Astronomers know very well that the Sun is getting brighter very slowly, and in a billion years or so it will make the Earth too hot to live on.
Now a scientist is proposing a radical solution that would allow humans to live on the planet for longer – physically moving it away from the sun.
Albert Zylstra, professor of astrophysics at the University of Manchester, suggests shifting the Earth about three million miles away from the sun.
Right now, Earth orbits the sun at a distance of 93 million miles (150 million km), but that needs to be extended to at least 96 million miles (155 million km), he says.
This movement will extend from a year to 380 days, which means we’ll have to insert an extra 15 days into the calendar year somewhere.
Moving Earth away from the sun would require an asteroid to perform a gravity-assisted or “slingshot” maneuver, already commonly used to accelerate satellites. But it will take a billion years to reach the required distance
“The Earth will get warmer and warmer – the best estimates are that in a billion or two billion years, the oceans will start to boil,” Professor Ziegelstra told MailOnline.
Soon we will be like Venus, with temperatures of several hundred degrees Celsius, so we will have to move before that happens.
“In order to make the living world last more than a billion years, we need to move a few million kilometers away from the sun.”
To explain how the ambitious project will work, a bit of simple astrophysics is necessary first.
When a planet (like Earth) slows down in its orbit, it is moving closer to the Sun, due to the enormous gravitational force our star has on its planets.
Likewise, when a planet accelerates in its orbit, it is moving away from the sun, in part because this speed allows it to better resist the sun’s gravity.
Just like all planets in the solar system, the Earth is gradually spiraling away from the sun — but not enough to cool the planet significantly.
Professor Zijlstra’s concept of moving away from the sun would involve gravity assist or a “slingshot” maneuver, already commonly used to accelerate spacecraft after they have been launched from Earth.
By getting too close to a planet, such spacecraft can take advantage of the planet’s gravity to increase its speed, causing the planet itself to slow down slightly in its orbit.
And as we know, due to the laws of physics, when a planet slows down, it gets closer to the sun.
It is a little known fact that gravity slingshots can also be used to reduce the speed of a spacecraft, which has the opposite effect on the planet, speeding it up in its orbit.
As the planet speeds up in its orbit, it drifts away from the sun.
The scientist suggests that getting an asteroid to perform a “slingshot” maneuver with Earth could move us further from the sun (file photo)
This is the basic concept the project will work on, but instead of a spacecraft (which would be very small) Professor Ziegelstra proposes using a huge asteroid – about 30 miles (50 km) in diameter, the size of a major city.
He proposes to somehow change the asteroid’s orbit while it’s in space, perhaps by propelling it with a robotic probe at a certain angle and speed.
If pushed successfully, the asteroid will make a loop around the sun and head back toward Earth, before blasting itself into Earth’s orbit.
This will slow down the speed of the asteroid and, most of all, speed up the Earth – although doing the whole process just once won’t be enough.
“Since the Earth needs to speed up in order to get away from the sun, we need to let the asteroid lose speed as it travels into the inner solar system,” said Professor Ziegelstra.
Do this a million times and the Earth will speed up by the amount we need.
After a million flights, the Earth is in its new orbit.
“Since we have a billion years for this move, this means that we only need one flyby of the asteroid every thousand years.
Do this once every thousand years, and in a billion years we can move the Earth just enough to keep its temperature constant while the sun shines.
In the end, it feels like a big enough job just for NASA, or even a bunch of ISAs working together.
Meanwhile, the costs involved are sure to be many times more than last year’s NASA DART project to propel an asteroid at a cost of $324.5m (£258m).
The public may also have concerns about such a huge asteroid approaching Earth, especially considering that it was an asteroid that wiped out the dinosaurs.
Professor Ziegelstra asserts that there are two types of global warming that must be addressed.
The first, well-publicized, is caused by greenhouse gas emissions from human activities, such as the burning of fossil fuels.
Meanwhile, the second, less well-known form of global warming involves the natural brightness of the Sun, which, as it is, will make the Earth too hot to live on in about a billion years.
“It’s been a very long time coming, but scientists are getting paid to find solutions to the problems of the future, before anyone else has thought of it,” he told MailOnline.
This concept is not a solution to the current human-caused global warming.
It takes a long time to help us now – we need to solve human-caused global warming in other ways.
“But it will resolve long-term changes in the sun.”
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