There are a couple of things to keep in mind. First, the more exotic the isotope, the shorter its half life (the average time it takes before undergoing beta-decay and transforming into a slightly more stable element). For most elements there are usually just one to two stable forms. All others will decay, and the further in mass you get from the stable forms, the quicker this decay happens. It's kind of hard to make any physical object with a material that exists for a fraction of a second.
Second, for any given element there is a lower mass and an upper mass boundary. There is a physical limit to what types of particles one can create. Beyond these boundaries, called the driplines when applied to the entire nuclear chart, particles are 'unstable'. I use unstable in the vernacular nuclear sense; particles will evaporate from the core until the remaing particles are bound. This, as mentioned above, still doesn't mean the particle is 'stable' in the common sense of the word.
Lastly, the NSCL cylcotron produces the rarest particles, the particles with the lowest probability for creation (i.e. very low cross section) at a very low rate, sometimes as low as an event per day.
The article is about the construction of a next generation nuclear facility at the NSCL. The US as in all other science fields, is gradually falling behind European and Japanese counterparts. The few other other major nuclear labs in the world (not to be confused with the super-expensive high energy facilities like Cern and Fermilab) are bringing online new facilities that will enable nuclear researchers to study more exotic elements, elements with stranger properties closer to that limit of stability. The MSU proposal is located here: http://www.nscl.msu.edu/future/isf/.
There is a lot of interesting research to be done. Many of the biggest unanswered questions in physics are in nuclear physics. One mentioned in the article is the creation of elements. We are indeed created from stars, since the big bang left us with just some helium and hydrogen. The other elements are created in nuclear processes that occur in the giant nuclear furnaces of stars. Interested folks should look online for additional information.
There is a incredibly large region of the nuclear chart that currently cannot be reached because present beam facilities don't have the energies and intensities to produce the particles at a rate sufficient for research. It would be very neat if we could get there.
I think the kilogram is the last unit of measurement that hasn't been defined in terms of fundamental physics phenomena.
Most definitions depend on the (hopefully) invariant properties of nature and are removed from effects of man. Nobody can drop the definition of the meter stick; its definition cannot be changed by war, by incorrect handling, by temperature, by location, by time. The definition of the meter is the same whether you are on mars or earth.
I remember reading some time ago that people are worried that the mass of the kilogram is changing. Diffusion of atoms into and away from its surface and even its infrequent handling may change its mass. The precision of the kilogram is limited by these uncertainties.
To recap:
meter - Length that the speed of light travels in 1/299,792,458th of a second.
second - Duration of 9,192,631,770 transitions between two hyperfine levels of a cesium 133 atom.
kilogram - Weight of a chunk of metal in a jar.
Media portrayal is extremely important for the development of new talent. I think a lot of young people, especially young women, are turned off from the sciences and other technical fields because of misconstrued ideas of what the respective work enviornment is like.
Personally, if I didn't fall into the sciences by chance, and had to choose a discipline by wading through the different offerings, I might have been discouraged from physics. Who wants to spend their days around reclusive wierdos who are so engaged in their work that they have little interest or time for social activities?
You latter learn that this is (mostly) false, but sometimes that knowledge requires actually getting involved in the discipline. Maybe SesameStreet should introduce Bob, the CS swinger.:)
Chlorine might indeed rise from the ocean in prodigious quantities. The problem wasn't pure chlorine, but CFCs. Pure chlorine rarely makes it into the upper atmosphere. CFCs however were a perfect vehicle for delivering chlorine into the upper atmosphere where each cholorine atom could ionize several thousand O3 atoms.
A few years back the man who had discovered and characterized CFC's effects (he won a nobel prize for it) talked to our colloquim. I find it a bit distasteful to accuse him and his collegues of inflating their claims. Also remember that their claims weren't winning them friends and fortune; they were raising their flag in front of an industry that had no intention of stopping production. I find that many ecologists end up in this position. I don't see how broaching enviornmental problems wins them any money. It's the people who back up those with the pockets to pay who seem to have the most to gain financially. Thus said, I prefer not to think of the world as a place where ever single person is doing back door deals and slinking around like little weasles.
I would agree with you that sometimes Greenpeace's rhetoric is a bit strong, but I wouldn't throw out what they say just because of that. In my eyes the case that humans are contibuting to global warming has grown from possible to quite likely. In the past few years several major reports have been published that are quite damning because they back up their claims with mountains of high quality research.
If I got any of the science wrong, please forgive me...
I'm not going to get into whether online piracy is right or not. I just think that the porn industry's situation seems different than that of Hollywood and the record industry, and that whatever works for the porn industry might not work for other media makers.
I'm going on hearsay now, but it seems that there are a ton of porn movies released all the time. Such a bulk of low quality limited distribution titles limits illegal trading. There's enough people out there interested in "Pirates of the Caribbean" that if you go online you're guaranteed to find a download at a decent connection speed. On the other hand, if you were looking for something like "Butt Knockers 2" I would bet my dog and fish you couldn't find it (especially since I made up the name...). The DVDs are released to such a limited audience, and there's just too many titles to be effectively traded online.
You'd think with such outlandish prices that professors might make a decent pull from a publishing deal. This isn't true; they get only a pittance of the book sale price, $3 - $4 dollars per book.
I have a professor who authored a physics textbook. The book sells for about ninety dollars. He gets about three dollars per book. If you bother taking the fraction, it's pretty pathetic.
I suppose Halliday, Resnick and Walker might have their beach homes, but for the thousands of less conspicuous authors, I'm suspecting they might barely make enough, over a year's duration, to cover the cost of a new transmission.
Slashdot Mirror
There are a couple of things to keep in mind. First, the more exotic the isotope, the shorter its half life (the average time it takes before undergoing beta-decay and transforming into a slightly more stable element). For most elements there are usually just one to two stable forms. All others will decay, and the further in mass you get from the stable forms, the quicker this decay happens. It's kind of hard to make any physical object with a material that exists for a fraction of a second. Second, for any given element there is a lower mass and an upper mass boundary. There is a physical limit to what types of particles one can create. Beyond these boundaries, called the driplines when applied to the entire nuclear chart, particles are 'unstable'. I use unstable in the vernacular nuclear sense; particles will evaporate from the core until the remaing particles are bound. This, as mentioned above, still doesn't mean the particle is 'stable' in the common sense of the word. Lastly, the NSCL cylcotron produces the rarest particles, the particles with the lowest probability for creation (i.e. very low cross section) at a very low rate, sometimes as low as an event per day. The article is about the construction of a next generation nuclear facility at the NSCL. The US as in all other science fields, is gradually falling behind European and Japanese counterparts. The few other other major nuclear labs in the world (not to be confused with the super-expensive high energy facilities like Cern and Fermilab) are bringing online new facilities that will enable nuclear researchers to study more exotic elements, elements with stranger properties closer to that limit of stability. The MSU proposal is located here: http://www.nscl.msu.edu/future/isf/. There is a lot of interesting research to be done. Many of the biggest unanswered questions in physics are in nuclear physics. One mentioned in the article is the creation of elements. We are indeed created from stars, since the big bang left us with just some helium and hydrogen. The other elements are created in nuclear processes that occur in the giant nuclear furnaces of stars. Interested folks should look online for additional information. There is a incredibly large region of the nuclear chart that currently cannot be reached because present beam facilities don't have the energies and intensities to produce the particles at a rate sufficient for research. It would be very neat if we could get there.
I think the kilogram is the last unit of measurement that hasn't been defined in terms of fundamental physics phenomena.
Most definitions depend on the (hopefully) invariant properties of nature and are removed from effects of man. Nobody can drop the definition of the meter stick; its definition cannot be changed by war, by incorrect handling, by temperature, by location, by time. The definition of the meter is the same whether you are on mars or earth.
I remember reading some time ago that people are worried that the mass of the kilogram is changing. Diffusion of atoms into and away from its surface and even its infrequent handling may change its mass. The precision of the kilogram is limited by these uncertainties.
To recap:
meter - Length that the speed of light travels in 1/299,792,458th of a second.
second - Duration of 9,192,631,770 transitions between two hyperfine levels of a cesium 133 atom.
kilogram - Weight of a chunk of metal in a jar.
Media portrayal is extremely important for the development of new talent. I think a lot of young people, especially young women, are turned off from the sciences and other technical fields because of misconstrued ideas of what the respective work enviornment is like.
Personally, if I didn't fall into the sciences by chance, and had to choose a discipline by wading through the different offerings, I might have been discouraged from physics. Who wants to spend their days around reclusive wierdos who are so engaged in their work that they have little interest or time for social activities?
You latter learn that this is (mostly) false, but sometimes that knowledge requires actually getting involved in the discipline. Maybe SesameStreet should introduce Bob, the CS swinger. :)
Chlorine might indeed rise from the ocean in prodigious quantities. The problem wasn't pure chlorine, but CFCs. Pure chlorine rarely makes it into the upper atmosphere. CFCs however were a perfect vehicle for delivering chlorine into the upper atmosphere where each cholorine atom could ionize several thousand O3 atoms.
A few years back the man who had discovered and characterized CFC's effects (he won a nobel prize for it) talked to our colloquim. I find it a bit distasteful to accuse him and his collegues of inflating their claims. Also remember that their claims weren't winning them friends and fortune; they were raising their flag in front of an industry that had no intention of stopping production. I find that many ecologists end up in this position. I don't see how broaching enviornmental problems wins them any money. It's the people who back up those with the pockets to pay who seem to have the most to gain financially. Thus said, I prefer not to think of the world as a place where ever single person is doing back door deals and slinking around like little weasles.
I would agree with you that sometimes Greenpeace's rhetoric is a bit strong, but I wouldn't throw out what they say just because of that. In my eyes the case that humans are contibuting to global warming has grown from possible to quite likely. In the past few years several major reports have been published that are quite damning because they back up their claims with mountains of high quality research.
If I got any of the science wrong, please forgive me...
If you're refering to the James Webb telescope, a supplemental page to the one you linked says a launch date isn't scheduled until August of 2011.
I'm not going to get into whether online piracy is right or not. I just think that the porn industry's situation seems different than that of Hollywood and the record industry, and that whatever works for the porn industry might not work for other media makers.
I'm going on hearsay now, but it seems that there are a ton of porn movies released all the time. Such a bulk of low quality limited distribution titles limits illegal trading. There's enough people out there interested in "Pirates of the Caribbean" that if you go online you're guaranteed to find a download at a decent connection speed. On the other hand, if you were looking for something like "Butt Knockers 2" I would bet my dog and fish you couldn't find it (especially since I made up the name...). The DVDs are released to such a limited audience, and there's just too many titles to be effectively traded online.
You'd think with such outlandish prices that professors might make a decent pull from a publishing deal. This isn't true; they get only a pittance of the book sale price, $3 - $4 dollars per book.
I have a professor who authored a physics textbook. The book sells for about ninety dollars. He gets about three dollars per book. If you bother taking the fraction, it's pretty pathetic.
I suppose Halliday, Resnick and Walker might have their beach homes, but for the thousands of less conspicuous authors, I'm suspecting they might barely make enough, over a year's duration, to cover the cost of a new transmission.