The ability to detect gravitational waves could help astronomers piece together clues about everything from the evolution of the universe to the nature of dark matter, an elusive substance that is thought to make up 70 percent of the cosmos.

Farewell, Cassini!

After spending 13 years orbiting Saturn, NASA’s Cassini spacecraft ended its prolific mission by plunging into the atmosphere of the ringed planet on September 15. The school-bus-sized space probe launched into space in October 1997 and arrived at Saturn in June 2004. During its lifespan, Cassini studied Saturn and its rings and moons in unprecedented detail, snapping more than 453,000 pictures in the process. [Watch: The Story Behind Cassini’s Final Moments]

Modified human embryos

In July, researchers at the Oregon Health & Science University in Portland announced that they had created viable genetically modified human embryos. The unprecedented feat was made possible with the help of a revolutionary gene-editing tool known as CRISPR-Cas9.

None of the modified embryos was allowed to develop into a baby. But the study ignited a fierce ethical debate about whether CRISPR should be used to correct disease-causing mutations. [Read more: 11 amazing feats the gene-editing tool CRISPR just made possible]

Somersaulting robot

The year saw all sorts of cool new robots, from Peeqo, a bot that communicates using GIFs, to the adorable companion robot Kuri. But the most impressive bot of 2017 was an improved version of Atlas, a humanoid robot first developed by Boston Dynamics in 2013. In November, the company released a dramatic video showing Atlas performing a series of increasingly difficult box jumps, ending with an impressive finale: a perfectly executed backflip.

Atlas keeps its balance when jostled or pushed and can get up if it tips over. Boston Dynamics

But don’t worry: Atlas isn’t designed to compete against humans in the gym, but to carry out search and rescue missions and perform tasks deemed too dangerous for humans.

Great Pyramid secret revealed

Scientists in Egypt announced in November that they had detected a previously unknown “void” inside the Great Pyramid of Giza. It was the first time since the 19th century that a major interior structure was found within the 4,500-year-old pyramid, which is located along the Nile River a few miles from Cairo, Egypt.