Agreed. I worked for the NSA several years ago, and the importance of the air gap was paramount. I don't see how they can possibly be thinking of getting rid of that.
Even assuming that you have one physical machine running n independent virtual machines which are absolutely and utterly independent of each other (note that I don't think this is actually possible, I'm saying just assume that it is), there remains the problem of getting information in and out of the box. As it stands, you've got seperate ethernet cables, routers, the whole nine yards for the outside internet and the classified intranets. With VMWare, would you be running that over one physical network? I suppose you could try to tunnel the secure box's connections over the unsecure ethernet, but that just seems to me like you're asking for trouble.
Basically, it boils down to, with two networks and an air gap, you know you're secure as much as is humanly possible. The moment you start running all your data over one pipe, you open yourself up to all sorts of trouble, with intercepted connections, eavesdropping, and all that. I can't ever see this sort of thing being approved by the people in charge of security, no matter how much the cost-cutters beg.
Lame. I'm sorry old guy in the bed with a destroyed trachea, but Phillip Morris wont change their product until
idiots like you decide to stop putting a roll of burning tobacco between your lips. Quit bitching and accept
responsibility for what you have done to yourself.
I'd say he *has* accepted responsibility, actually, the responsibility of trying to get other people out there to not make the same mistake as he did. What, he's supposed to say "oops, I screwed up." and just sit in bed? No, this guy's working trying to actually make the world a better place by preventing other people from ending up like him. Have you taken any action to make the world a better place today?
I agree, smoking is stupid - but at the same time, I've lost a fair number of relatives who I loved dearly to lung cancer. My mom's sister wasn't stupid. She was a damn intelligent woman, a loving mother, and had the best damn sense of humor in my whole extended family. But she got hooked on cigarettes back in the 60s and it took its toll, fatally. My uncle's partner passed away a few years ago, and let me tell you, a collapsed lung is an ugly thing. Drowning in your own blood is an ugly thing. But even after this, even knowing how deadly they were, it took my uncle Bob years to quit himself, because of how addictive the things are.
Are these people's deaths their own fault? To some extent, yes. But honestly, they made their decisions to smoke 30-some years ago, back when they didn't know any better. But the tobacco companies did. That's a crime. And today everybody knows better, or at least they should. And so I applaud the man in the commercial - and everyone else in that foundation - for working on getting the information out, so that people know the consequences of their decisions.
Still, with all of that, NASA rolled out Atlantis a few weeks ago, knowing that a concern about--you guessed
it!--the SRB separation mechanism would likely delay the launch. The cost of rolling out and rolling back is
expensive, yet in the name of good PR, NASA did it anyway. Idiots.
I'm not sure where you're getting this information from. NASA rolled out Atlantis fully intending to launch her. However, after that was done test results came back on some spare cables which were found to have decayed while in storage. NASA then decided to roll back Atlantis and take whatever steps were necessary to test the SRB comm cables in her, even though those cables were believed to be fine.
This is an example of the system working. NASA was all set to launch, but when they found out there was even a slight chance that the cables they were using might be frayed, simply because they found a completely different set of cables elsewhere that was, they made the decision to roll the shuttle back to the VAB, at a cost of millions of dollars and a delay of weeks. They did the tests, the cables did indeed check out A-OK, and now they can launch in clean conscience. There's nothing idiotic about any of this as I see it.
As I have said in another post elsewhere, most of these objections are un-founded. The beam of a laser *does* spread out over distances, and it spreads out a heck of a lot when you're dealing with as the tremendous distances between stars. Beyond that, it's actually very easy to broadcast a *wider* beam, in fact easier than sending a narrow beam. Just de-focus the telescope you are using to aim your laser and you can have the beam as wide as you want. It's very, very easy to get a beam easily wide enough to cover an entire solar system at once.
Beyond that, there is no problem about having to calculate the motions of stars over time. We're trying to target close-by stars, which means the travel time is *not* the thousands of years you talk about, but rather only tens or hundreds, which means the stars move hardly at all. Even for more distant stars, note that the galaxy takes a quarter *billion* years to rotate once. Even ten thousand years doesn't move anything all that far. Besides, measuring and tracking the proper motion of stars isn't the computational hassle you seem to think it is. We know the proper motion for thousands of stars, and NASA is working on improving that tenfold with the upcoming SIM mission.
You also seem to think that broadcasts leaking out in all directions are the way to go. THat's not at all clear, because any broadcast spread over the whole sky will necessarily be weak in power. By focusing the beam through a telescope, whether radio or optical, you can get beam powers hundreds of thousands of times brighter than with an omnidirectional transmitter. So even for radio communications, I'll take the extra effort of aiming at different stars for a hundred thousand times stronger signal, thank you very much.
1. Optical communication across interstellar distances is going to suffer from severe extinction (signal absorption
by intervening dust). Even if you can generate a laser pulse brighter than the sun, interstellar extinction is a big
problem to overcome.
Yes, extinction is going to be a consideration. But it's not all that hard to overcome. Look at it this way: If your laser pulse is 100x brigher than your sun on this side of the dust cloud, it's going to be 100x on the other side, too, even if both the sun's light and the star are both reduced by a factor of ten or whatever. They scale together. Anywhere you can see our sun from, and more, you could see our lasers. In fact, if you use a laser on the redder side of things, say even in IR, you're going to have much smaller extinction for your laser than for the star's light, and you'll win out even more in the long run.
Furthermore, radio signals suffer phase shifts and delays due to the intersteller medium. This tends to spread out a signal, originally sent at a narrow wavelength range, into a broader and fainter signal. You don't have this problem with IR or optical lasers, so that's a win for them.
2. A laser beam is very tightly confined, and would have to be aimed very precisely in order to "hit" it's target. The
probabability that the Earth would just happen to cross one of these "lines of communication" is incredibly small.
Wah, major error! Time to go brush up on your optics some more. A laser beam does spread out as it travels, in exactly the same way and at exactly the same rate as radio waves do. Diffraction-limited optics is the same for all frequencies:
S = lambda/D*R
That is, the beam size is proportional to the wavelength, divided by the size of your transmitting telescope, times the distance the beam has traveled. For larger lambda (i.e. radio) you need to use a larger telescope to get as focused a beam - but we do that already, that's why radio telescopes are so much larger than optical ones. Besides which, you neglect the fact that it's *trivially* easy to send as wide a beam we want, just by de-focusing the telescope a little or using a smaller telescope. It's sending narrow beams that's hard! Wide is easy.
The long and the short of it is this: By the time ANY signal, radio, optical, or whatever, has traveled the many lightyears to some other star, the beam will have spread out to be *much* larger than the target solar system. This is true because all forms of light spread out the same way as they travel, and because it's trivial to send as wide a beam as we want just by de-focusing things a bit.
I mean there is no REAL difference between "radio" and "light" is there? They're both EM particle/waves aren't
they?
Yes, this is absolutely right. They're just different frequencies, different sizes if you will, of the same basic thing. However, you still need different technologies to deal with them: You can't broadcast radio with your flash light, and you can't see anything by the light of a cell phone tower. For a variety of technical reasons, it might be easier for a large civilization to use lasers to communicate instead of radio. Not necessarily easier, just maybe. And so that means it's worth at least taking a look!
For example, lasers are small and can be re-targeted between stars very rapidly. Paul Horowitz has some designs for a setup with moving mirrors which lets you keep your laser stationary but aim its beam at dozens of stars every second. Radio, on the other hand, requires tremendous dish antennae to aim properly, so you can't slew between many stars anywhere near as fast. If you're an alien civilization trying to broadcast to as many targets as you can with limited resources, this might be a good reason to choose the optical over the radio.
Re:QUANTUM TELEPORTATION POSSIBLE?
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Would it be possible to create a huge bose-einstein condensate, break it in half and flatten it out?
It's not nearly as easy as you describe it, no. You probably could seperate a BEC into two smaller condensates, but I don't see any easy way to do it without breaking the entanglement between the two parts. Flattening it out could maybe be accomplished by a sufficiently perverse arrangement of electric and magnetic fields, but remember, the condensates we're talking about these days are *very* small, exist only in vaccuum chambers, and involve only a small handfull of atoms. We're not going to be manufacturing person-sized sheets of BECs any time soon.:-)
If so, then you would merely need to transport the two 'gateways' whereever you wanted and teleport between the two
locations.
I'm afraid not, no. That's not how quantum entanglement works. Even though you can get instantaneous action at a distance, there's still no way to transmit information faster than light. Basically, all entanglement tells you is that when you measure thingy A, then whatever answer you get, instantly you know thingy B is in the same state. They're both spin up, or both protons, or both right-handed photons, or whatever. But you have no way of controlling *what* they both are, you just know they're the same. There's no way to take your unmeasured thingy A and force it to be spin up, which would force thingy B to be also spin up. All you can do is measure it and know that you're also getting a measurement of thingy B at the same time, no matter how far away it is.
No FTL communications or transfer that we could use, alas.
Nope. [was Re:Artificial Black Holes]
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I've heard that this capability might allow scientists to create artificial black holes.
No, I don't think it can. What's been achieved here by Hau & Lukin is, as has been said in some of the other posts, more accurately described as taking a pulse of light and storing it in a gas of atoms in such a way that you can get the original pulse back out later, rather than actually stopping an individual photon in one place. That, as far as relativity says, is physically impossible; The rest frame is undefined for massless particles so it's meaningless to try to think of what one would look like if it could be stopped.
And since all that's been done here, fundamentally, is taking some energy and storing it in atoms, albeit in an extremely clever way, it has nothing to do even remotely with the way light is trapped by the warping of spacetime near a singularity. The neat applications of this work are in quantum computing and communications, as has been said, not in designer black holes.:-)
And let me add that I had the good luck to work with Lene Hau when I was an undergraduate five years ago, working on building some equipment for rubidium BEC experiments much like this. It was a great experience and I learned a lot of good experimental science from her, so I'm very pleased with her success lately, even though I ended up going off in a different direction myself so I only worked with her for the one semester.
But you've got to admit that the signal from a Sol-like system is a lot harder to detect than the signal from
one of these systems with huge planets close in or tidally locked.
Absolutely.
My point is that more time is needed to look for hard-to-find systems before we can begin to discuss if
current models can reproduce the range of mass distributions observed.
Well, yes and no. We certainly need a lot more data before we can be confident in saying that systems like our own are rare. But the current problem right now is that our current models can't explain the formation of 17 jupiter mass planets at all, and we know that there's at least a couple of those out there. So at the very least we need to expand the range of types of planets and solar system we can model. But I agree with you that we don't yet have anywhere near enough data to say anything definitive about the distribution.
On a more technical note: We discover planets from the wobbling of the suns. Wouldn't this imply that the results we find depend on
the method we use? How much does our own sun wobble, and can we detect how many planets our sun has because of it? If we
can't even classify our own sun correctly using the same technique, there's no reason to draw any final conclusion in the first
place.
Yes, absolutely. The motion of all the major bodies in the solar system including the sun, the planets, and most of the larger asteroids, is known to extremely high precision. After all, we can (usually!) fly space probes to Neptune and only be a few dozen miles off target after a journey of several billion - that takes some serious accuracy in our knowledge of the orbits, so NASA put a lot of effort into refining that knowledge thirty years ago, and it's quite good.
With that, it's simply a matter of taking the radial velocity measurements of other stars, and subtracting off the motion of the sun to get the proper answers. All those graphs you see on exoplanets.org and elsewhere are relative to the center of mass of the solar system, not to the Earth itself. But since the solar system orbits are known so well, this subtraction can be done to a very high degree of accuracy and essentially doesn't contribute any uncertainty to the final results.
Don't know what the definitive answer is, but my guess is it's just time and $$. Once they get all the dishes properly converted over so they can work as single-dish astronomical instruments, then they'll start thinking about maybe hooking them together, but I doubt that will be for a while. Doing interferometry would require a lot of setup in terms of building a correlator and connecting everything up to it, and it seems like these guys are still just getting going with the site and also are trying to do stuff on a low budget. But yeah, it'd certainly be great if they can do that eventually.
On the other hand, the article indicates that the thing's mass is
17 times Jupiter's, while it is within 10% of Jupiter's diameter.
Just a note that the number for its diameter is an absolute and complete guess, albeit an educated one. There's no actual observational data to back that up yet. Basically, if you assume the planet is made out of the same stuff as Jupiter (hydrogen and helium) and that it masses 17 times what Jupiter does, and you plug those numbers into your equations for modeling the size of a planet, then you get an object only slightly different in size than Jupiter, despite the large difference in mass. The reason is that since the planet is composed of gases, it is extremely compressible: As you add more mass, it just gets denser and denser rather than bigger and bigger. This is also the explanation for why Saturn is so close in size to Jupiter while massing only about a third as much - it's very low density. Indeed, a 17 jupiter mass object is expected to be *smaller* than Jupiter, not larger, since it will be so much more dense due to the stronger gravity.
The real question is could we detect our own solar systems at these distances (>100 LY from Earth) with these methods. I'm no
astronomer, but I don't think so.
The distance doesn't actually matter all that much, as we're looking at doppler shifts rather than images, and the doppler shift is the same for all distances. So the only way the distances comes in is that farther away things are fainter, and thus require bigger telescopes and longer integrations to get the same signal to noise.
That said, while I haven't ran the numbers myself to check, Geoff Marcy says that he could indeed detect Jupiter if he were in some other star system - he couldn't have five years ago, but he could now. The biggest issue is simply that to detect a planet which takes 12 years to go around the sun (e.g. Jupiter) you need data which spans a good part of 12 years. To see planets out past that is correspondingly harder. We've got ~ 6 years of data now, less for many stars. It'll be interesting to see how things play out over the next decade or so with this.
In fact, my bet is that the next big discovery will be earth sized moons around the transiting planetary system HD 209458, as you can
detect the presence of a moon by timing the exact moment of the beginning of the planets' eclipse of the parent star. It requires a lot of
careful work, though...
Have you seen the results of the HST STIS observations of 209458? Dave Charbonneau gave a talk on them here in the fall, although I can't find the paper online on ads or arXiv right now. Really great stuff, photometry accurate to one part in something like ten thousand, and the punchline (well, one of the punch lines) was that they were sensitive to the detection of moons of 1 Earth mass or larger. Didn't see any, of course, but it's quite exciting that they were able to get the error bars even that tight. Certainly NGST could drop them low enough to see Ganymede-class objects, and SIM could probably detect 'em too, though through a completely different method. The real question is whether anyone can beat that and do it on the ground sometime before 2005.:-)
When the next generation of big, badass telescopes goes into production, it's going to be neat to see how man moons this guy has
It'll be a good long while before we can see any moons on these guys - we can't even directly see the planets yet, much less anything smaller. All of the detections thus far have been via indirect effects, specifically the motion induced in the parent star by the planet's orbital motion around it. While you could in principle detect moons around the planet in the same way, it would require precision several orders of magnitude higher than what we have now.
That said, it certainly seems plausible for objects of this size of have moons (after all, Jupiter has at least 28 and Saturn 30, using the latest numbers announced yesterday - yes, we're still finding new moons around them even now!) but I don't think anyone would consider it at all 100% certain - we have no idea how the big guy especially formed, and thus no a priori reason to think it's necessarily anything like the formation of our own giant planets.
If anywhere in explored/known space is going to have a M-Class planet to live on, this
seems like a likely candidate.
Nope. With a 17-40 M_Jup object in a 2.9 AU orbit with 0.2 eccentricity, and a 7-10 M_Jup object in at 0.3 AU leave effectively no space for terrestrial planets in between them. Any smaller worlds which were there at one point have most likely been ejected from the system by gravitational effects from the giants. (Think billiards with planets, only one of the balls you're using is a bowling ball.) I *really* doubt we're going to find any Earth-like worlds in this system.
Let me try to provide some perspective on what I think Geoff may have meant when he called these planets "frightening" - I'm a student in the Berkeley astronomy department and so I know him personally.
While I haven't actually talked with him yet about these particular planets, and thus can't -definitively- answer the question of why he chose that particular word, I can at least extrapolate what he was getting at from conversations I've had with him at points over the past year or so.
Ten years ago, we thought we understood the solar system, at least in its general structure of small rocky planets in close, and gas giants further out. Five years ago, Mayor and Queloz found the first exoplanet, and it's been a landslide since then. Marcy and co. have *tons* more planets in their data analysis pipeline, and while I don't know any of the specifics, I bet some of them are at least as surprising if not more so. It's a credit to the whole team that they just pile on more and more observations and only publish once they're really really sure of their data and conclusions. So when we say we know about over 50 extrasolar planets today, we're quite confident in those facts.
And here's the kicker: Not a single one of the solar systems we have discovered looks even remotely like our own.. Either you've got giant planets way close in by the primary, or they're farther out but in highly eccentric orbits which leave no room for the possibility of terrestrial planets, or else now they're ridiculously high mass. The nice organized pattern of our own solar system? Nowhere to be found.
It may very well be that our home is the exception and these supermassive, close in, and highly eccentric gas giant planets are the rule instead. If, ten years from now, after the SIM spacecraft has flown and we've surveyed tens of thousands of stars looking for planets, it may well be that star systems like our own are vanishingly rare. And if that's the case, then the chances of their being other Earths out there, other worlds which we could someday colonize, or on which might evolve other intelligent races, then that becomes much, much less likely. No Tattooines, no Vulcans, no Wunderlands, just lots and lots of Jupiters. And that's what's frightening about all this.
With the proper computer equipment, they might be able scan large chunks of sky quickly, due to the
speed of the dishes. Plus, they'd be a perfect reference check for the SETI folk, due to the speed at
which they can test a signal and localize it.
It's not quite that easy. The sorts of signals we deal with in astronomy are really quite faint. To get good signal-to-noise, you generally have to point at one spot on the sky for a good while - minutes to hours, usually. Hence the desire for the dishes to track exactly at the rotation rate of the Earth, but in the opposite direction, thereby enabling them to stare in one spot while the Earth turns under them. Yes, with faster slew you could glance at a large area of the sky quite rapidly, but you wouldn't get any usable data that way.
Anyone have any idea if there's an email or snailmail address for someone at the FCC we can complain to? Perhaps a write-in campaign with a couple thousand people all saying that they vow to never purchase any consumer electronics containing the "obliteration code" would accomplish something. Then again, maybe not, but it's worth it to at least get the ball rolling.
The *kids*, on the other hand, will grow up believing that the normal way of the world is for corporations
to have ulimate control over everything.
Not a chance. My little sister is 16. She's online every day with her friends, IM'ing away and trading MP3s on Napster. She just got a CD-RW to enable her to copy CDs and burn MP3s to disk and all that. And it's not just her - damn near the entire net-enabled population between middle school and college is having a hell of a good time trading music. You think they're going to just give that up? You think that the teenagers of the world are going to just sit back and let corporations tell them what to do? You seem to be forgetting that one of the hallmarks of youth is rebellion against whoever and whatever you're not supposed to be doing.:-)
Rather, I see a generation growing up that doesn't particularly give a damn about overly restrictive copyright laws and is going to keep on having fun and using technology to do so in ever more interesting ways. I just hope that we get people in the legislature who see this way before too long.
So how many slashdotters out there went to CTY, CTD, TIP, or the like? How many of you credit these programs with changing your lives? *grin*
It's true, what others have said about the importance of learning social skills. However, the way to do this is not through baseball or whatever. The way to do it is by bringing lots of brilliant kids together and letting them socialize with each other. Academic summer programs like CTY are IMO probably the best way to do this, because they draw kids from a much wider area and thus can draw a larger number of wonderful minds, while at the same time putting them in a fun summer camp environment that caters to the fact that smart kids are still kids after all and want to run around and throw frisbees and go swimming, in between learning Scheme and writing novels.
I can still remember the very first day I spent at CTY (F&M, july of '93) so very clearly. The scene that stands out most in my mind is sitting in the lounge in the dorm and talking about computers and space travel with a bunch of other 13 year olds. It just totally blew me away to finally be meeting kids my own age I could connect with. The experiences I had there that summer, and the following summers, completely changed me around from a total introvert, alone and nervous, to a very outgoing and self-confident young man with lots of other (very smart;-) friends.
Flash forward three or four years. Many of the people I knew from CTY ended up with me at Harvard, or nearby at MIT, or Princeton, or wherever. Four years after that, we're grad students spread out all over the place, but we're still great friends, and a bunch of us get together for New Year's every year. I absolutely credit CTY for changing my life by bringing together the right people at the right time.
The only peer group for a gifted kid is other gifted kids. So do whatever you can to help your youngster find his peers, and he and they will thrive.
Io does actually have a bit of an atmosphere, mostly sulpher gases and other things you don't really want to breath, but you're correct that it wouldn't be enough to burn up the space craft; it would impact the surface and eventually get buried in one of the frequent lava flows. This is considered acceptable because the conditions on Io are harsh enough that we're pretty damn sure (a) there's no native life there (b) even if some bacteria stowed away on Galileo, they couldn't live there either. Both of these hold true for Jupiter, too. And even if you leave them both aside, the impact velocity with Jupiter will be vastly higher (it's next to impossible to hit Jupiter at anything *less* than 70,000 kph due to our old friend Mr. Humongous Gravity Well.) so the impact heating will be that much greater, moving us into the realm of serious overkill sterilization by heating. Which is, of course, precisely what we want.
Others have already commented on some of the factual inaccuracies in your post, and on the fact that it's frankly impossible to turn any of these space craft over to third parties unless those parties have their own multi-billion dollar deep space communications networks. Beyond that, though, I have to question your basic assumption that it's bad for NASA to end a mission when it runs out of money.
Sure, it would be great if NASA could fund every mission indefinitely! But heck, it would be nice if people would pay us humble grad students a million bucks a year, too. That's just not going to happen. In the real world of science, with limited funding, you have to balance the potential return of spending $X on some experiment with the potential return of $X on a -different- experiment. Sometimes it makes sense to extend the lifetime of the first experiment - Witness the fact that the Voyager and Pioneer spacecraft are all still returning valuable data today, witness the DS1 extended mission, witness the fact that Galileo is still working today several years after the "end" of its mission. NASA *does* extend missions, when it makes scientific sense to do so But sometimes you really have gotten as much as you can from a mission, or sometimes you have new projects you want to start that need the money. Then in that case it *does* make sense to terminate older missions and start new ones. Do realize that the decision to extend Mission Y for another two years usually means postponing or even cancelling Mission Y+1. It's not nearly as simple or as one-sided as you seem to think it is.
From the article: Some of her finds include: Xena: Warrior Princess vet Jay Laga'aia, who's playing a loyal security officer, and Aussie Leeanna Walsman, who'll take on the physically-demanding role of a new highly-killed bounty hunter.
Highly killed, huh? Tough job, but someone's gotta do it...
Is there some advantage that a single mirror gives that cannot be duplicated using multiple smaller mirrors?
No, not if given a sufficiently large number of smaller mirrors, but that number may be very large. But multiple mirror systems (which are called interferometers) are much, much harder to build than single mirror systems. Before getting into the real details, here's a quick crash course in telescope design:
The two most important properties of any telescope are its light-gathering power and its resolution. The first is how many photons per second it can catch. This is directly related to the area of the scope: a 8m scope has 16x the area of a 2m scope, so it needs 1/16 the exposure time to get a comparable image. In other words, a single VLT dish can capture as many photons from a given source in an hour and a half as the Hubble would get in a full day. So obviously bigger scopes are better. In the case of OWL, a 100m telescope has the same area as 100 10m telescopes. So you'd need a pretty hefty array to get the same light gathering power.
The second property we care about is the resolution, which is the size of the details which can be seen in images from the telescope. This is where interferometer arrays really shine. A telescope with finer resolution can see smaller details, obviously a good thing. Now without going into the details, the resolution is limited by quantum mechanics to be proportional to Wavelength/Diameter, where Wavelength is the wavelength of light you are using and Diameter is the side-to-side diameter of the telescope. So to see fine details, you want W/D to be as small as possible. There are two ways to do this.
Way one: Use as small a wavelength as possible. If you use a bigger wavelength, you need a larger diameter to compensate and still get decent images- which is why radio scopes (large wavelength) are all humongous.
Way two: Use as large a diameter as possible. Here's the kicker, which is why arrays are so desirable: In a properly built interferometer, the "Diameter" is NOT the diameter of a single dish, but rather the total side-to-side distance of the entire array! So if you've got two 1m telescopes 100m apart from each other, you have the resolution of a 100m telescope! (but only the light-gathering power of a 1.4m telescope, because that's all the area you have.)
Now, the thing is, hooking together the elements of an interferometer to get this good a resolution is highly nontrivial. You don't just take a different picture with each scope and superimpose them in photoshop. Rather, you have to mix together the full raw signals from each telescope in a very precise way so that the phases of the different signals interfere with each other, canceling out in some parts, adding up in others, and giving you the super-detailed final product you desire.
In the case of radio, the frequencies dealt with are on the order of a couple hundred megahertz. (Higher frequencies in the GHz can be mixed down to MHz via heterodyne receivers.) We have electronic components that can work at MHz speeds - amplifiers and high-speed tapes and relays and all that. Thus it's possible to do all the mixing in electronics, which is how the VLA in New Mexico works, and how the world-wide VLBA works, too. Take a dozen scopes around the world, have them all observe things simultaneously, recording onto high-speed mag tapes, then Fedex all the tapes to a computer center and run them all through a correlator, and out pop your images.
In contrast, at visible light, we're dealing with frequencies many orders of magnitude above what our fastest electronics can handle. There's no way in hell we can handle petahertz signals in electronics right now. Which means the only way to do the mixing is optically: stick a mirror at the focus of all the telescopes, and physically direct all the light from all of them to the same focal plane, via light paths of -exactly- the same distance (and we're talking "nanometers" when we use the word "exact" here.) Right now the limit for this sort of thing is a hundred meters or so, barely. It will be many, many years before we can pull off a 1 km optical interferomter on the ground, but there are certainly people working on it.
This is, unsurprisingly, really damn hard. Only in recent years have we started having any success with optical interferometry at all. It's very new technology. It's extremely promising, in that you can use it to get vastly higher resolution than you can with a single dish scope, but it's very difficult and extremely costly. Couple that with the fact that you still need large telescopes to have enough collecting area to see faint objects, and it becomes clear that there will still be a place for large single scopes for a long time to come.
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Even assuming that you have one physical machine running n independent virtual machines which are absolutely and utterly independent of each other (note that I don't think this is actually possible, I'm saying just assume that it is), there remains the problem of getting information in and out of the box. As it stands, you've got seperate ethernet cables, routers, the whole nine yards for the outside internet and the classified intranets. With VMWare, would you be running that over one physical network? I suppose you could try to tunnel the secure box's connections over the unsecure ethernet, but that just seems to me like you're asking for trouble.
Basically, it boils down to, with two networks and an air gap, you know you're secure as much as is humanly possible. The moment you start running all your data over one pipe, you open yourself up to all sorts of trouble, with intercepted connections, eavesdropping, and all that. I can't ever see this sort of thing being approved by the people in charge of security, no matter how much the cost-cutters beg.
I'd say he *has* accepted responsibility, actually, the responsibility of trying to get other people out there to not make the same mistake as he did. What, he's supposed to say "oops, I screwed up." and just sit in bed? No, this guy's working trying to actually make the world a better place by preventing other people from ending up like him. Have you taken any action to make the world a better place today?
I agree, smoking is stupid - but at the same time, I've lost a fair number of relatives who I loved dearly to lung cancer. My mom's sister wasn't stupid. She was a damn intelligent woman, a loving mother, and had the best damn sense of humor in my whole extended family. But she got hooked on cigarettes back in the 60s and it took its toll, fatally. My uncle's partner passed away a few years ago, and let me tell you, a collapsed lung is an ugly thing. Drowning in your own blood is an ugly thing. But even after this, even knowing how deadly they were, it took my uncle Bob years to quit himself, because of how addictive the things are.
Are these people's deaths their own fault? To some extent, yes. But honestly, they made their decisions to smoke 30-some years ago, back when they didn't know any better. But the tobacco companies did. That's a crime. And today everybody knows better, or at least they should. And so I applaud the man in the commercial - and everyone else in that foundation - for working on getting the information out, so that people know the consequences of their decisions.
I'm not sure where you're getting this information from. NASA rolled out Atlantis fully intending to launch her. However, after that was done test results came back on some spare cables which were found to have decayed while in storage. NASA then decided to roll back Atlantis and take whatever steps were necessary to test the SRB comm cables in her, even though those cables were believed to be fine.
This is an example of the system working. NASA was all set to launch, but when they found out there was even a slight chance that the cables they were using might be frayed, simply because they found a completely different set of cables elsewhere that was, they made the decision to roll the shuttle back to the VAB, at a cost of millions of dollars and a delay of weeks. They did the tests, the cables did indeed check out A-OK, and now they can launch in clean conscience. There's nothing idiotic about any of this as I see it.
Beyond that, there is no problem about having to calculate the motions of stars over time. We're trying to target close-by stars, which means the travel time is *not* the thousands of years you talk about, but rather only tens or hundreds, which means the stars move hardly at all. Even for more distant stars, note that the galaxy takes a quarter *billion* years to rotate once. Even ten thousand years doesn't move anything all that far. Besides, measuring and tracking the proper motion of stars isn't the computational hassle you seem to think it is. We know the proper motion for thousands of stars, and NASA is working on improving that tenfold with the upcoming SIM mission.
You also seem to think that broadcasts leaking out in all directions are the way to go. THat's not at all clear, because any broadcast spread over the whole sky will necessarily be weak in power. By focusing the beam through a telescope, whether radio or optical, you can get beam powers hundreds of thousands of times brighter than with an omnidirectional transmitter. So even for radio communications, I'll take the extra effort of aiming at different stars for a hundred thousand times stronger signal, thank you very much.
1. Optical communication across interstellar distances is going to suffer from severe extinction (signal absorption by intervening dust). Even if you can generate a laser pulse brighter than the sun, interstellar extinction is a big problem to overcome.
Yes, extinction is going to be a consideration. But it's not all that hard to overcome. Look at it this way: If your laser pulse is 100x brigher than your sun on this side of the dust cloud, it's going to be 100x on the other side, too, even if both the sun's light and the star are both reduced by a factor of ten or whatever. They scale together. Anywhere you can see our sun from, and more, you could see our lasers. In fact, if you use a laser on the redder side of things, say even in IR, you're going to have much smaller extinction for your laser than for the star's light, and you'll win out even more in the long run.
Furthermore, radio signals suffer phase shifts and delays due to the intersteller medium. This tends to spread out a signal, originally sent at a narrow wavelength range, into a broader and fainter signal. You don't have this problem with IR or optical lasers, so that's a win for them.
2. A laser beam is very tightly confined, and would have to be aimed very precisely in order to "hit" it's target. The probabability that the Earth would just happen to cross one of these "lines of communication" is incredibly small.
Wah, major error! Time to go brush up on your optics some more. A laser beam does spread out as it travels, in exactly the same way and at exactly the same rate as radio waves do. Diffraction-limited optics is the same for all frequencies:
S = lambda/D*R
That is, the beam size is proportional to the wavelength, divided by the size of your transmitting telescope, times the distance the beam has traveled. For larger lambda (i.e. radio) you need to use a larger telescope to get as focused a beam - but we do that already, that's why radio telescopes are so much larger than optical ones. Besides which, you neglect the fact that it's *trivially* easy to send as wide a beam we want, just by de-focusing the telescope a little or using a smaller telescope. It's sending narrow beams that's hard! Wide is easy.
The long and the short of it is this: By the time ANY signal, radio, optical, or whatever, has traveled the many lightyears to some other star, the beam will have spread out to be *much* larger than the target solar system. This is true because all forms of light spread out the same way as they travel, and because it's trivial to send as wide a beam as we want just by de-focusing things a bit.
Yes, this is absolutely right. They're just different frequencies, different sizes if you will, of the same basic thing. However, you still need different technologies to deal with them: You can't broadcast radio with your flash light, and you can't see anything by the light of a cell phone tower. For a variety of technical reasons, it might be easier for a large civilization to use lasers to communicate instead of radio. Not necessarily easier, just maybe. And so that means it's worth at least taking a look!
For example, lasers are small and can be re-targeted between stars very rapidly. Paul Horowitz has some designs for a setup with moving mirrors which lets you keep your laser stationary but aim its beam at dozens of stars every second. Radio, on the other hand, requires tremendous dish antennae to aim properly, so you can't slew between many stars anywhere near as fast. If you're an alien civilization trying to broadcast to as many targets as you can with limited resources, this might be a good reason to choose the optical over the radio.
It's not nearly as easy as you describe it, no. You probably could seperate a BEC into two smaller condensates, but I don't see any easy way to do it without breaking the entanglement between the two parts. Flattening it out could maybe be accomplished by a sufficiently perverse arrangement of electric and magnetic fields, but remember, the condensates we're talking about these days are *very* small, exist only in vaccuum chambers, and involve only a small handfull of atoms. We're not going to be manufacturing person-sized sheets of BECs any time soon. :-)
If so, then you would merely need to transport the two 'gateways' whereever you wanted and teleport between the two locations.
I'm afraid not, no. That's not how quantum entanglement works. Even though you can get instantaneous action at a distance, there's still no way to transmit information faster than light. Basically, all entanglement tells you is that when you measure thingy A, then whatever answer you get, instantly you know thingy B is in the same state. They're both spin up, or both protons, or both right-handed photons, or whatever. But you have no way of controlling *what* they both are, you just know they're the same. There's no way to take your unmeasured thingy A and force it to be spin up, which would force thingy B to be also spin up. All you can do is measure it and know that you're also getting a measurement of thingy B at the same time, no matter how far away it is. No FTL communications or transfer that we could use, alas.
No, I don't think it can. What's been achieved here by Hau & Lukin is, as has been said in some of the other posts, more accurately described as taking a pulse of light and storing it in a gas of atoms in such a way that you can get the original pulse back out later, rather than actually stopping an individual photon in one place. That, as far as relativity says, is physically impossible; The rest frame is undefined for massless particles so it's meaningless to try to think of what one would look like if it could be stopped.
And since all that's been done here, fundamentally, is taking some energy and storing it in atoms, albeit in an extremely clever way, it has nothing to do even remotely with the way light is trapped by the warping of spacetime near a singularity. The neat applications of this work are in quantum computing and communications, as has been said, not in designer black holes. :-)
And let me add that I had the good luck to work with Lene Hau when I was an undergraduate five years ago, working on building some equipment for rubidium BEC experiments much like this. It was a great experience and I learned a lot of good experimental science from her, so I'm very pleased with her success lately, even though I ended up going off in a different direction myself so I only worked with her for the one semester.
Absolutely.
My point is that more time is needed to look for hard-to-find systems before we can begin to discuss if current models can reproduce the range of mass distributions observed.
Well, yes and no. We certainly need a lot more data before we can be confident in saying that systems like our own are rare. But the current problem right now is that our current models can't explain the formation of 17 jupiter mass planets at all, and we know that there's at least a couple of those out there. So at the very least we need to expand the range of types of planets and solar system we can model. But I agree with you that we don't yet have anywhere near enough data to say anything definitive about the distribution.
Yes, absolutely. The motion of all the major bodies in the solar system including the sun, the planets, and most of the larger asteroids, is known to extremely high precision. After all, we can (usually!) fly space probes to Neptune and only be a few dozen miles off target after a journey of several billion - that takes some serious accuracy in our knowledge of the orbits, so NASA put a lot of effort into refining that knowledge thirty years ago, and it's quite good.
With that, it's simply a matter of taking the radial velocity measurements of other stars, and subtracting off the motion of the sun to get the proper answers. All those graphs you see on exoplanets.org and elsewhere are relative to the center of mass of the solar system, not to the Earth itself. But since the solar system orbits are known so well, this subtraction can be done to a very high degree of accuracy and essentially doesn't contribute any uncertainty to the final results.
Don't know what the definitive answer is, but my guess is it's just time and $$. Once they get all the dishes properly converted over so they can work as single-dish astronomical instruments, then they'll start thinking about maybe hooking them together, but I doubt that will be for a while. Doing interferometry would require a lot of setup in terms of building a correlator and connecting everything up to it, and it seems like these guys are still just getting going with the site and also are trying to do stuff on a low budget. But yeah, it'd certainly be great if they can do that eventually.
Just a note that the number for its diameter is an absolute and complete guess, albeit an educated one. There's no actual observational data to back that up yet. Basically, if you assume the planet is made out of the same stuff as Jupiter (hydrogen and helium) and that it masses 17 times what Jupiter does, and you plug those numbers into your equations for modeling the size of a planet, then you get an object only slightly different in size than Jupiter, despite the large difference in mass. The reason is that since the planet is composed of gases, it is extremely compressible: As you add more mass, it just gets denser and denser rather than bigger and bigger. This is also the explanation for why Saturn is so close in size to Jupiter while massing only about a third as much - it's very low density. Indeed, a 17 jupiter mass object is expected to be *smaller* than Jupiter, not larger, since it will be so much more dense due to the stronger gravity.
The distance doesn't actually matter all that much, as we're looking at doppler shifts rather than images, and the doppler shift is the same for all distances. So the only way the distances comes in is that farther away things are fainter, and thus require bigger telescopes and longer integrations to get the same signal to noise. That said, while I haven't ran the numbers myself to check, Geoff Marcy says that he could indeed detect Jupiter if he were in some other star system - he couldn't have five years ago, but he could now. The biggest issue is simply that to detect a planet which takes 12 years to go around the sun (e.g. Jupiter) you need data which spans a good part of 12 years. To see planets out past that is correspondingly harder. We've got ~ 6 years of data now, less for many stars. It'll be interesting to see how things play out over the next decade or so with this.
Have you seen the results of the HST STIS observations of 209458? Dave Charbonneau gave a talk on them here in the fall, although I can't find the paper online on ads or arXiv right now. Really great stuff, photometry accurate to one part in something like ten thousand, and the punchline (well, one of the punch lines) was that they were sensitive to the detection of moons of 1 Earth mass or larger. Didn't see any, of course, but it's quite exciting that they were able to get the error bars even that tight. Certainly NGST could drop them low enough to see Ganymede-class objects, and SIM could probably detect 'em too, though through a completely different method. The real question is whether anyone can beat that and do it on the ground sometime before 2005. :-)
It'll be a good long while before we can see any moons on these guys - we can't even directly see the planets yet, much less anything smaller. All of the detections thus far have been via indirect effects, specifically the motion induced in the parent star by the planet's orbital motion around it. While you could in principle detect moons around the planet in the same way, it would require precision several orders of magnitude higher than what we have now.
That said, it certainly seems plausible for objects of this size of have moons (after all, Jupiter has at least 28 and Saturn 30, using the latest numbers announced yesterday - yes, we're still finding new moons around them even now!) but I don't think anyone would consider it at all 100% certain - we have no idea how the big guy especially formed, and thus no a priori reason to think it's necessarily anything like the formation of our own giant planets.
If anywhere in explored/known space is going to have a M-Class planet to live on, this seems like a likely candidate.
Nope. With a 17-40 M_Jup object in a 2.9 AU orbit with 0.2 eccentricity, and a 7-10 M_Jup object in at 0.3 AU leave effectively no space for terrestrial planets in between them. Any smaller worlds which were there at one point have most likely been ejected from the system by gravitational effects from the giants. (Think billiards with planets, only one of the balls you're using is a bowling ball.) I *really* doubt we're going to find any Earth-like worlds in this system.
Ten years ago, we thought we understood the solar system, at least in its general structure of small rocky planets in close, and gas giants further out. Five years ago, Mayor and Queloz found the first exoplanet, and it's been a landslide since then. Marcy and co. have *tons* more planets in their data analysis pipeline, and while I don't know any of the specifics, I bet some of them are at least as surprising if not more so. It's a credit to the whole team that they just pile on more and more observations and only publish once they're really really sure of their data and conclusions. So when we say we know about over 50 extrasolar planets today, we're quite confident in those facts.
And here's the kicker: Not a single one of the solar systems we have discovered looks even remotely like our own.. Either you've got giant planets way close in by the primary, or they're farther out but in highly eccentric orbits which leave no room for the possibility of terrestrial planets, or else now they're ridiculously high mass. The nice organized pattern of our own solar system? Nowhere to be found.
It may very well be that our home is the exception and these supermassive, close in, and highly eccentric gas giant planets are the rule instead. If, ten years from now, after the SIM spacecraft has flown and we've surveyed tens of thousands of stars looking for planets, it may well be that star systems like our own are vanishingly rare. And if that's the case, then the chances of their being other Earths out there, other worlds which we could someday colonize, or on which might evolve other intelligent races, then that becomes much, much less likely. No Tattooines, no Vulcans, no Wunderlands, just lots and lots of Jupiters. And that's what's frightening about all this.
They're actually sort of annoying to work in. You can't listen to the radio while you code, you see. :-/
It's not quite that easy. The sorts of signals we deal with in astronomy are really quite faint. To get good signal-to-noise, you generally have to point at one spot on the sky for a good while - minutes to hours, usually. Hence the desire for the dishes to track exactly at the rotation rate of the Earth, but in the opposite direction, thereby enabling them to stare in one spot while the Earth turns under them. Yes, with faster slew you could glance at a large area of the sky quite rapidly, but you wouldn't get any usable data that way.
Anyone have any idea if there's an email or snailmail address for someone at the FCC we can complain to? Perhaps a write-in campaign with a couple thousand people all saying that they vow to never purchase any consumer electronics containing the "obliteration code" would accomplish something. Then again, maybe not, but it's worth it to at least get the ball rolling.
Not a chance. My little sister is 16. She's online every day with her friends, IM'ing away and trading MP3s on Napster. She just got a CD-RW to enable her to copy CDs and burn MP3s to disk and all that. And it's not just her - damn near the entire net-enabled population between middle school and college is having a hell of a good time trading music. You think they're going to just give that up? You think that the teenagers of the world are going to just sit back and let corporations tell them what to do? You seem to be forgetting that one of the hallmarks of youth is rebellion against whoever and whatever you're not supposed to be doing. :-)
Rather, I see a generation growing up that doesn't particularly give a damn about overly restrictive copyright laws and is going to keep on having fun and using technology to do so in ever more interesting ways. I just hope that we get people in the legislature who see this way before too long.
It's true, what others have said about the importance of learning social skills. However, the way to do this is not through baseball or whatever. The way to do it is by bringing lots of brilliant kids together and letting them socialize with each other . Academic summer programs like CTY are IMO probably the best way to do this, because they draw kids from a much wider area and thus can draw a larger number of wonderful minds, while at the same time putting them in a fun summer camp environment that caters to the fact that smart kids are still kids after all and want to run around and throw frisbees and go swimming, in between learning Scheme and writing novels.
I can still remember the very first day I spent at CTY (F&M, july of '93) so very clearly. The scene that stands out most in my mind is sitting in the lounge in the dorm and talking about computers and space travel with a bunch of other 13 year olds. It just totally blew me away to finally be meeting kids my own age I could connect with. The experiences I had there that summer, and the following summers, completely changed me around from a total introvert, alone and nervous, to a very outgoing and self-confident young man with lots of other (very smart ;-) friends.
Flash forward three or four years. Many of the people I knew from CTY ended up with me at Harvard, or nearby at MIT, or Princeton, or wherever. Four years after that, we're grad students spread out all over the place, but we're still great friends, and a bunch of us get together for New Year's every year. I absolutely credit CTY for changing my life by bringing together the right people at the right time. The only peer group for a gifted kid is other gifted kids. So do whatever you can to help your youngster find his peers, and he and they will thrive.
Io does actually have a bit of an atmosphere, mostly sulpher gases and other things you don't really want to breath, but you're correct that it wouldn't be enough to burn up the space craft; it would impact the surface and eventually get buried in one of the frequent lava flows. This is considered acceptable because the conditions on Io are harsh enough that we're pretty damn sure (a) there's no native life there (b) even if some bacteria stowed away on Galileo, they couldn't live there either. Both of these hold true for Jupiter, too. And even if you leave them both aside, the impact velocity with Jupiter will be vastly higher (it's next to impossible to hit Jupiter at anything *less* than 70,000 kph due to our old friend Mr. Humongous Gravity Well.) so the impact heating will be that much greater, moving us into the realm of serious overkill sterilization by heating. Which is, of course, precisely what we want.
Sure, it would be great if NASA could fund every mission indefinitely! But heck, it would be nice if people would pay us humble grad students a million bucks a year, too. That's just not going to happen. In the real world of science, with limited funding, you have to balance the potential return of spending $X on some experiment with the potential return of $X on a -different- experiment. Sometimes it makes sense to extend the lifetime of the first experiment - Witness the fact that the Voyager and Pioneer spacecraft are all still returning valuable data today, witness the DS1 extended mission, witness the fact that Galileo is still working today several years after the "end" of its mission. NASA *does* extend missions, when it makes scientific sense to do so But sometimes you really have gotten as much as you can from a mission, or sometimes you have new projects you want to start that need the money. Then in that case it *does* make sense to terminate older missions and start new ones. Do realize that the decision to extend Mission Y for another two years usually means postponing or even cancelling Mission Y+1. It's not nearly as simple or as one-sided as you seem to think it is.
Highly killed, huh? Tough job, but someone's gotta do it...
No, not if given a sufficiently large number of smaller mirrors, but that number may be very large. But multiple mirror systems (which are called interferometers) are much, much harder to build than single mirror systems. Before getting into the real details, here's a quick crash course in telescope design:
The two most important properties of any telescope are its light-gathering power and its resolution. The first is how many photons per second it can catch. This is directly related to the area of the scope: a 8m scope has 16x the area of a 2m scope, so it needs 1/16 the exposure time to get a comparable image. In other words, a single VLT dish can capture as many photons from a given source in an hour and a half as the Hubble would get in a full day. So obviously bigger scopes are better. In the case of OWL, a 100m telescope has the same area as 100 10m telescopes. So you'd need a pretty hefty array to get the same light gathering power.
The second property we care about is the resolution, which is the size of the details which can be seen in images from the telescope. This is where interferometer arrays really shine. A telescope with finer resolution can see smaller details, obviously a good thing. Now without going into the details, the resolution is limited by quantum mechanics to be proportional to Wavelength/Diameter, where Wavelength is the wavelength of light you are using and Diameter is the side-to-side diameter of the telescope. So to see fine details, you want W/D to be as small as possible. There are two ways to do this.
Way one: Use as small a wavelength as possible. If you use a bigger wavelength, you need a larger diameter to compensate and still get decent images- which is why radio scopes (large wavelength) are all humongous.
Way two: Use as large a diameter as possible. Here's the kicker, which is why arrays are so desirable: In a properly built interferometer, the "Diameter" is NOT the diameter of a single dish, but rather the total side-to-side distance of the entire array! So if you've got two 1m telescopes 100m apart from each other, you have the resolution of a 100m telescope! (but only the light-gathering power of a 1.4m telescope, because that's all the area you have.)
Now, the thing is, hooking together the elements of an interferometer to get this good a resolution is highly nontrivial. You don't just take a different picture with each scope and superimpose them in photoshop. Rather, you have to mix together the full raw signals from each telescope in a very precise way so that the phases of the different signals interfere with each other, canceling out in some parts, adding up in others, and giving you the super-detailed final product you desire.
In the case of radio, the frequencies dealt with are on the order of a couple hundred megahertz. (Higher frequencies in the GHz can be mixed down to MHz via heterodyne receivers.) We have electronic components that can work at MHz speeds - amplifiers and high-speed tapes and relays and all that. Thus it's possible to do all the mixing in electronics, which is how the VLA in New Mexico works, and how the world-wide VLBA works, too. Take a dozen scopes around the world, have them all observe things simultaneously, recording onto high-speed mag tapes, then Fedex all the tapes to a computer center and run them all through a correlator, and out pop your images.
In contrast, at visible light, we're dealing with frequencies many orders of magnitude above what our fastest electronics can handle. There's no way in hell we can handle petahertz signals in electronics right now. Which means the only way to do the mixing is optically: stick a mirror at the focus of all the telescopes, and physically direct all the light from all of them to the same focal plane, via light paths of -exactly- the same distance (and we're talking "nanometers" when we use the word "exact" here.) Right now the limit for this sort of thing is a hundred meters or so, barely. It will be many, many years before we can pull off a 1 km optical interferomter on the ground, but there are certainly people working on it.
This is, unsurprisingly, really damn hard. Only in recent years have we started having any success with optical interferometry at all. It's very new technology. It's extremely promising, in that you can use it to get vastly higher resolution than you can with a single dish scope, but it's very difficult and extremely costly. Couple that with the fact that you still need large telescopes to have enough collecting area to see faint objects, and it becomes clear that there will still be a place for large single scopes for a long time to come.