To reduce global warming, an astronomer has proposed building a solar shield to reduce the amount of sunlight reaching Earth, combined with a tethered and captured asteroid as a counterweight.

Engineering studies using this approach could begin now to create a viable design that could mitigate climate change decades from now, explains proponent István Szapudi, an astronomer at the University of Hawaii's Institute for Astronomy.. Their work is published in the Proceedings of the National Academy of Sciences.

One of the simplest approaches to reduce global temperature is to shield Earth from a fraction of the sunlight.. This idea, called a sun shield, has been proposed before, but the sheer amount of weight needed to make a shield massive enough to balance the gravitational forces and keep it from being blown away by solar radiation pressure, makes even the most lightweight are prohibitively expensive.

Szapudi's creative solution consists of two innovations: a tethered counterweight instead of just a massive shield, making the total mass more than 100 times less, and the use of a captured asteroid as a counterweight to avoid throwing most of it. of the mass from Earth.

“In Hawaii, many use an umbrella to block the sunlight as they walk during the day.. I was thinking, could we do the same for Earth and thus mitigate the impending catastrophe of climate change?”. said Szapudi.

Szapudi began with the goal of reducing solar radiation by 1.7%, an estimate of the amount needed to prevent a catastrophic rise in global temperatures.. He found that placing a tethered counterweight toward the sun could reduce the weight of the shield and counterweight to approximately 3.5 million tons, about a hundred times lighter than previous estimates for an untethered shield.

While this number is still well above current launch capabilities, only 1% of the weight, some 35,000 tons, would be the shield itself, and that's the only part that would have to be launched from Earth.. With newer and lighter materials, the mass of the shield could be further reduced. The remaining 99% of the total mass would be asteroids or lunar dust used as a counterweight.. Such a tethered structure would be faster and cheaper to build and deploy than other shield designs.

Today's largest rockets can only lift about 50 tons to low-Earth orbit, so this approach to managing solar radiation would be challenging.. Szapudi's approach takes the idea into the realm of possibility, even with today's technology, whereas previous concepts were completely unachievable.. Furthermore, it is crucial to develop a lightweight but strong graphene strap that connects the shield to the counterweight.