Last week, Republican Representative Louie Gohmert of Texas asked a US Forest Service employee if her agency or the Bureau of Land Management could alter the moon’s or Earth’s orbit to reverse the impacts of human-caused climate change during a congressional hearing. Doesn’t that seem like an entirely appropriate plan? Let’s get started.
First, we must assess our current situation—the givens in our equation for shifting the Earth. Our planet orbits the sun at a distance of 149.6 million kilometers and receives enough sunlight to maintain around 15 degrees Celsius. On the other hand, the latter statistic represents an increase of little more than one degree Celsius from Earth’s average temperature over the previous century. In other words, the planet is suffering from a low-grade fever. According to current consensus forecasts, if left unchecked, that fever is expected to get considerably worse, rising Earth’s average temperature by another one degree Celsius by the 2060s. Such an increase would effectively make certain currently crowded portions of the world uninhabitable, jeopardizing the long-term viability of global civilization as we know it.
According to Britt Scharringhausen, a planetary astronomer at Beloit College, radiative equilibrium, or the balance between incoming energy from the sun’s rays and energy emitted by Earth, is critical to our knowledge of our planet’s fluctuating temperature. Scharringhausen jotted out the following equation to describe it.
The temperature of the Earth is Teq, the temperature of the sun is T, the radius of the sun is R, the distance to the sun is X, and the albedo, or reflectivity, of the Earth, is A. Albedo is a metric that quantifies how well our planet reflects solar radiation, with a value of 0 indicating perfect absorption and 1 indicating perfect reflection. There is a link between climate change and albedo: Snow and ice have a high albedo, reflecting up to 90% of the sunlight that strikes them back into space. Snow and ice caps melt as a result of anthropogenic warming, lowering Earth’s albedo. That, in turn, leads to an increase in the global average temperature.
Some of the variables in this equation are naturally changing. As it ages, our star gently swells and brightens, becoming somewhat larger and more luminous. While it will take the sun 100 million years to grow in luminosity by 1%, Ethan Siegel, a theoretical astrophysicist and science writer, estimates that our greenhouse-gas-emitting global civilization will increase the solar energy retained by Earth 1% within the next few hundred to 1,000 years.
We need to lower a variable on the right side of the equation to make Earth cooler: We can’t readily reduce the sun’s temperature or radius. Cutting our heat-trapping, albedo-shifting greenhouse gas emissions is definitely out of the question. So, following Representative Gohmert’s recommendation, let’s increase X, the sun’s distance. All we have to do now is find a technique to shift the Earth’s mass of 5.972 septillion kilograms away from our star. Isn’t it simple?
According to Scharringhausen’s estimates, a three-degree-C drop in temperature to offset present and near-future anthropogenic warming would necessitate a three-million-kilometer relocation of our planet away from the sun. Scharringhausen calculates that 5 x 1031 joules would be enough to drive all 5,972,000,000,000,000,000,000,000 kilos of Earth’s mass three million kilometers out of its current orbit. Because annual worldwide electricity production is roughly 1019 joules or 0.0000000000002 percent of what we’d need to move the globe, these calculations provide difficulty for Representative Gohmert’s plan. That also assumes we can apply all of that energy to Earth at 100% efficiency, which is physically impossible due to thermodynamic laws.
We haven’t addressed what shape this applied energy will take, leaving aside such details. There’s also the literal nuclear option: according to Scharringhausen, one approach scientists have advocated for moving an asteroid is to fire a nuclear weapon near it. She continues, “It will basically melt part of the asteroid, and the escaping rock vapor will work like rocket exhaust and drive the asteroid along.”
When scaled sufficiently, such a system may theoretically be powerful enough to modify a planet’s orbit. According to Geza Gyuk, director of astronomy at the Adler Planetarium in Chicago, it would take a billion times more nuclear explosions than we have ever launched to move Earth the requisite distance, or the equivalent of dropping an atomic bomb every second for 500 years. The approach of repeatedly detonating nuclear bombs near the Earth’s surface to vaporize sections of it and use it as rocket exhaust has various disadvantages. The most significant negative effect for our purposes is that the blasts themselves would heat the Earth, defeating the claimed goal of reversing global warming.
Engineering close planetary flybys to drain off the energy of other celestial objects, such as passing asteroids or comets, would be a gentler approach. Spacecraft that raise their speed by passing close to a planet to grab a fraction of its orbital energy use this strategy in reverse with tremendous success. The problem with the mechanism for moving our planet, according to Siegel, is scale: the total mass of the asteroid belt is only 4 to 5% of that of the moon or 0.05 to 0.06 percent of that of Earth. According to him, using the mass of the whole asteroid belt in flybys would only move Earth away from the sun by 748,000 kilometers, or a fourth of the distance we’d require. And a single off-course collision with our planet would unleash devastation comparable to the asteroid strike that wiped out the dinosaurs in global extinction.
Fortunately, we have a far larger space rock right in our backyard: the moon. Could we slingshot our planet into a larger orbit by cutting the gravitational rope between the moon and the Earth? Not in any way that we are capable of accomplishing today, according to Siegel, and the ramifications would be terrible. A moonless Earth would have substantially darker nights, shorter days, and harsh, unpredictable seasons due to a destabilized axis of rotation, in addition to greatly lower tides.
What if, instead of eliminating our natural satellite, we changed its orbit around the Earth? According to Matteo Ceriotti, a rocket scientist at the University of Glasgow’s James Watt School of Engineering, increasing the radius of the moon’s orbit by 10% would affect Earth’s trajectory around the sun in the long run.
Ceriotti claims that we could collect and accelerate material from the moon. It would take 300 trillion years to extract enough material from the lunar surface using a 100-gigawatt laser, or nearly the same amount of power as every single wind turbine in the United States. There’s also the previously mentioned nuclear option, which it might use to relocate the moon instead of the Earth. Manually extracting lunar material with conventional rockets is another less messy option.
“We would require 7 x 1016 missions if we were able to create a spaceport on the moon and a rocket equal to SpaceX’s Falcon Heavy to carry off moon material into deep space,” Ceriotti says. That’s 70,000 trillion launches of rockets. In comparison, humanity has only achieved 70,780 launches during the whole of the space age, with more than half of them failing to exit Earth’s atmosphere.
Humans may add a twist to the flyby idea by putting asteroids on a crash course with the moon, according to Gyuk. To make a significant change, we’d need kilometer-sized comets crashing into the moon every second for a couple of hundred years. However, an off-course projectile might result in planetary mass extinction.
Because of the enormity of the change required to elevate the Earth’s orbit, any intervention would almost certainly have to endure millions of years at the very least, which creates an unforeseen societal dilemma, according to Gyuk: “We don’t have precedent for planning across such huge periods.” Throughout truth, no civilization has ever lasted more than a few thousand years in human history.
Finally, even if humanity were able to change our planet’s orbit using any of these ways, they wouldn’t be able to rest easy, according to Siegel. “Even if we could make this tremendous adjustment in Earth’s orbit,” he argues, “it doesn’t free us from the obligation that we’ll need to make this change as long as the quantity of greenhouse gases in our atmosphere continues to rise.”
That seems to me like a heartfelt endorsement of our fossil-fuel-dependent status quo! Starting right now and lasting indefinitely, we should devote all of our resources to altering Earth’s orbit. Sure, it’s a Sisyphean undertaking, with humans as Sisyphus and Earth as the rock pushed uphill inexorably. But at the very least, we’d be able to keep driving our awesome SUVs! I propose that we get to work.
Maddie Bender is the author.
