What’s that up in the sky?
It’s a bird, it’s a plane, no -- it’s the Sun.
Oh…
The Sun, as we know it, is a bright, friendly ball that makes life on Earth possible.
Earth isn’t the only planet in the Solar system, and yet, it’s the only one with
complex forms of life.
So it’s not just that the friendly Sun makes our planet an oasis in a vast space desert.
The Sun could also finally be the most harmful thing our planet will face.
But, more on that in a bit.
Can you believe that the Sun doesn’t care about us?
Or life.
Or planets.
It’s highly radioactive, and it’s already destroyed the atmosphere and oceans on Mars.
Is it going to destroy Earth too?
Or do we have a chance to survive?
Well, unlike other planets, the Earth is protected from radiation.
Deep inside its mantle, there’s a mixture of boiling metals that create a huge magnetic
field around the Earth.
It’s good for us because that field doesn’t allow radiation to reach the surface.
There’s also an ozone layer, which works the same way.
Earth is located in the so-called Goldilocks zone, or circumstellar habitable zone.
What that technical gobbledygook means is, it’s not too far and not too close to the
Sun, and water can exist in its 3 states here – liquid, gas and solid.
These are basically ideal conditions for all living beings.
Hollywood has shown us dozens of dangers that could destroy life on the blue planet – from
a huge asteroid, to the invasion of aliens.
But there’s a real danger that could eventually burn all signs of life away (unless asteroids
and aliens don’t do it first), and that’s the Sun.
Like any star, it goes through different phases of evolution – from a cloud of star dust
to a dense stellar remnant – a white dwarf.
Now, the Sun is somewhere in the middle of its life.
Hydrogen inside its core burns and turns into helium; the same one we fill balloons with,
right.
But if you inhale the sun, instead of sounding goofy, you’d just burn up.
Bad idea.
Scientists say that it’ll take about 7 billion years for all the hydrogen to burn away and
be replaced by helium.
As a result, the Sun will be getting hotter and brighter – by about 10% every billion
years.
And this is where the problems for the planets start, as the average temperature on the surface
of the Earth will be 120 °F higher.
This will lead to a greenhouse effect like what we see on Venus now.
In the long run, the water will be blown away from the atmosphere by a stronger solar emission.
In 3.5 billion years the Sun will be 40 % brighter than it is now.
Imagine a frying pan with water in it left on a sunlit kitchen table.
The water would evaporate almost immediately.
And this is what’ll happen to the oceans at that time.
They’ll become so hot that they’ll evaporate without boiling.
Needless to say, but I’ll say it anyways, It’ll be a very hard time for plants and
animals.
Only some will survive, but not for long.
When steam gets into the atmosphere, the Solar ultraviolet light will decompose water molecules
and hydrogen, which are necessary to build any living cell, and spread them into space.
The Sun will keep growing and eventually turn into a red giant, which will absorb Mercury,
Venus and probably Earth.
But even if our home survives, it’ll be a roasted piece of rock rather than the beautiful
blue planet we’ve known our whole life.
You’re upset that our best friend is going to betray us?
Cheer up! 7 billion years is plenty long enough to prepare for survival.
And here are the solutions that scientists can offer.
One of the most obvious decisions would be to leave the sinking ship in a lifeboat.
Or rather, fly away in a spaceship.
In 1930, British science fiction author, Olaf Stapledon, described a future when Earth becomes
uninhabitable and the next generations had to move to Venus and Neptune.
Stephen Hawking, like some other outstanding scientists, thought it was necessary to create
a human colony on other planets and the Moon so that human beings could survive any catastrophe
capable of destroying life on Earth.
But let’s come back to escaping the planet.
To evacuate 7 billion people, we would need about a billion space shuttles.
Even if we launched 1000 shuttles daily, which is – well – impossible, it would take
2700 years to move all the population from the planet.
And yes, since Venus would be destroyed too, we’d have to get much father from the Sun;
and the flight would take years.
And if you think weightlessness is fun, you’d be disappointed.
Without gravity, our bodies age quickly and develop all sorts of illnesses.
Years without gravity and protection from solar radiation will do no good to anyone.
And then, it’s not like there’s a comfortable 5-star hotel on a different planet, waiting
for us to move in.
People on Earth need oxygen to breathe, gravity to walk, water to drink, food to eat.
The conditions we need to live are too complicated to reproduce anywhere outside the Earth.
This is exactly what drove scientists to a surprising idea.
Why not take Earth, with all its resources and inhabitants, and move it to a safe distance
from the Sun?
Scientists say that when the Sun turns into a Red giant, the Goldilocks zone will be 1.5
times farther from where it currently is, which is where Mars’s orbit is now.
Sounds crazy, and yet scientists have a way to solve this too.
Launching a rocket into space pushes Earth in the opposite direction, just like a backfire.
The problem here is that the Earth is too big, and it would take a billion 10-ton rockets
launched in the same direction to change the Earth’s speed by 20 nanometers per second.
That’s nothing compared with its actual speed of 19 miles per second.
Another way is roughly what we saw in “Armageddon”: a nuclear explosion close to or on the surface
of a space body can change its trajectory.
It can work well with an asteroid; the film wasn’t that far off after all.
But the problem with Earth again is that it’s too big.
And another thing: any explosion means destruction, and that’s what we’re trying to avoid
in the first place.
Since the Earth’s size and mass are not to be sniffed at, maybe we need some method
where they aren’t important.
Light has energy but doesn’t have mass.
A focused ray of light, such as a laser, can take energy from the Sun, and in that case
the Earth’s mass is irrelevant.
And yet, even if we use a huge and powerful laser like Breakthrough Starshot, whose goal
is to deliver a spaceship outside the Solar system to explore the neighboring stars, it
would still take 3 billion years to change the orbit of the planet.
We could also reflect the Solar energy directly with a kind of Solar canvass built close to
Earth.
Sounds good, but it would have to be really big – 19 times bigger than the Earth’s
diameter.
Well, maybe one day we’ll have the right kind of technology.
After all, a billion years is 5000 times longer than Homo sapiens have been living on the
planet.
Look how far we’ve come from living in caves and chasing mammoths!
We might think up something useful by that time.
There’s still another way to save our home from the growing Sun.
It’s a kind of interplanetary pool.
The technique known as a gravity slingshot is used for 2 rotating bodies and uses their
gravity to change the speed.
It’s been widely used for launching interplanetary explorers.
Let’s say, spaceship Rosetta, which visited comet 67P in 2014-2016, came close to the
Earth twice during its 10 years’ journey to get a speed-up from it.
Without this boost, its mission would’ve been impossible.
I wonder why they didn’t just send Tom Cruise – he would have dealt with this for sure.
Ok, kidding aside.
The planet got an impulse from the explorer too.
It had no effect on Earth just because it’s so big, but what if we could use something
bigger?
Say, asteroids.
They can influence the Earth’s trajectory.
Maybe a single time wouldn’t have much effect, but this action can be repeated a lot of times
to reach the goal.
Some places in the Solar system are full of small asteroids and comets – even modern
technologies are enough to move them.
Donald Korycansky and Gregory Laughlin from the University of California and Fred C. Adams
from Michigan have developed that idea.
They say that if we take an asteroid with a 60-mile diameter and put engines in it,
it’ll pass the Earth's orbit every 6000 years, each time giving it part of the energy.
As a result, the planet will be thrown out 18 miles, just like a swimmer pushed out by
a wave from a passing motor boat.
After 6 billion years and a million meetings with the asteroid, it’ll reach the orbit
of Mars.
Look easy?
Well, it's still a theory.
It's one thing to move a small spaceship, and quite another to move a whole asteroid
that could destroy life on the planet if the scientists miscalculate.
Oops.
My bad.
Let's hope they think up something safer by the time we need to do something ASAP.
Do you think human beings will leave Earth for another planet or move it to a different
orbit?
Let me know down in the comments!
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