2023-08-04 12:45:26
The Earth is warming rapidly and the scientific community is working on multiple ideas to reduce the effects of global climate change. An astronomer has proposed an extreme, effort-intensive but potentially providential strategy: a sunshade shield to reduce the amount of solar radiation reaching Earth. This parasol would have a captured asteroid tethered to it to serve as a counterweight.
One of the simplest in concept but most difficult to implement approaches to reducing global temperature is to shield the Earth from a fraction of the Sun’s light. This idea, often described as a planetary sunshade or planetary canopy, has been proposed before, but the large amount of material required to make a sunshade massive enough to balance gravitational forces and prevent solar radiation pressure from pushing it out of place makes even the lightest materials prohibitively expensive. expensive.
The solution proposed by the author of the new study, Istvan Szapudi of the Institute for Astronomy at the University of Hawaii at Manoa, in the United States, consists of two innovations: a counterweight attached to the sunshade instead of a massive sunshade without a counterweight, which makes the total mass of the parasol to be a hundred times less, and the use of a captured asteroid as a counterweight to avoid having to transport most of the mass from Earth.
Szapudi began exploring the concept with the goal of reducing solar radiation by 1.7%, an estimate of the amount of mitigation 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 parasol and counterweight to approximately 3.5 million tons, about a hundred times lighter than previous estimates for an untethered parasol.
While this mass is still well above current space launch capabilities, only 1% of the total weight, or about 35,000 tons, would be the sunshade itself, and that would be the only part that would have to be launched into space from the Land. With newer, lighter materials, the mass of the sunshade could be further reduced. The remaining 99% of the total mass would be the asteroid used as a counterweight. Setting up this sunshade and counterweight assembly attached to each other by cables would be quicker and cheaper than other planetary sunshade designs.
Today’s largest rockets can only lift tens of tons to low-Earth orbit, so the planetary sunshade, even in this less heavy and less difficult version, would be a logistical and economic challenge. Still, Szapudi’s design concept is achievable with today’s technology, while previous concepts were completely unachievable on our near-future technological horizon.
Artist’s impression of the proposed parasol attached to an asteroid that serves as a counterweight. (Illustration: Brooks Bays/UH Institute for Astronomy)
The next step in this line of research should be to initiate engineering studies to create a feasible sunshade design. A key component that will require a lot of work is the cable that will be used to attach the sunshade to the asteroid. Surely it is not made of any conventional material, but of a material worked on a nanometric scale to provide it with the maximum resistance to breakage with the least possible weight.
If, finally, this idea prospers, it could materialize within a few decades.
The study is titled “Solar radiation management with a tethered sun shield”. And it has been published in the academic journal PNAS (Proceedings of the National Academy of Sciences). (Source: NCYT from Amazings)
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