(Intro)

Throughout 2018, the scientific community said hello to a whole new generation of researchers and thinkers, but we also said some goodbyes.  There's no way we could make a complete list of the great minds we lost this year, but even mentioning a few of them can give you an idea of how varied their fields were and in one case, how the most important new knowledge doesn't always come from the scientists themselves.  So here are just a few of the contributors to science we lost in 2018 and why they will be sorely missed.

Stephen Hawking's friends nicknamed him Einstein as a kid but these days, his own name has started to become synonymous with genius and for good reason.  Born in Oxford in the UK, Hawking's intelligence was clear from an early age.  Despite his father's advice to study medicine, at 17, he accepted a scholarship to study physics in his home city at the University of Oxford.  After graduating, he continued his studies in cosmology at Cambridge, which is where he made what are arguably his greatest contributions to our understanding of the universe.

Hawking's research centered around black holes, areas of the universe with such a strong gravitational pull that beyond a certain point of no return, nothing can escape, or so we thought.  Hawking showed that over time, black holes actually could emit a certain type of energy, now known as Hawking radiation, and in the process, they would shrink.  One of the weird quirks of quantum mechanics is that pairs of particles just kinda spontaneously pop into existence, one made of regular matter and the other made of anti-matter, which has the opposite properties.

Normally, these pairs immediately destroy each other, because that's what happens when matter and anti-matter come into contact, but Hawking showed that if this happens at the edge of a black hole's point of no return, the anti-matter particle could be drawn into the black hole and annihilate both itself and another particle that was already inside the black hole.  The black hole would then lose a tiny amount of mass, shrink a bit, and emit some of that Hawking radiation.

One of the coolest things about this discovery was that it involved both general relativity and quantum mechanics, which don't usually go together.  General relativity is what physicists use to explain the very massive and very fast, quantum mechanics is what they use to explain the super tiny.  Both these theories work well for their respective aspects of the universe, but the math isn't really cross-compatible.  This quantum stuff happening at the edge of black holes, which are very much a relativity thing, did combine some principles of both theories, and after decades spent poking around black holes, Hawking eventually turned his attention to combining those two major theories for real in the search for the so-called theory of everything.  

While he had some good ideas, including a theory of imaginary time, which is about as complicated as it sounds, he never solved this particular problem, but he wasn't one to dwell on failure and like, a theory of everything is a pretty high bar.  Hawking died on March 14 from ALS, the disease that paralyzed him over the course of his life.  He was 76.  

Beside his discoveries, he also wrote several science books, gave countless public lectures, some using only his famous text-to-speech translator, and was on a whole bunch of TV shows, and with every lecture, book, and appearance on The Simpsons, he popularized science in a way no one else could.

On the biology side of things, this year science also lost Ruth Gates, a marine biologist who spent much of her career working to save coral reefs.  Raised on Jacques Cousteau documentaries, Gates was obsessed with corals from an early age, a passion that eventually led her to become director of the Hawaii Institute of Marine Biology and the first woman elected as president of the International Society for Reef Studies.  

By applying molecular technologies developed in the 1990s to coral biology, she made important discoveries about the vital relationships between corals and their algae and how rising sea temperatures can break that communication, but Gates did more than just help us understand corals.  She also helped us protect them better.

For the last few years, she and her team have been working on breeding what are basically super-corals, robust varieties that are better prepared for coral bleaching events and the environmental challenges of the future.  Gates died on October 25th from surgical complications at the age of 56, but the coral breeding project and her efforts to save marine life will go on.

Wildlife on land lost an important ambassador this year, too.  In June, the field of animal behavior and communication mourned one of its biggest and hairiest contributors, Koko the gorilla.  It might be a little unconventional to include her on a list like this, given that she wasn't, you know, a scientist or human, but she complete re-wrote many of our ideas about animal intelligence.

Born in the San Francisco Zoo in 1971, Koko quickly mastered a form of sign language through her mentor, Francine Patterson.  She could sign more than 1,000 words and understood more than 2,000 words of verbal English.  Over the years, the self-described queen, and yes, she really signed that, graced the cover of National Geographic twice, cared for several adopted kittens, and befriended Robin Williams, among many other things.  

Because Patterson could effectively talk to Koko, we could make new discoveries about gorillas' cognitive abilities just by asking.  For example, when famously asked "Where do animals go when they die?", Koko replied, "A comfortable hole."  With her home at San Francisco Zoo and Patterson by her side, Koko was comfortable throughout her life and hopefully also in death, since she died in her sleep, and now we say goodbye.

Thank you for watching this episode of SciShow and thank you especially to our community on Patreon for your support.  It's because of you that we're able to keep making videos like this.  You bring our little family together to make this stuff for the whole world, and if you're not a Patron and you want to learn more about how you can join us, you can check it out at Patreon.com/SciShow.

(Endscreen)