but you should be more careful: people might take you seriously.
If you're not joking, um, you're missing something. There are an awful lot of observational clues that support the BB, and more particularly inflation -- this is probably kicking a dead horse, but the major ones:
Cosmic microwave background: In the BB theories, this is intepreted as the highly redshifted afterglow of the time when the (very hot, around 3000 K) universe became transparent. It's pretty hard to explain it in other ways, especially given that it is a perfect blackbody spectrum (to within something like one part in 10^5).
Hubble expansion: was this what you were referring to in the "Dopper effect theory" bit above? I have no clue. This has certainly not been "discredited" -- it's an observation that any theory must explain.
Ratio of light elements: The ratios in which certain elements (ie, Hydrogen to Deuterium) are found are very well predicted by BB theory. This is possibly the coolest constraint -- I don't really want to go into it here, but trust me.:-) (Elements higher on the periodic table were not formed in the big bang -- up to Iron, they were processed in stars, and after that, produced only in supernovae. Or so the theory goes.)
There are others, but you get the idea. Point is, inflationary Big Bang (the "inflation" part is more complicated than I want to explain here, but you need it, too, to explain the homogeneity of the CMB) is still very much alive.
First, congrats on an informative post. I had no idea how confused people would be about the "flat universe" bit -- you're quite right, that just means that the universe is precisely at the boundary between "open" and "closed," meaning it will never collapse back on itself. This is what I get for not reading here for a whole day.:-) Although I would clarify that there is a difference between simply an "open" universe (one that never collapses, with say Omega of 0.2), and a "flat" (Omega = 1) universe -- if you like, you can think of an Omega =1 Universe as being the case where, if you added one more proton, the universe would collapse eventually, and if you subtracted one more proton the universe would expand indefinitely. There are other differences, but those are more complicated.
BUT I strongly disagree with your comment that this was "old news." Nothing is ever old news, until it has been proven and re-proven and proven again. Period. Yes, there has been ample evidence that there is not enough matter to close the universe (ie, Omega_matter is not equal to one). There have even been articles published to the effect of "cosmology is solved" -- by something to the effect of Omega_baryonic = 0.1, Omega_non-b = 0.2, Omega_lambda =0.7, where the last term is an "equivalent density" arising from the cosmological constant term. I don't buy this (and I think a lot of other people don't buy it, either) because there are an awful lot of unanswered questions -- vacuum energy, fine, but show it to me. ("Demonstrations" of the Cassimir effect have failed to convince me so far, but maybe I'm being thick-headed.) And as I understand it (caveat: I'm no inflation expert), inflation predicts topological defects in the universe that have yet to be found (so far, anyway). It may be that we have the right picture -- then again, maybe not. Inflation's a damn good theory, but every piece of supporting evidence is still, at this point, a big deal (IMHO).
Enough ranting. My point is just that this was really a beautiful experiment, with a reasonably significant result. That's all.
In general I'd agree with you, but my impression (I don't know the authors involved, so please correct me if you know I'm wrong) was that this particular paper had gone through nothing more than the informal sort of "hey, do you see anything wrong with this" sort of critique among friends. (I'm basing this largely on the fact that a) one usually posts something like "accepted to ApJ" in the "comments" field if it's actually been accepted, and b) I'd never heard of this until a few days ago.)
I can't provide more details about the Willy's statue thing beyond just hearsay, but this seemed like an appropriate place to mention a more recent stunt I quite liked.
Every year (as probably anyone who's actually reading this knows), there's a large parade before "Beer-Bike," where all the colleges basically line up on trucks and go around the Inner Loop, dousing each other with an astonishing number of water balloons and other sundry items. Unfortunately (from my point of view, at least), a couple colleges who lie along the parade route have firehoses (or in one case, a fire truck) which they bring out every year and drench passers-by with. That's one part of the story.
Another part: as, again, most of you probably know, all the colleges are connected by a vast system of steam tunnels underground. It has become increasingly difficult to gain access to these tunnels -- some number of years ago, the administration started installing gates periodically throughout the tunnels and securing them with big beefy locks. PLUS, most of the entryways to the tunnels are either a) manholes, which are hard to use in daylight, or b) in parts of the colleges which are very hard to get to.
The "hack," perpetrated by a friend of mine, was just to quietly go into the tunnels the morning of Beer-Bike and lie in wait; when our group was about to pass by the waterhose-bearers, we signaled him by walkie-talkie and he shut off the water to the offending college for the few minutes it took for us to pass by. The looks of confusion from the people manning the firehose were great. After we had gone by, we signaled our comrade in the tunnels once more, so he could turn the water back on and the other floats could get happily drenched.
This was impressive for a few different reasons. To get in the tunnels as quickly and effectively as he did, the guy who did this had basically cracked the entire lock system at Rice -- this took the better part of a year, but by measuring keys and cores and such, he was eventually able to construct a series of master keys which would open most doors on campus. He also had to get a key for the steam-tunnel locks, which was another story. Finally, he had to spend quite a while tracking down the correct valves and things in the basement -- we wanted to be quite sure we were turning off only and precisely what we needed to. All in all, a good trick.:-)
I really don't think the major significance of this is in "confirming" the existence of the extrasolar planet -- the science that underlies those (prior) detections is pretty damn hard to poke big holes in, while the work described here in some ways assumes the existence of a planet. Let me try to explain a bit more. We know a whole hell of a lot about gravity, and the way things under its influence move -- this is why, to pick a "gee whiz" example, we can send satellites on fantastically accurate trajectories through the solar system. Given that knowledge, by far the simplest way to explain observered Doppler shifts in the spectra of some stars is to posit the existence of other bodies orbiting around those stars. And this is really a marvelous thing: that given our knowledge of the way things move under gravity, we can deduce all kinds of things about the mass of the orbiting object, its period of rotation, etc (all up to some factor of the inclination angle -- this is why the recent detection of a transit was so neat).
Now, the current endeavour. What they've done here is to take a spectrum of the star and, since there is supposed to be an orbiting planet, said that the part of the spectrum which is variable on the same timescale as the planet's supposed orbit is the reflected light from that planet. This seems a perfectly reasonable thing to do. But note that there are lots of other ways to explain simple variability -- the supposition that this is reflected light from the planet depends on the prior work.
The detection of elements in the atmosphere works because atoms have discrete transitions in energy -- each of these transitions corresponds to some wavelength photon, more or less. We know these transitions very, very well, and we use them a lot -- so for instance, I can tell you that a prominent forbidden-line transition of Oxygen [OIII] happens at 5007 angstroms, or that Halpha (a transition from the 3rd to the 2nd energy levels of H) occurs at 6563. You get the idea. So if you look at the spectrum and you see certain transitions, you know the elements which can produce those transitions must be present (modulo certain other concerns, which I'm ignoring here).
Finally, this is almost precisely the sort of thing that the Terrestrial Planet Finder (and later, the TP Imager) -- basically a space-based interferometer -- are designed to do. They'll go up, hopefully, in the next decade or so. The idea is that with high enough resolution, you could actually discern light from the star vs. light from the planet, without resorting to this "subtracting out the variable component" stuff -- then you could do the same sort of spectral analysis, and come up with a determination of what's in the planet's atmosphere. This would, you see, be cool.
A friend of mine introduced me to this during undergrad, and I was instantly a fan. Sure, the texts aren't that pretty to look at as is, but dump them into an Emacs buffer, add a few LaTeX markup tags, and suddenly you've got a decent-looking copy of whatever. (This is especially nice with texts which are relatively short -- I remember in particular having a tex-ified version of the Communist Manifesto.:-))
I find this interesting, mainly because it makes me think of previous work SGI has done in the large-computer arena; more to the point, I'm wondering if they're turning to this approach in part because some of their previous work has suffered deeply from a lack of linear scalability.
I'm thinking in particular of the Blue Mountain machine at LANL -- this was/is a big set of SGI Origin 2000 boxes; I don't actually remember offhand, but I seem to recall that they ran Irix, etc, and used typical MPI message-passing crap for most applications. Never mind. Anyway, point is that there were some problems with getting a linear performance increase on the machine as more and more processors were added; we're talking, incidentally, of thousands of processors. Some problems were to be expected -- clearly it's naive to expect totally linear speedup as you increase the number of processors, even for extremely well parallelized code. But some of the things we saw were just ridiculous -- there was, for instance, a sort of catastrophic breakdown at about 4000 processors; this has probably been solved for some time now, but not without an awful lot of work being done to do so. For some more info about this, check out this page at LANL, among others.
Don't get the impression, btw, that I'm against SGI getting into this area -- I happen to like the company quite a bit, think they have some extraordinary products, etc etc. I'm just a little wary these days when I see them talking about massively parallel machines.
This was sent out to some HST-project folks on Saturday. I haven't checked all the mainstream media reports, probably you can get a more cogent picture there -- this is just FYI. Oh, and "SM3A" is the Servicing Mission, currently scheduled for Dec. 6.
After getting in touch with the gyro craftsman ("Hans"), the project decided to try to turn gyro 1 on and off again. This was done about 1:00 local time. This did not seem to do any good. The start up cycle went up to about 500 milli-amps (over 700 ma was expected) and then down to the 350 ma level it had been at after the failure this morning. There was no indication that the gyro moved, it certainly did not get into sync. At this time, there is not a good understanding of what actually failed. The "lube patch" theory is now not seen to be completely consistent with the data. The gyro engineers at GSFC and Allied will be reviewing the data and looking at a wider range of possible failure scenarios over the weekend. No further attempt will be made to turn the gyro on until next week.
There will be a meeting/telecon sometime Monday afternoon to review the data and analyses. Meanwhile, the working expectation is that we will stay in zero gyro mode until SM3A. The instruments will be recovered from safe to hold next week. The current plan is to work through the plans for the recoveries on Monday and carry them out on Tuesday. The recoveries will be done in real-time, but an RTCS will be needed for the FOC recovery. The project will be reviewing the situation to identify any housekeeping activities necessary during the period before SM3A. They are also reviewing the process for closely monitoring performance in the zero gyro mode, since this will be by far the longest time we have been in this mode.
This isn't a comment so much as a question -- I'm just curious as to what phenomena/theories you're thinking of. I couldn't think of something offhand which would a) predict all previously observed stuff and b) not imply some sort of wave propagation equivalent. Ie, it's well known (and, given the nick, you're probably aware:-)) that no scalar theory of gravity (eg, Nordstrom metric) can accurately predict gravitational deflection of light; I'm just not clear on what well-posed alternatives exist. Then again, I don't know GR that well.:-)
I think this article is largely missing the point. GR has been amply proven, at least to the extent that LIGO isn't going to add much to the proofs -- gravity waves exist (see earlier post about a Nobel given out for this work).
A large part of what makes LIGO interesting -- at least to those who believe it will work (see below) -- is the prospect of eventually being able to do some real astronomy with the thing; that is, the idea that particular astrophysical phenomena would send out unique and detectable gravitational wave signatures.
Kip Thorne, one of the world's bad-asses on this subject, I think talks about LIGO in his book from a few years back, Black Holes and Time Warps. Highly recommended if you're interested in this sort of thing.
Finally, it's worth pointing out (as the article did not) that there are real questions about the odds of getting useful data out of the thing. Admittedly, I trust Thorne's opinion on this a lot more than most, but there's definitely a pretty narrow zone where a) we'll detect lots of gravitational waves with LIGO and b) we wouldn't have detected them already. (If I'm not mistaken, there have been small-scale versions of LIGO done already.) I wish I could point you to a link on this, but I can't think of anything useful.
You're probably aware of this, but there is a hard physical limit on how fast any physical computation could happen, though that limit might never be reached (due to other factors that would come into play before then). That hard limit comes from the Heisenberg uncertainty principle -- one way of stating this is, roughly, (delta Energy) * (delta Time) > h (Planck's constant). This is a fundamental property of the universe as we (think we) know it, and I can't think of a way that any computational device could get around it. That is, if you're switching something within a particular energy band, there is a hard limit on the timeframe it will take to do that, given by the above equation.
Hope that helps (?). I'm not really qualified to answer the other parts of your question, so I won't.:-)
First off, some of you may be interested to see an article Gold published a few years ago in a journal -- the abstract (and maybe the whole thing) is available through the Harvard astronomy and astrophysics abstract service; just search for "Thomas Gold" under "author." Alternatively, you can try using this URL but I'm not sure if that's actually permanent or what. Gold argued here that the presence of hydrocarbons on other objects in the solar system might imply(!) the presence of sub-surface microbial lifeforms on those objects. (So this isn't exactly along the same lines as the WP article, but deals with the same set of subjects.)
And yes (as has been mentioned by others), my guess is the reporter (not Gold) messed up with the "hydrocarbons forming in the Big Bang" line -- it doesn't even really make sense to talk about this, since the "Big Bang" phraseology typically only refers to the idea of an initial formation followed by eras of matter/radiation coupling, etc. (That is, by the time the Universe had cooled down to the point where hydrocarbon formation was possible, it was beyond the point typically dealt with in "Big Bang" theories.)
Finally, a couple words on the peer review process. No, it's not perfect -- people can, and probably occasionally do, use the system to further their own careers (by, for instance, delaying or rejecting a competitor's work). But the scientific community isn't blind to these problems, and hasn't been for a long, long time -- in part because of this, I'd go out on a limb and say that most of the time, it works pretty well. Don't screw over other people, lest ye be screwed. Probably the biggest problem I see with the system is one that's inherent to any system designed to check over articles before their publication -- it takes an awful lot of time to go over a paper with a fine-toothed comb, looking for errors or misconceptions and the like, and it's awfully easy to shirk a little on the quality of the review. (And remember, the way peer review works is something like this: you get a letter in the mail from, say, the Astrophysical Journal, saying "Dear So-and-so, as an expert in the field would you please take the time to comment on the enclosed paper and issue a recommendation for or against publication? And, by the way, please do this in the next week.") This is, perhaps, not conducive to either high-quality reviews or cheery reviewers. But it's probably not avoidable.
Slashdot Mirror
If you're not joking, um, you're missing something. There are an awful lot of observational clues that support the BB, and more particularly inflation -- this is probably kicking a dead horse, but the major ones:
Cosmic microwave background: In the BB theories, this is intepreted as the highly redshifted afterglow of the time when the (very hot, around 3000 K) universe became transparent. It's pretty hard to explain it in other ways, especially given that it is a perfect blackbody spectrum (to within something like one part in 10^5).
Hubble expansion: was this what you were referring to in the "Dopper effect theory" bit above? I have no clue. This has certainly not been "discredited" -- it's an observation that any theory must explain.
Ratio of light elements: The ratios in which certain elements (ie, Hydrogen to Deuterium) are found are very well predicted by BB theory. This is possibly the coolest constraint -- I don't really want to go into it here, but trust me. :-) (Elements higher on the periodic table were not formed in the big bang -- up to Iron, they were processed in stars, and after that, produced only in supernovae. Or so the theory goes.)
There are others, but you get the idea. Point is, inflationary Big Bang (the "inflation" part is more complicated than I want to explain here, but you need it, too, to explain the homogeneity of the CMB) is still very much alive.
BUT I strongly disagree with your comment that this was "old news." Nothing is ever old news, until it has been proven and re-proven and proven again. Period. Yes, there has been ample evidence that there is not enough matter to close the universe (ie, Omega_matter is not equal to one). There have even been articles published to the effect of "cosmology is solved" -- by something to the effect of Omega_baryonic = 0.1, Omega_non-b = 0.2, Omega_lambda =0.7, where the last term is an "equivalent density" arising from the cosmological constant term. I don't buy this (and I think a lot of other people don't buy it, either) because there are an awful lot of unanswered questions -- vacuum energy, fine, but show it to me. ("Demonstrations" of the Cassimir effect have failed to convince me so far, but maybe I'm being thick-headed.) And as I understand it (caveat: I'm no inflation expert), inflation predicts topological defects in the universe that have yet to be found (so far, anyway). It may be that we have the right picture -- then again, maybe not. Inflation's a damn good theory, but every piece of supporting evidence is still, at this point, a big deal (IMHO).
Enough ranting. My point is just that this was really a beautiful experiment, with a reasonably significant result. That's all.
Every year (as probably anyone who's actually reading this knows), there's a large parade before "Beer-Bike," where all the colleges basically line up on trucks and go around the Inner Loop, dousing each other with an astonishing number of water balloons and other sundry items. Unfortunately (from my point of view, at least), a couple colleges who lie along the parade route have firehoses (or in one case, a fire truck) which they bring out every year and drench passers-by with. That's one part of the story.
Another part: as, again, most of you probably know, all the colleges are connected by a vast system of steam tunnels underground. It has become increasingly difficult to gain access to these tunnels -- some number of years ago, the administration started installing gates periodically throughout the tunnels and securing them with big beefy locks. PLUS, most of the entryways to the tunnels are either a) manholes, which are hard to use in daylight, or b) in parts of the colleges which are very hard to get to.
The "hack," perpetrated by a friend of mine, was just to quietly go into the tunnels the morning of Beer-Bike and lie in wait; when our group was about to pass by the waterhose-bearers, we signaled him by walkie-talkie and he shut off the water to the offending college for the few minutes it took for us to pass by. The looks of confusion from the people manning the firehose were great. After we had gone by, we signaled our comrade in the tunnels once more, so he could turn the water back on and the other floats could get happily drenched.
This was impressive for a few different reasons. To get in the tunnels as quickly and effectively as he did, the guy who did this had basically cracked the entire lock system at Rice -- this took the better part of a year, but by measuring keys and cores and such, he was eventually able to construct a series of master keys which would open most doors on campus. He also had to get a key for the steam-tunnel locks, which was another story. Finally, he had to spend quite a while tracking down the correct valves and things in the basement -- we wanted to be quite sure we were turning off only and precisely what we needed to. All in all, a good trick. :-)
Now, the current endeavour. What they've done here is to take a spectrum of the star and, since there is supposed to be an orbiting planet, said that the part of the spectrum which is variable on the same timescale as the planet's supposed orbit is the reflected light from that planet. This seems a perfectly reasonable thing to do. But note that there are lots of other ways to explain simple variability -- the supposition that this is reflected light from the planet depends on the prior work.
The detection of elements in the atmosphere works because atoms have discrete transitions in energy -- each of these transitions corresponds to some wavelength photon, more or less. We know these transitions very, very well, and we use them a lot -- so for instance, I can tell you that a prominent forbidden-line transition of Oxygen [OIII] happens at 5007 angstroms, or that Halpha (a transition from the 3rd to the 2nd energy levels of H) occurs at 6563. You get the idea. So if you look at the spectrum and you see certain transitions, you know the elements which can produce those transitions must be present (modulo certain other concerns, which I'm ignoring here).
Finally, this is almost precisely the sort of thing that the Terrestrial Planet Finder (and later, the TP Imager) -- basically a space-based interferometer -- are designed to do. They'll go up, hopefully, in the next decade or so. The idea is that with high enough resolution, you could actually discern light from the star vs. light from the planet, without resorting to this "subtracting out the variable component" stuff -- then you could do the same sort of spectral analysis, and come up with a determination of what's in the planet's atmosphere. This would, you see, be cool.
Man that was a long post. Hope it helped, though.
A friend of mine introduced me to this during undergrad, and I was instantly a fan. Sure, the texts aren't that pretty to look at as is, but dump them into an Emacs buffer, add a few LaTeX markup tags, and suddenly you've got a decent-looking copy of whatever. (This is especially nice with texts which are relatively short -- I remember in particular having a tex-ified version of the Communist Manifesto. :-))
I'm thinking in particular of the Blue Mountain machine at LANL -- this was/is a big set of SGI Origin 2000 boxes; I don't actually remember offhand, but I seem to recall that they ran Irix, etc, and used typical MPI message-passing crap for most applications. Never mind. Anyway, point is that there were some problems with getting a linear performance increase on the machine as more and more processors were added; we're talking, incidentally, of thousands of processors. Some problems were to be expected -- clearly it's naive to expect totally linear speedup as you increase the number of processors, even for extremely well parallelized code. But some of the things we saw were just ridiculous -- there was, for instance, a sort of catastrophic breakdown at about 4000 processors; this has probably been solved for some time now, but not without an awful lot of work being done to do so. For some more info about this, check out this page at LANL, among others.
Don't get the impression, btw, that I'm against SGI getting into this area -- I happen to like the company quite a bit, think they have some extraordinary products, etc etc. I'm just a little wary these days when I see them talking about massively parallel machines.
Cheers.
After getting in touch with the gyro craftsman ("Hans"), the project decided to try to turn gyro 1 on and off again. This was done about 1:00 local time. This did not seem to do any good. The start up cycle went up to about 500 milli-amps (over 700 ma was expected) and then down to the 350 ma level it had been at after the failure this morning. There was no indication that the gyro moved, it certainly did not get into sync. At this time, there is not a good understanding of what actually failed. The "lube patch" theory is now not seen to be completely consistent with the data. The gyro engineers at GSFC and Allied will be reviewing the data and looking at a wider range of possible failure scenarios over the weekend. No further attempt will be made to turn the gyro on until next week.
There will be a meeting/telecon sometime Monday afternoon to review the data and analyses. Meanwhile, the working expectation is that we will stay in zero gyro mode until SM3A. The instruments will be recovered from safe to hold next week. The current plan is to work through the plans for the recoveries on Monday and carry them out on Tuesday. The recoveries will be done in real-time, but an RTCS will be needed for the FOC recovery. The project will be reviewing the situation to identify any housekeeping activities necessary during the period before SM3A. They are also reviewing the process for closely monitoring performance in the zero gyro mode, since this will be by far the longest time we have been in this mode.
This isn't a comment so much as a question -- I'm just curious as to what phenomena/theories you're thinking of. I couldn't think of something offhand which would a) predict all previously observed stuff and b) not imply some sort of wave propagation equivalent. Ie, it's well known (and, given the nick, you're probably aware :-)) that no scalar theory of gravity (eg, Nordstrom metric) can accurately predict gravitational deflection of light; I'm just not clear on what well-posed alternatives exist. Then again, I don't know GR that well. :-)
A large part of what makes LIGO interesting -- at least to those who believe it will work (see below) -- is the prospect of eventually being able to do some real astronomy with the thing; that is, the idea that particular astrophysical phenomena would send out unique and detectable gravitational wave signatures.
Kip Thorne, one of the world's bad-asses on this subject, I think talks about LIGO in his book from a few years back, Black Holes and Time Warps. Highly recommended if you're interested in this sort of thing.
Finally, it's worth pointing out (as the article did not) that there are real questions about the odds of getting useful data out of the thing. Admittedly, I trust Thorne's opinion on this a lot more than most, but there's definitely a pretty narrow zone where a) we'll detect lots of gravitational waves with LIGO and b) we wouldn't have detected them already. (If I'm not mistaken, there have been small-scale versions of LIGO done already.) I wish I could point you to a link on this, but I can't think of anything useful.
Just my two cents. :-)
Hope that helps (?). I'm not really qualified to answer the other parts of your question, so I won't. :-)
And yes (as has been mentioned by others), my guess is the reporter (not Gold) messed up with the "hydrocarbons forming in the Big Bang" line -- it doesn't even really make sense to talk about this, since the "Big Bang" phraseology typically only refers to the idea of an initial formation followed by eras of matter/radiation coupling, etc. (That is, by the time the Universe had cooled down to the point where hydrocarbon formation was possible, it was beyond the point typically dealt with in "Big Bang" theories.)
Finally, a couple words on the peer review process. No, it's not perfect -- people can, and probably occasionally do, use the system to further their own careers (by, for instance, delaying or rejecting a competitor's work). But the scientific community isn't blind to these problems, and hasn't been for a long, long time -- in part because of this, I'd go out on a limb and say that most of the time, it works pretty well. Don't screw over other people, lest ye be screwed. Probably the biggest problem I see with the system is one that's inherent to any system designed to check over articles before their publication -- it takes an awful lot of time to go over a paper with a fine-toothed comb, looking for errors or misconceptions and the like, and it's awfully easy to shirk a little on the quality of the review. (And remember, the way peer review works is something like this: you get a letter in the mail from, say, the Astrophysical Journal, saying "Dear So-and-so, as an expert in the field would you please take the time to comment on the enclosed paper and issue a recommendation for or against publication? And, by the way, please do this in the next week.") This is, perhaps, not conducive to either high-quality reviews or cheery reviewers. But it's probably not avoidable.
Have fun.