Giant Sun "Umbrella" Tied To Asteroid Might Help Fight Global Warming, Says Scientist

To help combat the effects of global warming, scientists have proposed an innovative idea to shield Earth from the sun with a spaceborne "umbrella" of sorts. Astronomer Istvan Szapudi, of the University of Hawai'i Institute for Astronomy, came up with the idea called solar shield to reduce the amount of sunlight hitting Earth. 

"In Hawai'i, many use an umbrella to block the sunlight as they walk about during the day," Mr Szapudi said in a statement. "I was thinking, could we do the same for Earth and thereby mitigate the impending catastrophe of climate change?" he added. 

In his paper, published in Proceedings of the National Academy of Sciences (PNAS) journal, Mr Szapudi acknowledged that this is not the first time this idea of space-based solar radiation management (SRM) shield or shade has been proposed. But he explained that what makes his creative approach different is the plan to tie to giant shield to a captured asteroid as a counterweight. 

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

Mr 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. According to the press release, the scientist found that placing a tethered counterbalance toward the sun could reduce the weight of the shield and counterweight to approximately 3.5 million tons, about one hundred times lighter than previous estimates for an untethered shield.

"While this number is still far beyond current launch capabilities, only 1% of the weight-about 35,000 tons-would be the shield itself, and that is the only part that needs to be launched from Earth," the press release read. 

In other words, Mr Szapudi's plan is to launch the counterweight, which will be attached to the solar shield by a strong graphene tether, and then slowly open once in space, allowing it to gradually fill with lunar dust or asteroid material. 

The scientist believes that such a tethered structure would be faster and cheaper to build and deploy than other shield designs. However, some of the largest rockets can carry about 50 tons to low Earth orbit, which poses a big challenge to this particular SRM plan. Also, developing a light-weight but strong graphene tether connecting the shield with the counterweight is crucial, the press note read.