It came from beyond the Large Magellanic Cloud. The signal, a mere 20 milliseconds long, captured the moment when two black holes slammed together – a cataclysm that sent ripples through spacetime and onwards to Earth, where they made instruments chirp and scientists cheer. “We have detected gravitational waves,” said David Reitze of the Laser Interferometer Gravitational-Wave Observatory (Ligo). “We did it.”

The announcement ranked as the physics discovery of the year, confirming Einstein’s century-old theory of gravity and putting the Ligo team on course for a Nobel. But the real excitement is yet to come. For the first quarter of a million years, the cosmos was hidden from astronomers. Now scientists can build gravitational wave observatories and, with them, look back to the birth of the universe. We can study the moment of creation.

It wasn’t the only time astronomers celebrated in 2016. In August, the European Southern Observatory in the Chilean desert saw changes in the light coming from Proxima Centauri, the star nearest to the sun. An Earth-sized planet was pulling the red dwarf around. What thrilled astronomers was that the newly discovered world lay in the star’s habitable zone, that Goldilocks region of space where the temperature is right for liquid water, and along with water, perhaps life. The discovery brought the question, “Are we alone?” to our cosmic doorstep – and with it the realisation that such planets are not rare.

Stephen Hawking is convinced that aliens are out there, but he’s wary of inviting them over. In his 2016 film, Stephen Hawking’s Favourite Places, he warned that meeting up with a technologically advanced bunch of cosmic hooligans might do for humanity what Christopher Columbus did for the Native Americans.

Hawking is equally suspicious of artificial intelligence. Yes, superintelligent machines might solve our greatest challenges, but not if they wipe us out instead. Fortunately, that threat remains a distant one.

Facebook Twitter Pinterest Magic mushrooms, or medicine? Photograph: Martin Bond/Science Photo Library

For some people, merging with robots makes sense. Nathan Copeland, a 28-year-old who broke his neck in a car crash, had a robot arm wired directly into his brain. He could move it by thinking, and through signals passed back to his brain, experience a sense of touch. By providing sensory feedback, researchers are edging towards their ultimate goal: robotic limbs that move and feel like real ones.

More than 25 US states have now legalised marijuana for medical uses, but could magic mushrooms be next? A handful of small studies found that psilocybin (the ingredient that made for happy hippies in the 1970s) could lift severe depression in one group of volunteers, and reduce anxiety and depression in cancer patients. For Stephen Ross, director of addiction psychiatry at NYU Langone Medical Center, the latter results were unprecedented. “We don’t have anything like it,” he said.

“More work needed” was the take home from another trial in 2016; this time for a male contraceptive. At last it seemed that men could shoulder the responsibility for birth control, and all it required was, well, a little prick. The bimonthly hormone jab was nearly as effective as the female pill, but the trial was halted after 20 men dropped out. Some suffered from depression and acne; others had to contend with soaring libidos.

Of the 130 million or so babies born this year, one that arrived in April marked a scientific first. A Jordanian boy was created with DNA from three people (his parents, plus a healthy donor) to prevent him from inheriting a serious genetic disease. The US team who performed the treatment in Mexico say the boy is healthy, but such diseases can take hold later in life. In December, the fertility regulator in the UK gave clinics the green light to apply for a licence to offer the procedure, known as mitochondrial replacement therapy, paving the way for similar births in Britain.

Every year has its own advances, but all tell the story of science. Great ideas work or fail. Achievements are lauded, but make us think twice. With each, we understand that little bit more about ourselves and the universe. And if none of it makes much sense yet? Well, we can always ask the aliens.

• Where did it all go right? For a more positive view of the world in 2017, follow the Guardian’s Half Full online series, with reports on innovative ideas and solutions to the challenges of the day. Wishing you all a happier new year.