The 5 most groundbreaking scientific achievements of the decade

As we are fast approaching the futuristic-sounding year 2020, it’s a time for reflection on the past decade. The world has seen some pretty major scientific achievements in the last 10 years, as discoveries and developments decades in the making were finally realized. New Atlas rounds up five of the most ground-breaking, history-making milestones of the 2010s.

The Higgs boson

In 2012, a new elementary particle was discovered at CERN that caught the attention of the world – even those who may not normally be across particle physics news. But that’s because this was no ordinary particle. This newcomer was none other than the Higgs boson.

While it may have captured the public imagination due to its dramatic but inaccurate nickname, “the God particle,” the Higgs boson was an incredibly exciting find for a number of reasons.

It was the final elementary particle predicted by the Standard Model of particle physics, it gives mass to other elementary particles, and scientists had been hunting for it for almost 50 years.

Prior to the 1960s, the Standard Model had a bit of a problem: according to its predictions, elementary particles called bosons should have no mass – but observations show they do. In 1964, three teams of scientists independently came up with similar mechanisms for how they gain mass.

According to the prevailing idea, a quantum field uniformly pervades the universe. Bosons feel this field, which slows them down and in the process, gives them mass. This field would be mediated by a brand new boson that had yet to be discovered – and it wouldn’t be for another 48 years.

The predicted field, mechanism and boson all eventually came to be named after Peter Higgs, one of the physicists who first proposed it.

And sure enough, in 2012 scientists at CERN’s Large Hadron Collider finally found a particle consistent with the predicted properties of the Higgs boson. Further research later confirmed it to be the elusive Higgs, and two of the researchers responsible for proposing it – Higgs himself and Francois Englert, a physicist on another team – were awarded the 2013 Nobel Prize in Physics.

In the years since, further experiments at CERN showed that all measurements of the Higgs boson, including its spin, parity, mass and interactions with other particles, agreed with the predictions of the Standard Model.

Closing a half-century hunt for the Holy Grail of particle physics, the Higgs boson is easily one of the most important scientific achievements of the decade.

CRISPR gene-editing

The ability to edit the genes of living humans and other organisms has been a staple of science fiction for decades – and this decade, it became a reality. The CRISPR gene-editing system is poised to revolutionize medicine, potentially helping us fight the big ones like cancer and HIV, as well as tackle non-health problems. But of course, it’s not without its controversies.

Clustered regularly interspaced short palindromic repeats (CRISPR) is a family of DNA sequences naturally used by bacteria as a self-defense mechanism. In recent years scientists realized they could co-opt this mechanism as a tool for genetic engineering, by combining CRISPR with a guide RNA sequence and an enzyme, usually Cas9.

When used in cells or living organisms, the guide RNA directs the tool to the desired section of DNA, where the Cas9 enzyme neatly cuts it. That can be used to snip out troublesome genes – such as those that cause disease – and insert new, beneficial ones.

So far, this technique has shown promise in fighting many different diseases, including traditionally tricky ones like cancerHIVmuscular dystrophyprogeria, and genetic forms of blindness and heart disease.

But CRISPR’s potential extends beyond editing ourselves. We can edit plants to make crops with better yields or nutrition, edit insects to stop them spreading disease, or edit pigs to grow human organs for transplant.

Of course, as promising as CRISPR seems, the tool raises ethical issues that are still in the process of being addressed. Studies have suggested that CRISPR raises the chances of a cell developing cancer down the track, and could cause unintended mutations throughout the genome. These results are hotly debated.

It all came to a head in November 2018, when Chinese scientists announced the birth of twin girls as the world’s first CRISPR-edited human babies. Professor Jiankui He and his team injected the CRISPR machinery into the embryo, deleting a gene known as CCR5. In doing so, the girls should develop an immunity to HIV.

The problem is the experiment was conducted largely in secret, sidestepping years of considered debate about ethics. Some scientists pointed out that the function of CCR5 is poorly understood, and deleting it could make the girls more susceptible to common illnesses like the flu.

After this reckless move, calls have been made for a moratorium on human germline editing until these ethical questions can be sorted out.

Despite this, CRISPR trials in humans are still going ahead – just not in embryos. They began in China in 2016, in attempts to fight lung cancer, but results have yet to be published. Two trials kicked off in the US in 2019, with one targeting three types of cancer and the other sickle cell disease, with extremely promising early results.

It may have had a rocky start, but CRISPR gene-editing will likely go down in history as one of the most important breakthroughs in medicine, as well as for uses we haven’t even considered yet.

Gravitational waves

In 2015, physicists detected ripples in the very fabric of spacetime as they washed over Earth after traveling more than a billion light years. This confirmed a prediction made by none other than Albert Einstein a century ago.

When Einstein put forward his general theory of relativity in 1916, it implied that certain events involving objects with huge masses would generate shockwaves in spacetime itself – a phenomenon that came to be called gravitational waves.

Although they’re created by some of the most energetic events in the universe, by the time these waves reach Earth they’re only warping reality by less than the nucleus of an atom. That, of course, made them impossible to detect for almost 100 years – until technology finally caught up.

The technology responsible is the Laser Interferometer Gravitational-wave Observatory (LIGO), housed in two huge facilities in Louisiana and Washington. Each of these twin detectors is made up of two 4-km-long (2.5-mi) tunnels in an L shape. Extremely precise instruments watch over lasers beamed down these tunnels for minuscule disturbances in the beams, which can be attributed to gravitational waves washing over the facility.

And sure enough, on September 14, 2015, both LIGO detectors picked up their first-ever signal. The waves were produced in a collision between two black holes about 1.3 billion light-years away.

Dozens of signals have poured in since that first detection, picked up by LIGO as well as the Virgo facility in Italy, which fired up in 2017. Most have been the result of two black holes merging, but others have included a black hole swallowing a neutron star, and two neutron stars colliding.

It’s that lattermost scenario that gave us the most impressive fireworks show. Soon after one gravitational wave detection in 2017, observatories all around the world detected a whole host of electromagnetic signals from the same source, including light waves, a gamma ray burst, X-rays, and radio waves.

For solving a century-old mystery, the 2017 Nobel Prize in Physics was awarded to physicists Rainer Weiss, Kip Thorne and Barry Barish for their roles in the first detection of gravitational waves.

This isn’t the end of the story either. LIGO received an upgrade in April 2019, with future works planned to make it even more sensitive. The KAGRA observatory in Japan is also due to join the hunt in December. Together, quieter and more distant events can be picked up, unlocking ever more mysteries of the cosmos.

The exoplanet boom

Over the course of human history, we’ve continuously zoomed out to get a wider view of our place in the universe. Our world expanded from one continent to the entire Earth. Then we realized Earth isn’t the center of everything but just one planet of several orbiting the Sun. Eventually we discovered that even our solar system isn’t special, but one of countless such others. And this decade, we got our first real look at just how many others are out there.

The first few exoplanets – a planet orbiting a star other than the Sun – were discovered back in the 1990s, but things didn’t really pick up until the Kepler Space Telescope launched in 2009. This observatory was designed to watch 150,000 stars simultaneously, monitoring how often their light dimmed. If a regular pattern was seen, it suggested a planet was passing between the star and Earth.

Using this technique (known as the transition method), Kepler discovered over 2,600 exoplanets during its nine-year run. With help from other projects like HARPS, WASP, and TESS, that number has now grown to around 4,100. And we can infer a lot about what these worlds are like, by studying their atmospheres, composition, mass, what types of stars they orbit and how far away they are from those stars.

From this, we’ve learned about all sorts of incredible planets worthy of pulpy sci-fi stories. There are water worldspitch-black planets, and some hotter than stars. There’s a planet that’s just one giant diamond, and another with clouds made of rubies and sapphires. On others it rains rocks, glass or sunscreen.

But perhaps the most intriguing exoplanets of all are those that are more Earth-like. After all, these are the best candidates for us to finally answer the question, “are we alone in the universe?” And it turns out, potentially habitable exoplanets are fairly common.

One of the biggest hauls came in 2017, with the discovery of seven rocky, roughly Earth-sized exoplanets orbiting TRAPPIST-1. Three of these orbit within the habitable zone of the cool red dwarf star, and follow-up studies have shown there could be significant amounts of water present, making them some of the best contenders for habitable planets outside our solar system.

And we’re only just beginning. Plenty more projects are set to launch in the next few years, looking for new worlds or studying known ones in detail. We wouldn’t be too surprised if our next “decade in review” roundup includes the detection of extraterrestrial life.

The climate crisis

It may not be the good kind of achievement, but in the past decade we’ve broken more climate records than at any other point in human history. As the effects of climate change became more visible, the issue really came to the forefront of the public’s attention recently. New studies revealed the extent of the situation, and plans were set in motion to address it.

Overwhelming evidence shows a sharp uptick in atmospheric carbon dioxide (CO2) levels after about 1750 – not-so-coincidentally, around the time of the Industrial Revolution. As a direct result, surface temperatures around the world have been steadily rising ever since, with a particularly sharp uptick occurring in the second half of the 20th century. This, in turn, is leading to a variety of run-on effects.

While we’ve known about it for a long time, climate change has dominated this decade in science, as tangible consequences begin to flare up. According to NASA and NOAA, 2016 was the hottest year since records began in 1880, and the top five are the last five. July 2019 holds the record for hottest month.

Other recent studies have revealed just what this excess heat is doing to the world. A State of the Climate report for 2018 showed that extreme weather events like hurricanes, floods, droughts and wildfires are becoming more intense and common. Glaciers and polar ice are shrinking, and sea levels are rising.

In 2015, atmospheric CO2 climbed above 400 parts per million for the first time in about three million years. This also means the oceans are absorbing more of the gas, making them more acidic. The combination of warmer and more acidic waters saw Australia’s Great Barrier Reef hit with back-to-back bleaching events in 2016 and 2017. While it’s gone through similar trauma in the distant past, experts believe the current changes struck too quickly for the Reef to fully recover from.

But there’s still hope. In 2015, almost 200 countries signed onto the Paris Agreement, pledging to cut back on greenhouse gas emissions in order to keep global temperatures from rising 2° C (3.6° F) above pre-industrial levels. Reports from the Intergovernmental Panel on Climate Change (IPCC) say that to meet those goals, unprecedented changes will be needed in all aspects of society – and if 2019’s climate strikes and protests are any indication, society is warming up to the idea.