There are a lot of things out there that we can't see with our naked eyes. There are also a lot of things out there that are extremely hard (or maybe impossible) to detect with even our most sensitive detectors. One example of this was my last post about dark matter. Another example is what I want to talk about today: neutrinos.
Neutrinos are much like the WIMPs that I talked about last time. Neutrinos do not carry a charge so they tend not to interact with matter in the same way that particles that carry a charge interact with matter. That is a little hard to think about so I want to give a concrete example. Imagine a sheet of atoms. This sheet can represent anything, but we shall say that it is the surface of a desk. If you take a close look at all of the atoms they are surrounded by electrons. They electrons are negatively charged and surround the positively charged core of the atom like a cloud. Now, think of another atom falling toward the surface of the desk. This atom also has an electron cloud. From basic physics we know that like charges repel and that is just what happens. Basically one electron cloud hits the other electron cloud and they atoms repel from each other. That is how it it is with a normal atom.
In the case of the neutrino it is different. The neutrino has no electric charge. This means that it is not repelled by the electric charge of the electron cloud. The neutrino can basically slid effortlessly though the electric cloud. In other words the neutrino will not bounce off from the surface and will go though. There is a case where the neutrino will not go though the surface. That is when the neutrino interacts with the atom by smashing into the atoms nucleus. You would think that that would happen a lot, but the fact is that the diameter of a normal atom is about 10^5 times that of its nucleus. This means that a atom is mostly made up of "empty space," and the chances of actually hitting the nucleus are very small indeed. Even though the chances are small that is the only time we actually detect a neutrino. The fact is that 50 million neutrinos that are produced in the sun pass though our bodies every second and hardly any of them actually interact with us. That is how hard it is to detect these things.
Now that the basics of the neutrino are covered, I want to get into this news story. It seems that the High Energy Accelerator Research Organization (Know as KEK for it's Japanese name) located in Ibaragi prefecture produced a neutrino that was detected 295 kilometers (183 miles) away by the Super Kamiokande detector in Gifu prefecture on the 24th of this month.
This is actually amazing because there are a lot of countries that are in the race at the moment to produce and detect neutrinos and this was the first time it has ever happened. The article does not really got into that many details so I wonder how they know this was the neutrino that was produced by the KEK. It could have just been a coincidence that they detector detected a neutrino from the sun at the same time as the neutrino was produced by the group at KEK. I would really like to hear more about this story and see how they set up their experiment. For now all I can say is that it looks like something amazing happened, but I am not so sure yet.
Any way, it is now time for the word of the day. Today's word is ニュートリノ(にゅうとりの). It is pronounced nyuutorino and it means neutrino. It is just another big piece in the puzzle of science.
See you next time at JJNN
Showing posts with label neutrino. Show all posts
Showing posts with label neutrino. Show all posts
Friday, February 26, 2010
Monday, July 14, 2008
JJNN Monday: Science - 01
Welcome again to JJNN for Monday July 14th, 2008. Today is science day.
This is actually a bit of sad new. You can see the article here. It seems that a great name in science died of colorectal cancer on July 10th at 12:30 pm. His name was Totsuka Youji and he died at the age of 66.
Totsuka Youji a did most of his work in the field of study of neutrinos. I want to give a very quick background on his life. He was born on March 6th 1942, which means he was born during the middle of World War II. He went to school and ended up getting his PhD from Tokyo University in 1972. After he got his PhD he worked his way up in Tokyo University from research associate to associate professor to professor in 1987. As well as his work at Tokyo University he also became the director of the Kamioka observatory and the Institute for Cosmic Ray Research.
Because of Totsuka Youji's work we now know some interesting things about neutrinos. Before we get into what he found out I want to talk a little bit about neutrinos. neutrinos are funny little elementary particles. They travel close to the speed of light and go straight though solid objects without slowing down at all (in most cases). Why do you think that these particles can go though most matter without slowing now? Well the answer is that they are like electrons with no charge so they are not effected by electromagnetic forces. They can only be effected by the weak nuclear force. Weak nuclear forces only act over a short distance so it is more likely neutrinos can mover over long distances without being slowed down.
These particles are made by nuclear decay like that seen in the sun or when high energy solar rays strike atoms. There are 3 different types of neutrinos out there. They are all made by slightly different processes, but I won't go into that. The names of the 3 types are electron neutrinos, tau neutrinos and muon neutrinos. I bet these particles seem exotic and rare, right? Well, the fact of the matter is that according to this about 50 trillion of these particles go though any human being.
Those are interesting facts, but what Totsuka Youji found out about neutrinos is even more interesting. First, he is the person that found out that the neutrino has a very small, yet detectable, mass. Before it was thought that these particles did not have a mass and it was sort of like light, but he helped to prove that theory was not true. Second, he helped to prove that while neutrinos are moving though space they turn into different types of neutrinos and turn back again. Both of those discoveries are pieces of information that will help us to know more about the neutrino and other things in the universe.
Before going onto the word of the day I want to talk about how we know that neutrinos exist in the first place. Like I said before, neutrinos do not play well with other matter (by the fact that they go though it), so how can we detect neutrinos in the first place. Well even though the neutrino goes though most materials, if it goes though enough stuff it is bound to hit something because of probability alone. So, a good neutrino detector is one in which there is enough of a substance that is isolated from things like cosmic rays and constantly watched for an interactions. Super Kamiokande in Japan uses a lot of water that is surrounded by phototubes that will pick up the Cherenkov radiation given off by the neutrino when it collides with something. Other detectors use different materials.
Any way, it is now time for the word of the day. Today's word is ニュートリノ(にゅうとりの). It is pronounced nyuutorino and means neutrino. I remember the first time I heard about neutrinos and the fact that there are so many of them going though our bodies every second of every day. That is probably one of the things that really made me want to study science (thanks Nova).
That's it for today. See you next time at JJNN.
This is actually a bit of sad new. You can see the article here. It seems that a great name in science died of colorectal cancer on July 10th at 12:30 pm. His name was Totsuka Youji and he died at the age of 66.
Totsuka Youji a did most of his work in the field of study of neutrinos. I want to give a very quick background on his life. He was born on March 6th 1942, which means he was born during the middle of World War II. He went to school and ended up getting his PhD from Tokyo University in 1972. After he got his PhD he worked his way up in Tokyo University from research associate to associate professor to professor in 1987. As well as his work at Tokyo University he also became the director of the Kamioka observatory and the Institute for Cosmic Ray Research.
Because of Totsuka Youji's work we now know some interesting things about neutrinos. Before we get into what he found out I want to talk a little bit about neutrinos. neutrinos are funny little elementary particles. They travel close to the speed of light and go straight though solid objects without slowing down at all (in most cases). Why do you think that these particles can go though most matter without slowing now? Well the answer is that they are like electrons with no charge so they are not effected by electromagnetic forces. They can only be effected by the weak nuclear force. Weak nuclear forces only act over a short distance so it is more likely neutrinos can mover over long distances without being slowed down.
These particles are made by nuclear decay like that seen in the sun or when high energy solar rays strike atoms. There are 3 different types of neutrinos out there. They are all made by slightly different processes, but I won't go into that. The names of the 3 types are electron neutrinos, tau neutrinos and muon neutrinos. I bet these particles seem exotic and rare, right? Well, the fact of the matter is that according to this about 50 trillion of these particles go though any human being.
Those are interesting facts, but what Totsuka Youji found out about neutrinos is even more interesting. First, he is the person that found out that the neutrino has a very small, yet detectable, mass. Before it was thought that these particles did not have a mass and it was sort of like light, but he helped to prove that theory was not true. Second, he helped to prove that while neutrinos are moving though space they turn into different types of neutrinos and turn back again. Both of those discoveries are pieces of information that will help us to know more about the neutrino and other things in the universe.
Before going onto the word of the day I want to talk about how we know that neutrinos exist in the first place. Like I said before, neutrinos do not play well with other matter (by the fact that they go though it), so how can we detect neutrinos in the first place. Well even though the neutrino goes though most materials, if it goes though enough stuff it is bound to hit something because of probability alone. So, a good neutrino detector is one in which there is enough of a substance that is isolated from things like cosmic rays and constantly watched for an interactions. Super Kamiokande in Japan uses a lot of water that is surrounded by phototubes that will pick up the Cherenkov radiation given off by the neutrino when it collides with something. Other detectors use different materials.
Any way, it is now time for the word of the day. Today's word is ニュートリノ(にゅうとりの). It is pronounced nyuutorino and means neutrino. I remember the first time I heard about neutrinos and the fact that there are so many of them going though our bodies every second of every day. That is probably one of the things that really made me want to study science (thanks Nova).
That's it for today. See you next time at JJNN.
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