Since inflation theory (originally proposed by Linde in 1985 IIRC) predicts (well, demands might be a better term) that the cosmological constant be equal to zero, this is a victory for this theory, albeit one that practically everyone involved in cosmology expected a long time ago.
Inflation theory originally required Omega_m=1, Omega_Lambda=0 (no cosmological constant). Since the supernovae results indicating an accelerating universe, it has generally been accepted that there is a cosmological constant. Typical favored values these days are Omega_m=0.3, Omega_Lambda=0.7, which is a flat (total=1) universe. Inflation theory has been revised to allow a cosmological constant, provided the universe is still flat.
My point is that inflation does not require a zero cosmological constant, and the claim of a flat universe doesn't, either. Indeed, if the Boomerang results did indicate both a flat universe and zero lambda, they would be suspect because this would constrain Omega_m to equal 1, which would contradict many observations.
What do we have in orbit that could do sub-millimeter imaging of the earth? A Hubble-sized (2.2m) mirror at 200 km operating at about 4000 angstroms has a diffraction limit in excess of 40mm.
Do you propose that we have a 90-meter telescope in orbit? Or one that's orbiting low enough to collide with a small mountain?
No, it's not "red." The image on the page is not a visible-spectrum photograph; it's most likely false-color from the lower end of the X-ray spectrum
Must be a different Palomar than I use, then. The one I know is on the ground, and is an optical telescope. The mirror is polished to optical tolerances, and operates at normal incidence instead of grazing incidence. The atmosphere there is not magically transparent to X-rays, and in fact it's probably not transparent to much at all today, since it's raining.
If it's at z=5.5, then 1500 A in the observer frame is 230 A in the rest frame, which should give you quite a nasty sunburn.
I'm assuming they used interferometry, though the article didn't say so?
No. There is a testbed optical interferometer at Palomar, but it's used for things like binary stars. It's an engineering test for the Keck interferometer.
You want interferometers and space telescopes to look at small detail, better than the 0.5 to 1 arcsecond you get through the atmosphere. But that doesn't matter here! You still get basically all of the light from the quasar on your mirror (as the atmosphere is pretty transparent), and it doesn't matter if it's smeared out a little. There's no detail to see, anyway.
And it was Mt. Palomar and Kitt Peak to boot. I've been expecting this stuff to come from Hawaii. Kudos to the scopes on the continental US!
Agreed, but note that the spectrographic followup was at Keck. That's a common mode of operation these days: If you can image it on the 200, you can get a low-resolution spectrum at Keck.
I guess this officially beats the Hubble Deep Field which WERE the most distant objects found in the universe.
I think that previously, the most distant objects were quasars found by the Sloan Digital Sky Survey folks.
I don't think you understand how these measurements work.
The HST Key Project you're refering to was a project to determine the Hubble constant, H_0. Lots of people have measured H_0 and get a variety of values. The Key Project people got theirs. If you combine a value of H_0 with other cosmological parameters that you think are correct, you can get an "age of the universe". That's what Slashdot and the NY Times like to report, but it's not the fundamental quantity that was measured.
Now, you've got Dan picking out quasars on the 200-inch and he gets a spectrum at Keck. The photons don't land on the detector and announce, "Hey! I've been flying for 14 billion years! It's nice to finally excite an electron!" No, you get a spectrum that tells you the redshift. Dan converts the redshift into a distance using his favorite value of H_0, which might not be the same as the Key Project's.
You used to hear about problems because stellar astronomers would believe that the ages from globular clusters (based on stellar physics) were older than the age of the universe (from measurements of cosmological parameters). That's not what's happening here. Here, you just have people favoring different values of H_0, because they think one value was obtained more reliably than the other.
If you think the Hubble Space Telescope is some sort of failure, you don't know what you're talking about. Its initial problems were repaired, quite quickly IMHO for the task involved, and it's been a remarkably productive scientific instrument that's fully lived up to its potential. (The corrective optics were installed less than two years after launch; it's now been ten years since launch, and it's going strong. That's really not so much "downtime", especially when you consider that the telescope wasn't useless despite the figure error, and much of the early time would have been for engineering time anyhow.)
Now when we launch SIRTF and other instruments so far away that the shuttle can't repair them, the price for technical problems will be profoundly higher.
I live in Pennsylvania and there are so many damned specialized license plates that it's really starting to get annoying. For example, if you donate money to some "save the animals!" thing, you get a license plate with an owl on it. There are several variations of that theme. Then there's another one for D.A.R.E., one for every public university, and various military ones (I suppose I shouldn't whine too much about those). And there are probably others I don't know about.
The worst of which, from the standpoint of recognition, is the Pennsylvania "Flagship Niagra" plate. It has white lettering on a pale brown image, giving very little contrast between the lettering and the background. The State Police were opposed to this design for good reason, but I gather that PennDOT or the state legislature ignored that practical matter and made the decision on aesthetic grounds.
I just visited the PennDOT web page to try to link to a picture of this plate, but it appears not to be available these days. I wonder why...
Since most everyday Linux apps are GPL or BSD, and therefore come with source, who even cares?
Well, obviously, those apps aren't the reason that FreeBSD can run Linux binaries. Things like Maple, WordPerfect, and Acrobat Reader are.:-)
Works great for commericial developers, who can target Linux and get another OS for free. It would be nice if they'd spend an extra couple of minutes to make their installers work on a FreeBSD system, though. That's usually what needs a little hacking, in my experience. Fortunately, once somebody does it once, it often ends up in the Ports Collection and you can let that install from your media instead.
The only *BSD machines we have in this lab are testing IPv6, they seem fine but a bit old-school for my liking. Takes all sorts though.
Well, you know, Unix is kind of old, and FreeBSD developers generally like Unix a lot, and have considerable experience with a variety of different Unix systems. I think this is less true of Linux folks. Heck, I started with Linux, but have since embraced Unix in all forms. With apologies to George Orwell, some Unix are more Unix than others!
It would actually by hard to send a payload (e.g. nuclear waste) into the sun, because when you start out in the earth's orbit, you have a great deal of angular momentum that you have to dispose of. Of course, it might be doable if the garbage scow is, say, fusion-powered.:-)
Something that just occurred to me upon reading that the FBI is getting concessions, and recalling that Louis Freeh (the FBI director) has been so anti-crypto.
The US government does not prohibit US citizens from using cryptography, no matter how strong, as far as I know. PGP and so on are just fine for US citizens to use. The government just doesn't allow their export.
So, the crypto regulations that the US has are, in theory, supposed to prevent foreign interests from getting strong crypto. The regulations don't work, of course, but that's the motivation for them.
The FBI is a domestic law-enforcement agency. Practically everybody it's supposed to be watching is already allowed to use crypto. The people who would benefit from the export regs (if they actually did anything) would be the CIA and the NSA, which monitor international communication.
So, why is the FBI in a position to receive concessions when the export regs are relaxed? They shouldn't be in a position to benefit from the regulations in the first place!
I'm saying that the neutrino background is a lot higher than the radio background, because radio waves are easily absorbed, and because there's an enormous neutrino background from the epoch of matter-antimatter recombination. The closest parallel to that in the radio is the cosmic microwave background, which has a much smaller energy density and is not in a band we use for communication. I think you have no sense whatsoever of the differences involved. Just because there are natural sources for both doesn't mean that they are equal in magnitude.
Right, I assume that's what's meant by "if you can produce and detect neutrinos." On top of the concern you've written, there's also the problem that there's an enormous background of neutrinos whizzing around from stars, supernovae, and the matter-antimatter annihilation after the big bang. Separating your signal from this noise would be difficult, I would think, even if you could detect neutrinos readily.
The first solar neutrino detector was at the Homestake gold mine in Lead, South Dakota. It used perchloroethylene, a cleaning fluid, to provide chlorine which would be converted to argon in a reaction with neutrinos. You have to count the argon atoms periodically, so you don't get immediate notification of an event, nor good time resolution.
Mont Blanc uses a liquid scintillator, which emits a flash when a neutrino event occurs. This approach has the advantage of providing immediate notification and good time resolution.
The detector with the coolest name is Super Kamiokande, in Japan. It was originally designed to detect proton decay by observing the Cerenkov radiation from the fast electrons that would be a decay product, but it also can detect neutrinos. It also provides immediate notification and good time resolution.
The most famous result from neutrino detectors is that the observations of the solar neutrino emission do not agree well with theoretical predictions.
In addition to the detection of solar neutrinos, neutrino detectors also scored big-time by detecting the neutrino burst of supernova 1987a. Because neutrinos pass through just about anything, these observations were useful probes of what was happening at the center of the SN.
FreeBSD on Intel supports 4 GB of RAM. I don't know about Alpha. FreeBSD also supports files of up to 8 TB on FFS. Note that this is considerably longer than 2 GB.
Responding to those parts of your comment that I can actually parse: Quasars are very distant. Any determination of their age will require using H_0. That's what the Key Project has made a measurement of. It makes no sense to say that the new measurement of H_0 is wrong because computations using it produce results inconsistent with a different value of H_0, but that's what you're doing. Now, it makes more sense to estimate the age of something nearby, which you can do without using H_0, thereby getting a lower bound on the age of the universe in a way independent of cosmological parameters. The classic way to do this is isochrone fitting of globular clusters. You look at a GC near our galaxy, and use stellar models to determine the GC's age based on which stars are still around (massive, bluer, more luminous stars die earlier). Now, first, these methods used to give much different answers, with age(GC) considerably larger than age(Universe). That's bad. But more recent determinations of most quantities typically allow age(GC) age(Universe), with some time for GC's to form, within the errorbars. Putting that aside, there are a few problems with this method anyway: 1) It's been written here at least twice, and I'll make it a third. The HST H_0 Key Project did not measure the age of the universe. They measured H_0. To get t_0, you also need other cosmological parameters. And the difference between t_0 for an empty universe and a flat universe for a given H_0 is considerable, 50%! 2) If your stellar models are wrong, your isochrones that you use to fit GC stellar populations are wrong. Why assume that the GC method is right, and the measurements of H_0 and other parameters are wrong? Hell, they're probably all wrong! Anyway, may I suggest that you drop the flamebait and consider the possibility that the folks who have devoted their life to this science might have an edge over you in this matter? It's pretty presumptuous to stand up and declare work to be wrong when you hardly know anything about it.
First, the universe doesn't have an area, it has a volume. Three dimensions and all that. So if its radius goes up by a factor of two, the volume goes up by a factor of eight.
One of the important cosmological parameters, Omega (in its various subtypes, such as "Omega mass", "Omega baryonic", "Omega lambda" (the cosmological constant), "Total Omega") is essentially a measure of the density of the universe.
I assure you that it's the media. Wendy Freedman presented some of this Key Project's results at Caltech a few weeks ago, and while it was an interesting colloquium, nobody was running around thinking anything was more settled than it was the day before. You can be assured that in almost all cases, the scientific community (including the authors of a result) are a lot more conservative than the media in reporting it.
I also find it alarming that almost everywhere that I've seen the media report this result, it's phrased as "the age of the universe". They Key Project members produced a new measurement of the Hubble constant; the age of the universe requires knowing both the Hubble constant and other cosmological parameters which this project was not trying to measure, AFAIK.
While the blurb on Slashdot says the article is "about Linux," I'd like to point out that it's about free software in general, and Mom was running NetBSD in particular.
Slashdot Mirror
Indeed. Proof is for mathematicians.
Inflation theory originally required Omega_m=1, Omega_Lambda=0 (no cosmological constant). Since the supernovae results indicating an accelerating universe, it has generally been accepted that there is a cosmological constant. Typical favored values these days are Omega_m=0.3, Omega_Lambda=0.7, which is a flat (total=1) universe. Inflation theory has been revised to allow a cosmological constant, provided the universe is still flat.
My point is that inflation does not require a zero cosmological constant, and the claim of a flat universe doesn't, either. Indeed, if the Boomerang results did indicate both a flat universe and zero lambda, they would be suspect because this would constrain Omega_m to equal 1, which would contradict many observations.
What do we have in orbit that could do sub-millimeter imaging of the earth? A Hubble-sized (2.2m) mirror at 200 km operating at about 4000 angstroms has a diffraction limit in excess of 40mm.
Do you propose that we have a 90-meter telescope in orbit? Or one that's orbiting low enough to collide with a small mountain?
Must be a different Palomar than I use, then. The one I know is on the ground, and is an optical telescope. The mirror is polished to optical tolerances, and operates at normal incidence instead of grazing incidence. The atmosphere there is not magically transparent to X-rays, and in fact it's probably not transparent to much at all today, since it's raining.
If it's at z=5.5, then 1500 A in the observer frame is 230 A in the rest frame, which should give you quite a nasty sunburn.
No. There is a testbed optical interferometer at Palomar, but it's used for things like binary stars. It's an engineering test for the Keck interferometer.
You want interferometers and space telescopes to look at small detail, better than the 0.5 to 1 arcsecond you get through the atmosphere. But that doesn't matter here! You still get basically all of the light from the quasar on your mirror (as the atmosphere is pretty transparent), and it doesn't matter if it's smeared out a little. There's no detail to see, anyway.
Agreed, but note that the spectrographic followup was at Keck. That's a common mode of operation these days: If you can image it on the 200, you can get a low-resolution spectrum at Keck.
I think that previously, the most distant objects were quasars found by the Sloan Digital Sky Survey folks.
I don't think you understand how these measurements work.
The HST Key Project you're refering to was a project to determine the Hubble constant, H_0. Lots of people have measured H_0 and get a variety of values. The Key Project people got theirs. If you combine a value of H_0 with other cosmological parameters that you think are correct, you can get an "age of the universe". That's what Slashdot and the NY Times like to report, but it's not the fundamental quantity that was measured.
Now, you've got Dan picking out quasars on the 200-inch and he gets a spectrum at Keck. The photons don't land on the detector and announce, "Hey! I've been flying for 14 billion years! It's nice to finally excite an electron!" No, you get a spectrum that tells you the redshift. Dan converts the redshift into a distance using his favorite value of H_0, which might not be the same as the Key Project's.
You used to hear about problems because stellar astronomers would believe that the ages from globular clusters (based on stellar physics) were older than the age of the universe (from measurements of cosmological parameters). That's not what's happening here. Here, you just have people favoring different values of H_0, because they think one value was obtained more reliably than the other.
If you think the Hubble Space Telescope is some sort of failure, you don't know what you're talking about. Its initial problems were repaired, quite quickly IMHO for the task involved, and it's been a remarkably productive scientific instrument that's fully lived up to its potential. (The corrective optics were installed less than two years after launch; it's now been ten years since launch, and it's going strong. That's really not so much "downtime", especially when you consider that the telescope wasn't useless despite the figure error, and much of the early time would have been for engineering time anyhow.)
Now when we launch SIRTF and other instruments so far away that the shuttle can't repair them, the price for technical problems will be profoundly higher.
The worst of which, from the standpoint of recognition, is the Pennsylvania "Flagship Niagra" plate. It has white lettering on a pale brown image, giving very little contrast between the lettering and the background. The State Police were opposed to this design for good reason, but I gather that PennDOT or the state legislature ignored that practical matter and made the decision on aesthetic grounds.
I just visited the PennDOT web page to try to link to a picture of this plate, but it appears not to be available these days. I wonder why...
Yes, lots of places use SSNs for ID numbers, and that's bad.
What you're missing that's even worse in this case, is that it's on a badge that you have to wear for everyone to see.
Well, obviously, those apps aren't the reason that FreeBSD can run Linux binaries. Things like Maple, WordPerfect, and Acrobat Reader are. :-)
Works great for commericial developers, who can target Linux and get another OS for free. It would be nice if they'd spend an extra couple of minutes to make their installers work on a FreeBSD system, though. That's usually what needs a little hacking, in my experience. Fortunately, once somebody does it once, it often ends up in the Ports Collection and you can let that install from your media instead.
The only *BSD machines we have in this lab are testing IPv6, they seem fine but a bit old-school for my liking. Takes all sorts though.
Well, you know, Unix is kind of old, and FreeBSD developers generally like Unix a lot, and have considerable experience with a variety of different Unix systems. I think this is less true of Linux folks. Heck, I started with Linux, but have since embraced Unix in all forms. With apologies to George Orwell, some Unix are more Unix than others!
It would actually by hard to send a payload (e.g. nuclear waste) into the sun, because when you start out in the earth's orbit, you have a great deal of angular momentum that you have to dispose of. Of course, it might be doable if the garbage scow is, say, fusion-powered. :-)
Something that just occurred to me upon reading that the FBI is getting concessions, and recalling that Louis Freeh (the FBI director) has been so anti-crypto.
The US government does not prohibit US citizens from using cryptography, no matter how strong, as far as I know. PGP and so on are just fine for US citizens to use. The government just doesn't allow their export.
So, the crypto regulations that the US has are, in theory, supposed to prevent foreign interests from getting strong crypto. The regulations don't work, of course, but that's the motivation for them.
The FBI is a domestic law-enforcement agency. Practically everybody it's supposed to be watching is already allowed to use crypto. The people who would benefit from the export regs (if they actually did anything) would be the CIA and the NSA, which monitor international communication.
So, why is the FBI in a position to receive concessions when the export regs are relaxed? They shouldn't be in a position to benefit from the regulations in the first place!
The web side of Hotmail is FreeBSD, the mail side is Solaris.
I've never heard any claim that Yahoo uses Linux. Can you provide a reference?
I'm saying that the neutrino background is a lot higher than the radio background, because radio waves are easily absorbed, and because there's an enormous neutrino background from the epoch of matter-antimatter recombination. The closest parallel to that in the radio is the cosmic microwave background, which has a much smaller energy density and is not in a band we use for communication. I think you have no sense whatsoever of the differences involved. Just because there are natural sources for both doesn't mean that they are equal in magnitude.
I was under the impression that it's still an open question whether neutrino oscillations occur.
Right, I assume that's what's meant by "if you can produce and detect neutrinos." On top of the concern you've written, there's also the problem that there's an enormous background of neutrinos whizzing around from stars, supernovae, and the matter-antimatter annihilation after the big bang.
Separating your signal from this noise would be difficult, I would think, even if you could detect neutrinos readily.
Mont Blanc uses a liquid scintillator, which emits a flash when a neutrino event occurs. This approach has the advantage of providing immediate notification and good time resolution.
The detector with the coolest name is Super Kamiokande, in Japan. It was originally designed to detect proton decay by observing the Cerenkov radiation from the fast electrons that would be a decay product, but it also can detect neutrinos. It also provides immediate notification and good time resolution.
The most famous result from neutrino detectors is that the observations of the solar neutrino emission do not agree well with theoretical predictions.
In addition to the detection of solar neutrinos, neutrino detectors also scored big-time by detecting the neutrino burst of supernova 1987a. Because neutrinos pass through just about anything, these observations were useful probes of what was happening at the center of the SN.
Notes for a talk I gave in an undergrad class are available at http://wopr.caltech.edu/~mph/papers /neutrino.ps. References to other works are included.
FreeBSD on Intel supports 4 GB of RAM. I don't know about Alpha. FreeBSD also supports files of up to 8 TB on FFS. Note that this is considerably longer than 2 GB.
FreeBSD does have an Alan Cox. It's just
a different one.
"Collect the entire set."
Responding to those parts of your comment that I can actually parse: Quasars are very distant. Any determination of their age will require using H_0. That's what the Key Project has made a measurement of. It makes no sense to say that the new measurement of H_0 is wrong because computations using it produce results inconsistent with a different value of H_0, but that's what you're doing. Now, it makes more sense to estimate the age of something nearby, which you can do without using H_0, thereby getting a lower bound on the age of the universe in a way independent of cosmological parameters. The classic way to do this is isochrone fitting of globular clusters. You look at a GC near our galaxy, and use stellar models to determine the GC's age based on which stars are still around (massive, bluer, more luminous stars die earlier). Now, first, these methods used to give much different answers, with age(GC) considerably larger than age(Universe). That's bad. But more recent determinations of most quantities typically allow age(GC) age(Universe), with some time for GC's to form, within the errorbars. Putting that aside, there are a few problems with this method anyway: 1) It's been written here at least twice, and I'll make it a third. The HST H_0 Key Project did not measure the age of the universe. They measured H_0. To get t_0, you also need other cosmological parameters. And the difference between t_0 for an empty universe and a flat universe for a given H_0 is considerable, 50%! 2) If your stellar models are wrong, your isochrones that you use to fit GC stellar populations are wrong. Why assume that the GC method is right, and the measurements of H_0 and other parameters are wrong? Hell, they're probably all wrong! Anyway, may I suggest that you drop the flamebait and consider the possibility that the folks who have devoted their life to this science might have an edge over you in this matter? It's pretty presumptuous to stand up and declare work to be wrong when you hardly know anything about it.
First, the universe doesn't have an area, it has a volume. Three dimensions and all that. So if its radius goes up by a factor of two, the volume goes up by a factor of eight.
One of the important cosmological parameters, Omega (in its various subtypes, such as "Omega mass", "Omega baryonic", "Omega lambda" (the cosmological constant), "Total Omega") is essentially a measure of the density of the universe.
I assure you that it's the media. Wendy Freedman presented some of this Key Project's results at Caltech a few weeks ago, and while it was an interesting colloquium, nobody was running around thinking anything was more settled than it was the day before. You can be assured that in almost all cases, the scientific community (including the authors of a result) are a lot more conservative than the media in reporting it.
I also find it alarming that almost everywhere that I've seen the media report this result, it's phrased as "the age of the universe". They Key Project members produced a new measurement of the Hubble constant; the age of the universe requires knowing both the Hubble constant and other cosmological parameters which this project was not trying to measure, AFAIK.
If they don't have ssh, that's what S/Key is for.
While the blurb on Slashdot says the article is "about Linux," I'd like to point out that it's about free software in general, and Mom was running NetBSD in particular.
Whatever this system is, it's not the first.
A good overview of extrasolar planets may
be found at http://www.ph.adfa.edu.au/e-mamajek/ex o.html.