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  • The Sun's core is shrinking.

  • But as its core shrinks,

  • the Sun itself grows larger.

  • And it will continue to grow,

  • until one day,

  • it engulfs the Earth.

  • Every one billion years,

  • the Sun becomes 10% hotter.

  • But here on What IF,

  • we're going to take billions of years

  • and condense the action into one month.

  • Get ready,

  • because we're going to be moving

  • really fast this time.

  • Instead of one billion years,

  • it would only take four days

  • for the Sun to become 10% hotter.

  • This means you'll see the Earth

  • engulfed by the Sun in just one month.

  • That is,

  • if you're still around to witness

  • the final event.

  • On day one,

  • you'd be blissfully unaware

  • of the tragedy about to befall Earth.

  • Maybe it's a little hotter,

  • but that's just weather.

  • It happens.

  • But by day four,

  • space agencies across the globe

  • would be sounding the alarm bells.

  • By this time,

  • the Sun would be about

  • 10% brighter and hotter.

  • And while 10% doesn't sound like a lot,

  • it will be the beginning of the end for us.

  • As the Sun heat up,

  • more and more water from Earth's surface

  • will evaporate into the atmosphere.

  • This will increase the

  • greenhouse gas effect,

  • causing global temperatures to skyrocket.

  • All of a sudden,

  • it will become very humid,

  • and very hot.

  • But the Sun's high-energy light would

  • bombard the atmosphere,

  • splitting those water molecules

  • into hydrogen and oxygen.

  • Earth will begin to lose its water.

  • And you won't be able to escape

  • the lethal radiation on Earth's surface.

  • If you want to survive,

  • you'll have to go deep underground.

  • But even under a protective layer

  • of Earth's soil,

  • you won't be safe for long.

  • By day 16,

  • the Sun would be almost 40% brighter.

  • Our planet's oceans will boil,

  • and there won't be any moisture left

  • in the atmosphere.

  • The beautiful,

  • lush Earth that you grew up on

  • will become a hot,

  • dry,

  • barren rock.

  • Around day 20,

  • the Sun would run out of hydrogen.

  • So instead,

  • it will start to burn helium in its core.

  • The Sun is now a red giant star,

  • and would expand rapidly

  • while losing its mass.

  • The Sun's gravitational pull on Earth

  • would be weakened,

  • and our planet would begin to drift away

  • from the expanding Sun.

  • But not far enough.

  • According to researchers Klaus-Peter Schroder and Robert C. Smith,

  • the Earth would only have moved about 0.0002 astronomical units.

  • An astronomical unit

  • is the distance between Earth and Sun.

  • While Earth is moving away

  • from the encroaching Sun,

  • the red giant would grow up to 1.2 AU in radius.

  • The Sun would be larger than Earth's orbit.

  • It would swallow the planet whole.

  • Once it's inside the Sun's atmosphere,

  • Earth would collide with particles

  • of gas and spiral inward.

  • And Earth wouldn't be the only casualty

  • of the expanding Sun.

  • Mercury and Venus would be vaporized.

  • The rings of Saturn would melt.

  • Pluto would become much warmer.

  • And if there is a liquid surface,

  • and a thick atmosphere

  • on this distant dwarf planet,

  • it even might become inhabitable.

  • Unfortunately,

  • 30 days doesn't give the human race

  • enough time to prepare for such

  • a catastrophic event.

  • But if we had more time,

  • like billions of year's worth,

  • we could come up with an evacuation plan.

  • But that's a story for another What IF.

The Sun's core is shrinking.

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