What If

A scorching hot never-ending day on one side and a permanent frozen night on the other. This is what our planet would be like if it was tidally locked to the Sun. How would your life be different on this Earth? Where would you actually be able to survive? And what would happen to your sense of time?

635 light-years from where you are sitting, way out in outer space, lies a planet. The first planet to be discovered inside the habitable zone of a Sun-like star. Its name is Kepler 22-b. When a planet is located within a star's habitable zone, it means that there is a chance that liquid water exists on its surface. And where there's water, there’s also the possibility of life. Human life. What would the weather be like over there?

Antimatter is the most potent fuel source known to humanity. And it could be the secret to faster-than-light space travel. But where in the Universe would we find antimatter? How fast could it make your spaceship travel? And why would you want to stock up on bananas on your intergalactic trip?

Every year, around 140 million babies are born worldwide. And if we continue at this pace, 50 years from now the global population will reach 10.5 billion people. The world might get a bit crowded. So let's ban all babies for the next 50 years. What would life be like if we suddenly stopped procreating? When would our global population decrease dramatically? And what would happen when the baby ban was lifted?

A giant asteroid is headed our way. But no, it won't hit the Earth. This asteroid is about to slam into the Moon and crack it right in half. What would it be like to witness this epic collision? Would the Moon break clean in two? Or would it shatter into a million pieces? And how could one of these pieces wipe out life here on Earth?

If you could turn everything you touched into gold, how soon would your life become unbearable? Why would this superpower not make you rich? Why could things around you explode? And how could one touch end all life on the planet?

Welcome to Jurassic World. In real life. Let’s bring back some of the most dangerous creatures to ever roam the Earth. What could go wrong? How would we be able to clone dinosaurs? What would life with them roaming the Earth be like? And which ones would eat you for breakfast first?

The world has ended. The sky has fallen. Doomsday has come and gone. So now what? Let’s start rebuilding civilization, of course. How would you begin to come back from an apocalypse? What could you use from the remains of our old society? And how would you be able to remember anything?

Humanity’s nuclear arsenal is capable of destroying all life on Earth. Over. And over. And over. Maybe it's time we dumped it far away. We might want to inhabit other planets in the future, so how about our closest star? How many nukes could we throw at the Sun? What would be the price tag for this mission? And could we accidentally destroy our only source of daylight?

The biggest planet in the Solar System. And the smallest star in the known Universe. Today, they are on a collision course. EBLM J0555-57Ab is a red dwarf and the smallest star we've ever discovered. Jupiter is huge. It's about 11 times larger than Earth. But because it's mostly made of hydrogen, it's not massive enough to be a star. So what would happen if these two giants collided?

A giant, fork-tongued lizard with razor-sharp teeth. And a bite with bacteria-laced venom that's seeping into your flesh. Well, this is no legend. It’s a Komodo dragon. What would happen if you were attacked by one of these giant lizards? What would be your best bet to fight it off?

Every 75 years, a ball of fire streaks across the sky. But that's no fireball. It's Halley's Comet. And you're about to hitch a ride on it. Get ready for a journey around the Sun to the edge of the Solar System. And back again. What conditions would you find there? How would you manage to survive on your new icy home? And what would it have in common with a trip to a Hawaiian island?

All good things must come to an end. Sadly, Homo sapiens’ time on Earth is no exception. And someone would surely take our place as the dominant species. How could genetic engineering spell out the end for our species? What would distinguish the next Homo species from us? And could the world’s next dominant species not be human at all?

Oh my. Have you done something different with your peepers? Like maybe swapped them out for a pair of freakishly oversized fly eyes? They look functional. How would you see the world around you? What would you look like to other people? And how would this change your buzz life? Er, I mean love life?

Taller than a six-story building. Longer than three school buses. Ten times as heavy as an elephant. The largest dinosaur ever is coming back from extinction. What would life be like walking among these giants? How could we possibly tame these creatures? And how would they threaten to destroy human society? Why is it called argentine lizard?

It’s been over 200 million years since South America broke off Africa into its own continent. But now it’s behaving very strangely. It’s taking on water and going down. How would this whole continent turn into a sinking ship? What effect would this have on the rest of the world? And how would you and everyone else manage to escape?

The Sun isn't the biggest thing in our Solar System. And it’s not Jupiter, either. But close. It's Jupiter's very own magnetic field. What would it be like if Earth’s magnetic field was as huge as Jupiter’s? How much stronger would our magnetosphere become? Why would it make solar radiation worse? And how could this help you treat anxiety?

A rogue star is headed straight for our Sun. If these two stars slam into each other, it could spell the end of all life on our planet. How could a rogue star end up in our Solar System? What would this epic collision look like? And how much time do you have left to live? What is Gliese 710? Where in the Oort Cloud is it? Is a rogue star in our Solar System?

What are the most dangerous things you could jump into? Why is liquid mercury so dangerous? How can lake Natron located in Ol Doinyo Lengai turn you to stone? Why is potassium and sodium carbonate such a dangerous mix? What can stingrays do to you if you jumped into a pool of them? How scary is a pool of sharks? Can you even survive a fall into a volcano? Would you cool off in a pool of liquid nitrogen?

Some of the planets in our Solar System are gigantic. But what if they got even bigger? Let’s go up the planetary size chart and see what kind of chaos doubling the size of every planet would make. What would it be like to live on a super-Earth? How big would Jupiter need to get to become a star? And would Pluto finally regain its planetary status?

Millions of years ago, all the continents were one. Waiting to crack and spread into the world we know today. So how about we fast forward and bring two of them back together? South America and Africa. If these two landmasses fused together, how disastrous would that be? What new animal species would it create?

Get your bone flute and gather around the fire. Today on What If, we're taking you back to the time of woolly mammoths and saber-toothed cats. That's right. You're living in the Stone Age. If you were living day-to-day in this primitive world, what would you use as tools? How would you communicate with anyone? And would you have to eat your family?

Giant bugs are now roaming the Earth. If these behemoths existed, would humanity become bug food? How could a bird save your life? And why would Grandma’s jewelry come in handy? How strong is their chitin? Can you pierce through their exoskeleton?

What if I told you Latin America could have hosted one of the world’s greatest superpowers? Capable of changing the course of history in ways that only players like the U.S., China or Russia can today. And to do that, you'd only need one thing. Uniting all of its countries into a single state.

At Yellowstone National Park, all that stands between you and a pool of boiling, rotten-egg-smelling, acidic water is a humble boardwalk. And your good judgment. Stray off the path and you could be headed toward quite the swim. Heads up. Scorching temperatures would be just the start of your problems. How long could you survive your accidental dip in Emerald Springs?

Earth has gone through at least five major ice ages in its history. And you better start adapting now. Because another ice age is about to begin. Hypothetically. How would a new ice age change Earth as we know it? What could you do to survive on a frozen planet? And how are we already delaying another ice age?

Breaking news. Flags are flying at half-staff. The world mourns the death of a beloved monarch. Queen Elizabeth II has passed peacefully in her Balmoral Castle in Scotland. What will this mean for the future of the Commonwealth? How would this affect the economy? And what does Operation London Bridge have to do with this?

Tritium. It's that mysterious glowing element found in air, water and now inside you. That's right. You're going take this radioactive isotope and chug it down. So if you drank tritium, how could your body power a nuclear reactor? What would happen to your DNA? And would you glow in the dark?

Imagine Earth with an even 50/50 split between continents and oceans. Our planet covered half by land half by water. How would this change the planet as you know it? What new kinds of vacations could this make possible for you? And what does the color of your pee have to do with this?

An ancient creature is lurking in the ocean. It's double the size of a T.rex. Its gigantic jaws could crush a car. And now, it's on the hunt for you. Megalodon sharks haven't existed for more than two million years. But today, we're bringing these apex predators back to wreak some havoc.

Every year, beach lifeguards rescue tens of thousands of people. Four out of five times, it's from these rip currents, also called riptides. If you see the water do this, get out fast. If you don't, you might get caught in a riptide. What are the warning signs? Which direction should you swim if you want to survive? And what's pulmonary edema?

Birthday balloons falling limply to the ground. Satellites, medical scanners and TVs fading to black. And twinkling stars in the night sky disappearing one by one. All in just five seconds without helium. What would the loss of helium do to your body? How would the rest of the Universe react to this molecular on-off switch? Could this bring about the end of our Solar System? How could it affect CERN's Large Hadron Collider?

There are places in the Universe where you could turn to ash, freeze to death or be completely crushed by gravity. And you're about to visit them all. What conditions make some of these exoplanets so dangerous? What would happen if you set foot on them? And which planet would slash you up to bits and pieces?

Something is very wrong with our Sun. It’s turned into a spinning lighthouse of death. What would make the Sun so much more deadly than usual? Would there be any way life on Earth could survive this? Why would it feel like you're stuck at the bottom of the ocean? What's a pulsar planet like? Would there be eternal darkness on Earth? Will Earth still be habitable?

The Amazon rainforest stretches for millions of kilometers, hiding ancient tribes, animals and maybe something else. What if under this mysterious canopy lies an advanced civilization? How did we miss something so huge? Is the rainforest just an overgrown garden? Why didn't these people fight off the European conquest? What's the story behind the El Dorado myth? Did Francisco de Orellana discover any clues?

Today, we're going to build the highest bridge on planet Earth. Welcome to the Qinghai-Tibet Plateau, the “Roof of the World.”It’s home to the world’s tallest mountain, Mount Everest. But also the longest, deepest canyon on the planet, the Yarlung Zangbo Grand Canyon. This super canyon is 505 km (313 mi) long and 6 km (3.7 mi) deep. And it’s here that we’ll be taking on one of the most epic engineering challenges ever.

It’s invisible, deadly and sucking up every bit of matter in its path. The most massive black hole in the known Universe is headed right toward Earth. What would you see as it started to slurp up the Milky Way Galaxy? What kind of tasty dish would Earth become? And once it’s finished with us, where would it go next? Maybe the Orion Arm? Or perhaps the Oort Cloud?

The ground around the Empire State Building appears to be sinking. This historic landmark is about to get lost in a giant pit. And you will be coming down with it. If a sinkhole swallowed the Empire State Building, would you be safer at its top or bottom? What would the warning signs be? And could anything increase your chances of surviving?

Earth is the only life-supporting planet in our Solar System. Until now. Today, we're bringing Kepler 22-b into our planetary neighborhood. Where would this planet need to orbit within the Sun’s habitable zone? How would you go visit it? And would you find life when you get there?

It's about to get really hot down on Earth. Because all our oceans suddenly started to boil, sending steam into the atmosphere at an alarming rate. Why would all this water in the air lead to setting the planet on fire? How would you feel with all this extra humidity? And how could this make Earth a lot like one of our sister planets? Would there be a massive drought? How severe would the droughts be?

What if the Moon was more than just a lifeless rock? Under that bright light, it could be hiding an alien civilization. When did this alien life begin on the Moon? What would these lunar-dwellers breathe? And what would our neighbors look like?

The biggest planet in the Solar System has gone rogue. And now it’s heading straight toward Earth. You have 30 days till this gas giant wipes us all out. What speeds would Jupiter be traveling at? What kind of havoc would it wreak along the way? Is there any way we could survive getting eaten by a planetary Pacman? What would happen to the Asteroid belt?

Right now, wherever you are, you are spinning with our planet at hundreds of meters per second. But what if our planet started hitting the brakes until our world didn’t spin at all? Why would it be harder for you to move around? Why would some parts of the world actually benefit from this? And why could this slowdown provide you with the trip of a lifetime? What's the Coriolis effect?

The night is dark and stormy at the beach. A crowd prays to the thunder in the skies. All hail the god of chaos, who sleeps no more. Cthulhu, the great, green, bringer of madness rises! A colossal shadow emerges from the ocean. Wielding tentacles, wings and eyes that reach deep into your soul and your mind. If Cthulhu, the terrifying demi-god from classic literature, was here, who would it attack first? What would happen when you looked at it? And why would you bring out the big guns?

Jupiter may be the biggest planet in the Solar System, but its days are numbered. Because today, we’re using Earth’s biggest, baddest bombs to blow the gas giant into oblivion. How many nukes would you need to do the job? What obstacles would these rocket-bound bombs encounter on the way? Would one nuclear explosion ignite the entire planet? What are Kirkwood gaps?

Attention, humans. Shapeshifting alien lizards have taken control of your world. They’ve maneuvered themselves into positions of power. And they could be anyone. Where did these powerful reptilians come from? How could you tell if someone is a lizard in disguise? How could you possibly defeat these all-powerful overlords? Could they be from the Orion and Draco constellations?

Imagine that the Sun is on the verge of exploding. Or that a planet-killing asteroid is headed our way. Or maybe you just want to take the entire planet on a joy ride around the Universe. Well, fasten your seatbelts. Let’s pilot Spaceship Earth out of our Solar System. What would it take to free our planet from the Sun’s gravity? What out-of-the-box ideas would actually be the most efficient? And why would you need to nearly destroy everything on Earth to make this work?

uckle up. We're going to take the orbit of this rock and kick it into high gear. Behold the Moon breaking its planetary speed limit. How would this event flood cities? What would happen to the Earth's crust? Why would the Moon go rogue? What's the Roche limit? What is the basis of Kepler's third law?

You’ve traveled thousands of light-years through interstellar star systems. And now you’re stranded on a planet you know nothing about. As long as you’ve got oxygen, water and food aboard your spaceship, you should stay inside and figure out what you’ve got going on around you. But your supplies wouldn’t last forever. So the clock would be ticking.

With nearly eight billion people on the planet, things can feel pretty crowded. Let’s make things a bit tighter by housing every single person on Earth in one giant skyscraper. Pack up your things, we're all moving in together. But a building big enough for all eight billion of us doesn't exist yet. We're going to have to build one from the ground up.

Dark, mysterious and consuming everything around them, black holes will rip apart anything that passes their event horizons. But could there be more? What would happen if you fell into one of those monstrosities? How could you possibly travel through the black hole itself? And if you emerged on the other side, where would you end up?

Get ready for some serious burns and the instantaneous death of organisms. Let’s turn up the heat and bring the entire planet to a boil for five whole seconds. How would this apocalyptic heat wave affect the environment? What would this do to all living things on Earth?

Whether it was a global pandemic, a planet-wide volcanic event or a gigantic space rock, we reached the end of the line for our species. Every single human on Earth is gone. For good. While there’s no hope for humanity to make a comeback, we’d be leaving behind a lot of stuff. Cities. Highways. Waste. Time to see just how long it would take for the last remaining traces of human life to disappear.

Avatar's Pandora is the wildest, most beautiful and most deadly place in the galaxy. I mean, who wouldn't want to live here? But how could the air be lethal? What elements could make your body glow? How could a gas giant destroy Pandora's surface? What is tidal heating? Why wouldn't you be able to watch Netflix?

It's a small world after all, because today, we're shrinking Earth to the size of Pluto. But if our planet was this tiny, how would it alter the atmosphere? Why would the Earth get hotter? And how would gravity affect our water supply? Would we be tidally locked to the Moon? Would our planet still be habitable?

Out of all the planets in the Universe, Earth is clearly the best for life, right? Wrong. Earth may be great, but scientists have discovered a few worlds that could be even better for life. Behold, KOI 5715.01. Most of the contenders on our superhabitable planet list aren't the ones you could visit anytime soon. The top spot is held by one 3,000 light-years away from our Solar System. It exists in the Goldilocks zone of its star. So conditions wouldn’t be too hot or too cold for a key life-supporting ingredient to exist on its surface. Liquid water.

This is our Universe, an ever-expanding network of stars and galaxies. And this is your brain. Don't they look eerily similar to one another? Why are they so alike? Could your brain be a mini-version of the cosmos? Or could the Universe actually be part of some larger consciousness?

Imagine you had to experience an apocalypse every day. Volcanic eruptions, tsunamis, asteroid showers. Every day would be a struggle for survival. That’s because Earth is now a moon of Jupiter. Why are we being hit with so many asteroids? Could we survive in underground bunkers? And how much damage would Jupiter’s gravity cause?

Thousands of light-years from Earth, there could be another planet hospitable to life. Kepler 69c. And you’re about to travel to this alien world to see that life with your own eyes. What would it be like to make this epic journey so far across the Universe? What kind of planet would you be likely to find upon arrival? And if you did discover life, what would it look like?

These slithering creatures can live in the smallest corners of your home and the darkest places you don’t dare visit. Well, not anymore, because today we’re killing every single snake on Earth. How would this snake hunt begin? Would we have to invent a bioweapon to finish the job? And why would things get medieval?

Have you heard of something called water fasting? It's a type of fast that restricts everything except, well, water. Most people only water fast for 72 hours at most, but what if you did this for the rest of your life? You'd be fine, right? Haha, yeah. Not so much. What happens to your stomach without food? What damage will you do to your organs? And how many days can you last?

Pack your bags because you’re traveling through space to see Alpha Centauri. There’s just one problem. It’s going to take 100 years. But is it possible to sleep through the trip? Get comfy because you’re going nighty-night for an entire century. What technology would you need? What would happen to your body while you’re asleep? And what sort of stuff could be waiting for you in the future?

Mars didn’t always look like this. It may have once been covered in oceans. But what if we brought all the Martian water back and transformed the red planet into one that’s half blue? What would Mars look like if it was 50% land and 50% water? Where would we even find enough water to fill Martian oceans? And why might we have no choice but to nuke the red planet?

Ever since humanity discovered that there are other places outside of Earth, we've thought about leaving it. On this episode of What If we're going to do just that. But where would we go? Is building a ring world in space a possibility? Maybe terraforming Venus is our best option for a sustainable life. If we were to leave earth and create something like a ring world, where would we find the materials to do so? And if we lived on Venus, how different would it be from Earth? But before we blast off, why would we ever want to leave?