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Space is, for the most part, a vast, impersonal vacuum. But the part of it that includes our small precinct of the universe is a human-influenced environment upon which society depends. Increasingly, people need to think of it that way.

In a series of editorials over the past year, we have examined how we on Earth are more vulnerable to cosmic phenomena than ever before, how humans are changing the orbital ecosystem -- and how the world needs to respond.

Space hazards have always threatened this planet, even if those living here were not aware of them -- until recently. A giant asteroid impact probably killed off the dinosaurs, and a similar strike could someday eliminate the human race. Smaller asteroids are in some ways more threatening, though, because they are harder to see and more numerous yet still capable of devastating a city or even a country. Scientists have started launching space-based telescopes to track dangerous asteroids and testing methods to steer asteroids away from Earth: Ideas include simply slamming a spacecraft into an asteroid, subtly changing its course.

Other space-based dangers emerged as people became more dependent on electronics vulnerable to "space weather" -- ejections of radiation and magnetized particles from the sun that can frazzle power grids, satellites, radios, GPS devices, fiber-optic cables and other crucial modern-day infrastructure. Big solar storms happen about every 100 years, and we're probably overdue for one. Scientists can predict space weather, giving people hours' or even a few days' warning to gird infrastructure. But governments and utilities have to know how to act quickly when they get such warnings.

Then there are the problems humans are creating themselves. Junk that we've put into orbit surrounds the planet, and the number of things up there is rising rapidly. Even tiny pieces of debris, speeding as fast as bullets, can damage satellites that provide critical services on Earth's surface -- and, in the process, possibly create yet more debris that menaces other objects in orbit. Some space trash even ends up crashing unexpectedly onto land; one chunk, a stanchion from the International Space Station, hit a Florida home earlier this year.

Also dramatic, but something everyone can help address, is light pollution. Humans are making the sky brighter from below, through the use of increasingly intense and ubiquitous terrestrial lighting, and from above, via satellites and, yes, all that space debris reflecting sunlight down to earth. One study found that humans have made the sky 10 percent brighter per year over the past decade. "Skyglow" disrupts people's circadian rhythms and harms their sleep and their mental and physical health.

Congress should fund planetary defenses against asteroids and space weather. They can include space-based observatories to map asteroids and study the sun, tests of asteroid-moving techniques, and hardened electronic infrastructure resistant to solar ejections. There is all sorts of planning to do for how to respond when a threat is heading our planet's way.

Countries and companies that exploit space also need to pollute less. Along with other nations, the United States should develop standards for how and when people can launch satellites, rockets and more into orbit -- including disposal plans for the inevitable space junk -- and, perhaps, even suggestions on what the instruments we fire into space should be made of. Japan just built a satellite made mostly of wood, which poses fewer orbital dangers than metal. Dealing with space debris would also help cut skyglow, as would using outdoor lighting systems that, among other specifications, mostly point downward.

One understandable reaction to all these cosmic concerns: Humanity has a hard enough time taking care of its terrestrial environment; you're telling me there's another one to worry about? Unfortunately, yes. Even as humans struggle to preserve the ground we walk on or the air we breathe, governments all over the world need to take care of the zone far above our heads, too. Those who spend their lives studying space increasingly understand this imperative -- and what to do about it. Acting, however, is often the hardest part.