For the second year running, COVID-19 dominated the airwaves, our brainwaves—and so many other facets of our lives. But this was a rich year in other areas of science, too, with a bounty of discoveries about biology and medicine, human prehistory, and the physical world.
Now, we want to know which one you consider this year’s top breakthrough.
Starting today, and running through Monday, 6 December at 9 a.m. EST, you can cast your vote via Twitter poll for your favorite breakthrough in three categories: ancient origins, health and medicine, and from molecules to space. The winners of these three rounds of voting will enter the final contest, which will run from Monday, 6 December until Monday, 13 December. On Thursday, 17 December, the winner of the People’s Choice award will be revealed, and you’ll get a chance to compare it to Science’s own pick for Breakthrough of the Year.
So pull up a chair, kick back, and scroll through a year’s worth of fantastic discoveries. Then tell us which ones you think should be Science’s Breakthrough of the Year. Candidates are listed below. Happy reading—and voting!
Ancient origins
First footprints in the Americas?
Between 23,000 and 21,000 years ago, people squished through the mud along a lakeshore in New Mexico. If the dates for their preserved footprints are right, the discovery would be the strongest evidence yet that people reached the Americas thousands of years earlier than thought.
BENNET ET AL./SCIENCE
Dragon Man skull
Who was Dragon Man? The stunningly preserved skull, unveiled in a new Chinese journal this year, could be the most complete fossil of our long-lost sister lineage, the Denisovans. Or, some scientists say, a new human species. Either way, this 146,000-year-old has a story to tell.
Xijun Ni
Ancient soil DNA
For years, scientists have known that ancient sediments harbor DNA samples from our earliest human relatives. But this year, multiple teams made strides in finding—and untangling—those threads, rewriting the history of humans and animals living in caves from Spain to Siberia.
Devlin A. Gandy
The homeland of horses
The origins of horses—which transformed the lives of Bronze Age peoples—have long been shrouded in mystery. But a study of 300 ancient horse genomes found that the ancestors of all modern horses made their first appearance 4200 years ago on the western Eurasian steppe.
Ludovic Orlando
Ancient Origins: Choose your favorite. ⬇
— Science Magazine (@ScienceMagazine) November 29, 2021
Health and medicine
In vivo CRISPR
This year brought signs of success at using the CRISPR editing tool to modify genes inside the human body. An injection of genetic code for CRISPR reduced production of a toxic liver protein in several patients and modestly improved vision in two people with inherited blindness.
ELLA MARU STUDIO/Science Source
A psychedelic PTSD remedy
For decades, scientists trying to edge psychedelic drugs into mainstream medicine have faced an uphill battle. In May, they achieved results: They found that talk therapy plus the drug ecstasy effectively treated post-traumatic stress disorder in two-thirds of trial participants.
MULTIDISCIPLINARY ASSOCIATION FOR PSYCHEDELIC STUDIES
Early human development
Understanding early embryonic development can provide insight into miscarriages and birth defects and help scientists hone in vitro fertilization protocols. New ways to cultivate embryos from mice and stem cells could obviate the need to use real human embryos in some studies.
Weizmann Institute of Science
Powerful pills for COVID-19
Vaccines have dominated the fight against COVID-19, but a new weapon may soon be added to the arsenal: antiviral pills that suppress symptoms and prevent death if taken early enough in infection. Results from drug companies suggest they may prevent 30% to 89% of hospitalizations.
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Health and Medicine: Choose your favorite. ⬇
— Science Magazine (@ScienceMagazine) November 29, 2021
From molecules to space
Measuring muon magnetism
In April, new measurements confirmed that a fleeting subatomic particle called the muon may be ever so slightly more magnetic than theory predicts. That small anomaly—just 2.5 parts in 1 billion—is a welcome threat to particle physicists’ prevailing theory, the standard model.
REIDAR HAHN/FERMILAB
Uncovering Mars’s core
NASA’s InSight lander has faced no end of challenges on Mars. But this year, its marsquake readings yielded the first full view of the Red Planet’s crust, mantle, and core. The crust and mantle are thinner than Earth’s—but the core is vast, taking up more than half the planet’s width.
NASA/JPL-Caltech
Artificial intelligence predicts proteins
For 50 years, scientists have struggled to solve one of nature’s biggest challenges: predicting the 3D shape a string of amino acids will fold into as it becomes a working protein. Artificial intelligence delivered big results this year, predicting the structures of thousands of proteins and complexes.
Ian Haydon/Institute for Protein Design
Fusion’s day in the Sun
In an August result that surprised many, including researchers, the U.S. National Ignition Facility’s giant laser sparked a fusion reaction that came tantalizingly close to reaching the so-called “break-even” point, when more energy is produced by the reaction than went into it.
Lawrence Livermore National Laboratory
From Molecules to Space: Choose your favorite. ⬇
— Science Magazine (@ScienceMagazine) November 29, 2021
Correction, 29 November, 10:20 a.m.: The “Powerful pills for COVID-19” item has been updated to clarify the results from drug companies.