by A study led by the University of Utah has explored the potential of using lunar dust in space to create screens from sunlight to mitigate the effects of global warming on Earth.
In the investigation, different properties of dust particles, amounts of this element and the orbits that would be most suitable to shade the Earth were analyzed. The authors found that throwing dust from Earth to a way station at the “Lagrange point” between Earth and Sun (L1) would be most efficientbut it would require astronomical cost and effort.
The authors argue that Throwing lunar dust from the Moon instead could be a cheap and effective way to shade Earth.
The team of astronomers applied a technique used to study the formation of planets around distant stars, their usual research object. Planet formation is a messy process that kicks up a lot of astronomical dust that can form rings around the host star.
These rings intercept the light from the central star and radiate it back so that it can be detected on Earth. One way to discover stars that are forming new planets is to look for these dusty rings.
“That was the seed of the idea; if we take a small amount of material and put it in a special orbit between the Earth and the Sun and break it apart, we could block a large amount of sunlight with a small amount of mass”, Said -in a statement- Ben Bromley, professor of physics and astronomy, and lead author of the study.
“It’s amazing to contemplate how lunar dust – which took more than 4 billion years to create – could help slow the rise in Earth’s temperature, a problem that took us less than 300 years to produce,” said Scott Kenyon, co-author of the study of the Center for Astrophysics | Harvard & Smithsonian.
According to the work, which was published in the journal PLOS Climate, the effectiveness of a global shield depends on its ability to maintain an orbit that casts a shadow on Earth.
Sameer Khan, a university student and co-author of the study, led the initial exploration of which orbits could hold the dust in place long enough to provide an adequate shadow. Khan’s work demonstrated the difficulty of keeping powder where it is needed.
“Because we know the positions and masses of the major celestial bodies in our solar system, we can use the laws of gravity to track the position of a simulated sunshade over time in different orbits,” explains Khan.
Two scenarios turned out to be promising. In the first, the authors located a space platform at the L1 Lagrange point, the closest point between the Earth and the Sun, where the gravitational forces are balanced. Objects located at Lagrange points tend to stay on a trajectory between the two celestial bodies, which is why the James Webb Space Telescope (JWST) is located at L2, a Lagrange point on the opposite side of Earth.
In computer-generated simulations, the researchers shot test particles along the L1 orbit, including the position of Earth, the Sun, the Moon and other planets in the solar system, and tracked where the particles scattered. The authors found that, thrown accurately, the dust would follow a path between the Earth and the Sun, casting a shadow, at least for a while.
Unlike the JWST, which weighs 5.8 tons, the dust was easily knocked off course by solar winds, radiation, and gravity within the solar system. Any L1 platform you would need to generate an endless supply of new batches of dust to launch them into orbit every few days after initial dew has dissipated.
“It was pretty hard to get the shield to stay on L1 long enough to cast a significant shadow. Although this should not surprise us, since L1 is an unstable equilibrium point. Even the slightest deviation in the sunshade’s orbit can cause it to move rapidly out of place, so our simulations had to be extremely accurate,” explains Khan.
The Moon is the best point to throw the dust
In the second scenario, the authors shot lunar dust from the surface of the Moon towards the Sun. They found that the inherent properties of lunar dust were adequate to function effectively as a sun shield. The simulations tested how lunar dust dispersed along various paths, until they found excellent trajectories directed toward L1, which served as an effective solar shield.
These results are good news because it takes much less energy to launch dust from the Moon than it does from Earth. This is important because the amount of dust from a sun shield is large, comparable to the output of a large mining operation here on Earth. In addition, the discovery of new trajectories of solar shielding means there might not be a need to transport lunar dust to a separate pad on L1.
The authors stressed that this study only explores the potential impact of this strategy, rather than assessing whether these scenarios are logistically feasible.
“We are not experts on climate change or the rocket science required to move mass from one place to another. We’re just exploring different types of dust in a variety of orbits to see how effective this approach is. We don’t want to miss the opportunity to be a game changer on such a critical issue,” Bromley said.
One of the biggest logistical challenges, replenishing dust streams every few days, also has an advantage. In the end, solar radiation scatters the dust particles throughout the solar system; the solar shield is temporary and the particles of the shield do not fall on Earth. The authors say their approach would not create a permanently cold and uninhabitable planet, as in the science fiction story “Snowpiercer.”.
“Our strategy could be an option to address climate change,” Bromley said, “if what we need is more time.
With information from Europa Press
