In many fields (Astronomy, Physics, Math) it is standard practice for authors to pay page charges (often about $100 per page) to publish their articles. (Of course, in these fields most journals don't have any advertisements.) I see nothing unethical about it.
The obvious question is why should an author pay to print the article when they can post a pdf on their website or an online archive (such as arxiv.org). The answer is that scientists are judged (i.e., hired, tenured, promoted, etc.) based on their refereed publications. Posting the same things on your website will get you only a small fraction of the "credit". There are some exceptions (e.g., if you make a particularly important discovery), but from the scientist's point of view, why risk it? It's much safer to pay the ~$1000 page charges.
Personally, I wish that departments would recognize how much money could be saved if they were to stop using refereed publications as the primary criteria for judging their members.
I think we both agree that the NS could have been created well after most of the stars in the globular cluster.
For the moment, let's assume that the common envelope phase could form a planet (not impossible, but there's no evidence that it has happened either). First, as you note, stellar collisions are _relatively common_ in the cores of clusters, but still are a significant minority.
Second, since the NS-WD binary is in a ~180d orbit, I would expect the planet would form somewhere in that vicinity. Now, maybe the planet formed there, but then something moved the planet significantly further out (~100yr). However, this process would have to stop just before the planet completely escaped from the system. Seems like a stretch.
So while I can't say that it never happens or that there's no chance that this planet formed that way, it seems to me that your scenario is significantly less likely than the scenario which the authors proposed. A planet formed in a protostellar disk around a common MS star, the star passed near the cluster core and encountered a binary star, the binary-binary scattering encounter resulted in the formation of the triple system we see today.
While I understand the reasons for the beleif that planet formation would be difficult in a low metallicity environment, IMHO one of the main lessons from the previous planet discoveries is that we should be very skeptical of planet formation theories.
The white dwarf is in a ~180d orbit, while the planet is in a ~100yr orbit. So evaporated material recondensing (at least in the current arrangement of this system) is very far fetchend. I don't remember the details, but I beleive that Brad Hansen's white dwarf models include some ammount of heating by the pulsar. Steve would be able to correct me if I'm wrong on this.
The neutron star was _much_ farther away when the planet formed, and would not have been irradiating the planet significantly. Here's a graphic showing the sequence of events
First, there's no direct evidence that it's gaseous. We just assume that since it's so massive.
Second, the hypothesis that it formed via direct collapse from the disk, would be consistant with it being nearly all gaseous. However, most scientists beleice that the planets in our solar system formed by first accreting a bunch of rocky material to form a core which then accumulated a bunch of gas. Doing that in a low metallicity disk seems like it might be a bit difficult. But I expect others will try to perform simulations to see if that's really the case.
By making an H-R diagram for the globular cluster, the age for all the stars in the cluster is measured to be 12.7+/-0.35 billion years. They assume that the planet formed at the same time as the stars.
Yes, we knew that stars formed in low metallicity environments. But it might have been that the first generation of stars didn't have enough heavy elements in their disks to form planets. Now we know that at least one did form an object with a mass a few times that of Jupiter. Maybe this planet formed by direct collapse (like a star or brown dwarf), which would imply that maybe many modern giant planets form by direct collapse. Or maybe this planet got started by accretion (like most scientists think modern giant planets formed), in which case I suspect some theorists will have to think of some new wrinkles to explain how that can happen with so very few heavy elements in it's disk.
Yes, this is another interesting aspect of the story. We now have a much firmer constraint on the planet's mass, so if you define planets and brown dwarfs by their masses, then we are much more confident that it is a planet, and not a brown dwarf. However, we still don't know how it formed. Traditionally, brown dwarfs are assumed to form by direct collapse, while planets are assumed to form first by accreting a rocky core. Of course, we don't really know how this "planet" formed. Alan Boss advocates that it may have formed via direct collapse, like a brown dwarf, in which case the low metal abundance probably isn't so important. However, many scientists think that the accretion of a core first is more likely. Since we know that this planet exists and almost certainly formed in a low metallicity environment, that might be difficult in this case. I suspect someone will now attempt to simulate accretion of a planetary core in a low metallicity disk. I look forward to reading about their results.
Sort of... The planet is in orbit around a binary consisting of a pulsar and a white dwarf. Previously, the pulsar had been observed and small variations in the arrival times of the pulses allowed them to detect the white dwarf companion. Further analysis of the pulsar arrival times allowed them to infer the existance of another distant companion, but there was still considerable uncertainty in the mass and orbit, so it wasn't clear if it was a planet or brown dwarf. These new observations pin down the mass of the white dwarf, which, when combined with several additional years of pulsar timing data, demonstrate that the mass is about 2.5 Jupiter masses.
But, the really interesting part of this paper is that since they now have directly observed the white dwarf around the pulsar, they can measure its colors and infer it's age. Previously, there were two leading theories... 1. That there was a pre-existing pulsar-white dwarf binary and then the planet was captured from it's orbit around a star which passed by the pulsary-white dwarf binary. -or- 2. There was a pulsar-star binary which interacted with a star-planet binary, kicked out the original star, replacing the old stellar companion with the new star, and leaving the planet in a wide orbit. The new star evolved, expanded, transfered mass onto the pulsar, spun up it's rotational speed, became a white dwarf, and circularized it's orbit around the pulsar. The planet stuck around in a wider orbit and perturbed the inner binary slightly, imparting a small eccentricty to the pulsar-white dwarf binary.
Since we now know the white dwarf is young, scenario 2 is vastly more likely, and so we now better understand the formation mechanism for this system. That's the real news behind this discovery.
BTW- The original paper is avaliable in today's issue of Science and I think it should be readable for someone with one college astronomy class.
Forget the DeCSS T-shirts. Xerox is selling boxes of DeCSS source code in whitespace at Staples. And my department has a cabinet full of backup copies of the source. That should keep the RIAA busy for a good while.
If I were guessing in the absense of any data, then I would agree with you. However, there is data which appears to preclude such large rates of change. There is a narrow range of values for the rate of change which is consistant with this data. However, if you beleive theconstraints placed by the Oklo reactor, then the changes have to be oscillatory.
It's that same group saying the same thing again. Although I haven't reviewed their latest paper, I remember that I wasn't impressed with the statistical analysis of their data, as of the previous paper.
Personally, I won't find the evidence convincing untill another group takes some their own data and gets similar results. Given that many astronomers have similar sentiments, it seems that giving VLT time to the same group seems not the best use of VLT time.
Of course, if no other astronomers find the likelyhood of the discovery worth the effort of making the observations, then it may be difficult to get independant confirmation. Given that it would be a really big deal if true, I think that says a lot about how seriously the astronomical community takes these claims.
Yes, Michelson measured the speed of light very accurately. That allowed the measurement of the time delay for the reappearance of Jupiter's moons to become a way of measuring the distance from the Earth to the Moon accurately.
Galileo determined that light took finite time to travel and measured the speed of light. He used a crude telescope that third graders could build (if they bought a 1" lens), a clock, and grade school mathematics. The technique was to measure the time at which the Galilean satelites dissappeared and reappeared from behind the shaddow of Jupiter. Based on the difference between when the moons were observed to (dis)appear when the Earth and Jupiter were on opposite sides of the sun as opposed to when they were on the same side of the sun, we was able to determine that the speed of light was finite, the first step towards the developement of relativity. Of course, his measurements weren't very precise, since he didn't have a great measurement of the distance from the Earth to the Sun. In fact, once we had measured the speed of light in the laboratory, this technique was used to measure the distance from the Earth to the sun. I beleive this was the basis of the best measurements until the advent of radar (timing radio signals bounced off planets) and space probes (feeling the gravity of the planets).
You'd think a mathematician would be more precise. Every year many university juniors do the Stern-Gerlag experiment, as well as mossbauer spectroscopy, optical pump of rubidium vapor, etc.. So can those count? Or do those students not count?
Religion and science address different questions. If your question is "What do you expect will happen when you throw a ball with this initial position and velocity?", then science does a very good job of answering that question. If your question is "How should I treat another person who did something mean to me?", then science doesn't provide much of an answer. Religions do offer answers. Some people have religious beleifs that say "try to be nice to them anyway". Other people have religous beleifes that say "do something mean to them". Unfortunately, for relgious beleifs, it's hard to tell which one is correct or even if there is a correct answer.
I have a very old circut diagram and MS QuickBasic program for an 8 bit osciliscope that used the parallel port. Most of it could easily be translated to C, although I'd guess there's a much better library for reading data from the parallel port. It worked fine for about $50 of electronics from DigiKey. We used it mostly with a photocell for some simple interferometry experiments. It also worked with a microphone and I'm told someone else used it for a moisture sensor of some kind. I suppose I probably could dig it up if you're really interested, but there must be people who have done a better job since.
We had a good night too. Good weather, although there was still a
fair bit of skyglow near the horizon. Couldn't see the Milky Way, but
we had a view where we could lie down and see nearly all the night sky
at once. Although juding from the oohs and aahs when I didn't see
anything, there were some I was missing, maybe 5%, mostly from people
standing up looking near the horizon where I wasn't paying as much
attention since it was brighter. But most of the ones I saw were
plenty bright. It wasn't like there were many that I could just
barely see. Or maybe I just didn't notice those for all the bright
ones. I think the show was still going when twilight cut us off.
I'll know the rate once I play back the audio tape, but we
probably saw a few hundred total. The most spectacular were the long
bright green ones that left a trail that stuck around for several
seconds afterwards. A few even had a second burt. Probably 10-20
really bright ones with green tails. One was audible. Several times
there were multiple meteors visible at once. In any case,
it was a great show. Now need to get ready for my trip.
Since the PMTs have a vacumb inside, when the tubes are tightly packed, there's no (little) pressure tangential to the radius vector. I'd guess they'll put in "dummy detectors" or something to fill the space and keep the water from getting anywhere but on one face of the detectors.
I'd like it if Hollywood would provide alternative scenes, so that people who would prefer not to have cursing, sex, violence, etc., could watch scenes that make sense with the movie and don't include those. Hollywood could also make versions with extended sex scenes or particularly graphic violent scenes for people who are into that kind of thing. Seems to me like it could be an easy way to make more people really like a film.
It seems like they might be interested in going along with it, since that would increase the potential market for their film. For example a children's film could have a version with nothing remotely objectionalable for very little kids, a little implicit violence and/or sexual inuendo for older kids and adults who would prefer to avoid more objectionable material, and a another version with cursing and explicit violence and sex that teenagers wouldn't be embarassed to watch with their friends.
Another type of films that it might be particularly good for would be classics and "educational" films that parents and/or schools would like to share with kids.
But I would guess that the films that would gain the most extra profits from making multiple versions are you the "normal" films. I'd guess there are a lot of people who wouldn't want to go to an "adult theater", but would like to rent a normal DVD from Blockbuster- just like they'd rent the normal version- and from the privacy of their own home enjoy the "lots of extra graphic sex scenes" version. And people like me who are disturbed by violent scenes would be less likely to object when friends want to watch a movie, if we could compromise on watching the movie with the the "no explicit violence" option.
I'd guess Hollywood would choose do this on their own. It could simultaneously placate complaints about their content and sell even more copies to the masses.
While it's true there are multiple observatories, they aren't merely copies or bigger versions of each other. The different observatories are senstive to neutrions of different energies.
SuperK used ordinary (but pure) water. SNO used pure "heavy water", that is water where the hydrogen has a neutron. SNO has recently added salt to their heavy water, since comparing the reaction rates with and without the salt will provide a very interesting ratio for understanding the mass heirarchy of neutrinos. Other detectors have used other media for detecting neutrinos, such as gallium.
A couple of Japanese colleges say that SuperK was previously being targeted for budget cuts, and was fighting to maintain funding. They were concerned that if it would indeed take tens of millions of USDs to fix, then it may be cut. That would be a real dissappiontment.
Let's hope SuperK comes back on line, and that we don't have a galactic supernova go off while SuperK is being fixed.
Slashdot Mirror
In many fields (Astronomy, Physics, Math) it is standard practice for authors to pay page charges (often about $100 per page) to publish their articles. (Of course, in these fields most journals don't have any advertisements.) I see nothing unethical about it.
The obvious question is why should an author pay to print the article when they can post a pdf on their website or an online archive (such as arxiv.org). The answer is that scientists are judged (i.e., hired, tenured, promoted, etc.) based on their refereed publications. Posting the same things on your website will get you only a small fraction of the "credit". There are some exceptions (e.g., if you make a particularly important discovery), but from the scientist's point of view, why risk it? It's much safer to pay the ~$1000 page charges.
Personally, I wish that departments would recognize how much money could be saved if they were to stop using refereed publications as the primary criteria for judging their members.
Hi Scott,
I think we both agree that the NS could have been created well after most of the stars in the globular cluster.
For the moment, let's assume that the common envelope phase could form a planet (not impossible, but there's no evidence that it has happened either). First, as you note, stellar collisions are _relatively common_ in the cores of clusters, but still are a significant minority.
Second, since the NS-WD binary is in a ~180d orbit, I would expect the planet would form somewhere in that vicinity. Now, maybe the planet formed there, but then something moved the planet significantly further out (~100yr). However, this process would have to stop just before the planet completely escaped from the system. Seems like a stretch.
So while I can't say that it never happens or that there's no chance that this planet formed that way, it seems to me that your scenario is significantly less likely than the scenario which the authors proposed. A planet formed in a protostellar disk around a common MS star, the star passed near the cluster core and encountered a binary star, the binary-binary scattering encounter resulted in the formation of the triple system we see today.
While I understand the reasons for the beleif that planet formation would be difficult in a low metallicity environment, IMHO one of the main lessons from the previous planet discoveries is that we should be very skeptical of planet formation theories.
The white dwarf is in a ~180d orbit, while the planet is in a ~100yr orbit. So evaporated material recondensing (at least in the current arrangement of this system) is very far fetchend. I don't remember the details, but I beleive that Brad Hansen's white dwarf models include some ammount of heating by the pulsar. Steve would be able to correct me if I'm wrong on this.
The neutron star was _much_ farther away when the planet formed, and would not have been irradiating the planet significantly. Here's a graphic showing the sequence of events
The standard theory of the formation of Jupiter involves the accretion of a 5-20 Earth mass core which they accumulated nearby gasses.
The planet almost certainly formed before the pulsar went supernova.
First, there's no direct evidence that it's gaseous. We just assume that since it's so massive.
Second, the hypothesis that it formed via direct collapse from the disk, would be consistant with it being nearly all gaseous. However, most scientists beleice that the planets in our solar system formed by first accreting a bunch of rocky material to form a core which then accumulated a bunch of gas. Doing that in a low metallicity disk seems like it might be a bit difficult. But I expect others will try to perform simulations to see if that's really the case.
By making an H-R diagram for the globular cluster, the age for all the stars in the cluster is measured to be 12.7+/-0.35 billion years. They assume that the planet formed at the same time as the stars.
Yes, we knew that stars formed in low metallicity environments. But it might have been that the first generation of stars didn't have enough heavy elements in their disks to form planets. Now we know that at least one did form an object with a mass a few times that of Jupiter. Maybe this planet formed by direct collapse (like a star or brown dwarf), which would imply that maybe many modern giant planets form by direct collapse. Or maybe this planet got started by accretion (like most scientists think modern giant planets formed), in which case I suspect some theorists will have to think of some new wrinkles to explain how that can happen with so very few heavy elements in it's disk.
Yes, this is another interesting aspect of the story. We now have a much firmer constraint on the planet's mass, so if you define planets and brown dwarfs by their masses, then we are much more confident that it is a planet, and not a brown dwarf. However, we still don't know how it formed. Traditionally, brown dwarfs are assumed to form by direct collapse, while planets are assumed to form first by accreting a rocky core. Of course, we don't really know how this "planet" formed. Alan Boss advocates that it may have formed via direct collapse, like a brown dwarf, in which case the low metal abundance probably isn't so important. However, many scientists think that the accretion of a core first is more likely. Since we know that this planet exists and almost certainly formed in a low metallicity environment, that might be difficult in this case. I suspect someone will now attempt to simulate accretion of a planetary core in a low metallicity disk. I look forward to reading about their results.
Sort of... The planet is in orbit around a binary consisting of a pulsar and a white dwarf. Previously, the pulsar had been observed and small variations in the arrival times of the pulses allowed them to detect the white dwarf companion. Further analysis of the pulsar arrival times allowed them to infer the existance of another distant companion, but there was still considerable uncertainty in the mass and orbit, so it wasn't clear if it was a planet or brown dwarf. These new observations pin down the mass of the white dwarf, which, when combined with several additional years of pulsar timing data, demonstrate that the mass is about 2.5 Jupiter masses.
But, the really interesting part of this paper is that since they now have directly observed the white dwarf around the pulsar, they can measure its colors and infer it's age. Previously, there were two leading theories... 1. That there was a pre-existing pulsar-white dwarf binary and then the planet was captured from it's orbit around a star which passed by the pulsary-white dwarf binary. -or- 2. There was a pulsar-star binary which interacted with a star-planet binary, kicked out the original star, replacing the old stellar companion with the new star, and leaving the planet in a wide orbit. The new star evolved, expanded, transfered mass onto the pulsar, spun up it's rotational speed, became a white dwarf, and circularized it's orbit around the pulsar. The planet stuck around in a wider orbit and perturbed the inner binary slightly, imparting a small eccentricty to the pulsar-white dwarf binary.
Since we now know the white dwarf is young, scenario 2 is vastly more likely, and so we now better understand the formation mechanism for this system. That's the real news behind this discovery.
BTW- The original paper is avaliable in today's issue of Science and I think it should be readable for someone with one college astronomy class.
Forget the DeCSS T-shirts. Xerox is selling boxes of DeCSS source code in whitespace at Staples. And my department has a cabinet full of backup copies of the source. That should keep the RIAA busy for a good while.
If I were guessing in the absense of any data, then I would agree with you. However, there is data which appears to preclude such large rates of change. There is a narrow range of values for the rate of change which is consistant with this data. However, if you beleive theconstraints placed by the Oklo reactor, then the changes have to be oscillatory.
It's that same group saying the same thing again. Although I haven't reviewed their latest paper, I remember that I wasn't impressed with the statistical analysis of their data, as of the previous paper.
Personally, I won't find the evidence convincing untill another group takes some their own data and gets similar results. Given that many astronomers have similar sentiments, it seems that giving VLT time to the same group seems not the best use of VLT time.
Of course, if no other astronomers find the likelyhood of the discovery worth the effort of making the observations, then it may be difficult to get independant confirmation. Given that it would be a really big deal if true, I think that says a lot about how seriously the astronomical community takes these claims.
You're right it was Olaf Romer.
Yes, Michelson measured the speed of light very accurately. That allowed the measurement of the time delay for the reappearance of Jupiter's moons to become a way of measuring the distance from the Earth to the Moon accurately.
Galileo determined that light took finite time to travel and measured the speed of light. He used a crude telescope that third graders could build (if they bought a 1" lens), a clock, and grade school mathematics. The technique was to measure the time at which the Galilean satelites dissappeared and reappeared from behind the shaddow of Jupiter. Based on the difference between when the moons were observed to (dis)appear when the Earth and Jupiter were on opposite sides of the sun as opposed to when they were on the same side of the sun, we was able to determine that the speed of light was finite, the first step towards the developement of relativity. Of course, his measurements weren't very precise, since he didn't have a great measurement of the distance from the Earth to the Sun. In fact, once we had measured the speed of light in the laboratory, this technique was used to measure the distance from the Earth to the sun. I beleive this was the basis of the best measurements until the advent of radar (timing radio signals bounced off planets) and space probes (feeling the gravity of the planets).
You'd think a mathematician would be more precise. Every year many university juniors do the Stern-Gerlag experiment, as well as mossbauer spectroscopy, optical pump of rubidium vapor, etc.. So can those count? Or do those students not count?
Religion and science address different questions.
If your question is "What do you expect will happen when you throw a ball with this initial position and velocity?", then science does a very good job of answering that question. If your question is "How should I treat another person who did something mean to me?", then science doesn't provide much of an answer. Religions do offer answers. Some people have religious beleifs that say "try to be nice to them anyway". Other people have religous beleifes that say "do something mean to them". Unfortunately, for relgious beleifs, it's hard to tell which one is correct or even if there is a correct answer.
I don't think the clock chip is really necessary, If you're willing to read whatever voltage it's giving at the time.
I have a very old circut diagram and MS QuickBasic program for an 8 bit osciliscope that used the parallel port. Most of it could easily be translated to C, although I'd guess there's a much better library for reading data from the parallel port. It worked fine for about $50 of electronics from DigiKey. We used it mostly with a photocell for some simple interferometry experiments. It also worked with a microphone and I'm told someone else used it for a moisture sensor of some kind. I suppose I probably could dig it up if you're really interested, but there must be people who have done a better job since.
We had a good night too. Good weather, although there was still a
fair bit of skyglow near the horizon. Couldn't see the Milky Way, but
we had a view where we could lie down and see nearly all the night sky
at once. Although juding from the oohs and aahs when I didn't see
anything, there were some I was missing, maybe 5%, mostly from people
standing up looking near the horizon where I wasn't paying as much
attention since it was brighter. But most of the ones I saw were
plenty bright. It wasn't like there were many that I could just
barely see. Or maybe I just didn't notice those for all the bright
ones. I think the show was still going when twilight cut us off.
I'll know the rate once I play back the audio tape, but we
probably saw a few hundred total. The most spectacular were the long
bright green ones that left a trail that stuck around for several
seconds afterwards. A few even had a second burt. Probably 10-20
really bright ones with green tails. One was audible. Several times
there were multiple meteors visible at once. In any case,
it was a great show. Now need to get ready for my trip.
Since the PMTs have a vacumb inside, when the tubes are tightly packed, there's no (little) pressure tangential to the radius vector. I'd guess they'll put in "dummy detectors" or something to fill the space and keep the water from getting anywhere but on one face of the detectors.
It's estimated to take 2 years to replace the PMTs. That's a matter of logistics not funding.
I'd like it if Hollywood would provide alternative scenes, so that people who would prefer not to have cursing, sex, violence, etc., could watch scenes that make sense with the movie and don't include those. Hollywood could also make versions with extended sex scenes or particularly graphic violent scenes for people who are into that kind of thing. Seems to me like it could be an easy way to make more people really like a film.
It seems like they might be interested in going along with it, since that would increase the potential market for their film. For example a children's film could have a version with nothing remotely objectionalable for very little kids, a little implicit violence and/or sexual inuendo for older kids and adults who would prefer to avoid more objectionable material, and a another version with cursing and explicit violence and sex that teenagers wouldn't be embarassed to watch with their friends.
Another type of films that it might be particularly good for would be classics and "educational" films that parents and/or schools would like to share with kids.
But I would guess that the films that would gain the most extra profits from making multiple versions are you the "normal" films. I'd guess there are a lot of people who wouldn't want to go to an "adult theater", but would like to rent a normal DVD from Blockbuster- just like they'd rent the normal version- and from the privacy of their own home enjoy the "lots of extra graphic sex scenes" version. And people like me who are disturbed by violent scenes would be less likely to object when friends want to watch a movie, if we could compromise on watching the movie with the the "no explicit violence" option.
I'd guess Hollywood would choose do this on their own. It could simultaneously placate complaints about their content and sell even more copies to the masses.
While it's true there are multiple observatories, they aren't merely copies or bigger versions of each other. The different observatories are senstive to neutrions of different energies.
SuperK used ordinary (but pure) water. SNO used pure "heavy water", that is water where the hydrogen has a neutron. SNO has recently added salt to their heavy water, since comparing the reaction rates with and without the salt will provide a very interesting ratio for understanding the mass heirarchy of neutrinos. Other detectors have used other media for detecting neutrinos, such as gallium.
Of course this is just wild speculation, but...
A couple of Japanese colleges say that SuperK was previously being targeted for budget cuts, and was fighting to maintain funding. They were concerned that if it would indeed take tens of millions of USDs to fix, then it may be cut. That would be a real dissappiontment.
Let's hope SuperK comes back on line, and that we don't have a galactic supernova go off while SuperK is being fixed.