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NASA To Test New Atomic Clock
edesio writes "Many satellites and spacecraft require accurate timing signals to ensure the proper operation of scientific instruments. In the case of GPS satellites, accurate timing is essential, otherwise anything relying on GPS signals to navigate could be misdirected. The third technology demonstration planned by NASA's Jet Propulsion Laboratory is the Deep Space Atomic Clock. The DSAC team plans to develop a small, low-mass atomic clock based on mercury-ion trap technology and demonstrate it in space."
Having once worked on GPS Satellite's clocking system, I was surprised that the AF was so against usage of atomic clocks phased-locked to crystals for accurate timing. Maybe the latest news about Galileo using atomic clock changed their mind?
You certainly typed a lot of words to say "I don't know what the fuck I'm talking about". As far as scientific theories go relativity has a lot of very strong experimental support. Though I suppose if you want to say it's "obviously wrong" you might want to include some actual experimental verification or even peer reviewed papers of such a claim, you know, to enlighten us bozos.
I'm a loner Dottie, a Rebel.
Besides your link to some dude's blog, what is your support for saying Einstein's theories are "obviously wrong"?
If his theories are wrong, how do you deal with the fact that they have been supported with countless experiments, and our GPS system depends on his theories to keep accurate timings down to the billionth of a second?
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
but it will take........TIME!!!!! Muahahahhahahaha!
And you link to a blog which states
"This way, the scientific establishment will slowly but surely be forced to return to reality, the reality of the existence of a real, physical ether with fluid-like properties."
You realize that the "ether" theory has been absolutely blown out of the water, right? Countless experiments were conducted to determine our motion through this either. all experiments showed the speed of light does not depend on the observer's velocity. It was only after these countless experiments that science finally accepted that there is no absolute vantage point.
But if you don't even understand this, you should presume to disagree with Einstein. Free speech may entitle you to disagree... but free speech also entitles the rest of us to call you out for the uninformed person that you are.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
Oh, that is YOUR article? BWAHAHAHAAA. Sorry, I will stop arguing with you now. Only an idiot continues to argue with fools.
See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
... you might have heard about PHARAO, a caesium clock which is planned to fly on the ISS in 2013. Accuracy target is 1E-16.
All they need to do is send 1 male and 1female astronaut up, pretend to tell them to have sex, and then pretend to find out they exhibit all the typical dysfunctions your 40+ laze abouts do.
Then send them up again, tell them them to take these special space sex placebos, and put out a press release along the lines of "First Child Conceived In Space Thanks To New Sex Pills!".
Tesla was a genius, and in the quote you gave I believe he was right... but also wrong. Space cannot curve if space is nothing. But space is not nothing. The work of people like Riemann and Lobachevski have shown that space can in fact possess properties inherently. This makes a kind of sense: when we talk about 5 feet of space, that space has an objective reality and possesses some property (namely, dimension) that allows use to quantify it. Einstein deals with this question somewhat BTW.
Interestingly enough, if you go back to the philosophy of people like Aristotle, "matter" can possess any level of properties, including (in theory) insensate but quantitative dimensionality (i.e. "empty" space). So space could be "material" in this original sense, allowing for curvature, yet be "empty", in the sense that it lacks tangibility (which is really what we mean by "empty" anyways).
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ESA will get there first, with the Atomic Clock Ensemble in Space (ACES), intended for the ISS in 2013, which should be good to ~ 10**-16 and will include a test of relativity. I believe that this is the JPL clock, which is aiming at 10**-15 stability, and a 2015 launch. (Both are fairly low earth orbits, with the JPL clock intended for an Iridium satellite.)
So, the JPL effort is cool, and I would love to see one flown to Mars or truly deep space, but this is one case where the Europeans are in the lead.
Its a technology demonstration for hardware that will eventually make deep space navigation better.
This is being run out of the JPL navigation section and is intended to improve long-term capabilities with a small investment.
Last week the newspapers were filled with the discovery of "impossible" particles traveling faster than the speed of light.
And while Relativity must be subjected to the highest standards of evidence(and is), this discovery of course must be accepted as the complete truth as soon as it comes out.
earlier the Pioneer space probes also refused to adhere to the law
I love how the Pioneer Anomaly is always used as proof of whatever crackpot theory someone wants it to, or dis-proof of whatever theory they want to discredit even if only tangentially related. But in reality, anomalies like this are usually best understood by more fully understanding the circumstances. For example, once someone went to the trouble to more accurately model the way light would reflect off of the Pioneer probe's structure, suddenly the Pioneer "anomaly" went away.
Oh, I'm sorry, was I only allowed to assume that all of science was wrong when figuring out what was going on with a weird observation? Theories are fair game, but the methodologies and calculations used to determine if the theory's predictions are correct can't be updated? It was called an "anomaly" before, ergo Relativity must be wrong?
And... you think this is a more intelligent way of approaching science?
In the future they will look back to relativity with equal disbelief as to the "Earth is flat" concept.
You mean they'll view it as a theory that fit all available evidence better than any other available theory, up until the time that it didn't and then it was abandoned? You're probably right. BTW, that happened a lot earlier than most of you folks who trot out the Flat Earth Theory think. The earth was understood to be round, and even it's circumference calculated with a surprising degree of accuracy, in around 200 B.C. But comparing Relativity to the Spherical Earth Theory (which is wrong) would be too honest.
Relativity, like the flat or spherical earth theories, will last as long as it's the best theory -- and unlike the Flat Earth, but more like Classical mechanics, it is likely going to be close enough to correct that it will still be used for a wide variety of circumstances even in this hypothetical future you envision.
The relativity theory not only goes against common sense
Quantum Electrodynamics pisses all over your precious "common sense" while cackling like Pennywise the Clown, yet it has been verified experimentally to 15 decimal places.
Even basic probability goes against common sense, but guess which one does a better job of predicting what you should bet on a hand in poker.
But hey, I have to admit, Tesla said Relativity had to be wrong, so I guess it must be.
But wait, those mainstream scientists who "worship" Albert Einstein still adhere to QED and QM even though Einstein said they didn't make sense and he didn't like them.
Gee, I wonder which group of people it is -- mainstream science or "rebel" science --that actually evaluates theories on their merits, and which just picks authority figures who say what they want to hear?
physical ether with fluid-like properties... a fundamental thinking error has been made by Maxwell in his equations.
Kinda funny how they propose an aether theory, while also saying Maxwell is wrong (despite truly ridiculous amounts of verification), when the whole reason the aether theory was proposed in the first place was to explain how the speed of light in a vacuum could be constant, as implied by Maxwell's equations, in the presence of relative motion.
Keeping my fingers crossed....
And that's... pretty much all you're doing, isn't it? Scientists have been subjecting their theories to every test they can come up with, developing alternative ones and comparing the predictions they make to the evidence, and seeing which comes out best and picking that one. Crackpots pick one or two things that are difficult to explain, claim that proves them completely right and everything else wrong, and ignore the mountains of evidence their crackpot theory can't explain.
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Well, first, this is a NASA technology demonstration mission for a clock needed by JPL. That means that NASA is going to validate that this clock will work in space, so that JPL can use it where they operate (i.e., deep space, the Moon, Mars and beyond).
Second, yes, the very best modern clocks work differently with and without gravity. This is basically because the atoms used are so cold they are moving at human type velocities, and so gravity can't be ignored. The best terrestrial clocks are the fountains - take very cold atoms, moving at ~ 1 meter per second in a trap and shut off the trap. Some of the atoms (the ones that happen to be moving up) will ballistically go up, and then fall back down. (This is much like tossing your keys up 1 meter or so, and then catching them, except with single atoms.) The gravity is used to collimate the pulse of atoms going up and down, and (with timing the round trip) to select only the ultracold ones coming down. By timing the round trip, you can really select a particular set of velocities - the better constrained the velocity dispersion, the better constrained the clock read out.
NONE of that works in zero-G, and PHARAO (I am more familiar with this clock that the JPL Hg Ion one) is completely re-designed to use fountain-like ideas in a linear beam. I am not sure it would even work on the ground, and it definitely needs zero-g to meet its performance goals.
Time keeping is getting better and better. I just happened upon this article recently which gives some history on timekeeping and what some of the latest efforts are working on: http://www.sciencenews.org/view/feature/id/334983/title/The_Ultimate_Clock.
Here's an excerpt (emphasis added):
Why not just put the atoms in a magnetic torus field or a circular track rather than a linear track? Seems they already use magnetic fields to sort out the atoms to get the ones in the correct phase.
You basically don't want to accelerate the atoms if you don't have to, and in a ring they would be constantly accelerating. Gravity is a little different, as it is very smooth and doesn't require contact with structure, magnetic fields, etc.
Deep Space clock, AKA, Pulsar.
Experiment: You measure 1 meter out, and then turn 90 degrees to your right, measure 1 meter out, turn 90 degrees right, and measure 1 meter, how far will you be from the starting point? Answer: 1 meter
Similar experiment: You measure 1 km, turn 90 degrees, and do this twice more, how far will you be from the starting position? Answer: 1 km
Similar experiment: You measure 10,000 km, turn 90 degrees, and do this twice more, how far will you be from the starting position? Answer: Approx. 0 km (Why? Because the earth is nearly spherical with a circumference of around 40,000 km, and you have traversed 1/4 of that distance along 3 geodesics, leading back to your starting position.)
This is why that quote by Tesla is incorrect. You cannot assume that local flat measurements mean that space is naturally flat. It may be naturally curved. If your assumption is that the earth is flat, you might reject the third experiment. But the third experiment helps to verify that the earth is naturally round. Likewise if you assume that space is Euclidean, then you might reject large-scale measurements that seem inconsistent with local measurements. But there is the problem again: you reject measurements that are out of line with your assumptions. (In fact, a property of any Reimannian manifold is that it is smooth, meaning it is possible to "zoom in" far enough anywhere such that local measurements would be consistent with a flat manifold.)
Sorry, didn't read all the rest of your article.
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Were you a Payload Officer at 2 SOPS? And, are you referring to the Space or Ground segment? If you mean the backup clocks in the Mod, then that's slightly outside my knowledge. As far as the Space Segment, they've been reliably using Cesium and Rubium (atomic) clocks for over 3 decades. They don't want to change because it's known, reliable, etc. I was curious to note the newest generation of satellites dropped the 4th clock, and now launch with only 3. Since each clock is only usable a number of years (varies too much for me to generalize), I'd have thought they kept all four just in case the electrical system outlives normal design life, and you end up needing to go with a 4th clock when the 3rd one becomes too "deviant".
I think the GPS relevence is buried at the bottom of the article. Cesium and Rubidium clocks are both accurate to the nanosecond. That's just about as accurate as can be practical. The new atomic clock, however, they're saying is accurate LONGER. On GPS Satellites, the original satellites (Block I, II, IIA, IIR) launched with Cesium and Rubidium, 2 each. Usually you have one operational, sometimes one on "ready standby", and the other two off. As each atomic clock reaches the end of its mission-usable life, it's turned off. It become's "mission-unusable" (not a real term, I just made that up) when it's signal varies outside a normal window of acceptable predictability in terms of its output signal. There are design differences, such as Rubidium clocks have to stay within a tenth of a degree (F) in temperature stability (if memory serves correct). So, if they can create a clock that's more stable, for a longer period of time, this has huge potential for future GPS satellites. However, since we just awarded contract to Boeing the contract for IIF birds, with only 2 of 12 launched, it's going to be a very long time (decade at best) before you'd see this in a GPS satellite. Design life has also expanded from 7 to 12 years for each satellite (for point of reference Block I only had a design life of 3 years since they were R&D), so this pushes any usage even farther out since we're going to go longer before replacements need to be launched.
Like most science, it won't do any of that immediately, but if it proves itself, it might make most of that better & cheaper.
Taxes pay for GPS. Farmers use GPS to track crop yield so they can fertilize more efficiently. Using high accuracy GPS to repave roads, or build bridges properly is a no-brainer. GPS might help the ambulance get to you and back to the hospital seconds *before* you're dead. So yes, a better clock can improve all those aspects of your life. SWEET!!
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