Hank Green: 2013 has been an awesome year for science.  It began with one of the greatest discoveries ever made in physics and ended this month with a mind-blowing discovery about the history of the human species.  I'm Hank Green for SciShow News with three of the greatest discoveries of 2013.  

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Hank: You know it's gonna be a good year when it starts off with the discovery of what makes us have mass.  On March 14th, physicists with CERN, the European organization for nuclear research, announced their confirmation of the particle they suspected had been discovered in the summer of 2012.  After two years of smashing trillions of photons together in the largest particle accelerator ever, they'd succeeded in generating enough energy to conjure up the Higgs Boson.  According to theory proposed by Francois Englert and Peter Higgs in 1964, a field called the Higgs Field permeates the universe, and when particles interact with this field, we perceive that interaction as mass.  The Higgs Boson was thought to be a physical indicator of that field's existence, so since mass and energy are equivalent, generating enough energy could theoretically turn a particle from the Higgs field into an observable mass-having particle, if only for an instant.  CERN physicists did the math to predict how much mass a particle would have and how it would decay, and in late June last year, when they finally produced a particle with the predicted mass 126 times the size of a proton, they figured it was their guy.  Still, it took nine more months for some of the greatest minds in the world to calculate whether it decayed at the exact pattern they predicted and it did.  In addition to corroborating the theory of why everything we think of as 'stuff' has mass, finding the Higgs also helps fill in some important gaps in the standard model of physics, instead of assumptions that we have about how the universe works.

And what could top a discovery like that?  Well, probably nothing short of proof of past life on Mars.  Which Curiosity didn't do.  At least yet.  My favorite rover has been probing Gale Crater since it landed there in August 2012 looking for evidence that Mars once had life, or may even now be able to sustain it.  And this year, they discovered plenty of evidence of one of life's favorite things, water.  In February, it sent us images of ancient dried up stream beds and took the first ever sample from another world, drilling into a rock dubbed 'Rocknest'.  Not only was Rocknest found to be rich in sulfur, nitrogen, hydrogen, oxygen, phosphorus, and carbon, the so-called six life sustaining elements, it was made out of mudstone, a type of stone that only forms in wet, non-salty, pH neutral environments.  Basically, nice fresh drinkable water, the kind of stuff you want coming out of your tap.  

Then, in September, Curiosity took its first scoop of soil and found it to be 2% water by weight, which is really high.  Because Mars is super windy, it's like a giant mixer, so scientists think that this soil sample is representative of the entire planet.  NASA experts say that this means that theoretically future explorers may be able to get all the water they need just by heating up some soil.  

And then, earlier this month, Curiosity released another load of data that reinforced February's results in a new location, even more features formed by water and a new sample of mudstone from a rock called 'Sheepbed'.  The prevalence of this mudstone in Gale Crater led researchers to conclude that it was once a giant lake.  And the complexity of its water shaped formations make them think that the lake was around for a long time, maybe hundreds of thousands of years.  So, a banner year for SciShow's favorite robot explorer and something tells me Curiosity will continue to surprise us in 2014.  

Finally, back on Earth, we discovered new members of our evolutionary family and pulled off the monumental task of sequencing the entire genome of a Neanderthal.  Now, we've only done this for 69 living human beings, but anthropologists from the Max Planck Institute in Germany were able to do it using material from a 280,000 year old toe bone discovered in a Siberian cave.  Having sequenced the genome, their work is far from over.  They're now comparing its contents with our own genome and those of other ancestors to learn about the changes that took place along our evolutionary path.  The results will be available within the next year, so maybe I'll be telling you about them when we talk about the greatest discoveries in 2014.  

And on top of that, an even older human ancestor was identified this month.  Human remains were found in a cave in Northern Spain back in the 90s, but it wasn't until this year that anthropologists looked at its mitochondrial DNA and realized the remains were 400,000 years old, making it the oldest DNA from a human-like species ever recovered.  Some suggest that the specimen is a member of Homo Heidelbergensis, while others think it was a Denisovan, a close relative to Neanderthals whose remains have only been found in Asia.  But until we know more about its genetic makeup, nobody can be sure what kind of human ancestor it is.  Sometimes, the most intriguing discoveries are ones that provide us not with new answers, but with new questions.  

So to recap, in 2013, we discovered why we have mass, which is so fundamental that it sounds absurd to say.  That there was once and still is lots and lots and lots of water on Mars.  And we learned as much information as we possibly could about any individual, living or dead, from a 280,000 year old toe, and possibly discovered a whole new kind of person.  So, what discoveries shocked or impressed you this year?  Let's talk about it in the comments below, and don't forget to follow us on Facebook and Twitter, and go to YouTube.com/SciShow and subscribe.  And thanks to all our Subbable subscribers, who literally make SciShow possible.  To learn how you can subscribe and what neat-o customized perks you can get, go to Subbable.com now.

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