UTSA professor eyes stardust as way to cool the Earth

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Yet, the dust is far more than theoretical. The composition of stardust could be critical to addressing the impacts of climate change, now and into the future. Greenhouse gasses — which primarily are composed of carbon-dioxide, methane and nitrous oxide — clog the Earth’s atmosphere daily, absorbing infrared radiation and heating up the planet. If shot into the stratosphere, a material discovered in stardust could reflect light, subsequently cooling the Earth’s temperature down.

While a process like this is years away from implementation, it could provide a temporary solution to climate change — allowing time for actual action, such as reducing greenhouse gasses and limiting the fossil fuel industry, to take place.

All of this work, however, starts in the lab with Speck and her team. Not just any material can be shot into the Earth’s atmosphere. It has to be perfect.

“It all has to do with the combination of elements that we’re using,” Speck said. “We need to know exactly how the material will react and that’s a lot of research.”

How to avoid nuclear winter

When Speck refers to launching space dust into the sky, she likes to bring up the 2013 post-apocalyptic movie, “Snowpiercer.” In the film, officials shoot reflective materials up into the stratosphere to combat climate change. Unfortunately, they release too much and the Earth freezes over, plunging the world into a never-ending nuclear winter.

“We’re really trying to avoid that,” Speck said.

This is why the stardust is only a temporary solution for the heat, and why the research is so long-term. The team has to analyze what kind of light the material reflects, if it absorbs any light, how it affects infrared and ultraviolet light, how long the substance will be effective, and what size the material needs to be.

Additionally, the team would love it if they could find a common material to work — such as one that naturally occurs on Earth or in space — rather than a rare mineral that eventually would expire.

So far, Speck is most interested in a substance called silicate. Silicate minerals are one of the most common minerals on Earth, found in rocks such as quartz, mica and olivine. It’s also found in stardust. The material called silicon carbide naturally occurs in space, but predominantly it’s produced synthetically on Earth. Scientists initially identified silicon carbide in space by comparing the properties of the synthetic version.

“There could be a silicate combination that doesn’t occur on Earth, but we can find it in space,” Speck said. “Silicon carbide is very heat-resistant, so it wouldn’t be destroyed easily if we shot it up into our atmosphere. It might be a good option, but we just don’t have the answer for that just yet.”

But Speck can’t just go up into space and bring down stardust to analyze. Instead, she models the dust in her lab by creating samples of a variety of material combinations based on what she sees in space. Then she and her team are better able to see what properties would work best in combating climate change.

If the team isn’t absolutely certain how the material will react to every possible condition in the atmosphere, there could be serious problems — the dust might have no effect at all or freeze the planet forever. Additionally, if the dust worked in reflecting light and heat once, doing it again and again could cause irreversible change.

“The hope is we’d cool down the Earth to give us more time,” Speck said, and “not just do it so we can keep using fossil fuels. That’s not the point.”

Frog on slow boil

The dust found in the stars and the dust produced from volcanoes when they erupt have a lot in common. The combination of materials could both cool down the Earth. In fact, volcanoes have been known to cool down the Earth before.

When Mount Pinatubo erupted in the Philippines in 1991, the dust that shot up in the sky and clouded the sun dropped temperatures for the entire world. For the next 15 months, the Earth’s temperature decreased about 1 degree Fahrenheit, which scientists believe was due to the volcano’s eruption. The dust reflected light from the sun until it settled down, warming the Earth back up again.

“That’s just one example of what we could find on Earth,” Speck said. “Volcanoes also contain an amount of silica.”

A lot of work is not just physics, however. It’s a team effort with geologists, chemists and material scientists all working on the same question. And when, in several decades, a substance is discovered, implementation would be a whole other concern.

For Speck, however, none of that necessarily matters right now. First it’s just stardust and volcano dust and avoidable nuclear winters. Climate dystopia is not just some future scenario, she said; the world has to handle these changes now.

“If you throw a frog in boiling water, it’ll jump out,” Speck said. “But if you put a frog in cold water and then boil the water, it won’t notice until it’s too late. Well, the pot’s almost boiling everyone.”

Elena Bruess writes for the Express-News through Report for America, a national service program that places journalists in local newsrooms. ReportforAmerica.org. [email protected]