With Earth warming up quickly, scientists around the world are brainstorming diverse strategies to limit the impacts of climate change.
István Szapudi, an astronomer at the University of Hawaiʻi Institute for Astronomy, has introduced an innovative idea—a solar shield to decrease the volume of sunlight reaching Earth, coupled with an asteroid acting as a counterweight.
This novel approach could lead to designs that begin mitigating climate change within a few decades.
The Solar Shield Proposition
A straightforward method of lowering global temperature is by shielding Earth from a portion of the Sun’s rays, referred to as a solar shield.
While this concept has been proposed before, the enormous weight required to construct a shield that can counterbalance gravitational forces and resist solar radiation pressure would make even the lightest materials excessively expensive.
Szapudi’s ingenious solution includes two new ideas: a tethered counterweight, reducing the total mass by over 100 times, and the utilization of a captured asteroid as the counterweight to circumvent launching most of the mass from Earth.
Inspiration from Everyday Life
Drawing parallels with people in Hawaiʻi using umbrellas to block sunlight during the day, Szapudi wondered if the same concept could be employed for Earth to mitigate the forthcoming disaster of climate change.
The Role of a Tethered Counterbalance
Szapudi’s calculations aimed at reducing solar radiation by 1.7%, a number estimated to prevent a catastrophic rise in global temperatures.
He discovered that introducing a tethered counterbalance towards the sun could significantly decrease the combined weight of the shield and counterweight to roughly 3.5 million tons, almost a hundred times lighter than prior estimates for an untethered shield.
Breaking Down the Mass
Although 3.5 million tons significantly exceeds current launch capabilities, only 1% of the weight—around 35,000 tons—would be the shield, the only component needing to be launched from Earth.
By employing newer, lighter materials, the shield’s mass could be further reduced.
The remaining 99% of the total mass would comprise asteroids or lunar dust serving as a counterweight, making such a tethered structure quicker and cheaper to construct and deploy compared to other shield designs.
Potential Challenges and Feasibility
Even with the largest rockets today, capable of lifting only about 50 tons to low Earth orbit, managing solar radiation with this method poses a significant challenge.
However, Szapudi’s concept renders the idea plausible with current technology, in contrast to previous proposals deemed entirely unattainable.
A crucial part of this proposal is the development of a lightweight yet robust graphene tether to connect the shield with the counterweight.
The study was published in PNAS.
