The year is rapidly drawing to a close, so what better time to reflect upon some of the greatest scientific discoveries and achievements of 2015? It’s been a big one, to say the least, so this mind-boggling list of our top picks is guaranteed to get your science senses tingling.
Liquid Water On Mars
Back in September, NASA promised us they had a big announcement up their sleeve, and boy did they deliver. On the 28th of that month, the agency presented to the world evidence of salty water flowing on the surface of Mars.
This evidence came in the form of recurring slope lineae, basically dark gullies streaking down the sides of craters, which were picked up by the Mars Reconnaissance Orbiter. Not only were the probe’s instruments able to show that these lines change seasonally, fading during the cooler months, but they demonstrated evidence for three different hydrated salts, suggesting that flowing brine is likely to blame.
But perhaps we shouldn’t take this as evidence that liquid water is plentiful on the Red Planet. A new study has suggested that features called Martian gullies, although not recurring slope lineae, are in fact due to dry ice, and not salty water. This could indicate liquid water might not be as abundant as hoped.
The dark streaks shown are recurring slope lineae. NASA/JPL/University of Arizona
A New Human Ancestor
Again in September, it was with great pleasure that scientists welcomed to the world a new addition to our family tree: Homo naledi. Thought to have lived around two million years ago, this newly discovered species was represented by more than 1,500 fossil fragments, from at least 15 individuals, all from one single cave in South Africa.
And it was these circumstances that led to perhaps the most significant hypothesis surrounding the find: This species was deliberately disposing of its dead in an isolated area, away from the elements, millions of years ago. Prior to this discovery, this ritualistic behavior was thought to be unique to our own species. This speculation came after other possibilities were ruled out, such as the bodies being dragged in by predators, or washed in by water.
The leader of the expedition, Lee Berger, hinted that the discoveries were far from over in this cave system, so perhaps 2016 will bring even more excitement.
Homo naledi. cc John Hawks_Wits University
New Horizons Arrives At Pluto
Our favorite dwarf planet is really, really far away from us. Billions of kilometers at its furthest point, in fact. But thanks to NASA’s New Horizons spacecraft, which swung by Pluto back in July, we now have some spectacular, close-up images of the icy world, which turned our ideas of this distant object on their heads.
Not only did the rugged surface show off features that were totally unexpected, such as clusters of mountains and dunes, but it turns out that the dwarf planet may even sport several volcanoes that may have once spewed out ice instead of lava. Called cryovolcanoes, these putative features are thought to have been active in the recent geological past, but more research is needed before their identity is confirmed.
New Horizons’ instruments weren’t only pointed at Pluto, though; the probe has also told us stories of the dwarf planet’s moons, like Charon, Nix, and Kerberos. But the discoveries are still far from over, as data will continue to pour in until at least mid-2016. And even that doesn’t mark the probe’s end, as it will eventually set its eyes on a new target, the Kuiper Belt object 2014 MU69, in 2019.
This view shows what you would see if you were approximately 1,800 kilometers (1,100 miles) above Pluto’s equatorial area. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Nuclear Fusion Reactor Switched On
At the hearts of stars, under temperatures as unimaginable as 15 million degrees Celsius (27 million Fahrenheit), atoms of the lightest elements – hydrogen and helium – smash together and fuse, forming heavier elements and releasing vast amounts of energy during the process.
What if we could replicate this here on Earth? It could potentially provide us with an almost unlimited supply of green energy, an extremely attractive proposition in light of finite fossil fuels and climate change. We’re not there yet, but scientists are certainly making progress: In early December, engineers from Germany’s Max Planck Institute fired theirs up, and announced they managed to successfully form and suspend helium plasma.
Ultimately, they need to be able to sustain hydrogen plasma, but working with helium is an important stride in the right direction.
Wendelstein 7-X (W7X) reactor. IPP/Thorsten Bräuer
Historic Climate Deal Reached
Among all these amazing discoveries, 2015 has been a depressing one for climate. Not only have we been continually surpassing average monthly temperatures, but some months have absolutely smashed temperature records, with October being the most notable. This year is set to be the warmest on record, but 2016 is predicted to be even worse.
Still, while these broken records are by no means cause for celebration, there has been reason for cheers. After weeks of talks and negotiations, the world finally came together to form a historic climate change deal in Paris. Agreed by 195 nations, warming is to be limited to below 2°C (3.6°F) by 2100, although the plan is to keep it as close to 1.5°C (2.7°F) as possible. That’s because many low-lying, developing nations could face dire consequences at anything above this, such as increases in natural disasters and devastating sea level rises.
Eiffel tower illuminated in green to honor the talks. Image credit: Yann Caradec/ Flickr; CC BY-SA 2.0
Gene Editing Comes To The Fore With CRISPR
Gene editing is about much more than creating designer dogs and teacup pigs (although both have been achieved this year). Not only have scientists managed to successfully modify the genomes of human embryos, igniting a discussion on the ethics of this subject, but a team also managed to use the technique to save the life of a baby girl whose aggressive leukemia failed to respond to drug treatment. Although it hadn't yet been trialled in humans, doctors were given special permission to edit donor cells so that they hunted down and attacked the girl's cancerous cells.
All of these stories have something in common: CRISPR, a tool we borrowed from bacteria. This allows scientists to home in on target sequences of DNA and subsequently nick them extremely precisely, enabling genes to be modified, removed, or even inserted. Ultimately, it is hoped that this well-established technique could help us eliminate hereditary diseases, but scientists and politicians will have to be assured of its safety before human DNA editing becomes widespread.
Should scientists be allowed to edit the genomes of humans? Image credit: Sergey Nivens/Shutterstock
Firefighter Gets A New Face
One of the most amazing stories from the last 12 months was that of Patrick Hardison, a 41-year-old firefighter from Mississippi who suffered severe facial injuries when a burning roof fell on him in 2001.
His face was left deformed and unrecognizable but this year, in a groundbreaking procedure, he was given the face of a brain-dead man called David Rodebaugh, who had been left in a vegetative state after a cycling accident. The match was made based on compatible height, weight, skin tone, hair color, and blood type.
The operation took 26 hours to complete and, several months later, Hardison's body has not rejected the new skin. He will soon be able to eat normal food and have drastically improved speech, giving him a completely new lease of life.
Patrick Hardison's life has been transformed by the operation (before, left, and after, right). NYU Langone Medical Center
Large Hadron Collider Finds A Pentaquark
First predicted to exist in the 1960s, the pentaquark had been long sought after by scientists. And a detection was finally made in 2015, thanks to CERN's Large Hadron Collider.
Made of five quarks – the smallest subatomic particles we know to exist – the pentaquark could help explain exactly how ordinary matter is made. It hints at a new type of matter, with the particle existing beyond our current knowledge of subatomic physics.
There is still much work to be done on the pentaquark. But there's little doubt that this was one of the major scientific breakthroughs of 2015.
How will the pentaquark affect our knowledge of subatomic physics? CERN/LHCb Collaboration
It truly has been an amazing year for science. Here's to 2016 being even better!
2
