Title: How Space Shapes Human History and Why the Future May Be in Asteroids

Humanity narrowly avoided a major disaster in 2012. That year, a giant magnetic bubble filled with solar plasma blasted from the sun and into the solar system. 

It missed Earth by about nine days.

What almost hit Earth was a coronal mass ejection (CME). If it had hit, the damage could have been catastrophic, said Dagomar Degroot, associate professor of history in the College of Arts & Sciences.

That’s because powerful CMEs can destroy the transformers that manage voltage on energy grids. Because transformers are difficult to replace, blackouts could affect entire regions of the world, possibly for years, Degroot said.

Solar events like CMEs are one of many space events that can impact human civilization. In his new book, Ripples on the Cosmic Ocean: An Environmental History of Our Place in the Solar System, Degroot studies how these cosmic events have shaped human history.

“When the sun changes and the sun’s influence on the solar system changes, I call that a ripple on the cosmic ocean that affects the space environment. Or when the moon’s or Mars’ environments seem to change. They’re ripples on the cosmic ocean, and when astronomers observe them, they affect humanity,” he said. “What I discovered in writing this book is that these ripples have had diverse, sometimes contradictory, sometimes profound impacts on human history, not just millions of years ago, but also in the last five centuries.”

Those space impacts include spurring technological breakthroughs, influencing social movements and generating conspiracy theories about alien life, he said. But as an environmental historian, Degroot is also interested in how human civilization can shape its corner of the cosmos to reduce its impact on Earth’s environment.

“I argue for creating environmental interventions in order to preserve life on Earth. I argue for things like mining the asteroids and creating solar power stations in orbit, things that could someday benefit everybody on Earth,” he said. “I argue for some of these interventions because the environments on Earth are special, full of life, and we depend on those environments.”

Learn about the threats posed by cosmic events, and discover Degroot’s vision of a human civilization settling in asteroid cities while preserving Earth’s climate.

Ask a Professor: Cosmic Threats to Earth and the Future of Humanity in Space

How does the sun affect modern human life on Earth?

The whole solar system is basically the sun and some parts left over from its formation. What we see with the sun is variations in what we call its output. Sometimes it sends a little bit more energy to Earth than other times. Those little differences actually add up, and they can influence Earth’s climate.

The sun is also a really complicated magnet. As magnetic field lines are constantly interacting, tangling and snapping open, you get solar flares and these huge ejections of particles from the sun, called CMEs, that impact the Earth. This activity also waxes and wanes.

Humanity has, in some ways, grown less vulnerable to changes in solar output, partly because of modern technology. But our technology also makes us more vulnerable to changes in solar magnetic activity, which can create electrical currents in the Earth’s crust and, among other things, fry our electrical grids.

Does the sun pose any existential threat to humanity?

Maybe. 

Scientists have long assumed that the worst solar storms that could be produced happened in 1859, the so-called Carrington Event. It didn’t have that much of an impact on Earth because electrification hadn’t spread very far. 

But if it happened now, we could lose every transformer in the northeastern U.S. Transformers are huge machines that are integral to electrical grids, and they’re almost impossible to replace. They’re highly specialized and customized, so you might need over a year to replace a broken transformer. 

If one transformer breaks in one part of the grid, that’s okay. But if you have a significant share of the transformers along the East Coast of the U.S. being irreversibly broken, then we would probably lose power for tens of millions of people, potentially for years.  There would be no electricity for transportation, communication, running water, medicine — you name it. Millions could die, and the national economy  — and actually, the global economy  — could collapse. 

And it turns out that there’s a real possibility that the sun can produce far more powerful storms than our technological civilization has ever encountered. Much more powerful than the Carrington Event. 

How would you quantify the risk of comets and asteroids impacting Earth?

This is a good news story — a story about how we came to recognize a risk to humanity and to Earth — one that’s created by ripples in the cosmic ocean, by asteroids and comets potentially smashing into us.

Recently, the double asteroid redirect (DART) mission smashed a probe into an asteroid and changed its orbit. It’s the first time we’ve purposely altered the orbit of an asteroid. More importantly, we’ve made amazing progress in the past 30 years in identifying potentially dangerous asteroids and ruling out that they can collide with Earth. 

But there’s still a risk, although one that’s much smaller than it once was. The problem is that the technology we would need to deflect a comet barreling down on us would be very different than the technology to alter the orbit of an asteroid, because you can find an asteroid and go to it years in advance and give it a nudge at one part of its orbit, which then dramatically alters another part of its orbit.

But comets suddenly show up from the outer solar system. Most of them we don’t see coming until they’re just months away. If you’ve got a comet going straight toward you as you’re orbiting the sun, then the only thing you could do would be to deflect it using very powerful nuclear bombs. That’s the only way to potentially get enough force, and in no way do we have that system available right now. 

Luckily, a comet rarely hits a planet. But there was a small chance of one smashing into Mars about a decade ago. And comet fragments pummeled Jupiter in 1994.

How has humanity started to shape space environments?

On Earth, we can launch all these rockets, and they’ve had a minimal impact so far on Earth’s atmosphere. But, for example, on the moon, you’re talking about an exosphere that is incredibly diffuse. When you land several dozen spacecraft on the moon, you’re injecting molecules that weren’t there before and altering something very small in a major way.

Does it matter if we change the environment on the moon or other bodies in space?

When you start landing astronauts on the moon and building a base on the South Pole, as space agencies and companies currently plan to do, the exosphere is transformed for the foreseeable future. For me, that matters a lot less than environmental changes on Earth. But there’s a whole argument for space environmental preservation, the idea that the moon has an inherent value.

The same goes for other planetary environments. If we bring humans to Mars, then we also bring our microbes. If there are any indigenous microbes there — there’s new evidence that suggests that maybe, there might be — then those microbes could very well be wiped out by [our] microbes. 

This is a really important thing, partly because if life did emerge independently on Mars, the implication is that life emerges anywhere there’s water. If that’s the case, that means almost certainly that life is common throughout the universe.

You seem to suggest humanity is close to becoming a multiplanetary species. How close are we?

I would say we’re probably still several decades away.

We’re now in what many people call a new space age, where companies like SpaceX and Blue Origin take the lead, and where there are more space agencies that can send probes across the solar system or dream of landing people on the Moon. 

Perhaps more importantly, there’s a new kind of ambition. It’s not just about exploring. It’s not just about doing science. It’s about actually using space resources and potentially bringing people to places like the Moon or Mars to stay.

What are the critical technologies that will empower humanity to take its next step in space?

Something like [SpaceX’s] Starship, where you have radical renewable capability, and you’ve scaled up your launch vehicle. Now, for the first time since the beginning of space travel, you can start to broaden that bottleneck of getting into space by radically reducing the cost of doing so. Something like Starship is a truly paradigm-shifting technology, or group of technologies, that could actually bring humans  — many humans  — to Mars.

The other thing is artificial intelligence. We’re on the verge of large language models being able to control machines and robots that can manipulate their surroundings. What this means is that you could have truly autonomous agents in outer space that are able to build with limited human supervision.

That gets to the third thing, which is 3D printing. It’s possible to imagine 3D printers that are able to produce things from space environments. Put all of these technologies together, and now it’s possible to imagine mining an asteroid, or building a solar power plant in space.

Are you suggesting that humanity should one day live in asteroid cities?

Maybe! If human numbers are to grow in the future, it may have to be in space. And there’s all the space we need for population growth in the asteroids between Mars and Jupiter. They could be hollowed out and spun up so they have gravity like Earth’s. It could be an alternative to settling Mars, where environments are incredibly hostile and you’ve potentially got living things you don’t want to destroy.

How would you envision humanity’s future in space?

For me, a good future for humanity in space would be one in which, in the next few decades, we leverage space resources using these revolutionary technologies to offworld some of the most destructive things we do on Earth, like some of our mining practices and energy generation, so that we preserve environments on Earth.

Then, in the next few centuries, maybe we start to move humans into outer space, onto space environments that have been remade for them. That serves a whole bunch of purposes. One of them is the reduction of risk to our species — if we’re spread out, there’s fewer risks to us. Another purpose could be to reduce human pressure on Earth’s environments. And another is to perpetuate life, allowing us to embark on the adventure of exploring the universe. It’s a utopian vision for what we can be as a species in the cosmos. But I think we need such visions in these times.