They propose to create a shield of lunar dust to protect the Earth from the Sun
A team of astrophysicists suggests that we could mitigate the effects of global warming by shooting lunar dust into space to shield Earth from sunlight.
On a cold winter day, the warmth of the Sun is welcome. However, as humanity emits more and more greenhouse gases, Earth’s atmosphere traps more and more solar energy and is constantly increasing in temperature. One strategy to reverse this trend is to intercept a fraction—between 1 and 2%—of sunlight before it reaches our planet.
Now, a study led by the University of Utah explored the potential of using dust to shield sunlight. They analyzed different properties of the dust particles, the amounts and the orbits that would be best suited to shade the Earth.
The authors found that launching dust from Earth to a way station at the “Lagrange Point 1” between Earth and the Sun (L1) would be more effective but would require astronomical cost and effort. But there is a more “affordable” alternative: dust fired from huge cannons positioned on the Moon.
“It’s amazing to contemplate how lunar dust, which took more than four billion years to create, could help slow the rise in Earth’s temperature, a problem that took us less than 300 years to produce,” added Scott Kenyon, co-author of the study published in PLOS Climate.
Simulated dust stream thrown between the Earth and the Sun. This dust cloud is shown as it crosses the sun’s disk, as seen from Earth. Streams like this, including those launched from the Moon’s surface, can act as a temporary umbrella. Credit: Ben Bromley/University of Utah.
To assess this possibility, the researchers used computer simulations to shoot dust from the Moon’s surface toward the Sun. They found that the inherent properties of lunar dust were just right to function effectively as a solar shield.
The simulations tested how the dust dispersed along various courses until they found excellent L1-directed trajectories that served as an effective sunscreen.
No “Snowpiercer” type scenario
The authors emphasize that this study only explores the potential impact of this strategy, rather than assessing whether these scenarios are logistically feasible.
“We are not experts in climate change or in the rocket Science required to move mass from one place to another. We are simply exploring different types of dust in a variety of orbits to see how effective this approach could be. We don’t want to miss out on what could be a Game changer for such a critical problem,” Bromley said.
One of the biggest logistical challenges, replenishing dust streams every few days, also has an advantage. Eventually, radiation from the Sun scatters the dust particles throughout the solar system; that is, the solar shield is temporary and the particles of the shield do not fall on the Earth. For this reason, the authors assure that their proposal would not create a permanently cold and uninhabitable planet, as in the Science fiction story Snowpiercer.
“Our strategy could be one option to address climate change, if more time is what we need,” Bromley concluded.
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