Aliens under the Ice – Life on Rogue Planets


Rogue planets are planets that travel through the universe alone. They inhabit the dark and vast space between the stars. Drifting alone through eternal darkness, no light warms their surfaces, and they’re exposed to the freezing cold of outer space. They know no seasons, no days, and no nights,
which could give away the passing of time. And yet, rogue planets might carry alien life to all corners of the galaxy. How would that work? And how does a planet become a rogue anyway? [Music] There are several very different things that get called rogue planets. For example, sub-brown dwarfs
— gas giants that form from collapsing gas clouds and are the boring little brothers of brown dwarfs. They’re a sort of failed star, and we’ll now stop talking about them. A far more interesting sort of rogue,
are terrestrial planets, similar to Earth, that got kicked out of their planetary system. Young star systems are dangerous places, where protoplanets are battling for the available mass, guzzling up as much material as possible. In this fight for dominance, they collide with each other, or get dangerously close to each other’s orbits. If a very massive planet moves its orbit closer to the star, it can kick smaller planets out of the system. But just because a planet has survived the growing pains of formation, doesn’t mean it’s safe. Planetary systems can be disrupted by flybys from stars, or black holes, at any point. Up to half of all planets born could end up as rogues. Scientists don’t agree on the numbers, but it’s likely that, at the very least, there are billions of rogue planets in the Milky Way alone. Most rogues will share the same depressing fate, as their star becomes smaller, day by day, the planet’s surface quickly cools down to minus 270 degrees Celsius. If they have oceans, they’ll freeze and become as hard as bedrock. Their atmospheres will sink down to the surface
and eventually freeze, too. But, weirdly enough, some of these frozen, dark deserts could harbor life. To understand how, let’s imagine a planet similar to Earth, in the same order of magnitude in terms of mass and composition. If we put it into deep space, how could it still support life? As far as we understand the nature of life, there is one indispensable ingredient it needs: liquid water. Water is important because it mixes things, both matter and energy, which lets interesting chemistry happen, like life. So our planet needs enough energy to keep at least a part of our oceans warm enough to sustain liquid water. Annoyingly, about 99.97% of Earth’s energy budget comes from the Sun. So our imaginary rogue earth needs to work with the 0.03 percent of energy it has left, which almost exclusively comes from its hot center. Earth’s inner core is a giant metal ball, about as hot as the surface of the Sun, that’s surrounded by the outer core made up of liquid metals that are very, very slowly solidifying releasing a lot of heat in the process. As long as this process is ongoing, our planet will be geologically active with solid and liquid material moving around and transporting energy to the surface where it can be harnessed as geothermal energy. While the hot core of every planet will cool off eventually, this process takes billions of years. Enough time for life to come into existence and thrive. There’s even one scenario that could allow an Earth-like planet to have oceans that are not frozen over. If the planet had an extremely dense
and high-pressure hydrogen atmosphere, the gas would not freeze and could trap enough of the heat trying to escape the planet to enable oceans that extend all the way to the surface. And there’s another possible way to stay warm: moons. If a rogue planet brings a moon or more along with them, a large enough moon could inject additional energy into the system via tidal forces. These forces stretch and squeeze the planet a little bit every day, like kneading dough, keeping it warm. But the most likely scenario for a rogue bearing life is one with sub-glacial oceans under a kilometer thick layer of mostly water ice. These are not completely absurd,
since we already have a few of them in the Solar System. So how could life sustain itself
at the bottom of a completely dark, cold ocean. On Earth, deep down in our oceans in complete darkness, in volcanically-active areas, there are hydrothermal vents called black smokers. They spew out a cloud of black material and hot water providing a constant flow of minerals from Earth’s mantle. Bacteria feed on the minerals and produce organic materials, which attracts crustaceans, bivalves, snails, fish, octopus, and tube worms up to 2 meters long. Not only are hydrothermal vents home
to an incredibly diverse group of living beings, but also a contender for the place
where life could have begun on Earth billions of years ago. In the dark ocean of a rogue planet,
similar events or volcanic activity, could be the starting point and basis for complex ecosystems we can only imagine right now. One upside an ecosystem in a rogue planet ocean has, is that the environment is extremely stable. The thick ice sheet protects it
from all sorts of extinction events, and, as long as the energy from the core keeps on coming, things stay pretty much the same. The most likely forms of life
are bacteria and other microorganisms. But, given enough time, more complex alien animals could feed
on the smaller beings and thrive. It’s not impossible that intelligent life
could emerge in such an environment. If it did, it would find itself in a pretty weird world. Constricted by an impassable wall of rock-hard ice at the top, and bedrock at the bottom. Without any plants to store star energy, there would be no wood, oil, or coal. Even if there were,
it’s not like you’d discover fire at the bottom of an ocean. Without this energy, metals may never be forged into useful things. Our intelligent alien friends might never break through the ice. They might never realize that there is such a thing as outside, and assumed that their small world is all there is. Millions of generations might live and die in these dark oceans, ignorant of the unbelievably big universe above the ice. Until the core of their planet cools off, and all life vanishes. As the oceans completely freeze, the remnants of cultures and ecosystems will be trapped in an icy grave forever. If you think about it,
it might be better not to be aware of all that. But the concept is disturbing and exciting. The universe might be teeming with life, trapped on planets that are basically impossible to leave. Worlds like this could frequently pass the Solar System,
without us even knowing. Maybe one day, in the far future, humans will set foot on one of these frozen worlds and try to say “hello.” Okay, so we love gloomy future scenarios, but let’s go back to the present
for a different kind of surprise. Many of you want to know how we make our videos, so we made a video about that. Kurzgesagt teamed up with Skillshare, our favorite online learning community for creators, to make a three-part series of classes where you can learn our unique animation style,
with scenes from our videos. But we’re not the only ones
telling you our tips and tricks there. A Skillshare Premium Membership
gives you unlimited access to more than 25,000 classes in all kinds of skills like, writing, design, and animation from experts who know their stuff. The Premium Membership is as low as $10 a month. But as a treat, the first 1,000 people to use the link in the description will get their first two months for free. If you’ve always wanted to see how we animate our videos, and learn to do it yourself, this is your chance.

100 thoughts on “Aliens under the Ice – Life on Rogue Planets”

  1. Apperntly Youtube thinks this is 3-5 year old content because I went to the recommended section, I found Pepper pig and this Johnny Johnny stuff. This means kids need to learn there could be planets that could contain life with no sun, and also have a entire civilization that doesn’t know there a whole galaxy outside their world. You know the normal stuff.

  2. I think if they smart they can make a teory about what is overthere and try to ger there meybe they can but its take alot of time

  3. Though to be fair, there are metals that react with water.
    Maybe if it caught alight, the intelligent life would notice, and use it for creating tools?

  4. From what I understood about human evolution, eating cooked food is the only way to be capable of getting enough nutrients that leave you with enough energy after hunting to give an organism the ability to start evolving their brain, right? So intelligent life couldn't exist without cooking. Unless scientist have come up with theories on other ways organisms could obtain enough extra nutrients to potentially evolve a brain thats intelligent, and I'm just out of the loop…

  5. What if we, humans, are under an "ice sheet" and we don't realize because of they way our organs perceive the universe? What if, for examples, living in the vacuum of space is only not possible because we don't have the physiology to do so, but other intelligent lifeforms can. They are now probably making a video on how it's possible that there is life in the universe, and they just can't find us because were stuck to our planet because of physiology constraints

  6. Think about this, we always think of aliens as more advanced and scarier species, more unique and diverse.
    But imagine… what if we're the most advanced and unique planet out there? What if some random far away planet wonders about how alien life would be so strange, and turns out we're the one they've always been wondering about?

  7. Perhaps these vents would be used to cook prey, and later to smelt metal via long but simple plant based fiber poles.
    The first melting would be hard, but through under sea nodules and manipulating of metals perhaps long tongs could be created. Then its merely a matter of technology and sociological pressure.
    Perhaps they could reach a point on par with us

  8. but what if it was the single celled micro-organisms that gained intelligence and became civilized, and from their perspective we humans are "unimaginable eldritch abominations" made from billions of beings specialized, fused together and stripped of their individuality

  9. have they heard about the word of god and jesus christ? we must bring religion to those icy ocean worlds or they will be sinning and go to hell!!

  10. Just one question: would the outer core not start solidifying at a much faster rate once we are away from the sun, thereby reducing the energy produced?

  11. 1:37
    when it said fly-bys by other stars and black holes, i had to stop and imagine this star system just chilling and then another star pulls up in a car, kidnaps one of the planets and just drives off.

  12. "If they have Oceans they'll freeze and become as hard as bedrock"

    So someone is using creative mode to form star systems?

  13. Actually, it would be possible for ice-planet species to develop metallurgy. They have the vulcanic vents and it's possible the chemically forge metals. Life finds a way!

  14. I'm a bit dissapointed that you didn't go into more detail on the likes of Enceladus and Europa. Why go all the way to interstellar space fora rogue planet if all you need to do is send a properly equipped mission to Jupiter or Saturn (which is obviously not a s simple as it sounds, but still).

  15. Yeah if you think of it there are aliens! even though we haven't seen any on camras and telescopes there probably micro organisms in the air!

  16. Intelligence takes up a lot of energy, doesn't seem possible that it would develop in an ultra low energy environment like one that would be found on a rogue planet.

  17. I have to say, this is the best Youtube channel on this whole site..It's why you have over 9 million subscribers..Thank You for your time and effort put into these videos this does not go unappreciated by me. Once again, Thank You.

  18. Not much we could do if one of these rogue planets drifted in to our solar system and was heading right for us collision course style..

  19. given the tyranids, a fictional space organism with the power to wipe out planets were originally from rogue planets, it would be scary to find lif

  20. surely a moon orbiting a planet and 'needing it like dough', keeping it warm, breaks the laws of thermodynamics? would the moons orbit generate heat forever? surely it can't

  21. Animals: dig out tiny pockets in the ice to hide in

    Pockets get deeper and deeper

    Animals start making big burrows in ice to live in

    Burrows get deeper and deeper

    Break surface

    Starts being able to go outside and evolves

  22. Nope nope nope nope nope nope NOOOOOPE. If beings are intelligent enough to build civilization, they are intelligent enough to drill upward and see what's out there.

  23. Its crazy that scientific knowledge is just the result of scientists agreeing with each other. Like, we know something is true because that one guys buddy agrees with him 😛

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