One day the last star will die and the universe will turn dark forever. It will probably be a red dwarf; a tiny kind of star. That’s also one of our best bets to find alien life, and might be the last home of humanity before the universe becomes uninhabitable. So, what do we know about them, and why are they our last hope? At least 70% of stars in the universe are red dwarfs. They are the tiniest stars out there, with only about 7 to 50% of the mass of our sun. Not that much bigger than our planet Jupiter, which is still huge though. They are also very dim. It is impossible to see them with the naked eye. You have never seen one in the night sky. Even with all our technology, we can only clearly observe red dwarfs in our neighborhood. Approximately 20 of the 30 stars close to earth are red dwarfs. Like all stars, red dwarfs fuse hydrogen into helium. But while more massive stars accumulate all the fused helium in their cores, red dwarfs stay convective, meaning that the helium and hydrogen constantly mix. So they use up their fuel incredibly slowly, before they are extinguished. Red dwarfs burn so slowly, that their average lifespan is between 1 and 10 trillion years by comparison, the Sun will survive for another 5 billion years Because the universe is only 13.75 billion years old not a single red dwarf has reached the later development stages Every single one of the trillions that exist is still a baby. Speaking of babies, the smallest star in the entire universe is also a red dwarf because small red dwarfs
are right on the verge of being a star at all. Just a tiny bit less hydrogen and
they are mere brown dwarfs: failed stars that cannot sustain a fusion reaction
for long. So what about aliens or a new home for Humanity? Since our Sun will die one day, we’ll eventually need to look for a new home and where there are habitable
planets, there might also be aliens. The Kepler space observatory found that at
least half of all red dwarfs host rock planets between half and four times the
mass of our Earth. Many of them are in the habitable zone — the area around a star where water can be liquid — but since red dwarfs burn at relatively
cold temperatures, a planet would need to be really close to be hospitable,
probably as close as Mercury to our Sun or even closer, which brings with it all
kinds of problems. For example, a planet this close to a star would probably be
tidaly locked, meaning the same side would always face it. This side would be
incredibly hot while the shadow side would be frozen, which makes it hard for
life to develop. Although a planet with a big enough ocean might be able to distribute the star’s energy and create some kind of stability. All the gravitation forces of a Red Dwarf could squeeze the planet and heat it up so much that it might loose all its water over time. These planets could end up like Venus, a hot burning hell. Another problem is that, many Red Dwarfs vary in their energy output They could be covered in star spots that can dim their emitted light by up to 40% for months Wich would cause oceans on planets to freeze over. At other times, they can emit powerful solar flares; sudden outbursts of energy incredibly powerful. These Red Dwarfs could double their brightness in minutes Wich could strip away sizable portions of a planet’s atmosphere and burn it, rendering its On the other hand, their extremely long life span is a big plus. A Red Dwarf with just moderate levels of activity, could be an amazing place for a planet that hosts life. Life on Earth has existed for about 4 Billion years And, we have about a Billion years left before the sun becomes so hot, that complex life on Earth will become impossible. We will either die out or leave Earth and look for a new home. We could build a civilization for potentially trillions of years, around a Red Dwarf with the right conditions. About 5% of the Red Dwarf in the Milky Way, may host habitable, roughly Earth sized planets. That would be more than 4 Billion in total. But, life may not even need a planet like Earth. Candidates for life around a Red Dwarf may be the moons of Gas Giants, also called Super Earths Really massive rocky planets. All alone, there are an estimated 60 Billion potentially habitable planets around Red Dwarfs. And, that’s in the Milky Way alone. So, Red Dwarfs might become really important for our survival in the future But, everything has to die at some point, even Red Dwarfs. When in Trillions of years, the life of the last Red Dwarf is about to end, it will not be a very spectacular event. As its hydrogen runs out, it shrinks, becoming a Blue Dwarf, burning out completely. After its fuel is spent, it’s transformed into a White Dwarf, an object about as small as Earth Packed very densely and made of degenerate gasses, mostly of Helium-4 nuclei. Having no more source of energy, it will cool extremely slowly over trillions of years. Until it becomes its final form: A cold Black Dwarf. White and Black Dwarfs are so fascinating, that they deserve their own video. Anyway.. It’s going to be a long time before the last in the Universe vanish It’s kind of uplifting to know that, if humanity succeeds in venturing into Space We have plenty of time, before the Universe turns out the lights. Our videos are made thanks to your support on Patreon.com, if you want to help us make more of them We really appreciate your support 😉

The Last Star in the Universe – Red Dwarfs Explained
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100 thoughts on “The Last Star in the Universe – Red Dwarfs Explained

  • February 8, 2019 at 4:03 pm
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    There's brand new stuff in the Kurzgesagt Merch Shop. Check it out here: shop.kurzgesagt.org

    Reply
  • July 8, 2019 at 7:43 pm
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    Teacher universe: You have only billion year left for your exam?
    Earth/humans: damn, i shouldnt have slept during class for 4 bill. year

    Reply
  • July 8, 2019 at 10:52 pm
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    Next time you can learn about redGiants and red supergiants

    Reply
  • July 9, 2019 at 9:08 am
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    I have learned more things from this channel than my school

    Reply
  • July 11, 2019 at 3:59 am
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    But Will We Live 2030 Dough?

    Reply
  • July 11, 2019 at 5:01 pm
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    Can’t we just make a artificial star

    Reply
  • July 12, 2019 at 9:28 pm
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    If Jupiter was a star it would be one of the smalllest stars

    Reply
  • July 13, 2019 at 8:46 am
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    If we Humans wanted to survive for long and let our species thrive as long as possible then we shouldn't waste time. Fighting against one another should be set aside. If we only have one goal then it's possible that our species can live longer.

    Reply
  • July 13, 2019 at 12:08 pm
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    play kreativeblocks help us reach 100 visits

    Reply
  • July 13, 2019 at 12:56 pm
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    5:29 little prince?

    Reply
  • July 14, 2019 at 5:22 am
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    You are awesome! I subscribed and slapped the bell!

    Reply
  • July 14, 2019 at 9:52 pm
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    we know the rules of the universe that nothing…lasts forever.
    that include darkness, changes will always happen..we just dont know what that change is..yet.

    Reply
  • July 15, 2019 at 2:58 pm
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    This is sooo sad T.T nothing last forever 🙁

    Reply
  • July 17, 2019 at 3:02 am
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    Kurzgesagt you really need to make a space 4X game with this art.

    Reply
  • July 17, 2019 at 10:56 pm
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    Slow like a turtle 🐢

    Reply
  • July 18, 2019 at 12:46 am
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    le me ask a question, eventually humanity will die?

    Reply
  • July 18, 2019 at 10:02 am
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    what if..the universe is fake? all made up…nasa pictures fake..all that.

    Reply
  • July 18, 2019 at 2:25 pm
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    The big bang was huge it nearly created about 200 about 188 universes are created. Damn, thats huge
    About 1 universe die about trillions of years so yeah we got more time

    Reply
  • July 18, 2019 at 6:37 pm
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    Oof, maybe we should put on sunscreen when the red dwarf heats up XD

    Reply
  • July 20, 2019 at 6:21 am
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    East or, West
    Our SUN is the Best.
    North or, South
    I've no no doubt..

    Reply
  • July 20, 2019 at 12:00 pm
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    One day, when the sun dies, humanity will have to look for a new home. Anyone taking bets if we will make it anywhere near such a far future? Btw amazing channel and videos guys.

    Reply
  • July 21, 2019 at 12:43 pm
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    remember…i pray for jesus that i trade Soul so if i die.i can get a galaxy,So ill make that spiral galaxy slowdown its consuming gas so i can rule it for trillion of Years…
    rather to be a stupid liar

    Reply
  • July 21, 2019 at 7:17 pm
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    wait whats our last hope
    red dwarfs white dwarfs or black holes?

    Reply
  • July 21, 2019 at 7:37 pm
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    O titulo ta em portugues mas o video e em engles

    Reply
  • July 22, 2019 at 5:08 pm
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    4:00 those ships look like kestrel cruisers from FTL: Faster Than Light

    Reply
  • July 23, 2019 at 3:37 pm
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    :Sun Hey, Who Turned Off The Lights! :Universe I Did! 🤣😂😆

    Reply
  • July 24, 2019 at 10:59 am
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    Trappist 1 is a red dwarf then…. We move 100 -500 light years away to Trappist -1
    I might take ~500,000,000-1,000,000,0 years
    And extinct to ~10 to 90 trillions of years to a quadrillion years!!!!!!

    Reply
  • July 25, 2019 at 7:28 am
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    1:23, blue stars are usually very hot, so… are they going to heat up?

    Reply
  • July 26, 2019 at 12:29 pm
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    5:25 he's quite disappointed isn't he?

    Reply
  • July 27, 2019 at 4:19 am
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    It sounds extremely arrogant to think that our species is going to outlive the sun. Who do people think they are?

    Reply
  • July 27, 2019 at 12:05 pm
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    Hey brownie here have some hydrogen

    Reply
  • July 27, 2019 at 6:40 pm
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    Happy but😿

    Reply
  • July 28, 2019 at 12:01 am
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    Then if our sun will die…. What is the purpose of making "mars" habitable?

    Reply
  • July 28, 2019 at 1:54 am
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    Don't worry! We will still be alive in heaven! 🙂

    Reply
  • July 28, 2019 at 6:56 pm
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    This beautiful but at the same time kinda depressing

    Reply
  • July 29, 2019 at 12:12 pm
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    Perhaps an artificial sun would be made

    Reply
  • July 30, 2019 at 8:08 pm
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    And my old Nokia would still be above 50% charged

    Reply
  • July 31, 2019 at 6:24 am
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    … Wüstenrot Moses tot.

    Reply
  • July 31, 2019 at 2:20 pm
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    Red dwarf : humanity’s last hope
    Then
    White dwarf : humanity’s last hope
    Then
    Black hole : humanity’s last hope

    Reply
  • July 31, 2019 at 3:49 pm
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    I love the gloomy soundtrack of this video

    Reply
  • July 31, 2019 at 7:26 pm
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    It's pretty cool that red dwarfs mix their hydrogen and helium.

    Reply
  • July 31, 2019 at 8:57 pm
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    Fascinating.

    Reply
  • August 2, 2019 at 4:47 am
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    can someone tell me how to get my recomended stuff off my list this stuff scares me

    Reply
  • August 3, 2019 at 12:52 am
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    Isso me inspira a tentar deixar um legado que dure séculos, talvez milênios

    Reply
  • August 3, 2019 at 2:39 am
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    I feel bad for the poor red dwarf.

    Reply
  • August 3, 2019 at 7:27 am
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    I'm here crying.

    Reply
  • August 3, 2019 at 1:23 pm
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    Tbh we ARE aliens

    Reply
  • August 3, 2019 at 3:04 pm
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    Screw planets, a Red Dwarf is the PERFECT star for a Dyson's Sphere. It wouldn't have to be as big as around other stars, and we could set the distance perfectly from the star so that tidal lock like a planet would be under in it's livable zone wouldn't be an issue, it could be temperate all "year" round. the livable area of such a structure would be enough for trillions of inhabitants. We could Terraform the interior as we pleased. The vast energy collected could be used to protect the sphere from interstellar objects.

    Reply
  • August 3, 2019 at 3:25 pm
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    WHENEVER I WATCH YOUR VIDEO I FEEL LIKE I AM DIFFERENT THAN ANOTHER 😂😂

    Reply
  • August 4, 2019 at 2:27 am
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    “””””””””our last hope”””””””””

    Reply
  • August 4, 2019 at 10:30 am
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    F ur merch

    kurzgesagt

    Reply
  • August 4, 2019 at 12:36 pm
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    New stars keep forming.

    Reply
  • August 4, 2019 at 9:35 pm
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    The sun was once a kid , then it became a successful star, not like failed stars. It founded a company called Solar System.

    When the sun was a child, it was bullied by jupiter. But now jupiter is a failed star and now works for the sun.

    Reply
  • August 4, 2019 at 11:06 pm
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    At the current rate I don't think that humanity will even last another 1000 years

    Reply
  • August 5, 2019 at 3:25 pm
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    Stop giving me depression!!

    Reply
  • August 5, 2019 at 8:11 pm
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    Wait, what about white dwarfs? I remember seeing a video on this channel saying that white dwarfs could be the last light before darkness…

    Reply
  • August 6, 2019 at 10:10 am
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    And then in the earth sized planets they will over populated now and hurt it like the earth

    Reply
  • August 6, 2019 at 11:46 am
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    Ahhh yes super positive
    It's all about the universe ending

    Reply
  • August 6, 2019 at 6:47 pm
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    there are so much stars in the universe like the sun ceres and various others thats not the last star but i liked ur video

    Reply
  • August 7, 2019 at 3:35 pm
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    4:02 kestrel hawe only 2 sets of engines

    Reply
  • August 7, 2019 at 4:11 pm
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    "There's alien (somewhere)"

    Me: ;-; No

    Reply
  • August 7, 2019 at 6:15 pm
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    Don't worry when our universe turn dark forever just jump to another dimention or universe

    Reply
  • August 8, 2019 at 8:33 pm
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    I do hope mankind dies with the sun and does not get to infect other planets…….basically man is a violent greedy stupid infection…….nothing special and the universe will not miss us

    Reply
  • August 11, 2019 at 8:19 am
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    the last star are white dwarfs!

    Reply
  • August 12, 2019 at 2:07 pm
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    0:42 Top right: To scale

    Reply
  • August 12, 2019 at 4:19 pm
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    Plot Twist: We are an experiment. We must go into the next dimension.

    Reply
  • August 12, 2019 at 10:24 pm
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    A hot burning hell. What the freak. Please flag the video.

    Reply
  • August 13, 2019 at 8:20 am
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    open YouTube
    ONE DAY THE LAST STAR WILL DIE

    Reply
  • August 13, 2019 at 11:52 am
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    But what if we have the technology to keep our sun alive before it dies?

    Reply
  • August 13, 2019 at 1:46 pm
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    uh oh kurzgesagt said the h e double hockey sticks

    Reply
  • August 13, 2019 at 2:18 pm
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    i hope the sun dosent blow up before we get to a nother solar sustem

    Reply
  • August 13, 2019 at 2:29 pm
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    New stars are born from a supernova and yeah I know when some stars collapse they turn into black holes but it is about a 60% 40% wich means that more stars proplbalny born daily

    Reply
  • August 14, 2019 at 11:48 am
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    Never been sad about something that will happen billions of years later.

    Reply
  • August 14, 2019 at 5:46 pm
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    I thought sun would last 5 billion years at least from here. But if it really is one billion then it makes finding a big enough timer easier

    Reply
  • August 15, 2019 at 2:30 am
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    Isn't there a possibility for another big bang? Surely the universe can do it again, guaranteeing another trillion years of light.

    I mean, the stuff the stars exist of doesn't just disappear, right?

    Reply
  • August 15, 2019 at 6:12 am
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    Were is all energy going to go ? 💡

    Reply
  • August 15, 2019 at 2:12 pm
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    Are you kidding me?
    There is translations for Marathi and not for Hindi

    Reply
  • August 15, 2019 at 3:03 pm
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    How do we move a planet in the universe to a star if all the water is gonna freeze

    Reply
  • August 15, 2019 at 10:24 pm
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    Sorry but the univers not is infinity??

    Reply
  • August 16, 2019 at 2:48 am
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    If descendants of humans, go to the stars and settle around red dwarfs, they may have time to figure out a way to crash brown dwarfs or other marginal mass objects together to make more red dwarfs.

    Reply
  • August 16, 2019 at 3:51 am
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    So Titan "Saturn's Moon" can be hospitable

    Reply
  • August 16, 2019 at 1:51 pm
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    Save on post

    Reply
  • August 16, 2019 at 9:58 pm
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    I could live perfectly without knowing this

    Reply
  • August 17, 2019 at 5:03 am
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    Stop it you are making me worried!!!

    Reply
  • August 17, 2019 at 5:07 am
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    Kurzgesagt: We will die soon
    Me: what?
    Kurzgesagt: watch every single one of my vids.
    Me: There are millions of way to die…
    Me: * brain explodes *
    Kurzgesagt: he knew to much.

    Reply
  • August 17, 2019 at 12:35 pm
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    I liked the video but you’re voice like this kinda made this video sad and depressing.

    Reply
  • August 17, 2019 at 4:11 pm
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    5:24 That "anyway" sounded so tired.

    Reply
  • August 17, 2019 at 4:11 pm
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    5:24 That "anyway" sounded so tired.

    Reply
  • August 17, 2019 at 4:40 pm
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    I feel that by the time we go over to red dwarfs we'll be advanced enough to create objects out of thin air, as we'd be billions and billions of more years advanced.
    Due to that, we'd be able to build planets, and stars.
    And if that isn't possible, humanity could find a way to escape this universe, and hop to the next one.

    Reply
  • August 18, 2019 at 1:59 pm
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    Oh my god that rose gave me serious goose bumps… I've got a lot of memories from my childhood connected to this book and I absolutely love the story

    Reply
  • August 18, 2019 at 9:42 pm
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    Where are the videos about white and black dwarfs? Where?

    Reply
  • August 19, 2019 at 10:59 am
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    He is so optimistic thinking we'll (human being) live enough time to reach others stars. That's cute

    Reply
  • August 19, 2019 at 5:11 pm
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    2:50 "Which means this side would be incredibly hot, while the shadow side would be frozen, which makes it hard for life to develop." – You have no proof for this. And it really doesn't make any sense. There is no reason why life could not (or would be hard for it) to develop on a tidally locked planet to its parent star. To the contrary, I think it could be even easier for life (NEEDS DEFINITION) to develop on a tidally locked planet.

    Reply
  • August 20, 2019 at 11:31 pm
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    The thumbnail looks like when your mom had u while on her period

    Reply
  • August 21, 2019 at 2:13 am
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    I'm not against any of this because I love listening to this kind of stuff but how do we really know that we have found the ONLY smallest star in the universe? How do we know there aren't more?

    Reply
  • August 21, 2019 at 3:50 pm
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    I’m scared 😱 of stepping on a hot star ⭐️

    Reply
  • August 21, 2019 at 9:09 pm
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    but the stars came from somewhere right so why can't new stars be made? its makes no sense that all would die out. all stars was created somehow why can't new be created to?

    Reply
  • August 21, 2019 at 10:32 pm
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    watched video expecting rimmer

    Reply

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