Astrophysicists Propose Moon Dust as a Sunshade for Earth
The Story
A team of astrophysicists proposed launching moon dust into space as a sunshade to slow global warming, publishing the geoengineering idea in the journal PLOS Climate.
The plan would send dust toward the first Lagrange point, one of five gravitational balance points between Earth and the sun where material can linger before dispersing.
Researchers estimated that launching about 10 billion kilograms of lunar dust each year could block roughly 1.8 percent of incoming solar radiation, the equivalent of about six days of sunlight annually.
Co author Benjamin Bromley noted that firing dust from the moon is easier than from Earth because of the moon's weaker gravity, and that the most efficient grain size is also the most plentiful on the lunar surface.
The concept faces steep obstacles, including energy needs comparable to more than 20,000 Saturn V launches and decades of mining infrastructure, plus governance and legality questions.
Critics such as Alan Robock argued for the simpler path of leaving fossil fuels in the ground, while Peter Irvine called the idea a 22nd century answer to a 21st century problem.
The plan would send dust toward the first Lagrange point, one of five gravitational balance points between Earth and the sun where material can linger before dispersing.
Researchers estimated that launching about 10 billion kilograms of lunar dust each year could block roughly 1.8 percent of incoming solar radiation, the equivalent of about six days of sunlight annually.
Co author Benjamin Bromley noted that firing dust from the moon is easier than from Earth because of the moon's weaker gravity, and that the most efficient grain size is also the most plentiful on the lunar surface.
The concept faces steep obstacles, including energy needs comparable to more than 20,000 Saturn V launches and decades of mining infrastructure, plus governance and legality questions.
Critics such as Alan Robock argued for the simpler path of leaving fossil fuels in the ground, while Peter Irvine called the idea a 22nd century answer to a 21st century problem.
Why It Matters
No moon dust has flown, but the sunshade idea found money in the stratosphere. Stardust Solutions raised $60 million in October 2025, the largest round for a geoengineering startup, and wants a deployable system by 2030, per Heatmap; by May 2026 it had shelved outdoor trials planned for April until a government sets the rules. Britain's ARIA is spending £57 million on 21 projects, £24.5 million of it outdoors, under an oversight committee chaired by Piers Forster, per Carbon Brief. Against them stand the EU Council, which called for a deployment moratorium on April 21, 2026, and the African Group, which opened non-use talks at UNEA-7 in December. Watch whether any ARIA balloon flies before 2027.
Go Deeper
Read the original reporting at Smithsonian Magazine.
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