Yeah... there are definite questions about how this was done, but there shouldn't be. They're working with relatively low-energy sources that should be easy to control and collimate and direct at a well-defined target without trouble from edge effects, etc. Even an undergrad should be able to compare the two materials better than these guys -- whose "scientific" conclusion is that their material works as well as lead, and contradicts known cross-section data. The only question in my mind is: are they incompetent or are they frauds?
My first thought was along these lines -- that Kv was kV and meant some sort of potential across an x-ray tube. But when I saw that the table had radioisotopes with the proper energies, it became obvious that they meant eV and not V, at least for the first part of the table. If they switched terminologies midway down the table, that's really bad, but it might be an explanation for the x-ray results.
However, this doesn't address my main objection, and I contend that the results are bogus. Are my calculations wrong about 0.5 mm of lead blocking more than just 52% of the Co-57 emissions?
And re: gamma rays vs. x-rays: obviously different fields of physics have slightly different definitions. The one I'm familiar with is just based upon energy; there's a not-too-well defined border between x-rays and gamma rays at about 0.1 MeV. Your definition, on the other hand, works in almost all cases, but I can give a few counterexamples; e.g. x-rays from astrophysical sources can be thermal/black body rather than electronic in origin, and gamma rays need not come from a nuclear process, but from, say, the annihilation of an electron with an anti-electron. But since yours is a reasonable definition, I withdraw my parenthetical objection in the original posting.
Heavy nuclei tend to stop particles, like alphas, betas, and neutrons, but electrons are opaque to em radiation like x-rays and gamma rays. So the "heavy nuclei, not electrons" is incorrect. But the argument remains the same.
I'm not even going to talk about the ludicrous "science" behind the fabric, and I'm not going to talk about how it tends to be heavy nuclei, not electrons, that stops ionizing radiation. Even without using those arguments, I can still show that they're full of shit.
Check out their "test results." (PDF file) Go to page 3 to see the blocking power of their fabric.
Error #1: There is no such unit as a Kv. They mean KeV, as in Po-210 emits an alpha particle with 5,300 KeV of energy. But this is minor.
Error #2: X-rays and gamma rays are both photons; they're only distinguished by their energies. But the X-ray results and gamma ray results (which overlap in energy, which, in itself, makes no sense) contradict each other. For example, why does the fabric block only 52% of 60KeV gamma rays, but 82% and 72% of 50 and 70KeV X-rays respectively? Makes no sense, but this is nothing compared to...
Error #3: The real killer, and what makes me suspect this is fraud, rather than mere incompetence. They use 0.5 mm of lead as the comparison for their gamma emitter tests. The radiation-absorbing properties of lead are well known, and easily accessible in handy-dandy tables. For example, the half-value layer (the amount of material needed to block 50% of incoming radiation) for a Co-57 source is 0.15 mm of lead (ref here ), so 0.5 mm of lead should block more than 90% of the radiation, not just 52%. Proof positive that they're full of shit.
Fuck them, and fuck New Scientist. (Pardon my French.)
Unfortunately, the author of that link doesn't know diddly. (Not your fault, but figured I'd straighten it out for the record.)
[A strangelet is] a substance formed when present energy is sufficient to allow quarks and gluons to overcome the strong nuclear force and become uniform matter.
Nope. The strong nuclear force isn't overcome at all. A strangelet is a substance formed by with an equal mix of up, down, and strange quarks. The whole mess is bound by gluons (which carry the strong force). Strange matter is, in theory, at a lower energy state than ordinary nuclear matter.
The strangelet itself is a possibility of quark matter which occurs when an up quark and down quark combine to form a strange quark, one that does not exist under normal conditions. If a large number of these transformations occured at the same time, a strangelet could be formed: quark matter consisting entirely of strange quarks.
Nope, and nope. Up and down quarks don't combine to form strange quarks. A strange quark is formed via the weak nuclear force -- either an up or a down quark turns into a strange quark, a lepton, and an antilepton (if I've managed to keep my Feynman daigrams straight). And strangelets are made of up, down, and strange quarks, not just strange quarks.
There are other basic mistakes, but I figured I'd correct at least the definition of strange matter.
Yes... some people believed that collisions would cause us to revert to a lower energy state of the vacuum. (Or that it would create black holes or strangelets.) The protesters caused enough trouble that Brookhaven had to commission a study to show that it wouldn't happen because cosmic-ray collisions can be even more energetic (and for other reasons).
Nowadays there are protests every time a new accelerator starts up.
Very confused article.
on
Rocking with RHIC
·
· Score: 5, Informative
For example, the researchers didn't "...[collide] the circular gold atoms slightly off-center" in order "to simplify their observations." The atoms just collide off center most of the time naturally.
A bit denser, but much more accurate story about RHIC is here.
European scientists have carried out the first experiments on
antimatter.
Wrong. They've been experimenting with antimatter for years. I think Carl
Anderson's 1930s work was the first. This isn't even the first experiment
with antihydrogen, or cold antihydrogen, for that matter.
Researchers in Geneva, Switzerland, have been able to trap and control
anti-hydrogen atoms in a chamber at a sufficiently low temperature to begin
studying their physics in detail.
Wrong. They haven't trapped it. Nor can they study the physics in detail
yet.
Now they say they can store these fragile objects for study as well,
allowing them to conduct simple experiments.
Wrong. They can't trap them, much less store them for any length of time.
By measuring the strength of the electric field, they hope to tell how
tightly an anti-atom is held together and shed light on the differences
between normal matter and antimatter that might explain why the Universe
exists in its present form.
Not quite. They are able to tell how tightly these particular positrons are
bound to their antiprotons, which reveals what quantum state the
antihydrogens are in; this doesn't tell you anything about the properties
of antihydrogen.
Cern physicist Jerry Gabrielse...
And, um, it's Gerry Gabrielse.
Much better articles available here, here, and here.
It's not interesting, at least to me. Every time NASA gets an oscillating signal of some sort, they convert it to sound waves and play it, hoping that the press mistakes it for something profound. They're seldom disappointed.
It's written by Wired's author; Wired paid for the rights to publish. It's either their intellectual property or the author's, depending on the agreement between them. So this is a proprietary work, not public domain.
Thanks for your condescension. I've read the fair-use section (107 of the copyright act)... have you?
There are four criteria determining whether something is fair use. First is the purpose -- commercial or non-profit educational. (There *are* differences between Slashdot and a university.) Second is the nature of the work. Third is the amount of quoted material (copying the whole article is less likely to be fair use than quoting a section.) Fourth is the competition for the market of the original publisher -- and Slashdot has a great overlap with Wired's audience, and fewer people will visit Wired's website because of this posting on Slashdot. Fair use can be pretty fuzzy sometimes, but not in this case.
It's illegal because it's a violation of copyright law. "Fair use" describes the conditions when you're able to reproduce a work without the permission of the author. Mr. Coward was right when he says that the posting doesn't fall under fair use... a section of the article would probably be fair use, but the whole thing is a no-no.
I think these are different objects; I think the Inca City is a southern formation, while the Cydonia area of Mars is in the northern hemisphere.
As for Maya constellations, it's been a long time since I've actually seen the names, but IIRC, they tended to be animals, so I doubt that Gemini was represented as twin humans.
...here, quickly improved it to 0.5 and 1 km, and then 10 km. Don't quite know why Nature thought this particular paper was so revolutionary -- wake me when they get to about 300 km, the minimal bounce-off-satellite trip.
I hope I'm never in that situation, and I don't really know for sure what I would do... but I'm fairly certain I *wouldn't* go out and buy Lorenzo's oil with this sort of information. I'd almost certainly try to get my hands on more information -- I'd ask for his papers and I'd write for his unpublished data. Then I'd make a judgment. However, I think I wouldn't base my conclusions on anecdotal evidence. Hopefully, I'll never have to test this theory.
As for wonder-drugs, I don't know of very many that are so ubiquitous that you can't do a good trial. People can still do trials with aspirin, after all. The real problem comes when you have an effective drug and want to test it against a new drug. Researchers have to ask themselves when it is ethical to have a placebo trial and deny a patient a reasonably effective medication in hopes of finding a better one.
It's true that peer review doesn't guarantee quality anymore than a score>=1 filter guarantees that you'll only see coherent, intelligent, and articulate posts on Slashdot. That being said, though, I'll wait until Mr. Lorenzo's Oil gets modded up a few points by his peers before I take him too seriously.
2) The study is performed by the guy who has the most to lose if it fails. Unavoidable sometimes, but it makes a study less credible.
3) It looks like he's already had some failed trials with people who've shown an onset of symptoms. This affects the probability of having a false positive effect in your corpus of research -- a false positive that is sure to get headlines.
4) Reading between the lines, it seems that their protocol was poor. "By the end of the study 76 per cent of the 68 boys getting the oil were still healthy and producing normal brain MRI scans. The same was true of no more than about one in three of the 36 boys who did not regularly get the oil."
This sounds like everyone got the oil at the outset. 66% of those who stopped taking the oil had degeneration while 24% of those who continued did. But, of course, parents are much more likely to stop giving their children oil if they think it's not working, so the placebo group will be artificially enriched with failures and the oil group will be artificially enriched with successes. But I can't say for sure because...
5) The study hasn't been peer-reviewed or even published.
Level 1 answer: A positron is a lepton and an antiproton is a baryon, so they can't annihilate each other.
Level 2 answer: The capture of a positron by an antiproton is possible, but very unlikely, because it's energetically unfavorable.
Level 3 answer: You're proposing the k-capture of a positron by an antiproton, which would yield an antineutron and a neutrino. Since the antineutron has more (anti)mass than the antiproton, the probability of this is extremely small, just as it's quite unlikely that a hydrogen atom will k-capture its electron and become a neutron. The reverse process, beta decay, *is* favorable, which is why a neutron can (and will) spontaneously become a proton and an electron (and antineutrino.) (Half-life of around 10-15 minutes, IIRC.) Presumably, an antineutron would also decay via a W-boson exchange into an antiproton, a positron and a neutrino. Measuring the properties of this decay and comparing it to the beta decay of a neutrino would be a *very* cool experiment.
Not quite... the stellar-collapse black holes are a few to a few hundred solar masses, which are lighter than the middleweights. The supermassives, like the ones at the center of our galaxy, are in the millions of solar masses category. The middleweights are in between.
As for primordial black holes, IIRC, they were theoretically allowed to have masses smaller than stellar-collapse black holes, but most models had them at hundreds of thousands of solar masses.
Not much more delicate than the balance between the stars themselves. From a distance, a black hole looks (gravitationally) pretty much the same as a handful of stars bound to each other. It's only when you get pretty close that the extreme curvature of spacetime starts making a difference.
September, 2002: Medium-size black holes actually do exist, according to the latest findings from NASA's Hubble Space Telescope, but scientists had to look in some unexpected places to find them.
April, 1999: The field of black holes, formerly dominated by heavyweights packing the gravitational punch of a billion Suns and lightweights just a
few times heavier than our Sun, now has a new contender -- a just-discovered mysterious class of "middleweight" black holes, weighing in at 100 to 10,000 Suns.
Slashdot Mirror
Yeah... there are definite questions about how this was done, but there shouldn't be. They're working with relatively low-energy sources that should be easy to control and collimate and direct at a well-defined target without trouble from edge effects, etc. Even an undergrad should be able to compare the two materials better than these guys -- whose "scientific" conclusion is that their material works as well as lead, and contradicts known cross-section data. The only question in my mind is: are they incompetent or are they frauds?
However, this doesn't address my main objection, and I contend that the results are bogus. Are my calculations wrong about 0.5 mm of lead blocking more than just 52% of the Co-57 emissions?
And re: gamma rays vs. x-rays: obviously different fields of physics have slightly different definitions. The one I'm familiar with is just based upon energy; there's a not-too-well defined border between x-rays and gamma rays at about 0.1 MeV. Your definition, on the other hand, works in almost all cases, but I can give a few counterexamples; e.g. x-rays from astrophysical sources can be thermal/black body rather than electronic in origin, and gamma rays need not come from a nuclear process, but from, say, the annihilation of an electron with an anti-electron. But since yours is a reasonable definition, I withdraw my parenthetical objection in the original posting.
... that the job application requires a non-refundable $75 fee?
and I meant "...why does the fabric block 100% of 60 KeV gamma rays, but only 82% and 72% of 50 and 70 KeV X-rays respectively?"
Heavy nuclei tend to stop particles, like alphas, betas, and neutrons, but electrons are opaque to em radiation like x-rays and gamma rays. So the "heavy nuclei, not electrons" is incorrect. But the argument remains the same.
Check out their "test results." (PDF file) Go to page 3 to see the blocking power of their fabric.
Error #1: There is no such unit as a Kv. They mean KeV, as in Po-210 emits an alpha particle with 5,300 KeV of energy. But this is minor.
Error #2: X-rays and gamma rays are both photons; they're only distinguished by their energies. But the X-ray results and gamma ray results (which overlap in energy, which, in itself, makes no sense) contradict each other. For example, why does the fabric block only 52% of 60KeV gamma rays, but 82% and 72% of 50 and 70KeV X-rays respectively? Makes no sense, but this is nothing compared to...
Error #3: The real killer, and what makes me suspect this is fraud, rather than mere incompetence. They use 0.5 mm of lead as the comparison for their gamma emitter tests. The radiation-absorbing properties of lead are well known, and easily accessible in handy-dandy tables. For example, the half-value layer (the amount of material needed to block 50% of incoming radiation) for a Co-57 source is 0.15 mm of lead (ref here ), so 0.5 mm of lead should block more than 90% of the radiation, not just 52%. Proof positive that they're full of shit.
Fuck them, and fuck New Scientist. (Pardon my French.)
[A strangelet is] a substance formed when present energy is sufficient to allow quarks and gluons to overcome the strong nuclear force and become uniform matter.
Nope. The strong nuclear force isn't overcome at all. A strangelet is a substance formed by with an equal mix of up, down, and strange quarks. The whole mess is bound by gluons (which carry the strong force). Strange matter is, in theory, at a lower energy state than ordinary nuclear matter.
The strangelet itself is a possibility of quark matter which occurs when an up quark and down quark combine to form a strange quark, one that does not exist under normal conditions. If a large number of these transformations occured at the same time, a strangelet could be formed: quark matter consisting entirely of strange quarks. Nope, and nope. Up and down quarks don't combine to form strange quarks. A strange quark is formed via the weak nuclear force -- either an up or a down quark turns into a strange quark, a lepton, and an antilepton (if I've managed to keep my Feynman daigrams straight). And strangelets are made of up, down, and strange quarks, not just strange quarks.
There are other basic mistakes, but I figured I'd correct at least the definition of strange matter.
Nowadays there are protests every time a new accelerator starts up.
A bit denser, but much more accurate story about RHIC is here.
European scientists have carried out the first experiments on antimatter.
Wrong. They've been experimenting with antimatter for years. I think Carl Anderson's 1930s work was the first. This isn't even the first experiment with antihydrogen, or cold antihydrogen, for that matter.
Researchers in Geneva, Switzerland, have been able to trap and control anti-hydrogen atoms in a chamber at a sufficiently low temperature to begin studying their physics in detail.
Wrong. They haven't trapped it. Nor can they study the physics in detail yet.
Now they say they can store these fragile objects for study as well, allowing them to conduct simple experiments.
Wrong. They can't trap them, much less store them for any length of time.
By measuring the strength of the electric field, they hope to tell how tightly an anti-atom is held together and shed light on the differences between normal matter and antimatter that might explain why the Universe exists in its present form.
Not quite. They are able to tell how tightly these particular positrons are bound to their antiprotons, which reveals what quantum state the antihydrogens are in; this doesn't tell you anything about the properties of antihydrogen.
Cern physicist Jerry Gabrielse...
And, um, it's Gerry Gabrielse.
Much better articles available here, here, and here.
It's not interesting, at least to me. Every time NASA gets an oscillating signal of some sort, they convert it to sound waves and play it, hoping that the press mistakes it for something profound. They're seldom disappointed.
INTErnational Gamma Ray Astrophysical Laboratory.
It's written by Wired's author; Wired paid for the rights to publish. It's either their intellectual property or the author's, depending on the agreement between them. So this is a proprietary work, not public domain.
There are four criteria determining whether something is fair use. First is the purpose -- commercial or non-profit educational. (There *are* differences between Slashdot and a university.) Second is the nature of the work. Third is the amount of quoted material (copying the whole article is less likely to be fair use than quoting a section.) Fourth is the competition for the market of the original publisher -- and Slashdot has a great overlap with Wired's audience, and fewer people will visit Wired's website because of this posting on Slashdot. Fair use can be pretty fuzzy sometimes, but not in this case.
It's illegal because it's a violation of copyright law. "Fair use" describes the conditions when you're able to reproduce a work without the permission of the author. Mr. Coward was right when he says that the posting doesn't fall under fair use... a section of the article would probably be fair use, but the whole thing is a no-no.
As for Maya constellations, it's been a long time since I've actually seen the names, but IIRC, they tended to be animals, so I doubt that Gemini was represented as twin humans.
...here, quickly improved it to 0.5 and 1 km, and then 10 km. Don't quite know why Nature thought this particular paper was so revolutionary -- wake me when they get to about 300 km, the minimal bounce-off-satellite trip.
As for wonder-drugs, I don't know of very many that are so ubiquitous that you can't do a good trial. People can still do trials with aspirin, after all. The real problem comes when you have an effective drug and want to test it against a new drug. Researchers have to ask themselves when it is ethical to have a placebo trial and deny a patient a reasonably effective medication in hopes of finding a better one.
It's true that peer review doesn't guarantee quality anymore than a score>=1 filter guarantees that you'll only see coherent, intelligent, and articulate posts on Slashdot. That being said, though, I'll wait until Mr. Lorenzo's Oil gets modded up a few points by his peers before I take him too seriously.
2) The study is performed by the guy who has the most to lose if it fails. Unavoidable sometimes, but it makes a study less credible.
3) It looks like he's already had some failed trials with people who've shown an onset of symptoms. This affects the probability of having a false positive effect in your corpus of research -- a false positive that is sure to get headlines.
4) Reading between the lines, it seems that their protocol was poor. "By the end of the study 76 per cent of the 68 boys getting the oil were still healthy and producing normal brain MRI scans. The same was true of no more than about one in three of the 36 boys who did not regularly get the oil."
This sounds like everyone got the oil at the outset. 66% of those who stopped taking the oil had degeneration while 24% of those who continued did. But, of course, parents are much more likely to stop giving their children oil if they think it's not working, so the placebo group will be artificially enriched with failures and the oil group will be artificially enriched with successes. But I can't say for sure because...
5) The study hasn't been peer-reviewed or even published.
*rim shot*
Level 2 answer: The capture of a positron by an antiproton is possible, but very unlikely, because it's energetically unfavorable.
Level 3 answer: You're proposing the k-capture of a positron by an antiproton, which would yield an antineutron and a neutrino. Since the antineutron has more (anti)mass than the antiproton, the probability of this is extremely small, just as it's quite unlikely that a hydrogen atom will k-capture its electron and become a neutron. The reverse process, beta decay, *is* favorable, which is why a neutron can (and will) spontaneously become a proton and an electron (and antineutrino.) (Half-life of around 10-15 minutes, IIRC.) Presumably, an antineutron would also decay via a W-boson exchange into an antiproton, a positron and a neutrino. Measuring the properties of this decay and comparing it to the beta decay of a neutrino would be a *very* cool experiment.
As for primordial black holes, IIRC, they were theoretically allowed to have masses smaller than stellar-collapse black holes, but most models had them at hundreds of thousands of solar masses.
Not much more delicate than the balance between the stars themselves. From a distance, a black hole looks (gravitationally) pretty much the same as a handful of stars bound to each other. It's only when you get pretty close that the extreme curvature of spacetime starts making a difference.
April, 1999: The field of black holes, formerly dominated by heavyweights packing the gravitational punch of a billion Suns and lightweights just a few times heavier than our Sun, now has a new contender -- a just-discovered mysterious class of "middleweight" black holes, weighing in at 100 to 10,000 Suns.