planetary moons are larger than Pluto, and Ceres - a dwarf planet in the asteroid belt - isn't all that far behind Pluto in size. So, yes, you could perhaps have dodecuple syzygy if 12 bodies were to be in alignment. Any thoughts on this, other than that I should maybe get a life, and maybe work on my restaurant reviews?
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This is truly amazing when you think about it: a picture of Pluto taken on the far side of the planet, looking back towards the Sun. That's not the Sun you see, but Pluto's atmosphere, lit up by sunlight. *Pluto*! "NASA Got Up Close and Personal with Pluto, The Data Blows Their Minds" by Drew Olanoff on techcrunch.com
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"How Small Is Planet Earth!" by Renaud Margry on facebook.com (Speakers down; the music gets to be a bit much - but *well* worth seeing.) Watch the video first, then investigate VY Canis Majoris. Are we really any more significant than ants? We have been cursed with self-awareness.
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