Top 20 Biggest Scientific Discoveries of the Century So Far

The average human cell is made up of 23 chromosomes, each containing hundreds to thousands of genes. In combination, these 23 DNA molecules serve as the instruction booklet for building a human being. In 2000, through the combined effort of a global community of researchers, we successfully mapped out a rough draft of the human genome, before completing a final draft in 2003. This took a colossal effort spanning over 10 years and remains, to this day, the single largest collaboration in the history of biology. Thanks to this groundbreaking work, we now have a fundamental understanding of our genetic makeup and DNA. Essentially, the Human Genome Project has given future generations of scientists the keys to unlock many mysteries of the human body.

Of the many strange and wondrous things that make up our universe, black holes are without doubt among the most captivating. But until recently, we’d only ever observed their effects, rather than the black holes themselves. In 2019, we finally got to gaze into the abyss. That year, the Event Horizon Telescope (actually a collaboration of radio telescopes around the world), brought us the first ever image of a black hole. Larger than our own solar system, it’s located at the heart of the Messier 87 galaxy, 53 million lightyears away. The image is an accomplishment that many once believed to be impossible - even within the scientific community.

The history of this substance can be traced all the way back to 1859, when English chemist Benjamin Collins Brodie first made observations suggesting its existence. But it would take almost 150 years before graphene was properly isolated. The honor of having made this breakthrough goes to physicists Andre Geim and Konstantin Novoselov, who cracked the graphene mystery in 2004. A monolayer of carbon atoms, graphene is a nanomaterial that’s at once harder than a diamond, but somehow also more flexible than rubber; it’s at once incredibly strong, incredibly light, and conductive. In short, it’s something of a miracle substance, and while its potential has yet to be fully realized, the theoretical applications could revolutionize many fields, from space travel to home electronics.

After sequencing human DNA, scientists have been able to do similar things for other species; and every genome we sequence gives us a better understanding of the world we live in today. But what about the distant past? Using bones from Neanderthals, a team based out of the Max Planck Institute for Evolutionary Anthropology in Germany mapped out the genome of our distant cousins. They published an initial draft in 2010, followed by a detailed full-coverage genome map in 2013. With this information, we’ve gained invaluable insights into our own evolutionary history - even learning that there was interbreeding between Neanderthals and our own species. Theoretically… this could also be used one day to bring Neanderthals back from the dead.

As you may have heard… since 2006, Pluto has been downgraded to the status of a “dwarf planet”. Upsetting, right? Thankfully, Pluto needn’t feel lonely. The year before it got demoted, in 2005, a team of scientists working at California’s Palomar Observatory discovered a previously undocumented object in our solar system. Initial estimates of its size were so big that there was talk of it being considered a 10th planet! Ultimately, it was categorized as a “dwarf planet” like Pluto due to its size, but that label disguises its significance. Eris represents something much larger: the endless discoveries to be made in space, even relatively close to home.

Much to the disappointment of alien enthusiasts, another decade has come and gone without the discovery of intelligent extraterrestrial life. Be that as it may, various off-planet findings did provide ample cause to hope. A European Space Agency mission to comet 67P/Churyumov–Gerasimenko found that it carried ingredients essential for the origin of life, including an amino acid. This has encouraged speculation that the initial sparks for life on Earth may have originated elsewhere. Furthermore, NASA confirmed the presence of organic compounds in the water vapors of Saturn’s moon, Enceladus - further bolstering the hope that life could exist in the moon’s subsurface ocean.

Once, not so long ago, we spoke of artificial intelligence as if it were a concept limited to the distant future and works of science fiction. But in reality, we’re already living in the age of AI. In 2016, the Google AI program, AlphaGo (which is part of DeepMind) bested the world champion of Go in 4 out of 5 matches. It’s a testament to the very real potential of computer learning, not to mention the superior processing power of artificial intelligence compared to the human brain. And this is by no means a one-off. Over the past decade, various AI programs have been beating some of the world’s top players in a variety of games, including poker, jeopardy and even Starcraft II!

Ebola outbreaks are deadly and devastating - especially when affected communities have inadequate access to medical treatment. In 2015 however, field trials of a vaccine developed in Canada and licensed to Merck proved hugely successful. In 2019, the vaccine was officially approved in Europe, with the American Food and Drug Administration soon following suit in mid-December the same year. The ebola vaccine wasn’t the only breakthrough of its kind however; we also saw the rollout of a malaria vaccine that performed similarly well in trial applications, as well as major improvements in HIV prevention and treatment.

Admit it… based on all the hubbub about DNA when we were kids, a LOT of us expected cloned dinosaurs by now. Well, although a baby dino petting zoo seems unlikely to open soon, we have gotten closer in the last few decades. In 2005, a team from North Carolina State University found a 68 million year old dinosaur femur, complete with blood vessels and cells. While the fossil is informative in its own right, it represents an even bigger discovery: soft tissue and proteins can survive within bones for millions of years. This flies in the face everything we previously thought we knew on the subject, and encourages us to seek out more soft tissue.

Dinosaurs, larger-than-life though they might be, are easy to wrap your mind around as a concept. This next breakthrough… not so much. But that doesn’t make it any less groundbreaking. During the Big Bang, the universe expanded from a hot and dense initial state, cooling over time. This process left a residual sign in the form of Cosmic Microwave Background Radiation, first discovered in the 1960s. In the early 2000s, a US team led by astrophysicist John Carlstrom managed to obtain incredibly detailed measurements of this radiation. Their data added support to the idea that the universe underwent a period of exponential expansion, and for the existence of dark matter and dark energy.

NASA gets a lot of flack for not doing more manned missions to space. But the simple reality is that the cost of sending people into space and getting them home safely again is astronomical. Elon Musk’s company SpaceX, however, has developed reusable rockets that should make space travel far more affordable heading into the next decade. In December of 2015, after a few failed attempts, SpaceX achieved its goal by successfully landing the craft in an upright position. In 2017, they achieved another milestone by reusing a recovered orbital class rocket. And with the first crewed launch of their Dragon craft scheduled for 2020, commercial space travel will soon become a reality.

These cave paintings might not set new standards for realism, but their age is mind-blowing. Discovered some 50 years ago in the Maros caves on the Indonesian island of Sulawesi, this ancient art was finally dated in 2019. Having been produced over 40,000 years ago, they can be counted amongst the oldest known works of art found anywhere on Earth. Much of the images have been worn away by the passage of time, but rough outlines of hands and animal illustrations remain. In terms of age, they’re rivalled only by the Chauvet Caves paintings of southern France discovered in 1994. Their identification forces us to reevaluate the history of human development in relation to representational art around the world.

Why, you might be thinking, would scientists choose to make synthetic bacteria? Though bacteria gets a bum rap and is associated with everything from food going bad to illness, bacteria is also essential to digestive health; gives us fermented foods like cheese; and plays a key role in the world ecosystem. From a scientific perspective, bacteria is also about as simple an organism as you can find - or make. In 2010, pioneering geneticist Craig Venter and his team wrote an original bacterium genome and brought it to life in a cell. Though such a breakthrough could lead to biological weaponry, it also paves the way for designer bacteria that helps us do everything from generating biofuels and recycling plastics to creating new vaccines.

Already, the 21st century has welcomed many new members to our family tree. 2003 brought us Homo floresiensis, nicknamed the Hobbit. The 2010s kicked off with another new species, Australopithecus sediba, which lived 2 million years ago. That same year, DNA was extracted from a tiny pinky bone that revealed a genome of an entirely new branch of ancient relatives, the Denisovans. Like Neanderthals, they’re thought to have been an offshoot of Homo heidelbergensis - a species that might also be our own direct ancestor. The Denisovan genome shows that they interbred with both humans and Neanderthals. Other new species include Homo naledi and Homo luzonensis - adding even more distinct faces to an already complex family tree.

As we mentioned, recent decades have been especially exciting for anyone interested in DNA. Researchers have managed not only to create synthetic genes, but also to edit DNA using the Crispr-Cas9 system. The possible applications are endless, although they also raise serious ethical questions. In 2018, Chinese researcher He Jiankui genetically modified twins in an attempt to make them HIV-resistant. The affair led to an international outcry, and new regulations on gene-editing. However, disease resistance is a real possibility of the technology; others include reverse engineering extinct species, cures to various genetic illnesses, and creating more durable crops. For those who look to works of science fiction as a roadmap to the future, Crispr is being heralded as the key to mastering humanity’s genetic destiny.

There are few forces more shrouded in mystery than dark matter - thought to make up 85% of our entire universe. The history of this concept can be traced back all the way to theories of Lord Kelvin, first expressed in 1884. The problem is, despite dark matter making up the majority of… well, everything, it’s not observable. So for decades, we’ve had no choice but to accept the existence of dark matter based on how it affects forces in our universe that are observable, like gravity. In 2006, however, the NASA Chandra X-ray Observatory witnessed two clusters of galaxies colliding, and the resulting display provided direct evidence to support the existence of dark matter.

Our search for life beyond planet earth has taken on many forms, but arguably the most promising approach has been in identifying potentially habitable planets - those with earth-like characteristics that could have given rise to intelligent life. Throughout the 21st century, we’ve found thousands of new planets beyond our solar system, but arguably the most exciting is Kepler 452b, the closest to an “earth-twin” discovered to date. It’s been said that, if we could reach it - which is unlikely with 1,400 light-years separating us - life there would be possible, though given the extreme gravity, colonists would experience notable physiological changes over time, including in bone strength.

Like black holes, gravitational waves have been theoretical for many years. It wasn’t until 2015 that their existence was finally confirmed. In short, gravitational waves are ripples caused by the movement of objects with sufficient mass through space. And that’s exactly what the LIGO and Virgos observatories in the U.S. and Europe respectively were able to observe directly (for the first time) following what has been identified as the distant collision of two black holes. What does this mean? Well, for starters, it’s the long overdue confirmation of an element of Einstein’s Theory of Relativity that even Einstein himself doubted. More importantly, however, gravitational waves are a measurable force that allows us to explore and understand previously unfathomable depths of space.

It doesn’t get much more monumental than this! In 2001, Astronomer Wendy Freedman earned herself a place in the history books when she helped rewrite them all! Freedman served as the co-leader of the Hubble Space Telescope Key Project, which had given itself the formidable task of measuring the rate at which the universe is expanding. Using this information, they were able to provide the most accurate estimate of the age of the universe offered up until that point in time. They estimated it at 13.7 billion years, with an uncertainty factor of 10%. In 2012, a NASA program supported this theory when data from its Wilkinson Microwave Anisotropy Probe project suggested an age of 13.772 years.

There’s something especially satisfying about a scientific discovery that’s been long in the making. First theoretically predicted in 1964, the Higgs boson (also known as the God Particle) was finally scientifically proven in 2012 using the Large Hadron Collider at CERN. And with the successful identification of this subatomic particle, the scientific community got a much clearer and definite picture of reality as we know it - a confirmation of why matter has mass. While that might seem like a very minor piece of the puzzle that is our universe, the Higgs Boson is . . . well, at the very heart of the matter. In the case of the standard model of particle physics, it was THE missing piece.