00:00Scientists have already found 24 planets that might be better for life than Earth.
00:04On our own planet, the habitable zone is barely a few percent of the surface.
00:08The deep ocean is pitch black.
00:11Billions of people are squeezed onto a thin strip of coastline.
00:14And Earth has already lost 70% of its living window.
00:17In 2020, researchers at Washington State University sifted through 4,500 stars and shortlisted
00:2324 candidates, each orbiting a star that burns up to 7 times longer than our sun.
00:26We were raised to believe Earth is perfect.
00:29But its score is barely a passing grade.
00:32So what does a planet that beats Earth actually look like?
00:35First, the most decisive factor isn't the planet.
00:38It's the star above it.
00:40The sun is a yellow dwarf, burns bright, burns fast, and it's already used up nearly half.
00:45All 24 candidates orbit orange dwarfs, smaller and gentler, burning slow and steady.
00:50They can last 20 billion years, some up to 70.
00:53For scale, the entire universe is only 13.8 billion years old.
00:58Not one orange dwarf has ever burned out.
01:01Humanity has never even witnessed one die.
01:03The sun is a short-tempered landlord.
01:06Orange dwarfs are far calmer, quiet for billions of years.
01:09What life fears most is never heat, and never cold.
01:12It's chaos.
01:14Next, size.
01:16The ideal planet weighs about 1.5 times Earth, roughly 10% wider.
01:20You'd think more gravity means harder to walk.
01:23But more gravity holds a thicker atmosphere.
01:26And with that, two things improve at once, more oxygen, and better shielding from cosmic
01:30radiation.
01:31And with 10% more diameter, there's surface area enough to fit two more asias.
01:36What does more oxygen do?
01:38Earth ran the experiment.
01:40300 million years ago, oxygen spiked to 35%.
01:44Today it's 21%.
01:46The result, dragonflies with 70 centimeter wingspans, the length of your forearm.
01:51Millipedes over 2 meters long, longer than you are tall.
01:54That was Earth's golden age.
01:56In denser air, every wingbeat lifts more weight, so flight takes less effort.
02:00On a high gravity planet, the sky could carry bigger things.
02:03Now climate.
02:06Those planets average about 5 degrees warmer, and wetter.
02:09Sounds like global warming, but it isn't.
02:11Warming is lethal because it's fast.
02:145 degrees over billions of years isn't a disaster.
02:17It's central heating.
02:18Look at Earth now, the Amazon holds 6% of the land and half of all species.
02:23Coral reefs cover under 1% of the ocean floor and feed a quarter of marine life.
02:28Now look at the poles, white, silent, almost nothing alive.
02:32Melt the ice caps, and from pole to pole you get rainforest, with lakes and rivers everywhere.
02:37The same planet could hold several times more life.
02:40Then there's age, and this one is the most striking.
02:43The ideal age is 5 to 8 billion years.
02:46Earth is 4.5 billion.
02:48In other words, Earth hasn't finished growing up, and its decline has already begun.
02:53Life took over 3 billion years to crawl from a single cell to an animal that could reproduce.
02:57An 8-dash-billion, year-old planet hands life 3 billion free years.
03:02Finally, geology.
03:04The bigger the planet, the slower its internal heat escapes.
03:07Heat remains, plates keep moving, the magnetic field holds.
03:11And that field is sunscreen.
03:13It deflects the solar wind.
03:15Look at Mars.
03:17Smaller, its core cooled early, its field died first, and the solar wind stripped it layer
03:21by layer.
03:22A planet that once had water and air became a red desert.
03:26Same star.
03:27Same starting line.
03:29Earth lived.
03:30Mars did not.
03:32So Earth didn't win by being excellent.
03:34Earth won by being just the right size, in just the right place.
03:37Of those 24, which scores closest to perfect.
03:41Kepler, 575.01, towards Cygnus, orbiting an orange dwarf every 55 days.
03:47Its mass is roughly twice Earth's, the only one checking several key boxes at once.
03:52Sound like somewhere we could move.
03:54Not so fast.
03:55First, it's 2,900 light years away.
03:58The light we see today left while the Zhou dynasty was still around.
04:02Voyager 1 would need over 50 million years to get there.
04:06Second, and this stings more, that planet has never been confirmed.
04:09It was even tagged a false positive once.
04:12We don't dare bet on whether it truly exists.
04:15The house we fell in love with may never have been built.
04:17And even if it's really there, half again the gravity doesn't make you fat.
04:21It means every step, every staircase, every night's sleep, you're carrying another body's
04:26worth of water weight.
04:27On Earth, a fall is a bruise.
04:29There, it might be a fracture.
04:31Higher oxygen also means fire ignites more easily.
04:35Our bodies are parameters Earth spent millions of years tuning.
04:38Swap the planet, and every parameter is wrong.
04:41So back to the first question, is Earth the most habitable planet for humans?
04:45No.
04:46Its star is short lived, it's a bit small, half of it is dark and half frozen, and it
04:51has wiped out life 5 separate times.
04:53It's an ordinary planet that barely passed.
04:55But it is the only one that made us.
04:58We weren't chosen by the universe.
05:00We just happened to grow on this patch of ground that fit us precisely.
05:03The universe is enormous.
05:05Those rainforest worlds, ocean worlds, skies full of giant creatures, they might really
05:10exist, turning quietly for billions of years, with no one to see them, no one to know.
05:15And all we can do is make sure this patch of ground, the one that fit us, doesn't turn
05:19uninhabitable before its time.
05:21Last question, if such a planet existed, ticket free, the only condition being that you can
05:25never come back, would you go?
