Bold Plan to Dim the Sun by Blasting Moon Dust Into Space Could Help Cool Earth

Astrophysicists show how to deflect solar radiation in an unexpected method.

Louis XIV, the longest-reigning king in French history, was known as "the Sun King" or "le Roi Soleil" due to his astonishing passion for dance. The star at the core of our solar system was unrelated to it. But oddly enough, the sun started behaving oddly throughout Louis XIV's reign.

Around 1645, it underwent a behavioral shift. Sunspots become quite uncommon. No sunspots were found at all in certain years. The power of the sun waned. The Maunder Minimum, which took place during a "Little Ice Age," was accompanied by an especially cold episode in the North Atlantic around 1650.

Things are moving in the other way right now. While the energy of the sun has remained mostly unchanged, the Earth is warming. The combustion of fossil fuels, which releases carbon dioxide into the atmosphere and traps heat, is the main cause of this rise in temperature. Temperatures are predicted to increase by more than 1.5 degrees Celsius over preindustrial levels in the next decades if CO2 emissions are not rapidly reduced. Temperature rises of more than 2 or even 3 degrees are possible in the worst-case circumstances.

Why not dull the sun? has been proposed as a contentious technological remedy in recent years. One of the most contentious theories for this process, known as solar geoengineering, proposes shooting sulfur particles into the atmosphere in a manner that resembles the explosion of volcanoes. The sun's beams would then be reflected back into space by the reflecting particles.

Due to the fact that it doesn't address the fundamental cause of climate change and the possible repercussions are not completely known, scientists and experts aren't yet sure that even attempting it is a smart idea. There is a non-zero chance that altering the atmosphere might lead to permanent consequences we haven't thought about and are ill-prepared for. It could also lead us to think that there is a solution to stop climate change without cutting back on carbon output. No, spoiler alert.

But what if we dropped the same particles into space rather than the atmosphere? If we tried some astroengineering, what would happen?

Three scientists examine potential ways to accomplish this by releasing reflecting dust particles into space in a new report that was published in the journal PLOS Climate on Wednesday. The scientists used computer simulations to determine that one option is to employ moon dust, shoot it into space from the lunar surface, and temporarily obscure our light.

The paper's first author, University of Utah theoretical astrophysicist Benjamin Bromley, emphasizes that the group's goal was not to provide a solution to the climate problem and that they are not climate experts. His primary area of study is the formation of planets, and Scott Kenyon of the Smithsonian Astrophysical Observatory, computer science student Sameer Khan, and he found inspiration in this process.

Because collisions create planets, Bromley explained, "we learnt from that research that a relatively modest quantity of dust may go a great way in absorbing starlight." "That made us consider dust as a means of reducing the sun's radiance."

According to Bromley, the idea would be similar to the situation that existed during Louis XIV's rule in France during the Little Ice Age. It would take a lot of dust, but if you could get it into space, it would effectively work to block 1% to 2% of the light, reducing solar energy.

A station that spews space dust out at the Lagrange point L1, which is located 900,000 miles within the Earth's orbit and directly between the sun and the Earth, was one of the team's initial concepts. At this point, gravity from the two bodies has a way of holding everything in place. (In fact, the James Webb Space Telescope is located at the opposite Lagrange point, L2, which is outside of Earth's orbit.)

In the simulations, the dust would soon drift away from the L1 location, which was an issue. The surface wasn't solid enough to support a dust barrier.

They turned their attention to something a little closer to their location: the moon. They created simulations that showed the most effective plan was to fire lunar grains from the moon toward L1.

Two things made lunar dust stand out, according to Bromley First of all, it may be rather effective at reflecting sunlight, and secondly, it turns out that the most effective grain size is also the one that is most prevalent on the surface of the moon.

He adds that this was a pleasant discovery that they were unaware of before the project began. However, one of the issues is how much dust is necessary. A second benefit of the moon is that it would be prohibitively expensive to continuously launch rockets filled with space dust to a platform out at L1.

The moon has a lesser gravity than Earth, so launching the dust from there will be lot simpler if we can get the equipment there, according to Bromley.

But what occurs once the dust is in space? The models, fortunately, indicated that the dust particles didn't actually rain back down on Earth. Instead, they would float away from the sun as they traveled into the endless night.

The proposal from the trio is not the first for a solar shield built in orbit. Curtis Struck of Iowa State University proposed a similar idea to employ moon dust in 2007. A group of MIT researchers put up the concept of "space bubbles" last year. To deflect oncoming sunlight, the plan is to launch a raft of bubbles into low-Earth orbit (L1). This would be a reversible procedure.

However, none of these strategies will be adopted rapidly enough to stop the present rise in temperature. However, we could have to resort to a "break glass in case of emergency" strategy if we set the Earth on an unstoppable course toward becoming a hothouse. Moon dust can be added to the list.

Despite the technical difficulties, Bromley believes that lunar dust should be investigated as a possibility if we reach a position when darkening the sun is a necessary step.