The biggest scientific breakthroughs of the last 25 years—and a few to watch
From decoding the human genome to exploring the universe, science has made huge strides in the 21st century.
While the 21st century has been bumpy, it has also ushered in monumental scientific and technological breakthroughs that have changed our world for the better. Advances in medicine have allowed for the creation of unprecedented genetic cures, fusion power has inched closer to reality, we’ve learned more about the ancient past on Earth, and in astronomy, we have glimpsed at things once thought to be impossible to render, like a black hole.
“I think there's been a terrific amount of momentum in science in the last quarter century,” says France Córdova, an astrophysicist who currently serves as the president of the Science Philanthropy Alliance and formerly led the U.S. National Science Foundation. “I would like to see that accelerated with investment. We really need to let a thousand flowers bloom.”
We’ve pulled together a list of the most exciting discoveries of the past 25 years, along with five tantalizing unresolved mysteries to watch that could be solved in the coming decades.
The completion of the Human Genome Project, and the advent of synthetic life
Launched in 1990, the Human Genome Project successfully sequenced a complete human genome for the first time in 2003, creating a powerful reference point for the approximately three billion base pairs of DNA that make up the genetic blueprint of our species. It was the largest collaborative biological project in history, and its completion sparked a new era of genomics that transformed countless fields—from forensics, to anthropology, to DNA ancestry tests, to gene treatments for Huntington’s disease and others.
Spearheaded by the U.S. National Institute of Health, the Human Genome Project helped to accelerate the novel field of synthetic biology, which aims to engineer new forms of living systems and organisms. The ability to sequence genomes of real organisms, from roundworms to humans, opened the door to rewrite that code in creative ways. To that end, scientists developed the first synthetic cell in 2010, the first synthetic DNA in 2012, and the first synthetic chromosomes in 2014.
The discovery and development of CRISPR
Decades ago, scientists observed that some bacteria have a kind of genetic immune system; when viruses attack them, they capture pieces of the invaders’ DNA and insert them into their own genome to better protect against future attacks.
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This natural system called CRISPR, which stands for “clustered interspaced short palindromic repeats,” has now been adapted into a gene-editing tool that has revolutionized countless fields, including medicine, biotechnology, and agriculture. It lets scientists cut and paste any piece of DNA, from single base pairs to whole sets of genes.
First released in 2012, CRISPR-based gene editing has led to many medical breakthroughs, including the first approved genetic cure for sickle-cell disease and beta-thalassemia (Casgevy) and enabled the birth of “Baby KJ,” a child born free of an otherwise fatal genetic condition. Jennifer Doudna and Emanuelle Charpentier, pioneers of CRISPR, earned a Nobel Prize for the technology in 2020.
“The development I'm most excited about happened this year,” says Doudna, who is the founder of Innovative Genomics Institute (IGI) Researchers developed and delivered a personalized CRISPR therapy for an infant with an ultra-rare disease in just six months. “It’s a proof of concept that on-demand gene editing for rare diseases is now possible,” she says. “This will change what can be offered to the thousands of children born each year with conditions medicine has never encountered.”
CRISPR is also fueling a boom in climate and architectural biotech, from disease-resistant crops to carbon-capturing microbes.
(Jennifer Doudna reflects on her career in an interview with Nat Geo.)
The first three parent baby
Nearly a decade ago, in 2016, a baby boy became the first child to inherit DNA from three parents. Though the vast majority of the child’s DNA came from a mother and father, a third donor provided healthy mitochondrial DNA to the baby’s genome. This technique, called mitochondrial replacement therapy, is used to reduce the risk of passing on rare mitochondrial diseases. As of 2025, babies born with three parents appear to be healthy so far.
AlphaFold solves the “protein folding problem”
For decades, biologists sought a way to predict the three-dimensional shape of proteins, the building blocks of life, from a simple readout of their chemical components. A protein’s shape determines how it works, much like a key’s shape determines which lock it can open. So, solving the “protein folding problem,” as the puzzle was called, would give scientists a superpowered ability to bioengineer molecules, accelerating development of life saving drugs.
Enter AlphaFold. Developed by Alphabet’s DeepMind laboratory, this AI program has revolutionized the process of predicting protein structure, DNA/RNA patterns, and with other cellular enigmas. The program has enabled researchers to game out how cell components fold and interact much faster than ever before, with an accuracy that approaches meticulous and time-consuming experimental results. The major leg-up has accelerated research into drug candidates and the mechanisms that undergird life. It earned the 2024 Nobel Prize in Chemistry.
Vaccine breakthroughs save millions of lives
One of the greatest achievements of the 20th century was the widespread distribution of vaccines, an effort that helped to eradicate devastating diseases, like smallpox and polio.
The 21st Century has kept the momentum going. Notably there was the development of the first Human Papillomavirus (HPV) vaccine which was approved in 2006, and contributed to a 62 percent drop in deaths from cervical cancer. Global efforts to distribute the vaccine are believed to have prevented 1.4 million future deaths.
The rapid development and approval of RNA vaccines during the Covid-19 pandemic in 2020 was a historic victory that curbed the spread of Covid—saving millions of lives. Now, RNA vaccine technology is being developed to prevent a host of infectious diseases and even some cancers.
CAR T-cell immunotherapy for cancer
After years of research, the first chimeric antigen receptor (CAR) T-cell immunotherapy was approved in 2017. This therapy uses genetically modify human T-cells (which are part of our immune system) to recognize and destroy cells from certain cancers. The approach has proved to be highly effective for certain cancers including lymphomas, leukemias, and multiple myeloma.
More than 90 percent of patients go into remission after the treatment, which is estimated to have saved tens of thousands of lives so far.
Graphene invented
Graphene is the strongest and thinnest material known, made of carbon atoms latticed into a two-dimensional honeycomb pattern. It was first theorized in 1947, but it wasn’t until 2004 that scientists produced the first graphene in the laboratory. The breakthrough won the 2010 Nobel Prize in Physics.
Beyond its superlative thinness and strength, graphene is extremely conductive and transparent. Because of its exceptional qualities, graphene has advanced many fields, and helped produce much more efficient water filters, fast-charging batteries, highly durable solar cells, and precise biosensors, to name a few technologies.
Higgs boson discovered
The Higgs boson is a small particle, with a mass just 150 times that of a proton, but its scientific impact is colossal. First predicted in 1964 by researchers, including its namesake Peter Higgs, the particle existed only in theory for decades as the hypothetical crown jewel of the standard model of particle physics, which describes the universe’s fundamental forces and elements. The particle is associated with the Higgs field, a quantum field that spans the universe and gives all elementary particles their mass.
But the detection of the Higgs boson remained out of reach until the construction of the Large Hadron Collider at CERN, which is the biggest and most powerful particle accelerator in the world. In 2012, CERN finally confirmed detection of the particle, ending a decades-long search and corroborating the standard model. The achievement earned the 2013 Nobel Prize in Physics.
Gravitational waves detected for the first time
Albert Einstein first proposed the idea of gravitational waves, ripples in the fabric of spacetime, in 1916, but he was doubtful any instrument would ever be sensitive enough to capture them. After nearly a century of grit, scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) finally cinched that dream with the first detection of a gravitational wave, forged by the merger of two black holes about 1.3 billion years ago.
As of 2025, hundreds of gravitational waves have been captured by LIGO and other detectors, opening a whole new window into the universe.
“It's not only a different way of looking at the universe, but it’s a technology that couldn't be imagined 100 years ago,” says Córdova. “There's a lot more to go, but it's just opened up so many discoveries.”
For example, gravitational waves have revealed unexpectedly massive mergers and confirmed several theories about black holes put forward by luminaries like Stephen Hawking and Roy Kerr. The achievement also earned the 2017 Nobel Prize in Physics.
Fusion power briefly achieves net gain
The Sun, and all other stars, produce voluminous light and energy by fusing atoms together in their cores—a process called nuclear fusion. Harnessing this literal star-power could potentially supply the world with abundant clean power.
While fusion power is still far from being realized, it has reached a major milestone. In 2022, scientists in the U.S. Lawrence Livermore National Laboratory demonstrated net energy gain, in which a fusion reaction produces more energy than was directly fed into the experiment. The success was repeated in 2023.
These results represent a physics breakthrough—a fuel that generates more energy than it directly absorbs. However, the experimental apparatus where these net gains were performed still burns way more power than the fuel’s output, so practical fusion plants are still a distant goal.
(Squeeze inside a fusion reactor with a Nat Geo photographer.)
First interstellar objects discovered
In 2017, astronomers discovered the first known interstellar object—an object that originated from another star system—speeding through the solar system. Known as ‘Oumuamua, its strange properties have generated debate ever since (and no: it’s not aliens.). Two more interstellar objects, both clearly comets, have since been spotted: 2I/Borisov in 2019 and 3I/ATLAS in 2025.
The Vera C. Rubin Observatory, which began operations in 2025, is expected to spot many more of these fascinating travelers in the coming years.
Event Horizon Telescope creates the first image of a black hole
Organizing a photoshoot for a black hole is no easy feat, but the global collaboration that created the Event Horizon Telescope (EHT) got it done in 2019. By synchronizing radio telescopes all around the world—essentially creating one Earth-sized observatory—the EHT team was able to capture incredible visuals of the supermassive black hole at the center of the Messier 87 galaxy some 55 million light-years from our solar system.
Robots make it to the very farthest reaches of the solar system
Over the past 25 years, our robotic space explorers have, to channel Star Trek, boldly gone where no probe has gone before. Our spacecraft have now journeyed everywhere from the solar corona to the interstellar wilds.
NASA’s Voyager 1 became the first spacecraft to enter interstellar space in 2012; at the other end of the solar spectrum, the Parker Solar Probe has dared to dive seven times closer to the Sun than any previous mission.
NASA’s New Horizons probe also became the first spacecraft to flyby Pluto in 2015, while several missions—from Japan’s Hayabusa spacecraft to NASA’s OSIRIS-REx—have returned snatched samples from asteroids and returned them to Earth.
James Webb Space Telescope gives us the oldest ever look at the universe
On December 25, 2021, space enthusiasts around the world held their breath as the James Webb Space Telescope (JWST), the most powerful space observatory ever built, launched from French Guiana. From orbit about a million miles from Earth, JWST has peered into the dawn of the universe (discovering new mysteries therein), glimpsed the skies of distant exoplanets, provided a fresh look at objects in our own solar backyard, and produced mesmerizing views of our cosmos. With 100 times the power of the Hubble Telescope, JWST is our sharpest eye on the universe—and it’s just getting started.
Thousands of planets discovered orbiting other stars
Though the first exoplanets were spotted in the 1990s, it wasn’t until the 2009 launch of NASA’s Kepler telescope that the age of exoplanetary discovery really got rolling. Over its nearly decade-long run, Kepler discovered over 2,600 exoplanets—an astonishing haul that confirmed, at last, that planets of all kinds are common around stars in our galaxy.
Since Kepler retired in 2018, a new generation of planet-hunting telescopes—including JWST and NASA’s Transiting Exoplanet Survey Satellite (TESS)—have continued to shed light on the many tantalizing worlds beyond our solar system. We’ve discovered planets that rain metal, potentially habitable planets, and “rogue” planets that roam interstellar space. As of 2025, we’re at 6,000 confirmed exoplanet detections and counting.
We can now directly attribute weather disasters to climate change
Scientists have known for decades that humanity’s consumption of fossil fuels is causing global temperatures to rise, and therefore amplifying extreme weather events like heatwaves, hurricanes, and wildfires. But it wasn’t until 2004 that researchers specifically attributed the severity of a natural disaster to climate change the severity—in that case, the deadly 2003 heatwave in Europe.
This study marked the dawn of climate attribution, a field that isolates our own human contribution to Earth’s complex climatic and environment shifts. Since then, we’ve learned that climate change can raise the odds of a severe weather event, such as the 2019 European heatwave, and can also intensify these natural disasters. For example, human-driven warming was linked to intense rainfall in Hurricane Harvey and the exceptionally dry vegetation that fueled the 2025 Los Angeles fires.
(Here’s how researchers connected the L.A. fires to climate change.)
The deep ocean reveals how life might have started
The century started off strong with the 2000 discovery of the Lost City, a vast field of hydrothermal vents that are similar to environments where life might have first emerged on Earth. Since then, scientists have mapped hidden seamounts, probed mysterious seafloor ecosystems, and discovered countless weird lifeforms—including the first known animal to lay its eggs on vents.
Long lost archeological treasures found with lidar
Lidar, which stands for Light Detection and Ranging, is a remote-sensing method that bounces laser light off surfaces to create precise 3-D maps. This technique has become widely affordable and practical for archaeological surveys over the past two decades, leading to an avalanche of discoveries about bygone cultures and settlements.
For example, archaeologists have spotted hundreds of previously unknown settlements across Mesoamerica, while also revealing fascinating new structures at established sites like Angkor Wat in Cambodia. Lidar has been a game-changer in particular for regions covered with dense foliage or remote wilderness, like Mesoamerica and the Amazon basin, by peering through the canopies to spot ancient structures.
Polar shipwrecks re-discovered after more than a century
In 1845, an expedition led by Captain Sir John Franklin set off from Britain to search for the fabled Northwest Passage that could connect the Pacific and Atlantic Oceans through the Canadian Arctic. The expedition ended in horror and ruin; both its ships, HMS Erebus and HMS Terror were abandoned, and all the crew members died of disease and exposure.
Seventy years later, Ernest Shackleton set out to Antarctica on the polar ship Endurance, which the crew also had to abandon in the ice, though most of the sailors luckily survived the ordeal.
All three of these ill-fated ships have been re-discovered: Erebus in 2014, Terror in 2016, and Endurance in 2022. The amazing effort to locate the ships reflects advances in polar exploration, marine archaeology, and, in the case of the Arctic ships, the essential input and memory of Inuit communities, who had passed stories about the ships down for generations.
The human family tree got more branches
Our species, Homo sapiens, is the sole surviving human lineage on Earth, but many extinct members of our hominin family have been discovered, or are now better understood, since 2000. Homo floresiensis, discovered in 2003, lived on the Indonesian island of Flores some 50,000 years ago; these relatives have been nicknamed “hobbits” for their small stature.
First discovered in Africa in 2008 and 2015 respectively, Australopithecus sediba lived around two million years ago, while Homo naledi emerged around 300,000 years ago. Both revealed transitional states between earlier hominins and later lineages, including our own. So, while we are the last humans standing, we are far from the only ones to walk the Earth.
Ancient DNA extraction rewrites history
In addition to discovering the bones of new relatives, scientists have also pioneered the field of ancient DNA to probe their genetic relationships. The methods used to extract and analyze this ancient DNA were perfected in the past 25 years.
In 2010, for example, scientists reported the discovery of Denisovans, an archaic human lineage that went extinct around the same time as the Neanderthals, using mitochondrial DNA from a finger bone. The remains of the first ancient human hybrid, the offspring of a Neanderthal and Denisovan, was discovered in 2012 and confirmed with ancient DNA in 2018.
Ancient DNA has also revolutionized our understanding of modern human history by reconstructing the lineages of various cultures in recent millennia and even tracking the spread of infectious diseases through these bygone peoples.
Dinosaur feathers discovered
The discovery of the first dinosaur soft tissue in 2005, along with many preserved samples of feathers, have confirmed earlier theories that even heavyweights like Tyrannosaurus rex likely sported feathers, perhaps with colorful displays. This updated decades-old assumptions that dinosaurs were scaly creatures.
Impeccably preserved Ice Age mummies found in permafrost
As global temperatures rise, the remains of many extinct Pleistocene “Ice Age” creatures are melting out of once-frozen soil called permafrost. Though permafrost thaw is a very concerning trend, the silver lining is the surfacing of exquisitely preserved mummies, such the 40,000-year-old mammoth and the 28,000-year-old cave lion cub "Sparta." Scientists have even managed to revive a roundworm that was frozen in permafrost 46,000 years ago, which may well be the world’s most impressive cryo-nap.
(The world’s first saber-toothed cat mummy has been found in Siberia.)
These tentative discoveries will be a big deal—if confirmed in the coming years.
A possible ninth planet in the solar system
In 2016, astronomers Mike Brown and Konstantin Batygin speculated that a hypothetical giant world might lurk about 20 times farther from the Sun than Neptune, a tantalizing claim that might explain the strange movements of objects observed in the far reaches of the solar system.
Ever since, scientists have been searching for any sign of this so-called Planet Nine, which is estimated to be anywhere from five to ten times as massive as Earth. The newly operational Vera C. Rubin Observatory may well shed light on this mystery in the coming years. As a fun twist, Mike Brown is also the astronomer who led the charge to demote Pluto to a dwarf planet. If Planet Nine is ever discovered, Brown will have the rare honor of having helped to both subtract and add a ninth planet to the solar system.
Google claims quantum supremacy
Quantum supremacy, also known as quantum advantage, is the threshold at which a quantum computer can perform a specific task that a classical machine would not be able to complete in any practical timeframe. Google, in partnership with Oak Ridge National Laboratory and NASA, claimed that they had achieved this supremacy in 2019 after its Sycamore quantum processor performed a sampling task in 200 seconds that would take a classical supercomputer about 10,000 years.
This early claim on supremacy has generated debate and pushback, so it remains to be seen whether it will be considered the inaugural example of quantum supremacy.
Dark energy may not be a constant
For decades, scientists assumed that the universe was expanding at a constant rate of acceleration, with “dark energy” being the term given to this constant. However, new results from the Initial Dark Energy Spectroscopic Instrument (DESI) in Arizona, which started surveying the sky in 2021, suggest that the universe’s accelerating expansion has actually been slowing down.
This tantalizing surprise hints that dark energy is an evolving force, and may not be a constant at all, upending one of the core assumptions of the standard model of cosmology.
New treatments and preventions for neurological disorders
An estimated 50 million people worldwide suffer from Alzheimer’s disease, a neurological disorder that causes memory loss, confusion, mood swings, and other symptoms that severely disrupt life. But a new class of recently FDA-approved drugs called anti-amyloid therapies hold some promise for treating this disease by targeting and removing amyloid plaques from the brain, which can slow its progression. Because these drugs have only been available to patients for a few years, their long-term efficacy is still being evaluated.
In addition, after a connection between the Epstein-Barr virus and multiple sclerosis was discovered, scientists renewed hope they could better treat or even prevent the autoimmune disease that gradually weakens nerve communication between the brain and body.
Now, a new clinical trial in the U.K. is testing this hypothesis with a vaccine.
Possible biosignatures discovered on Mars, Venus, and exoplanets
Science has entered a new phase in the search for alien life with the detection of multiple possible biosignatures inside our solar system, and beyond it. In 2019, a team reported the presence of the chemical phosphine on Venus, which could have a geological or biological source. Just within the past year, a team reported a possible biosignature in the skies of an exoplanet (the study’s results are still being debated), while NASA’s Perseverance rover discovered potential signs of ancient microbial life on Mars.
None of these discoveries are remotely “slam dunk” evidence of alien life, and all three have generated controversy—which will likely be the norm as similar discoveries rack up in the coming years. But though these results remain inconclusive, they demonstrate that the search for extraterrestrial life is starting to become grounded in a growing body of empirical evidence, not just theory and speculation.
What will the next 25 years bring?
It’s hard not to wonder what scientific advances the next 25 years will bring. How will new technologies—like AI, green energy, or quantum computing—reshape our lives and world by 2050?
Nobody knows, but Doudna has a recommendation.
“What strikes me most about the past 25 years is how many breakthroughs trace back to fundamental research that had no obvious practical application at the time,” she says. “CRISPR is a perfect example: my collaborators and I were studying how bacteria fight off viruses and that curiosity-driven work led to a technology now transforming medicine, agriculture, and even approaches to fighting climate change.”
Scientific momentum needs to be sustained, but even in the best conditions, there still will be challenges. “Getting these tools to the people who need them most—that's the harder problem we're still solving.”
