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Against the climate crisis, MIT imagines the craziest of sun visors

A concept not entirely devoid of interest, but a bit absurd and which should not make us forget that the fight against global warming is played out above all on Earth.

Global warming and all the problems associated with it continue to progress at a worrying speed, it is no secret to anyone. Despite this well-established observation, public authorities and large industrial groups are still struggling to provide large-scale solutions, while many interesting technologies in this context are already perfectly mastered.

Rather than reinventing the wheel when it is largely a problem of political and economic will, some researchers have therefore changed their approach and are now working on solutions as radical as they are absurd. This is the case of a team of researchers from the prestigious MIT.

Attacking global warming from the other end

Its members have indeed tackled the problem from the other end; instead of managing the consequences of global warming, it would be enough to make sure… that it doesn’t warm up at all. And to make this funny idea a reality, they came up with an even more unusual method: deploy a kind of gigantic sun visor between the Earth and its star!

The idea seems straight out of science fiction, but it still has some concrete foundations. It starts with the fact that blocking a small fraction of the solar energy reaching the Earth would be enough to completely reverse the curve of global warming, much faster than with all the countermeasures available on Earth.

“Geoengineering could be our last and only option. But most of these proposals are confined to the Earth, which poses enormous risks for ecosystems”; explain the researchers. However, “if we deviate 1.8% of incident solar radiation before it hits our planet, we could reverse global warming entirely”, they claim.

But the most interesting thing is the nature of the sun visor in question. The researchers imagined an armada of huge inflatable and semi-transparent bubbles capable of covering an area equivalent to that of Brazil! But there is no question of sending them to low Earth orbit, where they would be at best useless and at worst very problematic.

Deflecting 1.8% of incident solar radiation could be enough to dampen global warming. © MIT Senseable City

An armada of space bubbles parked at a Lagrange point

Instead, they should be installed at a Lagrange point. These are very particular points of space. They appear when one massive object orbits another, such as the Earth orbiting the Sun. In essence, they are points of balance where the gravity fields of the two bodies compensate each other.

These Lagrange points thus behave almost like a small invisible planet; a smaller object, such as a satellite, can then orbit around this point as it would orbit around a planet. This means that the object in question can remain almost motionless with respect to the two celestial bodies which define these Lagrange points.

For every two-body system like the Earth and the Sun, there are five different Lagrange points. In our case, there is a first one which is located precisely in the orbit of the Earth, but on the other side of the Sun; this is point L3. Two other points (L4 and L5) are located on the same orbit, and form an equilateral triangle with L3.

© Debiansid – Wikimedia Commons

On our side, the two most interesting are certainly the two closest to the Earth. Unlike the other three, they are not located in the orbit of the planet, but on either side.

Point L2, located about 1.5 million kilometers outside orbit, plays a very important role in astronomy; this is where NASA has decided to park the famous James Webb Space Telescope, which will unveil its first real scientific image on July 12th.

The last, L1, is located at the same distance, but between the Earth and the Sun. It is therefore a perfect location to place this funny space sun visor, since this point L1 will always be located precisely between the two celestial bodies. They could therefore make it possible to intercept a significant part of solar radiation.

An interesting, but very limited thought experiment

The researchers explain that it would be possible to precisely control this effect; it would be enough to burst some of these bubbles at a distance to allow more particles to pass. “Bubbles can be intentionally destroyed by breaking their surface balance. This would make this solar geoengineering fully reversible and significantly reduce the amount of debris,” the MIT team asserts… although that claim seems somewhat questionable.

Despite everything, this strange project still has several obvious limits, starting with the logistics of the operation. MIT suggests that it would be more interesting to make a simple film, then to build these spheres directly on site. But right now it’s more speculation than a plan based on already mature technology.

© MIT Senseable City

And there still remains the most important question, namely that of the viability of these bubbles in the long term. As it stands, the MIT concept seems to rely on various types of plastics. However, these materials simply do not have the slightest chance of resisting an impact with another celestial body, even if it is microscopic.

Remember that very recently, a micrometeorite managed to cause some minor damage to a JWST mirror. They are, however, specially designed to withstand these impacts. Suffice to say that in the absence of a revolutionary material, it seems simply impossible to prevent these bubbles from ending up in lint.

There is also the question of the “corpses” of these bubbles, which could continue to block part of the solar radiation without the operator being able to control them. A big problem, since the whole concept is based on a fairly fine control of the radiation that reaches the Earth.

The climate fight is fought on Earth, not in space

Fortunately, this is still only a kind of thought experiment. The current climate situation is certainly problematic, but not yet enough to justify squandering so many resources on such a risky project – especially since there are already technologies that can fight global warming. climatic.

As the latest IPCC report reminded us, today it is more a question of will than of feasibility. Let us therefore hope that those concerned will become aware of this in the sufficiently near future; because if we get to a stage where our only option is a project like this, it’s probably already too late.

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