As the 2010s come to an end, we can look back on an era rife with discovery. In the past 10 years, scientists around the world made remarkable progress toward understanding the human body, our planet, and the cosmos that surrounds us. What’s more, science in the 2010s became more global and collaborative than ever before. These days, major breakthroughs are likelier to come from groups of 3,000 scientists than groups of three.

So much has happened, thanks to so many, that National Geographic’s writers and editors decided not to whittle down the last decade into just a handful of discoveries. Instead, we’ve put our heads together to identify 20 trends and milestones that we found especially noteworthy, and that we think will set the stage for more amazing finds in the decade to come.

Detecting the first gravitational waves

In 1916, Albert Einstein proposed that when objects with enough mass accelerate, they can sometimes create waves that move through the fabric of space and time like ripples on a pond’s surface. Though Einstein later doubted their existence, these spacetime wrinkles—called gravitational waves—are a key prediction of relativity, and the search for them captivated researchers for decades. Though compelling hints of the waves first emerged in the 1970s, nobody directly detected them until 2015, when the U.S.-based observatory LIGO felt the aftershock of a distant collision between two black holes. The discovery, announced in 2016, opened up a new way to “hear” the cosmos.

In 2017, LIGO and the European observatory Virgo felt another set of tremors, this time made when two ultra-dense objects called neutron stars collided. Telescopes around the world saw the related explosion, making the event the first ever observed in both light and gravitational waves. The landmark data have given scientists an unprecedented look at how gravity works and how elements such as gold and silver form.

Shaking up the human family tree

View Images While primitive in some respects, the face, skull, and teeth (seen in this reconstruction) show enough modern features to justify H. naledi's placement in the genus Homo. Artist John Gurche spent some 700 hours reconstructing the head from bone scans, using bear fur for hair. PHOTOGRAPH BY MARK THIESSEN, NATIONAL GEOGRAPHIC

The decade has seen numerous advances in understanding our complex origin story, including new dates on known fossils, spectacularly complete fossil skulls, and the addition of multiple new branches. In 2010, National Geographic explorer-at-large Lee Berger unveiled a distant ancestor named Australopithecus sediba. Five years later, he announced that South Africa’s Cradle of Humankind cave system contained fossils of a new species: Homo naledi, a hominin whose “mosaic” anatomy resembles that of both modern humans and far more ancient cousins. A follow-up study also showed that H. naledi is surprisingly young, living at least between 236,000 and 335,000 years ago.

Other remarkable discoveries piled up in Asia. In 2010, a team announced that DNA pulled from an ancient Siberian pinky bone was unlike any modern human’s, the first evidence of a shadowy lineage now called the Denisovans. In 2018, a site in China yielded 2.1-million-year-old stone tools, confirming that toolmakers spread into Asia hundreds of thousands of years earlier than once thought. In 2019, researchers in the Philippines announced fossils of Homo luzonensis, a new type of hominin similar to Homo floresiensis, the “hobbit” of Flores. And newfound stone tools on Sulawesi predate modern humans’ arrival, which suggests the presence of a third, unidentified island hominin in Southeast Asia.

Revolutionizing the study of ancient DNA

As DNA sequencing technologies have improved exponentially, the past decade has seen huge leaps in understanding how our genetic past shapes modern humans. In 2010, researchers published the first near-complete genome from an ancient Homo sapiens, kicking off a revolutionary decade in the study of our ancestors’ DNA. Since then, more than 3,000 ancient genomes have been sequenced, including the DNA of Naia, a girl who died in what is now Mexico 13,000 years ago. Her remains are among the oldest intact human skeletons ever found in the Americas. Also in 2010, researchers announced the first draft of a Neanderthal genome, providing the first solid genetic evidence that one to four percent of all modern non-Africans’ DNA comes from these close relatives.

In another striking discovery, scientists studying ancient DNA revealed in 2018 that a 90,000-year-old bone belonged to a teenage girl whose mother was Neanderthal and whose father was Denisovan, making her the first hybrid ancient human ever found. In another find, scientists compared Denisovan DNA to fossil proteins to confirm that Denisovans once lived in Tibet, expanding the mysterious group’s known range. As the field of ancient DNA has matured, so too has its handling of ethical concerns, such as the need for community engagement and the repatriation of indigenous human remains.

Revealing thousands of new exoplanets

Human knowledge of planets orbiting distant stars took a giant leap forward in the 2010s, in no small part thanks to NASA’s Kepler Space Telescope. From 2009 to 2018, Kepler alone found more than 2,700 confirmed exoplanets, more than half the current total. Among Kepler’s greatest hits: the first confirmed rocky exoplanet. Its successor TESS, launched in 2018, is starting its survey of the night sky and has already bagged 34 confirmed exoplanets.

Ground-based surveys were also in on the action. In 2017, researchers announced the discovery of TRAPPIST-1, a star system just 39 light-years away that hosts a whopping seven Earth-size planets, the most found around any star other than the sun. The year before, the Pale Red Dot project announced the discovery of Proxima b, an Earth-size planet that’s orbiting Proxima Centauri, the star closest to the sun at a mere 4.25 light-years away.

Entering the Crispr era

DNA Hacking Tool Enables Shortcut to Evolution Watch: Learn—and visualize—how CRISPR technology works in this animated graphic video.

While Crispr-Cas9’s possible benefits are huge, the ethical quandaries it poses are also staggering. To the horror of the global medical community, Chinese researcher He Jiankui announced in 2018 the birth of two girls whose genomes he had edited with Crispr, the first humans born with heritable edits to their DNA. The announcement sparked calls for a global moratorium on heritable “germline” edits in humans.

Seeing the cosmos as never before

View Images The Event Horizon Telescope—a planet-scale array of ground-based radio telescopes—unveiled the first image of a supermassive black hole and its shadow in 2019. The image reveals the central black hole of Messier 87, a massive galaxy in the Virgo cluster. PHOTOGRAPH BY EVENT HORIZON TELESCOPE COLLABORATION

The 2010s brought with them several major observations that are revolutionizing our study of the universe. In 2013, the European Space Agency launched Gaia, a spacecraft that is collecting distance measurements for more than a billion stars in the Milky Way, as well as velocity data for more than 150 million stars. The dataset helped scientists make a 3D movie of our home galaxy, yielding an unprecedented look at how galaxies form and change over time.

In 2018, scientists released the final version of the Planck satellite’s measurements of the early universe’s faint afterglow, which contains vital clues to cosmic ingredients, structure, and rate of expansion. Puzzlingly, the expansion rate Planck saw differs from today’s, a potential "crisis in cosmology" that may require new physics to explain. Also in 2018, the massive Dark Energy Survey released its first batch of data, which will help with searches for hidden patterns in our universe’s structure. And in April 2019, scientists with the Event Horizon Telescope revealed the first-ever image of a black hole’s silhouette, thanks to a massive global effort to peer into the heart of the galaxy M87.

Unveiling ancient art

View Images A worker takes measurements of stone rings inside Bruniquel Cave in France that may have been constructed by Neanderthals. PHOTOGRAPH BY ETIENNE FABRE, SSAC

Discoveries from around the world have reinforced that art—or at least doodling—was an older and more global phenomenon that once thought. In 2014, researchers showed that hand stencils and a “pig-deer” painting in Sulawesi’s Maros cave sites were at least 39,000 years old, making them as old as Europe’s most ancient cave paintings. Then, in 2018, researchers announced the discovery of cave art in Borneo that’s between 40,000 and 52,000 years old, further pushing back the origins of figurative painting. And another 2018 find in South Africa, a stone flake that was cross-hatched some 73,000 years ago, may well be the world’s oldest doodle.

Other controversial finds stoked debate over Neanderthals’ artistic skills. In 2018, researchers unveiled pigments and perforated marine shells found in Spain that were 115,000 years old, when only Neanderthals lived in Europe. That same year, another study claimed that some of Spain’s cave paintings are 65,000 years old. Many cave-art specialists have disputed the find, but if it holds, it could be the first evidence of Neanderthal cave paintings. And in 2016, researchers announced that a French cave contained bizarre circles of stalagmites set up about 176,000 years ago. If cave bears didn’t somehow make them, the circles’ age suggests yet more Neanderthal handiwork.

Making interstellar firsts

Future historians might look back on the 2010s as the interstellar decade: For the first time, our spacecraft punctured the veil between the sun and interstellar space, and we got our first visits from objects that formed around distant stars.

Opening doors to ancient civilizations

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Breaking new ground in the solar system

In July 2015, NASA’s New Horizons probe made good on a decades-long quest to visit the icy world Pluto, sending back the first-ever images of the dwarf planet’s shockingly varied surface. And on New Year’s Day 2019, New Horizons pulled off the most distant flyby ever attempted when it snapped the first pictures of the icy body Arrokoth, a primordial leftover from the solar system’s infancy.

A little closer to home, NASA’s Dawn spacecraft arrived at Vesta, the second-biggest body in the asteroid belt, in 2011. After mapping that world, Dawn darted off to orbit the dwarf planet Ceres, the asteroid belt’s largest object—becoming the first mission ever to orbit a dwarf planet, and the first to orbit two different extraterrestrial bodies. Near the decade’s end, NASA’s OSIRIS-REx and JAXA’s Hayabusa2 visited the asteroids Bennu and Ryugu, respectively, with the goal of returning samples back to Earth.

Changing the course of disease

Pushing reproductive limits

View Images Using gene editing, two mouse moms birthed this pup, as described in a 2018 study. Grown to adulthood, the mouse born to same-sex parents now has her own babies. PHOTOGRAPH BY LEYUN WANG

Tracking down the Higgs boson

View Images A Higgs boson erupts from a collision of protons in an illustration. Illustration by Moonrunner Design Ltd., National Geographic

How does matter get mass? In the 1960s and 1970s, physicists including Peter Higgs and François Englert proposed a solution in the form of a novel energy field that permeates the universe, now called the Higgs field. This theorized field also came with its associated fundamental particle, what’s now called the Higgs boson. In July 2012, a decades-long search ended when two teams at CERN’s Large Hadron Collider announced the detection of the Higgs boson. The discovery filled in the last missing piece of the Standard Model, the spectacularly successful—albeit incomplete—theory that describes three of the four fundamental forces in physics and all known elementary particles.

Rewriting paleontology textbooks

In 2014, paleontologists also revealed new fossils of the predatory dinosaur Spinosaurus that suggested it was a semiaquatic predator—the first known among dino-kind. A year later, a team in China unveiled the stunning fossil of Yi qi, a truly weird feathered dinosaur with membraned wings like a bat’s. Also in the last decade, scientists’ interest in Myanmar’s 99-million-year-old amber has surged, revealing a feathered dinosaur tail, a primitive baby bird, and all sorts of invertebrates trapped in the fossilized tree resin.

Finding life’s building blocks on other worlds

In the last 10 years, space missions have given us a more sophisticated look at other worlds’ carbon-based organic molecules, which are necessary ingredients for life as we know it. The European Space Agency’s Rosetta mission orbited and landed on Comet 67P Churyumov–Gerasimenko. The data it collected between 2014 and 2016 gave us an astonishingly close look at the raw materials that ancient impacts might have brought to Earth. Before NASA’s Cassini probe died in 2017, it confirmed that the watery plumes of Saturn’s moon Enceladus contain large organic molecules, a clue that it has the right stuff for life. And in 2018, NASA announced that its Curiosity rover had found organic compounds on Mars, as well as a bizarre seasonal cycle in the red planet’s atmospheric methane levels.

Ringing climate alarms louder than ever

View Images Alexandria Villasenor, 13, skips school on Fridays to strike in the name of climate change. Every week, rain or shine, she sits on a bench in front of the United Nations in New York City with her signs, bringing attention to the issue of climate change. Villasenor and other young activists from across the country organized a global school strike for climate on March 15. PHOTOGRAPH BY SARAH BLESENER, THE WASHINGTON POST/GETTY

Discovering—and rediscovering—species

But along with these many finds, scientists have tallied the exponential rate of modern extinctions. In 2019, scientists warned that a quarter of plant and animal groups are threatened with extinction, suggesting that as many as a million species—both known and unknown to science—are now at risk of dying out, some within decades.

Kicking off a new spaceflight era

The 2010s were a pivotal transition period for spaceflight, as access to low-Earth orbit and beyond became a more global—and commercial—enterprise. In 2011, China launched its first space laboratory, Tiangong-1, into orbit. In 2014, India’s Mars Orbiter Mission arrived at the red planet, making India the first country ever to successfully arrive at Mars on its first try. In 2019, Israeli nonprofit SpaceIL attempted the first privately funded lunar landing, and China’s Chang’e-4 mission performed the first soft landing on the lunar farside. The global astronaut corps also grew more diverse: Tim Peake became the first professional British astronaut, Aidyn Aimbetov became the first post-Soviet Kazakh cosmonaut, and the United Arab Emirates and Denmark sent their first astronauts to space. What’s more, NASA astronauts Jessica Meir and Christina Koch performed the first all-female spacewalk.

In the U.S., after the last space shuttle mission launched in 2011, private companies angled to fill the void. In 2012, SpaceX launched the first commercial resupply mission to the ISS, and in 2015, Blue Origin and SpaceX became the first companies to successfully launch reusable rockets to space and then vertically land them back on Earth, a milestone for cheaper launches to low-Earth orbit.

Seeing animals’ unexpected sides

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Redefining the units of science