On cold winter days, the warmth of the sun is most welcome. But as humans emit more greenhouse gases, the Earth’s atmosphere traps more and more of the sun’s energy, causing the planet’s temperature to rise steadily. One strategy to reverse this trend is to block some of the sunlight before it reaches Earth.
For decades, scientists have considered using screens and other objects to block a sufficient amount (1-2%) of solar radiation to mitigate the effects of global warming. I’ve been New research is currently being conducted by scientists at the Center for Astrophysics. Harvard & Smithsonian and the University of Utah are exploring the possibility of using dust to block sunlight.
Paper published today in the journal PLOS Climatedescribes different properties of dust particles, the amount of dust, and the best trajectory for shading the Earth. The team found that throwing the dust from the Earth to a waypoint at a “Lagrange point” between the Earth and the Sun was most effective, but required astronomical costs and effort.
The team suggests moondust as an alternative, arguing that lunar dust emitted from the Moon could be a low-cost and effective way to cover the Earth.
“It’s amazing to think how lunar dust, which took more than 4 billion years to form, could help slow the rise in Earth’s temperature, a problem that took less than 300 years. Astrophysics academic center.
A team of astronomers applied techniques used to study planet formation around distant stars—their usual research focus—to the lunar dust concept. Planet formation is a messy process that kicks up astronomical dust that forms rings around host stars. These rings block light from the central star and re-radiate it in a detectable way.
That was the seed of the idea. If you put a small amount of material in a special orbit between the Earth and the sun and break it up, you can block a lot of sunlight with a little mass.” is the lead author of
cast a shadow
According to the team, the shade’s overall effectiveness depends on its ability to maintain a shadow-casting orbit on Earth. Utah undergraduate and study co-author Samir Khan led the first exploration where the orbit could hold the dust in place long enough to provide adequate shading.
“Since we know the positions and masses of the major bodies of the solar system, we can use the law of gravity to track the position of the simulated shade over time on several different orbits. You can,” Khan says.
Two scenarios were promising. In the first scenario, the author placed the space station platform at his L1 Lagrange point. This is the closest point of gravity equilibrium between the Earth and the Sun. Objects at Lagrangian points tend to stay along the path between the two objects. This is why the James Webb Space Telescope (JWST) is at his L2, a Lagrangian point on the other side of the Earth.
In computer simulations, the researchers launched particles containing the positions of the Earth, Sun, Moon, and other solar system planets from the platform into L1 orbits and tracked where the particles were scattered. The authors found that, if launched accurately, the dust follows a path between the Earth and the Sun, effectively shading it, at least for a while. The dust was easily blown off course by the solar wind, radiation, and gravity within the solar system. The team concludes that any L1 space station platform will need to create an endless supply of new dust batches to blast into orbit every few days after the initial spray dissipates. .
“It was pretty difficult to get the shield to stay on L1 long enough to cast a meaningful shadow, but that’s not surprising since L1 is an unstable equilibrium point,” Khan said. says. “The simulation had to be very accurate, because even a slight deviation in the trajectory of the sunshield can quickly deviate.”
In a second scenario, the authors shot moon dust from a lunar platform toward the Sun. They found that the unique properties of moon dust are just right for it to act effectively as a shade. The simulations tested how lunar dust scatters along different paths until we find a good trajectory directed toward L1 that acts as an effective sunshade.
The result is welcome news, the team says, because it takes much less energy to blow dust off the Moon than it does on Earth. This is important because the amount of dust required for a solar shield is comparable to the output of any large mining operation here on Earth.
“It’s amazing how the Sun, Earth and Moon are perfectly aligned to enable this kind of climate mitigation strategy,” Kenyon said.
Just a moonshot?
The authors emphasize that their new study only explores the potential implications of this strategy, rather than assessing whether these scenarios are logistically feasible.
“We are not experts in climate change or the rocket science required to move mass from one place to another. We’re investigating different kinds of dust, and we don’t want to miss a game-changer for such a critical issue,” says Bromley.
One of the biggest logistical challenges is replenishing the dust stream every few days. Solar radiation naturally disperses dust particles throughout the solar system. In other words, the shade is temporary and no particles fall to the earth. The authors affirm that their approach will not create a permanently cold, uninhabitable planet, as in the sci-fi novel “Snowpiercer.”
Original: Could space dust help protect Earth from climate change?
Than: Harvard-Smithsonian Center for Astrophysics | University of Utah
