What Happens in Space Matters on Earth

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It is often assumed that Earth is somehow separate from the rest of the universe. Yet environmental changes across the solar system have profoundly influenced human history.

Starting in the 14th century, the sun’s activity declined repeatedly for decades. When these collapses coincided with clusters of volcanic eruptions, waves of cooling and drying of certain places swept across the Earth. The consequences included crop failures that destabilized some of the greatest empires of the time. People around the world began to suspect that the climate might be changing, centuries before human-caused global warming began.

In the 19th century, the increasing use of electricity allowed another type of solar activity to influence human affairs: violent eruptions and plasma ejections caused by immense disturbances in the solar magnetic field. In the 20th century, the radio waves created by these flares repeatedly jammed military radars, nearly triggering a nuclear war. Currents generated by solar plasma have also destroyed power grids and disabled satellites.

Changes in the planet’s environment have also influenced history, often in surprising ways. Nineteenth-century astronomers misinterpreted dust storms on Mars, for example, as evidence of extraterrestrial civilization on a global scale. This “discovery” of extraterrestrial life caused a sensation, especially when Martians appeared several times to send a signal to Earth. Then, during the Apollo moon landing program, pioneering women at NASA created a global network of astronomers who discovered evidence of flares on the Moon. These eruptions appeared to endanger the astronauts. But they also promised to provide the fuel for a new era of interplanetary exploration.

Some believe that space exploration distracts us from more pressing problems on Earth. But in reality, astronomers and other space scientists have discovered many of the pressing threats facing human existence today.

The ozone layer, for example, is a veil of gas in the stratosphere that protects life on Earth from deadly solar radiation. In the 1970s, studies of chemical reactions in Venus’ atmosphere established that chlorofluorocarbon (CFC) gases, then widely used in refrigerators and aerosol cans, had opened an expanding hole in the ozone layer. Nations agreed to ban CFCs over the next decade. If they had not acted, the hole would have expanded to cover the Earth, devastating ecosystems and endangering human survival.

Space exploration helped reveal another, equally serious threat around the same time. In 1971, the Mariner 9 probe arrived on Mars just as a huge dust storm encircled the planet. By studying the effects of airborne dust on Martian temperatures, scientists have come to suspect that soot released into Earth’s atmosphere during nuclear war could also cool our planet. Eventually, they discovered that nuclear war would drop global temperatures to such an extent that it might be impossible for the remnants of humanity to recover. In the 1980s, the discovery of this potential “nuclear winter” motivated U.S. and Soviet leaders to reduce Cold War tensions and work toward arms control agreements.

Scientists, corporations, and governments have treated cosmic environments as if they lacked innate value and could be transformed at will. Today, we are entering a new space age marked by a rush for resources and territories across the solar system. We need a cosmic environmentalism that both focuses the exploitation of space on the needs of Earth and preserves the environments of other worlds.

At the dawn of the space age in the 1950s, Soviet and American officials developed plans to detonate a nuclear bomb on the Moon. The flash, they believed, would impress a global audience and irradiate part of the moon. Their plans proved impractical, but the Soviet and American militaries detonated nuclear bombs in space, briefly creating radiation belts that disabled the satellites.

At the same time, they failed to properly sterilize spacecraft sent to the Moon and perhaps other worlds, allowing bacteria from Earth to reach new planetary environments. Scientists have, for their part, developed projects aimed at transforming the climates of Mars and Venus, for example by deliberately introducing microorganisms likely to thrive in hostile environments. Both planets would become more habitable for human colonists, but toxic to any life forms that evolved there.

The proliferation and growth of space companies and agencies with revolutionary technologies appears to be creating a new space age characterized by the exploitation of cosmic environments. There are plans to melt the ice at the Moon’s south pole, colonize Mars and even mine asteroids. But despite claims to the contrary, we have found no planet B in the solar system, no place that matches the web of life on Earth.

So what should the new space age look like? I believe it should focus on modifying the lifeless environments around Earth in ways that help ease humanity’s burden on Earth’s environment. Space solar power plants, for example, could be built from lunar materials. They could transmit unlimited clean energy to the Earth, thereby slowing the rate of global warming. If this warming starts to get out of control, a swarm of tiny spacecraft – or even a redirected asteroid – could reduce a small portion of incoming solar radiation, thereby cooling the Earth.

Environmental changes in space have shaped history. It’s time to think about how we can make changes ourselves to preserve the future.

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Main image: Stockbym / Shutterstock

• Dagomar DeGroot

  Published on October 28, 2025

  Dagomar Degroot is an associate professor of environmental history at Georgetown University. A contributor to Washington Post, Nature, And Infinite timehe is the author of The Frosty Golden Age: Climate Change, the Little Ice Age, and the Dutch Republic, 1560-1720named one of the ten best history books of 2018 by the Financial Times. His most recent book is Ripples on a cosmic ocean: an environmental history of our place in the solar system.