UTSA professor sees stardust as way to cool Earth

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On the third floor of the Applied Engineering and Technology building at the University of Texas at San Antonio, Angela Speck’s office is a miniature space station. Images of the universe line the walls. There is a graph of the light spectrum on the ground. Books on physics, astronomy and solar eclipses are stacked on shelves. And the sofa is a brilliant purple – emblematic of a distant star in a distant galaxy.

Speck is a huge space fan, which is no surprise. As chair of the Department of Physics and Astronomy at UTSA, she has made it her mission to study the world outside Earth. Its deeper interest, however, is specific and often misunderstood. Stardust – the ejected material of dying stars – is simultaneously within every living being and largely a mystery. Researchers, like Speck, are studying the natural space stuff remotely, analyzing its composition and qualities.

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Yet the dust is much more than theoretical. The composition of stardust could be key to coping with the impacts of climate change, now and in the future. Greenhouse gases – which are primarily composed of carbon dioxide, methane and nitrous oxide – clog the Earth’s atmosphere daily, absorbing infrared radiation and warming the planet. If blasted into the stratosphere, material discovered in stardust could reflect light, subsequently cooling Earth’s temperature.

Angela Speck, professor and chair of UTSA’s Department of Physics and Astronomy, explains some of the science behind studying stardust using the light spectrum.

Jessica Phelps / Jessica Phelps

Although a process like this is years away from being implemented, it could provide a temporary solution to climate change – allowing time for concrete actions, such as reducing greenhouse gases and limiting the fossil fuel industry.

However, all of this work begins in the lab with Speck and his team. Not just any material can be thrown into the Earth’s atmosphere. It must be perfect.

“It all has to do with the combination of elements we use,” Speck said. “We need to know exactly how the material is going to react and that takes a lot of research.”

How to avoid nuclear winter

When Speck talks about throwing space dust into the sky, she likes to bring up the 2013 post-apocalyptic movie, “Snowpiercer.” In the film, officials shoot reflective materials into the stratosphere to fight climate change. Unfortunately, they release too much and the Earth freezes, plunging the world into an endless nuclear winter.

“We really try to avoid that,” Speck said.

That’s why stardust is only a temporary solution to heat, and why the search takes so long. The team needs to analyze what kind of light the material reflects, if it absorbs light, how it affects infrared and ultraviolet light, how long the substance will be effective, and what size the material should be.

Additionally, the team would love to be able to find a common material to work with – such as one that occurs naturally on Earth or in space – rather than a rare mineral that would eventually expire.

So far, Speck has been mostly 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 is also found in stardust. The material called silicon carbide occurs naturally in space, but is mostly produced synthetically on Earth. Scientists first identified silicon carbide in space by comparing the properties of the synthetic version.

Angela Speck, professor and chair of UTSA's Department of Physics and Astronomy, explains some of the science behind studying stardust.

Angela Speck, professor and chair of UTSA’s Department of Physics and Astronomy, explains some of the science behind studying stardust.

Jessica Phelps / Jessica Phelps

“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 easily destroyed if we threw it into our atmosphere. It might be a good option, but we don’t have the answer yet. »

But Speck can’t just go up into space and bring back stardust to analyze. Instead, she models 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 which properties would work best to fight climate change.

If the team isn’t absolutely sure how the material will react to all possible conditions in the atmosphere, there could be serious problems – the dust could have no effect or freeze the planet forever. Moreover, if dust once reflected light and heat, doing so again and again could cause irreversible changes.

“The hope is that we’re cooling the Earth to give us more time,” Speck said, and “not just so we can keep using fossil fuels. That’s not the point.”

Slow Boiling Frog

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

Angela Speck, professor and chair of UTSA's Department of Physics and Astronomy, studies how injecting small dust particles into the stratosphere can cool the Earth.

Angela Speck, professor and chair of UTSA’s Department of Physics and Astronomy, studies how injecting small dust particles into the stratosphere can cool the Earth.

Jessica Phelps / Jessica Phelps

When Mount Pinatubo erupted in the Philippines in 1991, dust that rose into the sky and darkened the sun sent temperatures plummeting around the world. Over the next 15 months, the Earth’s temperature dropped by about 1 degree Fahrenheit, which scientists believe was due to the eruption of the volcano. The dust reflected sunlight until it stabilized, warming the Earth again.

“This is just one example of what we might find on Earth,” Speck said. “Volcanoes also contain a quantity of silica.”

A lot of the work isn’t just physical, however. It’s a team effort with geologists, chemists and materials scientists all working on the same question. And when, several decades from now, 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 volcanoes and avoidable nuclear winters. Climate dystopia is not just a future scenario, she said; the world must deal with these changes now.

“If you throw a frog in boiling water, it will jump,” 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 almost boils everyone.


Elena Bruess writes for the Express-News through Report for America, a national service program that places reporters in local newsrooms. ReportforAmerica.org. elena.bruess@express-news.net

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