One company has a simple-sounding plan to help save the planet: take a food additive and the mineral that makes eggshells hard, produce tiny particles out of them, spray them into the atmosphere and cool the world.
Stardust Solutions, an Israeli-US company founded in 2023 and led by two former Israeli government nuclear physicists, is pushing ahead in the race to develop solar geoengineering, a controversial technology aimed at artificially bringing down global temperatures by dimming the sun.
There are many different solar geoengineering methods, but perhaps the most researched — and the one Stardust focuses on — involves spraying tiny particles into the stratosphere from high-altitude aircraft or balloons to reflect the sun’s energy away from Earth and back into space.
It’s an artificial version of a natural phenomenon. Volcanic eruptions sometimes spew so much sulfur dioxide into the atmosphere it can temporarily lower global temperatures. In 1991, the eruption of Mount Pinatubo in the Philippines injected enough into the atmosphere to produce cooling of 0.9 degrees Fahrenheit (0.5 Celsius) for more than a year.
As humans burn fossil fuels and heat the planet, the question of whether solar geoengineering can and should move from theory to reality is gaining prominence.
