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In this short explainer video, Universe Today publisher Fraser Cain explores the end of the Earth. How will our planet die? It might actually stick around for a long, long time. http://www.universetoday.com/103351/how-will-the-world-end/ ------------- There is almost nothing that could completely destroy the earth. Follow your instincts and ignore anyone raising alarms about its imminent demise. Oh sure, there's a pile of events that could make life more difficult, and a laundry list of things that could wipe out all of humanity. Including: asteroid strikes, rising temperatures, or global plagues In order to actually destroy the Earth, you would need significantly more energy, and there just happens to be enough, a short 150 million kilometers away: the Sun. The Sun has been in the main sequence of its life for the last 4.5 billion years, converting hydrogen into helium. For stars this massive, that phase lasts for about 10 billion years, meaning we're only halfway through. When the Sun does finally run out of hydrogen to burn, it'll begin fusing helium into carbon, expanding outward in the process. It will become a cooler, larger, red giant star, consuming the orbits of Mercury and Venus. Scientists are still unsure if the red giant phase of the Sun will consume the Earth. If it does, the Earth's story ends there. It'll get caught up inside the Sun, and spiral inward to its demise. Death by red giant in 5.5 billion years. If the Sun doesn't consume the Earth then we'll have a long, cold future ahead of us. The Sun will shrink down to a white dwarf and begin cooling down to the background temperature of the Universe. The Earth and the rest of the surviving planets will continue orbiting the dying Sun for potentially trillions of years. If we're exceedingly lucky, the Sun will get too close to another star, and the gravitational interactions will capture Earth in orbit, giving our planet a second chance for life. If not, the Earth will continue following the dying Sun around and around the Milky Way for an incomprehensible amount of time. At this point, the main risk to the planet is a collision. Or maybe it'll spiral inward over vast periods of time to be destroyed by the Sun, or collide with another planet. Or perhaps the entire Solar System will slowly make its way into the supermassive black hole at the center of the Milky Way. One last possibility. Physicists think that protons - the building blocks of atoms - might eventually decay, becoming smaller particles and pure energy. After an undecillion years - a 1 followed by thirty-six (36) zeros - half of the Earth will have just melted away into energy. But if protons don't decay, the Earth could theoretically last forever. The bottom line, the Earth was built to last.
Martin Archer has a look at how the world might end. Links NASA on why the world didn't end in 2012: http://www.nasa.gov/topics/earth/features/2012.html Life cycle of the sun: http://www.universetoday.com/56522/life-cycle-of-the-sun/ Martin Archer is on Facebook: https://www.facebook.com/DrMartinArcher Follow Facebook on Twitter: www.twitter.com/theheadsqueeze Like HeadSqueeze on Facebook: www.facebook.com/headsqueeze http://www.youtube.com/user/HeadsqueezeTV http://www.youtube.com/subscription_center?add_user=HeadsqueezeTV Sci Guide: Taking a twist on the latest science and tech news, our experts unravel some bizarre sideways tangents and discuss the latest gadgets like Google Glass, how ears might give us power in the future, and reveal the latest debates on the Big Bang Theory.
Hank gives us an inclusive overview of how everything in the universe is thought to have begun, and how cosmologists predict it will all come to an end. Now get happy! Like SciShow: http://www/facebook.com/scishow Follow SciShow: http://www.twitter.com/scishow References and image licenses for this episode in the Google document here: http://dft.ba/-38I3 Links to other pertinent SciShow videos: Dark Energy http://www.youtube.com/watch?v=ATwVApurIQ4 Climate Change http://www.youtube.com/watch?v=M2Jxs7lR8ZI Yellowstone Super Volcano http://www.youtube.com/watch?v=_PxDGiVQNg8 How to Stop an Asteroid: http://www.youtube.com/watch?v=OlbaYbWuPCU Tardigrades/Extremophiles: http://www.youtube.com/watch?v=6H0E77TdYnY The End of the Universe: http://www.youtube.com/watch?v=munzrxJ0OYQ @ 1:43 Fundamental Forces of Physics Playlist: http://www.youtube.com/playlist?list=PLsNB4peY6C6JDc1HcVKjjYzVB0BYEXexd
The evidence that the Universe began with the Big Bang is very compelling. 13.8 billion years ago, the entire Universe was compressed into a microscopic singularity that grew exponentially into the vast cosmos we see today. But what does the future hold? How will the Universe end? Astronomers have been pondering the ultimate fate of the Universe for thousands of years. In the last century, cosmologists considered three outcomes for the end of everything, and it all depended on the critical density of the Universe. If this critical density was high, then there was enough mutual gravity to slow and eventually halt the expansion. Billions of years in the future, it would then collapse in on itself again, perhaps creating another Big Bang. This is known as a closed Universe, and the final result is the Big Crunch. If the critical density was low, then there wouldn't be enough gravity to hold things together. Expansion would continue on forever and ever. Stars would die, galaxies would be spread apart, and everything would cool down to the background temperature of the Universe. This is an open Universe, and the end is known as the Big Freeze. And if the critical density was just right, the Universe's expansion goes on forever, but it's always slowing down, reaching a dead stop in an infinite amount of time. This creates a Flat Universe... also a Big Freeze. Fortunately, astronomers were able to measure the critical density of the Universe, using NASA's WMAP spacecraft, and they discovered that the actual density of the Universe predicts a flat Universe. So that's it, right? Of the three choices, the answer is #3. Unfortunately, nature had other plans, and came up with a reality that nobody expected. In 1998, a team of astronomers were observing distant supernovae to get a sense of how fast the Universe is slowing down and they made an amazing discovery. Instead of decelerating, as predicted by the critical density of the Universe, the expansion of the Universe is actually speeding up. Some mysterious force is pushing galaxies faster and faster away from each other, accelerating the expansion of the Universe. We now call this force "dark energy", and for the time being, astronomers have no idea what it is. All we know is that it's pushing the Universe apart. Distant galaxies are being accelerated away from us, and in trillions of years from now, they will cross the beyond the cosmic horizon and disappear from view. The evidence that we live in a vast Universe will disappear with them. But there's a further unsettling possibility about dark energy. Maybe the expansion pressure will increase, eventually overwhelming gravity on a local level. Galaxies will get torn apart, and then Solar Systems, and eventually atoms themselves will be shredded by the increasing dark energy - this idea is known as the Big Rip. So how will the Universe end? The force of dark energy will continue to accelerate the expansion of the Universe until distant galaxies disappear. Galaxies will use up all the gas and dust for stars and go dark, perhaps becoming black holes. Those black holes will decay and maybe matter itself will decay into pure energy. The entire Universe will become a cold, quiet place, where single photons are stretched across light years of space. Don't worry, though, that won't be for quadrillions of years from now.
SciShow Space gives you a blow by blow account of what’s going to happen to the sun -- and Earth. Hosted by: Reid Reimers ---------- Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records: http://dftba.com/artist/52/SciShow Or help support us by subscribing to our page on Subbable: https://subbable.com/scishow ---------- Looking for SciShow elsewhere on the internet? Facebook: http://www.facebook.com/scishow Twitter: http://www.twitter.com/scishow Tumblr: http://scishow.tumblr.com Thanks Tank Tumblr: http://thankstank.tumblr.com Sources: http://arxiv.org/abs/0801.4031
CURIOSITY continues Sunday, September 18, 2011 at 8PM e/p with HOW WILL THE WORLD END? on Discovery. | http://curiosity.discovery.com/#mkcpgn=ytdsc1 | Samuel L. Jackson explores the five most probable ways life as we know it on Earth could end.