What We Learned in Space and Astronomy News in 2019

It’s not easy to say that any particular space or astronomy development was the most important in a given year. But if we had to choose some highlights, we’d opt for these unforgettable events and findings.

You’ve seen black holes in science fiction movies and in illustrator’s impressions. But until the morning of April 10, you never saw what a black hole really looks like. And then there it was, the monstrous void at the middle of the galaxy Messier 87, staring back at you like the eye of Sauron.

The story of how one astronomer, Katie Bouman, became the face of the quest to visualize the singularity, was a good yarn, too.

It was a reminder that the space program was designed by men, for men, the science fiction novelist Mary Robinette Kowal wrote. NASA, she noted, is at its best when it is learning from mistakes, and it is highly capable of making improvements as it prepares to put the first woman on the moon.

NASA scientists compared Scott Kelly, the astronaut who spent 340 days on the space station, with his twin brother, Mark, on Earth. In orbit, Scott Kelly’s body experienced a vast number of changes, including mutations in DNA and declines in some cognitive tests. Many of the changes reverted once he returned to Earth, although some did not. Some scientists deemed the risks manageable; others saw the findings as a cautionary tale — a warning over whether long trips in space will ever be safe for humans.

Summer Worden filed for divorce in 2018 from Anne McClain, a NASA astronaut. This year while Ms. McClain was aboard the International Space Station, Ms. Worden accused her of identity theft and improper access of private financial records. Ms. McClain admitted to accessing Ms. Worden’s bank account, but said she had always been responsible for keeping the couple’s finances in order.

The case is not yet decided. However it turns out, more criminal allegations and other legal disputes are bound to emerge as more humans and their economic activity move to low Earth orbit and beyond.

Congress granted President Trump the authority and some budget to begin creating a Space Force. It’s unclear what exactly that force will look like. But in March, when India demonstrated an antisatellite weapon, it was a reminder that nation-states are looking beyond the bubble of Earth’s atmosphere as they make their defense plans for the future.

As NASA said goodbye to the Opportunity rover this year, its other rover, Curiosity, detected unusual signals on the red planet’s surface. A large spike of methane, a gas usually produced by living things on Earth, was detected in June. But just as scientists on Earth wondered if the signal was evidence of potential microbial life on the red planet, the gas was gone.

If that wasn’t puzzling enough, scientists said in November that they had detected varying amounts of oxygen, which was “confusing, but it’s exciting,” one said. While four new spacecraft could arrive at Mars next year, none will have instruments to study these gases.

Want to buy a trip to the space station? Soon, you might be able to — for at least $35,000 a night. You can also buy a $250,000 seat aboard a Virgin Galactic space plane that comes with a snazzy flightsuit. The target customer is obvious; only the wealthiest travelers will be able to afford the privilege of private spaceflight. Who gets to decide what happens in the commons beyond our planet is still an open question.

One private company, SpaceX, launched 120 satellites all by itself this year, the first nodes in one of several proposed orbiting mega-constellations that would beam internet service back to Earth. Astronomers fear that the night sky might never be the same.

Some people want to believe the moon landing was a hoax. Others are certain the truth is being kept from us. Here’s what we do know: A comet from beyond the bubble that contains you, me and everyone we know is hurtling through our solar system right now. In the days ahead, it will pass closer to Earth than it will ever come.

Then it will leave our solar system. If you miss it, don’t worry. More interstellar tourists will be passing through our neighborhood, which is just one tiny corner of one spiral arm full of stars that juts out from a supermassive black hole.