How the Universe Works - S09E04 - Aliens of the Microcosmos
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00:00The universe, vast, dynamic, and explosive.
00:12But this huge cosmos, with its billions of galaxies and countless stars, isn't the
00:17only one.
00:19We share our lives with another universe.
00:22The world of the small, of the viruses, of the bacteria.
00:28We call this strange, hidden kingdom, the microcosmos.
00:32The microcosmos is incredibly important, even though we can't see it, it's everywhere.
00:38It's almost like another universe or another world all in its own.
00:43It guided our evolution.
00:44We wouldn't be here without the microcosmos.
00:47And it keeps us alive.
00:49The microcosmos is responsible for the very oxygen that we breathe.
00:55And it will influence our future as we venture out into space.
00:59And if we were ever to find a place where there is life, potentially a new microcosmos,
01:06we would have no immunity if they're bad.
01:09We share our world with the microcosmos.
01:12Will we coexist in an uneasy peace?
01:15Or will it destroy us?
01:25A strange, invisible assassin stalks its prey.
01:36It attacks and hijacks the cell, forcing it to produce hundreds of new raiders.
01:44This is what happens when the microcosmos turns on us.
01:48In 2020, we experienced this invasion of the body snatchers firsthand.
01:54A tiny virus caused a global pandemic, COVID-19.
02:00This pandemic makes me see the world completely differently.
02:03Because there was an invisible universe, one that covers me and is within me, that I pretty
02:08much ignored for the most part.
02:11Maybe we ignore this other universe because it's invisible to the naked eye.
02:17We live in a largely invisible universe.
02:20We can't see everything that's going on.
02:22Some of the biggest stuff we can't see very well, and in fact, a lot of the littlest stuff
02:26we can't either.
02:28Just because something is too small to see doesn't mean it's not important.
02:32In fact, very, very tiny things have a huge impact on our lives.
02:38Some of these impacts are beneficial, but they're overshadowed by the devastating effects
02:43of disease.
02:45The longest running conflict that humanity has been engaged in is that against the microcosmos,
02:53our long-running battle against the bacteria and viruses that are trying to kill us.
02:59A century ago, we faced the Spanish flu.
03:03This absolutely annihilated Europe at the time.
03:06It caused millions upon millions of deaths.
03:08So this is definitely not the first pandemic.
03:11Quite frankly, probably isn't the last one.
03:13In a way, the coronavirus has forced us to come to a greater understanding of the microscopic
03:19world.
03:21The microcosmos is complex.
03:23While some parts kill us, others keep us alive.
03:28The microcosmos is important for us to survive in order for us to do all of the things that
03:33our body does in order for us to live and grow and thrive.
03:37Our lives depend on the microcosmos.
03:39The air we breathe and the surface of the earth around us has been profoundly affected
03:45by the microcosmos.
03:47The invisible microcosmos operates in every part of the world.
03:52This world that you can't see is everywhere, from geothermal hot springs, to glaciers,
03:58to deep sea hydrothermal vent systems.
04:03We have discovered that every cubic foot of Earth's atmosphere and its oceans contain
04:08millions of viruses.
04:10There are more viruses here on Earth than there are stars in the universe.
04:17That's incredible.
04:19Even though they're around 1-400 the thickness of human hair, stuck end to end, all the viruses
04:25on Earth would stretch 100 million light years.
04:30That's 40 times the distance to our neighboring galaxy, Andromeda.
04:35That really makes us ask, whose planet is this anyway?
04:38If you just added this up by sheer numbers, you would say this is the virus planet.
04:43The microcosmos has also taken over our bodies.
04:47We're only partly human.
04:49The fact that so little of my own body, of everyone's body, is human cells kind of leaves
04:54you wondering what's the rest of it made of, right?
04:56It is astonishing that we share our bodies with over 380 trillion viruses.
05:03And over 39 trillion bacterial cells.
05:07The average human has more bacterial cells inside their body than there are human cells
05:13inside their body.
05:14So what are we really?
05:16There are moments in the history of science that I actually remember where I was when
05:20they happened.
05:21When, for example, we detected two colliding black holes or something like that.
05:24But another one was when I realized that almost half our body is actually not human.
05:30I mean, that is crazy.
05:32For people that are scared of bacteria, that's a really interesting thing to know, right?
05:39Bacteria help us digest food, produce vitamins, and even influence our mood.
05:45But what are they?
05:48Bacteria are single-celled organisms with a cell wall and a central nucleus containing
05:53genetic material, RNA or DNA.
05:58They can move around and replicate.
06:02Viruses are completely different.
06:05In the universe, there are some mysteries that have actually personally made me kind
06:08of pause, given me goosebumps.
06:11And strangely enough, one of them is viruses.
06:14The mystery is how viruses can have so much impact on the world, despite their tiny size
06:20and apparent simplicity.
06:24Viruses are just a strand of genetic material, sometimes encased in a shell of protein.
06:30When compared to bacteria, which behave kind of like other normal cells that we're used
06:34to to some degree, viruses are very strange.
06:39We don't really understand viruses.
06:42We don't even know if they're alive or not.
06:44The question, are viruses alive, is actually more difficult to answer than you might think.
06:50What is the definition of life?
06:53What does it mean to be alive?
06:56NASA's definition of life is a self-sustained chemical system capable of Darwinian evolution.
07:03Entities that feed make energy and reproduce.
07:08Viruses can't do that on their own.
07:10They have to have a host cell to do that.
07:12They have the genetic material that they need, but none of the machinery.
07:17So they really have to infect a host.
07:20If not, they're useless.
07:23Inside a host's body, viruses latch onto the surface of cells and then take control.
07:32Viruses' life cycle is effectively to hack another cell.
07:37They have to inject that genetic material into a living cell, and then the cell is hijacked
07:41and starts making copies of the virus.
07:44Viruses then have to burst out of this cell, almost literally like that gory, grotesque
07:50scene in Aliens.
07:52They burst out from the inside.
07:54That's like a sailor-level horror movie.
07:59This method of replicating is chilling and doesn't answer the question of whether they're
08:05alive.
08:08That uncertainty may influence our search for life in space.
08:14One of the interesting things to think about is if we found a virus on another planetary
08:19surface, would we classify that as life?
08:21Would we say that we have found life?
08:24We don't know.
08:26But space viruses could be a sign of other extraterrestrial life forms.
08:32Viruses have to have a host cell to replicate.
08:34So if you find a virus, in essence you've found life.
08:40Viruses might lead us to extraterrestrial life.
08:43Now new research suggests that life on Earth may have come from space, brought to us in
08:50a cosmic bombardment when our planet was young.
09:01We find the microcosmos in every feature of Earth.
09:05But where did this strange kingdom of the very small come from?
09:09Some of its members are so weird, they look like aliens.
09:13Could they have come from space?
09:16There's this idea that microbes could have hitched a ride on a chunk of an asteroid that
09:20would fall to Earth.
09:22They could form on a different planet, something hits that planet, the rock that they're sitting
09:27on gets lifted and then hits the Earth as a meteorite.
09:31The idea of hitchhiking bugs sounds a bit wild.
09:35But we have found chunks of Mars on Earth.
09:39Perhaps these space rocks brought life.
09:42It's not completely ridiculous.
09:45We know that rocks, for example, could come from Mars and land on Earth.
09:48A giant asteroid impact on Mars could blow shrapnel into space that could land on Earth.
09:55To learn how, we must return to the early solar system, 4.5 billion years ago.
10:01Many infant planets orbit a new star, our sun.
10:05This infant solar system is chaotic.
10:08Collisions between planets are inevitable.
10:12The early solar system was like a pinball machine.
10:16Stuff was hitting, knocking stuff off, that would land somewhere, knock stuff off.
10:20The young Mars is in the line of fire.
10:23It already has primitive oceans and perhaps primitive life.
10:29A huge space rock smashes into the surface.
10:33We call the event the Borealis impact.
10:37It blows quadrillion tons of rock into space.
10:41It's not crazy to think that one of these chunks of rock traveling through our solar
10:46system has some hitchhikers on board.
10:49If there's some microbe riding on an asteroid that got blasted off of Mars, kind of feel
10:54sorry for it, right?
10:55It's just living there on Mars, doing whatever little Martian microbes do, and then a giant
11:01impact ejects this thing into space.
11:05In order to get from one planet to another, a cell would have to run a gauntlet.
11:13It's almost like winning a survival game show.
11:16You've got to survive being blasted off your home world.
11:20You've then got to survive the interplanetary journey inside a small lump of rock, being
11:27exposed to the vacuum of outer space, to cosmic rays, to UV radiation, being dried out and
11:34frozen.
11:35So the idea of moving life around the solar system or around the galaxy on asteroids poses
11:41a lot of different challenges.
11:44Just like the Borealis impact ejected so much rock from Mars, there were lots of opportunities
11:50for hitchhiking bugs to run the gauntlet of space.
11:54But could they survive the journey?
11:58To find out, astronauts on the International Space Station grew simple bacteria outside
12:05in space.
12:08After a year of being in open space, miraculously, some of these microbes survived.
12:15It's incredible.
12:17These microbes just could not be killed, even though they were in the worst possible environment
12:22for life.
12:23The mission, therefore, shows us that life can survive the environment and outer space.
12:30Life can be transferred between planets.
12:34Maybe life did get started on Mars, on our next-door-neighbor planet, and then was transferred
12:40here inside a meteorite.
12:43Maybe we are immigrants from Mars.
12:47Hitchhiking bugs may have arrived on Earth and kick-started the microcosmos.
12:53But now, recent studies of meteorites suggest that even if living microbes didn't make the
12:58journey, the building blocks that made them did.
13:04In November 2019, an international research team found an organic molecule called ribose
13:10in meteorites that had crashed on Earth.
13:15Ribose is a sugar.
13:17It's a simple sugar, but it is a sugar that is absolutely crucial to all life on Earth.
13:26Ribose is the sugar that makes up RNA.
13:29And RNA sits right in the linchpin of every cell.
13:36RNA is a simple form of genetic material that controls cellular function.
13:42It's found in most primitive creatures.
13:46Finding ribose on a meteorite is so important for us to understand the origins of the microcosmos
13:53because these are the building blocks.
13:55These are the things that it needs to get started.
13:58So understanding where these building blocks come from allows us to understand how the
14:06microcosmos might have evolved and started.
14:10The Rosetta mission found another building block for life out in space, a form of phosphorus
14:16on the comet 67P.
14:19This was astounding.
14:21Comet 67P was formed at the birth of the solar system, 4.67 billion years ago, and it hasn't
14:28changed since then.
14:29It's a time capsule from the birth of the sun and the planets.
14:34And it's been in the deep freeze ever since.
14:37So these forms of phosphorus that we found on comet 67P tell us what was available at
14:43the time the Earth was forming and then when life was getting started on primordial Earth.
14:50The early solar system contained many chemicals needed for life.
14:56It's an important discovery because it means that these compounds were around when the
14:59solar system was forming.
15:01So they would have been readily available for life to tap into and use to start forming
15:06cellular structure.
15:09These discoveries not only show that essential chemicals came to Earth, but that they exist
15:15throughout the solar system.
15:17We tend to think of the microcosmos as only existing on Earth in the sense that only Earth
15:22has these building blocks.
15:23But now these new observations suggest that the microcosmos, at least the building blocks
15:29for one, could exist beyond Earth and throughout the solar system.
15:36We got evidence for the widespread distribution of these building blocks in 2017.
15:43A strange space rock called Oumuamua raced through the solar system.
15:49The weird thing about Oumuamua is that it's clearly on a trajectory that came from deep
15:55space, interstellar space, that it literally came from another star.
16:02Even weirder, its color, its surface is red.
16:06And so that raised a lot of questions about what its composition could be.
16:10And one possibility is that it's actually filled with organic materials, which tend
16:15to have those colors, especially when exposed to the space environment.
16:20This suggests organic materials may travel through interstellar space.
16:25I think it's entirely reasonable that we could be getting organic materials that are the
16:30building blocks of life from outside of our solar system.
16:34There may be a molecular transport system throughout the galaxy.
16:38We could be receiving stuff from other bodies in our solar system and from bodies outside
16:44our solar system because stuff is moving around.
16:47Oumuamua is just the tip of the iceberg.
16:50There are probably lots of interstellar visitors passing through our solar system all the time.
16:56Comets and asteroids may have brought chemicals to kickstart the microcosmos.
17:03Now explosive new research suggests that space rocks hitting Earth did even more.
17:10Could the violent impacts themselves have helped life get started?
17:25How did the microcosmos, and life on Earth, start?
17:30Did asteroids and comets deliver the building blocks, phosphorous, ribose, and other organic
17:36compounds, or did they start life in other ways?
17:40New research suggests the impact of crashing space rocks could have provided the spark
17:46for life.
17:48The force of the impact actually triggered the creation of these molecules that are the
17:52building blocks of life.
17:58The energy from the impact breaks down and reforms molecules into new compounds.
18:04You can actually strip apart atoms and molecules, recombine them in more complex ways, and make
18:10the stuff of life in an impact.
18:13Over millions of years, complex organic materials fill Earth's oceans.
18:18Then, around 3.5 billion years ago, the process that kickstarted life began.
18:26Going back to the origins of life on Earth, it was a process.
18:31You began with large molecules that almost accidentally began to make copies of themselves.
18:36These became the first genetic material.
18:39Some of these larger molecules bound together and became the first sort of protocells.
18:44A protocell could represent this earliest pre-life stage of evolution.
18:52Protocells lack the full chemical machinery of modern cells.
18:59They're a simple cell membrane surrounding a glob of genetic material, like RNA, built
19:05from ribose and phosphorous.
19:09Now you have a barrier.
19:10Now you can actually control which chemicals come into the cell and which go out, and you
19:16protect the genetic code intact inside the cell.
19:20As that happened, evolution began to run with it.
19:24These simple cells grew more and more complicated, until, shazam, you get all life on Earth.
19:33All cellular life, anyway.
19:36Unlike bacteria, viruses are not cells.
19:41Scientists debate if they're even living things.
19:44So how, then, do viruses fit into the birth of life?
19:48Viruses aren't really thought of as playing a role in our evolutionary history, but we're
19:53just beginning to understand that that's simply not the case.
19:56What if viruses themselves were an essential cog in the machinery of life?
20:02How can we investigate if viruses helped life on Earth develop?
20:06They don't leave many clues about their past.
20:10The hard thing with understanding the evolutionary history of viruses is they don't leave a fossil
20:16record.
20:17There's no geology that we can go back and dig up and say, aha, this is when viruses
20:23first came about.
20:26We don't know when viruses entered the evolutionary game of life.
20:32Was it near the beginning or a little bit later?
20:35There's this crazy idea that viruses might actually have come first in the tree of life.
20:40When you think about the real origins of life, it had to start with something that simple,
20:45something that was just a molecule that could start replicating.
20:49A virus may be our best example of that transition from just complex chemistry to the beginnings
20:55of life.
20:57In this scenario, chemicals floating in the three-and-a-half-billion-year-old oceans formed
21:02a shell of protein around some simple genetic material.
21:07But did viruses evolve before anything else?
21:12The flaw in the virus-first hypothesis is that a virus has to have a host organism to
21:20replicate.
21:21So without a host, how does the virus replicate?
21:24And this is the question we have to ask ourselves when we think of viruses coming first on the
21:30evolutionary tree.
21:32Modern viruses can't replicate without a host.
21:36It's likely that ancient viruses couldn't either.
21:41Could early cells and viruses have joined forces in a way that benefited them both?
21:47Some new theories are suggesting that viruses in cellular life co-evolved and actually helped
21:54each other out and potentially even helped out the evolution of human life.
22:00How did this co-evolution work?
22:03We know that viruses today inject their genetic material into cells to manipulate them.
22:10Perhaps early viruses manipulated the genes of the first cells the same way.
22:16Think of this primordial soup and the genes, the RNA that's in this primordial soup being
22:22swapped between organisms, kind of like a swap meet.
22:25You bring something you don't need anymore and you pass it along to somebody else.
22:29So in this way, organisms sharing their genetic material back and forth offers a competitive
22:35advantage to each one.
22:37The virus might break off bits of the host's genetic material and mix it with their own.
22:44When the virus attacks another cell, it could pass on the mixed genes to its next host.
22:51In this sense then, viruses help stir things up.
22:56They shuttle genes between widely different organisms and therefore help drive evolution itself.
23:05Now probably almost all of these injections did nothing useful or maybe even killed the cell.
23:10But if one in a million injection changed something for the better, made it more complex,
23:15made it more able to survive, then that cell reproduced even more.
23:19If virally enhanced cells thrived in the primeval oceans, over time they might have evolved
23:26into more complex creatures and eventually into us.
23:30What's so crazy is to think about the fact that we could actually be descended from viruses.
23:35I am sure that a lot of my genetic code originally came from the injection of a virus.
23:41I love the idea that I might be descendant from a virus.
23:45Just coming from something that simple and evolving into something this complex is just
23:50a feat of nature.
23:53Viruses played a major part in human evolution.
23:56Around 8% of human DNA came from ancient viral infections.
24:01In fact, without them, we wouldn't be human.
24:06In our brains, we actually have relic viral DNA, so DNA that came from a virus.
24:12But this helps us.
24:14Without this, we don't think we would have consciousness.
24:19We also think that viral DNA helped us develop an immune system to fight off infection and
24:25gave us the ability to digest starch.
24:30The microcosmos has guided our evolution.
24:33It even created the air we breathe.
24:36But in doing so, it also triggered the largest mass extinction the Earth has ever seen.
24:47Planet Earth, 2.5 billion years ago.
24:52The microcosmos colonizes Earth's oceans.
24:56This is not a world we would recognize today.
25:01If you were to travel back in time, just on Earth, to see what it was like 2.5 billion
25:06years ago, it would look really different in many ways.
25:10There were oceans, and they had life in those oceans, but there weren't any land plants
25:16or land animals.
25:17It was just bare rock.
25:19So to think about a human going back in time to visit the really early Earth, they would
25:23find an utterly inhospitable planet.
25:26As a human, you'd be out of luck because there was no oxygen in the atmosphere at that time,
25:31so hopefully you brought a spacesuit.
25:34The atmosphere was fine for the billions of inhabitants of the early microcosmos.
25:40They were very slow-paced, and they did everything they did without any oxygen in the air.
25:46But this tranquil existence was about to change.
25:50For a long time, conditions on Earth were fairly static.
25:53But then, about 2.5 billion years ago, an evolutionary glitch changed everything.
26:00A clue to that glitch rests in strange rocky mounds, stromatolites.
26:09Stromatolites are almost like microbial cities.
26:12If you zoom down onto their scale, you'll see layer upon layer of bacteria, almost like
26:21the high-rise skyscrapers of one of our cities.
26:26The microcosmic high-rises are full of cyanobacteria.
26:31These bacteria can photosynthesize.
26:35Photosynthesis is a chemical reaction that takes place inside a plant producing food.
26:41Today, it's an important part of our planet's existence.
26:45Two and a half billion years ago, it was revolutionary.
26:50And it happened when ancient cyanobacteria similar to those in the stromatolites mutated.
26:57This mutation allowed cyanobacteria to take the energy from sunlight
27:02and use it to make sugars out of water and carbon dioxide.
27:07This gave cyanobacteria a huge evolutionary edge.
27:12They could now make more energy for themselves, so they could grow and reproduce faster.
27:18For everything else, it was a catastrophe.
27:22It produced oxygen as a waste product.
27:25Oxygen was no use to them, so they released it into the air,
27:29transforming Earth's atmosphere over millions of years.
27:33This byproduct, oxygen, is extremely toxic.
27:37The reason oxygen is so dangerous is that it's very reactive.
27:41It loves to combine with everything.
27:44So think about something rusting.
27:46Iron rusts because oxygen is actually combining with the molecules.
27:50It's called oxidation.
27:52So when oxygen was first released, it was tremendously dangerous.
27:56The new oxygen built up in the atmosphere,
27:59killing off species of microbes everywhere on the planet.
28:03Right when this happened, you would have had a mass extinction.
28:08This would have been a global mass extinction event.
28:11This was an unprecedented environmental disaster,
28:15probably in the entire history of the Earth up to that point.
28:18And I'm not even sure it's been paralleled even up to today.
28:21This may have been the single biggest catastrophe in our planet's history.
28:25This was the great oxidation event, and it changed our atmosphere,
28:29it changed our planet, and it didn't just end there.
28:33Something changed again.
28:35Another mutation allowed some of these bacteria
28:38to use that oxygen in their own metabolism.
28:42And that was a huge change.
28:47The ability to use oxygen was an incredible leap forward.
28:52The beauty of oxygen is that it allows a metabolism
28:56to process nutrients much more rapidly.
28:59It basically helps bodies burn these materials
29:03so that they can generate a lot more energy a lot more quickly.
29:06Organisms that figured out how to use oxygen for respiration
29:10ended up getting a huge kickstart of energy
29:13and gave them a huge advantage over other organisms.
29:16It supplied enough energy that organisms could become more complex,
29:21larger, multicellular.
29:24Really the tapping into oxygen and being able to use oxygen
29:29in our metabolism meant that it was a game changer,
29:33that we could evolve in ways that never would have been possible
29:37without cyanobacteria.
29:39Simple organisms became more complex.
29:43Single-celled creatures became multicellular.
29:47This gradual accumulation of oxygen into the atmosphere of the Earth
29:51was huge for the multicellular animal and life explosion
29:55that occurred as a result
29:57and was one of the most important events in Earth's history.
30:00This would have been a complete transformation
30:03of the Earth's atmosphere and physical setting.
30:06This is when the green Earth started to evolve.
30:10The great oxidation event changed the course of evolution
30:14leading to our complex world.
30:18It is really hard to overemphasize the importance of the microcosmos.
30:22Just the fact that I'm speaking to you, I'm breathing in and out,
30:25I wouldn't be doing that without the tiniest organisms on the planet.
30:30The microcosmos gave us life.
30:33Now it could wipe us out.
30:36Global warming is releasing potentially lethal bacteria and viruses.
30:42Are we facing a microcosmic zombie apocalypse?
30:51Siberia, present day.
30:53Rising temperatures are melting the Arctic permafrost,
30:57revealing land sealed under ice for tens of thousands of years.
31:03As that permafrost begins thawing out and melting with climate change,
31:08maybe that will release pathogens
31:11that have been locked up for potentially thousands of years.
31:16In 2014, researchers investigated melting Siberian tundra,
31:21a region larger than the USA.
31:25I've seen a lot of science fiction movies
31:27where scientists are digging around in the ice
31:29and find something bad from a long time ago.
31:31Scientists took samples of tundra soil to the lab
31:34and examined the contents.
31:36They found a frozen ancient virus.
31:40A virus locked in ice from over 30,000 years ago.
31:47Isn't this the start of like every horror movie?
31:51A scientist uncovers some deep secret of nature
31:54and then just open it up and unleash it on the world.
31:59Just like in a B movie,
32:01the team fed the virus to living single-celled creatures called amoebas
32:06to see if the virus still functioned after being frozen for thousands of years.
32:12The virus woke up, attacked the amoebas, and replicated.
32:18Bringing this ancient virus back to life was sort of waking up the undead.
32:25Scientists had no idea how this zombie virus would behave.
32:33Something about it was very, very different.
32:36It was huge compared to normal viruses.
32:40It was substantially larger than any virus that we had seen before.
32:46This is the Goliath of Goliaths among viruses.
32:52So large, it looks more like bacteria than a virus.
32:56We call these kinds of giant viruses meme-y viruses
33:00because they mimic other creatures like bacteria.
33:06One way the virus mimics bacteria is in the amount of its genetic material.
33:11It has 900 genes, eight times as many as a regular virus.
33:17Viruses are very simple.
33:20They don't require a lot of genes to function.
33:23But this virus has more genes than necessary.
33:29What is it doing with all these extra genes?
33:33We have now found other meme-y viruses.
33:3620 years ago, we had no idea that this complex type of virus even existed.
33:42We still don't know what all the extra genes do.
33:46This type of virus might even be able to generate its own energy,
33:50making it closer to bacteria than other viruses.
33:55Because it has so many extra genes,
33:58this is a virus that is not acting like a virus.
34:02We can't be sure how the Siberian meme-y virus will behave if released.
34:08And even if it only attacks amoebas,
34:11there could be other large, complex viruses buried in the ice.
34:16They may not be so safe.
34:19We know that there are large regions of the Earth that are locked in ice right now.
34:25There could be viruses that live inside that ice
34:30that, if the Earth gets too warm, could reactivate.
34:34These viruses could potentially be a threat to us.
34:39Recently, other dangerous frozen zombies have reanimated.
34:44Hidden in the dead.
34:47We tend to think of people who died in the past as not being able to affect us at all, right?
34:51They're gone. Their germs are gone.
34:53Unfortunately, this isn't exactly true.
34:56So, for people who were buried in tundra that's been frozen,
35:00they never really disappeared.
35:02And now, unfortunately, as the climate warms,
35:05these tundra environments are releasing frozen people and animals
35:11who died thousands of years ago.
35:15But it's not the dead people and animals that threaten us.
35:18It's the microbes inside them.
35:22In 2016, that threat became real when another area of Siberia thawed.
35:29A 12-year-old boy died, and dozens of people needed medical treatment.
35:342,000 reindeer also perished.
35:38The culprit? Reanimated bacteria called anthrax inside a melting reindeer.
35:45Anthrax is a common microbe found in soil.
35:50In medieval times, sometimes farmers would come back to find entire fields of dead animals.
35:57They didn't understand at the time what was going on.
36:00They attributed it to cursed fields.
36:03But we now know these are outbreaks of anthrax.
36:08The defrosted reindeer died nearly a century ago.
36:13The anthrax that killed it was safely locked away in the ice.
36:18The thawing out of regions like the Siberian permafrost
36:23could be almost like the inadvertent opening of Pandora's box.
36:28Once you open it, you don't know what's going to come out.
36:31It could be releasing ancient preserved microbes, bacteria, or viruses
36:38that have been laying dormant for hundreds, if not thousands, of years.
36:44These microbes are actually very different from what we have on Earth today.
36:49If we encountered these microbes, it's not really clear what would happen with our immune systems.
36:55It could be totally fine, but it could also wreak complete havoc on us.
37:02It's also not clear if modern drugs would help us beat any ancient microbes we unleash.
37:10Now, as humanity expands beyond Earth to new worlds,
37:14will we carry our microcosmos with us into space?
37:18Or have we already infected our cosmic neighborhood?
37:26Space is no longer the final frontier of the future.
37:31We're already exploring the solar system.
37:35We've sent probes to the planets and put boots on the moon.
37:40Now, NASA plans to land astronauts on Mars by the 2030s.
37:47As a science fiction nerd myself, without even breaking a sweat,
37:51I could name ten movies where people go to another planet
37:54and some disease, some alien life form is unleashed on humans and kills us all.
37:59I think that has it exactly backwards.
38:02If we try to settle on other planets, we have to be really, really careful
38:06and really, really think about how we are affecting them.
38:10As we launch more and more missions into space,
38:13we risk sending Earth's microcosmos with them,
38:17endangering the health of the solar system.
38:21And if we find a planet that actually has its own biosphere,
38:25that has life of its own, we need to be very careful about
38:28how we introduce our microbes to their microbes
38:31because it could really be catastrophic for them.
38:33It's serious because we're looking at places like Mars,
38:36like Titan, Saturn's moon, like comets,
38:40where life, or at least prebiotic life, could have existed.
38:43Or, in the past, there could have been a much more habitable environment.
38:48So, it's entirely possible that we are polluting,
38:52we are infecting these other objects with our own bacteria.
38:57If we contaminate a pristine world,
39:00we won't know which microbes were there first.
39:04Our bugs could even kill off the native ones.
39:08It may have already happened.
39:11Is it possible that we've already sent pathogens out among the stars,
39:17hitching rides on our spacecraft?
39:20We've sent missions to other worlds,
39:22and it could be that during those exploration periods,
39:25when we didn't really understand the microcosmos,
39:28we've already sent bacteria, we've already sent viruses to those worlds.
39:32So, we could have already infected them.
39:35We are absolutely sure that we have already infected other worlds.
39:39We are absolutely sure that we have already delivered some aspects
39:42of our own microcosmos to different worlds out there.
39:45Every spacecraft we send, we cannot get rid of every tiny little bacterium,
39:50every tiny little virus.
39:52Bits of us already are on Mars.
39:57You're looking good.
39:59The Apollo 12 mission brought back bits of the Lunar Robotic Probe,
40:03Surveyor 3, it found on the Moon.
40:06Analysis of the probe found a bacterial contamination.
40:10We don't know where it came from.
40:13If that thing was infected before we sent it to the Moon,
40:15and it sat on the Moon's surface for two years,
40:18in a vacuum, changing temperatures, radiation from space,
40:21that really is telling us that we can infect other planets,
40:25and we should take this very seriously.
40:28We're ramping up our space missions.
40:31We're sending probe after probe to planets all throughout the solar system.
40:36Taking care to not send our own diseases out onto other planets
40:42is something we actually have to care about.
40:45NASA does care.
40:47Before launching a new probe, a planetary protection team
40:50deep cleans every inch.
40:54You try to bake the spacecraft, you try to disinfect things.
40:56You build everything and keep everything within a clean room.
41:00Which has a pressure that blows dust out.
41:04Everybody wears what are called bunny suits,
41:07so nobody touches anything directly.
41:09But then, that's still not enough, because microbes are incredibly hardy.
41:14It's even more difficult to kill microcosmic stowaways
41:17if they're travelling inside an astronaut.
41:21In the not-too-distant future, we'll start sending not robot explorers,
41:26not probes to Mars, but people.
41:29An inherently dirty, mucky organism like myself,
41:35you can't sterilize a human, you can't remove all bacteria.
41:39We have to realize that we are bringing the microcosmos with us,
41:42and we may change worlds entirely without even noticing it.
41:48Planetary protection continues once the mission is landed.
41:52So thinking about planetary protection means we really have to think about
41:56our actions in a whole new way.
41:58For example, if the rover were to find a pool of water,
42:02we really couldn't get that close, because we could not guarantee
42:05that even after all of this time, there wasn't some kind of microbe
42:08that could jump ship into that pool of water
42:11and then live happily on Mars and reproduce.
42:17Potentially, our impact could be absolutely devastating
42:20on worlds that either have life or are emerging life.
42:23And so we just need to take that responsibility seriously
42:26and be careful with the way in which we explore them.
42:30Humans bear a responsibility for the safety of the cosmos.
42:33Our track record on Earth isn't good.
42:38When we look at the pattern of exploration or colonization
42:41that we use as humans, we are really invasive.
42:44We see a lot of destruction in our path.
42:47And we have to wonder if that's what we're going to do
42:50when we start to really explore and colonize outside of Earth.
42:53Like viruses, we also insist on spreading.
42:56We insist on spreading around our world, around our solar system.
42:59There is a great chance that we will cause utter destruction wherever we go.
43:05Our relationship with the microcosmos is complicated.
43:09It's killed millions of people.
43:12But without it, we wouldn't be here.
43:16This time we're living in is really causing us to reflect on the microcosmos.
43:20And the better we understand these microorganisms,
43:23the better able we are to deal with what's happening today.
43:26The coronavirus crisis reminds us we need to respect the world we cannot see
43:31and recognize that the microcosmos is every bit as important to us as the greater universe.
43:39It's so easy, especially right now in history, to hear the word virus
43:42and think about how harmful they are, how dangerous they are.
43:45But remember that you are actually a creature built of viruses yourself.
43:49As far as we know, we've never been without the microcosmos.
43:52Microbes were here before us, they'll probably be here after us.
43:56And we need them to live.
44:00The microcosmos, it's absolutely essential.
44:03We couldn't function, we wouldn't survive, we wouldn't be here without it.
44:07But it's also our greatest ally and it's also our greatest enemy.