I like to glance at the sun sometimes. I know I'm not supposed to, but every once in a while I just wonder what's so bad, and I just take a glance. My curiosity is usually rewarded with a few minutes of seeing strange glowing orbs in my vision where the sun used to be. Okay, so the sun is bad to look at, and most of us know why (imagine having those glowing orb-like things there permanently), but what makes the sun work? For decades, centuries, millennia, you name it, scientists have been searching for the key as to what happens inside the big glowing orange-yellow thing in outer space. Well fairly recently, we found out.
In 1920 a man named Sir Arthur Eddington proposed that the sun burned nitrogen (most of the air around you is nitrogen) and burned it so much that the nitrogens melted together to form helium. This all happened because not too long before this a great guy called Einstein said that E=mc^2. So basically, some energy was produced. That energy that we see is given off as light, and there's so much energy in that light that if you glance for even a single second, you will feel the side effects.
Scientists thought that was all fine and dandy, right up until a man named Wolfgang Pauli did a few calculations in 1929 and realized that not enough energy was being given out! Some of the energy was actually missing. As a good scientist knows, energy doesn't just go missing. It's always hiding somewhere, in some shape or form. So Pauli made the bold suggestion that some of the energy went off as a particle called a "neutrino" but also said there was no way to detect it. Not a great start? You can imagine not too many people were keen on believing that an "invisible" particle existed, and essentially Pauli was saying that the entire universe's existence was based on this particle.
Pauli said that every time a few nitrogens were burned together, exactly two neutrinos were produced. Since the sun does this trillions and trillions and trillions of times every second, there must be neutrinos all around us, flying by every second, even this far away as to be on earth. So we've arrived at a point in time where just a few crazy scientists believed that small invisible particles were flying all over the universe, and were actually fundamental to the creation of the universe. These guys were so crazy that they actually predicted mathematically that about a hundred billion solar neutrinos pass through your thumbnail every second. Neutrinos were actually thought to have no mass. That means they were just energy. Now not only were these things invisible, but they actually almost didn't exist! (Can you imagine something with no mass? It would just go through everything!)
This theory was mocked and laughed at by smart people all over the globe! So eventually, in 1965, a guy called Ray Davis devised an experiment. Maybe neutrinos were invisible, but their reactions with other particles weren't. Sort of like Harry Potter wearing an invisibility cloak would still react with things like flower pots. Ray filled a container (about the size of an Olympic swimming pool) with cleaning liquid. He predicted that every week, only about 10 neutrinos would hit a particle in this huge tank, and when they hit a particle, they would change it into something else. This tank was able to detect this, and if Mr. Davis was right, and 10 neutrinos did hit, then he would have proved his idea. Sadly, only 3 neutrinos hit, which was devastating to the experiment. (Imagine how much money it would have cost!)
A decade past with no explanation, until Physicists Vladimir Gribov and Bruno Pontecorvo (Russians, in 1969) came up with the idea that while the neutrinos were traveling the huge distances from the sun to earth, that they actually changed what they were. The idea was that the neutrinos changed from "red neutrinos" to "yellow neutrinos" to "white neutrinos" as often as they liked. And if that was true, then Ray Davis' experiment would only have detected the red neutrinos!
A problem! Hello? How can "neutrinos" change shape if they don't even exist? It just isn't possible. Many other people agreed, and more mockery and doubt arose from the idea.
It wasn't until 1998, in the Sudbury Neutrino Observatory (SNO) in Sudbury, Ontario, that 500 days of research collecting yielded crucial results! A new experiment was created which was able to detect all colors of neutrinos. The data gave the correct result of 10 neutrinos per week, and also showed that neutrinos do have mass, just barely any of it. It also proved that neutrinos performed "neutrino oscillations" and actually did change from one thing to the next (almost for no reason at all).
Ray Davis now had the right to say "Haha! I was right" and neutrinos did exist! Because they existed, that proved that the melting together of particles in the sun really did happen! And in 2002, Ray Davis and Masatoshi Koshiba were awarded the Nobel Prize for Physics, under the citation: "for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos."
So the 82-year old story of the neutrino comes to a rest. We now know for sure (and it is only within your lifetime) what really goes on inside the sun! Imagine, it took 82 years to detect something in which about a hundred billion of these things fly through only your thumbnail every second. The discovery has revolutionized particle physics, and given us a greater understanding of the miniature universe all around us. Ray Davis was the first person to truely look inside the sun.
Now I'm going to be like the neutrino and click off at the speed of light. Have a good day everyone!
Author's Note:For more information and references, please visit http://www.pbs.org/wgbh/nova/neutrino/missing.html. There are also many other interesting things about neutrino's there which you can see.