Scientists know that one day, billions of years in our future, our sun will expand to become a red giant and swallow up many of the planets in our solar system. This highly likely scenario includes the Earth and all of the future generations of humans that live on it when it happens. This has led some scientists to devise a way to change Earth’s orbit.
Theoretically, it is possible. Much like the way the recent movie the Wandering Earth did in using thrusters to change the Earth’s orbit while avoiding crashing into the gas giant Jupiter.
From thrusters to nuclear blasts, scientists have already come up with dozens of ways they could theoretically move objects from the Earth’s path in space. Just recently, NASA and the European Space Agency joined in a mission to test a brand new planetary defense system, along the lines of what you think of when you think about a movie like Armageddon. It’s called the Double Asteroid Redirect Test.
A recap of DART for those who don’t know: The space agencies are going to crash a probe into a moon orbiting an asteroid in an attempt to alter the moon’s course. The DART program is set for 2021. If successful, scientists may be able to scale up their efforts and move larger objects in the future.
Although the DART program wouldn’t work to move our planet because of the level of destruction involved, Matteo Ceriotti, a rocket scientist who lectures at the University of Glasglow, thinks we can use similar techniques or other techniques devised to move the Earth and save it from climate change. So what are our choices?
One option is called a gravitational slingshot, or a way for a craft to use gravity to move an object in space, as was demonstrated by the Rosetta craft that visited a comet in 2014 to 2016. Rosetta passed by the Earth two times, and the gravitational field of the Earth helped propel Rosetta faster. Much faster than any thruster ever could.
Although the Earth’s orbit wasn’t affected because it’s so large, we could theoretically use something much larger and multiple passes to slingshot the Earth to a different orbit. That something larger could be other asteroids and even comets, which we can already move using what’s called ΔV leveraging.
However, to move the Earth this way, we’d need millions of asteroids, and we would need:
“Each [asteroid pass] spaced out about a few thousand years apart, to keep up with the sun’s expansion.”
It seems like this option might just take a while to pull off.
Lasers and Solar Sails
A second viable option is using lasers. The theory holds that because light doesn’t carry any mass, but easily carries momentum, continuously powering up a laser or other beam of light could change the Earth’s orbit. According to the report:
“The required power would be collected from the sun, and no Earth mass would be consumed.”
This theory is already being studied by the Breakthrough Starshot project in an effort to explore space outside of our solar system. The biggest problem with this option is that our current technology isn’t powerful enough to pull off such a change in orbit. In fact, it would take about “300 billion, billion years of continual use to achieve orbital change.”
A similar way of achieving this is by using a solar sail deployed high above the Earth to reflect sunlight directly to the planet. The only problem with this is that it would take over a billion years to change the Earth’s orbit, and we’d have to use a solar sail that’s more than 19 times the size of the Earth to do it.
Another viable option so far is the electric thruster – an ion propulsion drive – one of which is currently in use on the Falcon Heavy, devised by the SpaceX program. Theoretically, we could fire these thrusters at the “trailing direction of Earth’s orbit,” but it would take billions of launches to move the planet to where it needs to go.
The problem is that even though the thrusters could move the Earth, our current thrusters would need to be supersized to have any real effect.
According to the report:
“The oversized thruster should be 1,000 kilometers above sea level, beyond Earth’s atmosphere … With an ion beam fired at 40 kilometers per second in the right direction, we would need to eject 13% of the mass of the Earth in ions to move the remaining 87%.”
In other words, we would have to destroy part of the Earth to move the rest of it, making this option far out of our reach at the moment.
Of the methods available, the slingshot seems to be the most viable at the moment using our current technology. However, even the slingshot maneuver won’t help us before climate change becomes so bad that it destroys the Earth, as scientists expect will happen well before the sun’s expansion does.
With some genius and luck, we can only hope that scientists will someday soon be able to either stop climate change (unlikely without the help of all fellow humans) or find another way to move the Earth – a more attainable one. Either that or develop true technology that allows us to move to and live on Mars, at least until we have the technology to move it, too.
Learn more about how our sun will turn into a red giant:
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