We may be able to use lunar dust to block sunlight, fight climate change

"The Sun, Earth, and Moon are in just the right configuration to enable this kind of climate mitigation strategy."
Chris Young
Sun and Moon
Sun and Moon


A team of scientists believes moon dust could be used to protect the Earth from climate change.

The new strategy, a form of solar geoengineering from space, would block a fraction of sunlight before it reaches our planet, a press statement reveals.

Lunar dust could protect us from climate change

Scientists have been investigating solar geoengineering for decades to block radiation from the sun and regulate Earth's climate. A new study by scientists from the Harvard–Smithsonian Center for Astrophysics and the University of Utah has suggested placing dust in orbit to shield Earth from sunlight.

In a new paper published in the journal PLOS Climate, the scientists describe different properties of dust they analyzed, the quantities required, and the orbital altitudes that would be suitable for their method.

The team found that the most effective method would involve launching dust from Earth to the stable orbital "Lagrange Point" between Earth and the sun. However, they also suggested a less costly method involving launching lunar dust directly from the moon.

"It is amazing to contemplate how moon dust — which took over four billion years to generate — might help slow the rise in the Earth’s temperature, a problem that took us less than 300 years to produce," explained study co-author Scott Kenyon of the Center for Astrophysics.

The researchers' idea came from the work they carry out on a daily basis investigating planet formation. When planets are formed, they emit vast amounts of cosmic dust, which forms rings around the planet's host star.

“That was the seed of the idea; if we took a small amount of material and put it on a special orbit between the Earth and the sun and broke it up, we could block out a lot of sunlight with a little amount of mass,” said Ben Bromley, professor of physics and astronomy at the University of Utah and lead author for the study.

The researchers decided they would investigate whether they could create a similar dust cloud using Lagrange Point 1 (L1), the closest point between the Earth and the sun where the gravitational forces are balanced. The James Webb Space Telescope similarly uses a stable orbital location at Lagrange Point 2, some 1.5 million km (1 million miles) from Earth.

Launching a lunar dust cloud to Lagrange Point 1

In computer simulations, the researchers found that they could precisely launch a cloud of dust to L1 and that it would follow a path between Earth and the sun, creating shade for Earth.

It is worth noting that they also pointed out their dust cloud could easily be blown off course by solar winds and radiation. This means their method would require a constant supply of dust every few days. Their lunar dust method would, therefore, be ideal, as there is a massive supply of dust sitting on the moon. That method would also be substantially cheaper to run continuously.

"It is astounding that the Sun, Earth, and Moon are in just the right configuration to enable this kind of climate mitigation strategy," Kenyon said.

Though the fact that dust must be constantly replenished provides a massive logistical challenge, it also means that any potential short-term damage to Earth would be reversible, and the dust wouldn't directly affect our atmosphere. According to a recent report by the U.S. National Academies of Sciences, Engineering, and Medicine (NASEM), solar geoengineering has its risks, but they are risks we may have to take.

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