Cosmological Time Scale 2. Created by Sal Khan.
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- Is it true that if you get sucked into a black hole, you'll be ripped appart atom by atom?(3 votes)
- You would get turned into very long and thin noodle some time after hitting the event horizon by the difference in gravity, then you would rip apart once you got to a microscopic chain of atoms and you couldn't stretch any further assuming the black hole was that large. Then your atoms would be shoved onto the singularity at the center, where it would be stuck until Hawking radiation sent it out perhaps billions of years later. And of course nobody would be able to tell what the heck your particles were once it came out.(9 votes)
- wher did the big bang even occure?(5 votes)
- Wow this page is old. You can now put a place (approximately) on where the Big Bang occurred. As mentioned above it is the Doppler shift. Every Galaxy is moving at it's own rate but all at about the same speed. Galaxy Andromeda is on a collision course with us (3 billion years before we have to worry about it) but Hubble is still witnessing Galactic convergences right now.
Jesus may have been on the Roman/Jewish census but never mentioned that he was the son of God. New DNA sequencing of parthogenetic life forms shows that if he was born of an immaculate conception, he would have to have been female!
New info shows that the Big Bang happened 13.739 Billion years ago, and that it is likely that a major Black Hole at the centre of each galaxy is crucial to it's integrity.
Scientist do not make things up (well, charlatans do) they use observable data and test it. Any experiment that cannot be reproduced is a failure of the original hypothesis. Often, that is a good thing, it promotes further investigation.
Thanks for reading.(2 votes)
- Is it possible that the "life" of light is 13.1 billion Years, i mean could the light by dessintegrated or "die"?(3 votes)
- My understanding is that light itself is not though to experience time. An individual photon is simultaneously emitted and absorbed, from it's own perspective. This implies that, unless something else stops it, a photon will not "die". There might be some stuff stopping it that we don't know about, but there doesn't seem to be any reason to believe that this is is the case.(4 votes)
- If the first "modern" humans were on earth over 200,000 years ago then why did it take over 195,000 years for them to start making things like say... a wheel?(3 votes)
- "Modern humans" doesn't mean modern only in technological sense, instead here it means when humans started interacting with each other, cooking food etc. So 200,000 years ago they just started out doing the basics, but for them the wheel was something huge which could reduce their muscular force and making things easy to carry etc. you can say that it lay foundation for today's engineering.(6 votes)
- Why is light the fastest possible speed?(4 votes)
- Anything that has no rest mass will travel at the maximum possible speed. Light being massless travels at this speed.(6 votes)
- how many dimensions are there in the universe?? and what are they??(2 votes)
- if the big bang was a small point that contained the entire universe in it, wouldn't it be so dense that it would a black hole?(5 votes)
- So, the dinosaurs became extinct because an asteroid hit Earth? How was the Ice Age created?(3 votes)
- The mass extinction of the dinosaurs and many other living things was caused by the impact of a large asteroid on the Earth sixty-five million years ago, called the Cretaceous–Paleogene extinction event.
The causes of ice ages are not fully understood.The consensus is that several factors are important: atmospheric composition, such as the concentrations of carbon dioxide and methane changes in the earth's orbit around the Sun ; the motion of tectonic plates resulting in changes in the relative location and amount of continental and oceanic crust on the earth's surface, which affect wind and ocean currents; variations in solar output; the orbital dynamics of the Earth-Moon system; and the impact of relatively large meteorites, including eruptions of super volcanoes.
So I may not have an exact answer to your question friend but as per scientists it's still not clear.(3 votes)
- How far from earth is the Webb telescope?(3 votes)
- it is "possible" but considering the evidence "unlikely", which if you do a little grunt research work anywhere from Wikipedia to basic biology and anthropology textbooks, is fairly well resolved. The question is whether we descended from Australpithecus or some other similar, earlier, group of hominids. At present the evidence suggests we are descended from some Australpithecus group, either Australpithecus africanus or Australpithecus afarensis. We might not, as you suggest, be related to any Australpithecus lineage but some other earlier lineage where the Australopithicine group was just a dead-end, but, given what we know this isn't entirely probable.(4 votes)
In the last video, we tried to relate what 13.7 billion years really means by compressing it to 10 years, which is still a pretty long time, at least from our perspective. And we saw that these huge periods of time, everything that's happened since the United States Declaration of Independence, all gets compressed into just five seconds. And that's not much when you think about 10 years. I mean 10 years, you could wait around a lot. That's a huge amount of time. So hopefully, that put things in perspective a little bit. What I want to do in this video is kind of do the same thing, but relate the 13.7 billion years, if that were a distance or the length of a time line, how big each of these periods would be. So just to start off, at the timeline-- I'm recording this in high definition right now. There should be 1,280 pixels wide, depending on where you're watching it. So maybe you're watching it on a high def TV. If the timeline was width of my screen right over here, if the timeline was the width of my screen here, so if that was 13.7 billion years, from there-- let's say this is the beginning of the universe and this is our present time. If that was 13.7 billion years, the amount of time that humans have been on this planet-- modern humans, so people who look and think like us-- the amount of time that we have been on this planet will not even be a pixel. This little dot I drew is multiple pixels. The amount of time we've been here would not even be a pixel. In fact, a pixel-- and that dot I drew here is about four pixels. But a pixel, just one little pixel on my screen, would represent 11 million years. Let me scroll over it. It would represent 11 million years. So if this was the timeline, the dinosaurs would have been extinct about six pixels from the end. So it would be right about-- so six pixels from the end is when the dinosaurs would have gotten extinct. And the amount of time that modern humans are on the planet wouldn't even register here. It would be 1/20 of that pixel over there. In fact, if we just expanded that very last pixel-- if we were to expand that very last pixel-- I'll do it in yellow-- that very last tiny pixel that you can't see, if we were expand that to the entire length of this screen again-- so if we were to just expand just that very last pixel-- so I'm saying everything on this yellow line could be contained in that very last dot right over there, then every pixel in this would still be 8,000 years. So the entire period of time that humanity has been on this planet on this scale-- so we've broken out this little tiny pixel here all the way out here, 200,000 years, that's on the order of about 25 of these pixels. So 25 of these pixels would be something like that, not even that, not even that. So 25 pixels on this screen-- at least at my resolution, is about that distance. So this is the fraction of just that pixel that is the amount of time humans have been on the planet. If you want the time since Jesus, it would be 1/4 of a pixel on this yellow scale. On this yellow scale, it would be 1/4 of a pixel. And the amount of time to the Declaration of Independence would be even a more minuscule amount of time. So that's one way to think about it. But these timelines to some degree also don't give justice. So another way to think about it, what if we had a time line that stretched from here, where I am, in this San Francisco Bay Area, if it stretched 1,300 kilometers to Seattle? So if this thing stretched 1,300 kilometers all the way to Seattle, so this thing, the Big Bang, would be sitting in Seattle. This would be sitting in Seattle. The universe-- well, the formation of the Earth and the solar system, this would be about 200 kilometers away, a little over 200 kilometers. And in the direction of Seattle, I don't know, that would get us in probably some part of northern California with redwoods and whatnot. But just to give an idea of 200 kilometers, that would get me from where I am near the coast of California to about the Nevada border. So still a pretty good distance relative to the entire timeline. The dinosaurs, the last land dinosaurs, when the Earth got hit by an asteroid this-- so remember, our whole timeline now stretches all the way to Seattle. This event now would have only occurred about 3,000 meters away. Or maybe I should just say three kilometers away or roughly about two miles. So that's still seems like a pretty good distance. But remember, our timelines stretches all the way to Seattle from the San Francisco area. So it's a pretty big timeline. So this is already a pretty small distance. But it gets even smaller. Australopithecus, this right over here, when they were roaming the Earth 3 million years ago, this gets reduced to a little bit more than a football field, about 150 meters, not kilometers. Let me write that in a color where there's some contrast. 150 meters is where-- so 150 meters in the direction of Seattle, if that's the timeline that we're talking about. And then the first humans, even shorter. It's only going to be 10 meters, 10 meters of this timeline that stretches all the way to Seattle. The birth of Jesus, 2,000 years ago, would be 10 centimeters, 10 centimeters on a time line that stretches from San Francisco to Seattle. And then finally, the Declaration of Independence, the American Declaration of Independence, would be 1 centimeter on a time line that stretches to Seattle. Anyway, I don't know if that put things in more or less perspective. But it was worth giving it a shot.