'Einstein Probe' Delayed

isorox writes "The BBC is reporting that a NASA satellite designed to test frame dragging, predicted by the theory of relativity, has been delayed for 24 hours because mission control couldn't verify the correct software had been loaded. The probe was proposed 35 years ago, but has never had the funding until now. The question remains is what happens if Frame Dragging isn't observed - will the experiment be wrong (in other words there's no point to it), or will we get faster-than-light ships for Christmas?"

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Know thy hypotheses....

[The Ape With No Name]

The question remains is what happens if Frame Dragging isn't observed - will the experiment be wrong (in other words there's no point to it),

Then you have a Type II error, methinks. It's not that you are wrong outright (like a Type I error. You've just missed the chance to reject the null hypothesis correctly was munged. Refine. Try again.

Re:NASA's near M$ like mistake!

[FrYGuY101]

As long as there is a link to the spacecraft, updating *shouldn't* be a problem, for the reasons you just listed. They can't afford to launch a satellite only to discover there was a bug in the software and have it be worthless, so they design them with the ability to update in mind.

Heck, remember when the Spirit Mars Rover crashed? They updated the software afterwards on both rovers to prevent future crashed from happening.

Re:Faster than light ships?

[pavon]

Except that the general theory of relativity was created because newtonian gravity violated the speed of light. If this test showed that frame dragging did not exist, we would be have to figure out a new way of making those two consistant, and (on the surface at least) one (unlikely) possibility would be that some things can travel faster than light.

what happens if Frame Dragging isn't observed

[asr_man]

I've read that frame dragging had already been reported in astronomical observations, and that this is expected to be an important but unsurprising laboratory confirmation of the phenomenon.

Re:NASA double checking stuff?

[Rosco P. Coltrane]

The American space program is one of the safest in the world

Funny, I sort of remember that Soyuz capsules have a better safety record than space shuttles. Hell, they're even used as emergency reentry vehicles on the ISS...

Re:verification

[aismail3]

FWIW: To elaborate on the "different sets of data" mentioned above, Wikipedia defines a theory as "a model or framework for understanding," and a law as "a scientific generalization based on empirical observations."

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how does frame dragging relate to warp speed?

[iamhassi]

This is a first, a /. article without enough links:
"...test frame dragging, predicted by the theory of relativity... will we get faster-than-light ships for Christmas?"

What does frame dragging have to do with faster-than-light?? The wikipedia link mentions nothing about how frame dragging has to do with faster-then-light, so I searched google and found this article on msn:

"Spinning black holes may pull in gaseous matter from their sister stars as a rapidly rotating "accretion disk," analogous to water circling down a bathtub drain.

The American scientists built on their previous research into the mass and spin of black holes to look for signs of space-time distortion, or frame-dragging.

In Einsteinian physics, the space-time continuum is often compared to a sheet of rubber. Mass creates a gravitational "dimple" in that space-time sheet. But a rotating object -- like a spinning black hole -- adds an extra twist to the dimple. Matter caught in that twist would appear to wobble in orbit around the object, like a toy top wobbling on its axis.

Cui explained that travelers passing close to a black hole would feel as if "nothing happened." But a distant observer would see the travelers being dragged around the black hole."

It's already been observed.

[Phanatic1a]

The question remains is what happens if Frame Dragging isn't observed.

Then they'd better figure out if their experiment was badly designed, because frame dragging has already been observed by other research platforms.

NASA's Rossi X-Ray Timing Explorer observed frame dragging in a distant system consisting of a binary pair of black holes. This was back in 1997.

Analysis of the motion of two earth-orbiting satellites, LAGEOS I and LAGEOS II, also reveals frame dragging going on. This was also over 4 years ago, and it's the result that this Einstein probe is supposed to refine.

examples of each?

[gandalf013]

1. Bad result, confirm prediction: Eddington's test of General Relativity.
2. Bad result, invalidate prediction: can't think of one now
3. Good result, contradict prediction: Michelson Morley experiment
4. Good result, confirm prediction: Tons of those I am sure. Discovery of Uranus comes to mind.

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Re:Is this gravity's magnetism

[Anonymous Coward]

Yes, you're right. Frame dragging is a "gravitomagnetic" effect. Gravitomagnetism doesn't quite behave like (electro)magnetism (for one, there's a different sign), but the analogy is valid: gravitomagnetism is to gravitoelectricity (= regular static graviation) as magnetism is to electricity. See, for instance, the text by Ciufolini and Wheeler.

Re:Faster than light ships?

[gilrain]

Hm, you're wrong there. As your speed approaches infinity, your mass also approaches infinity. Thus, the energy required to accelerate you ALSO approaches infinity. Therefore, it would take an infinite amount of energy -- more energy than you could get, even if you converted the entire universe to pure energy.

So, you'd have to already be traveling at, or greater than, the speed of light. It is impossible to accelerate past it. However, you're right that, even then, you would measure the speed of light as being exactly c faster than you. :)

Re:Faster than light ships?

[Anonymous Coward]

Doesn't the emission of entangled-quanta already violate thee speed of light?

No matter, energy, or information is propagated faster than light in quantum entanglement.

Also, I just took a course in the philosophy of physics but the one thing I never understood was how anything going was than the seepd of light would ruin Einstein's theory?

Einstein's theory itself doesn't forbid something from going faster than light. (However, there are problems with FTL objects and causality, such as observers for which effects take place before causes, and tachyons also destablize the vacuum in quantum field theory.) It does forbid objects from crossing the c barrier (which would require infinite energy).

If another THING was found that was faster as light and had the same speed in all inertial frames wouldn't that be sufficient?

In a theory with Lorentz symmetry (i.e., relativity), there is only one invariant speed: the speed of light. There can't be another speed (faster or slower than c) that is invariant in all inertial frames.

It also wouldn't need to violate the rule of not travelling faster than the speed of light since it could be mass-less and then as it approach and crossed C it mass would still be zero as opposed to approaching infinity.

In relativity, massless objects can travel at only one speed (c), neither faster nor slower.

The real reason for the launch delay.

[Anonymous Coward]

Disclaimer - I worked on the Gravity Probe B (GPB) team back in 1994-1995 while I was an undergraduate at Stanford. Due to personal interest, I watched the launch attempt on NASA TV.

While technically correct, the post's claim that the lauch was delayed "because mission control couldn't verify the correct software had been loaded" doesn't convey the whole picture of what happened.

Well prior to T minus 4 minutes, three weather balloons had reported excessive (out of limits) high altitude wind shear. This wind shear would have caused the launch to be delayed for 24 hours.

However, shortly after T minus 4 minutes, a fourth weather balloon reported that windshear had dropped to within acceptable limits. At this time, the flight profile of the delta II rocket needed to be updated to successfully guide the rocket through the high altitude wind shear and in to GPB's desired orbit.

The launch window for GPB is very narrow - about one second. This is because GPB needs to be in a polar orbit in the plane of a particular guide star.

A launch director from Boeing (Boeing made the delta II rocket) could not confirm that the flight profile had been successfully updated. So, with the clock counting down, he made the decision to "hold" the launch. Upon review, all the launch directors agreed that this was the correct decision.

So, you have a situation where, under time pressure, about 300 seconds before launch, due to changing launch conditions and unverifyable equipment status, a conservative and correct decision was made to delay the lanch 24 hours - until the next one second long launch window.

The other thing to consider is that the closer you get to launch, the more costly and complicated it is to abort the launch. So even though confirmation of a successful profile upload may have come later, if it hadn't, the costs of scrubbing the launch would be higher.

While it may be fun to bash NASA, just remember that it really is rocket science, at least in this case.

Re:The real reason for the launch delay.

[Anonymous Coward]

You caught me on that one - it's an assumption I made based on several factors.

The launch director listed the pages that the shutdown procedures began on. Depending on the exact time at which the launch was aborted, different sections of pages were used. Aborting during the last 60 seconds entailed flipping to "appendix L - the red pages". Red sounded ominous.

I'm also assuming that a delta II is a very complicated beast to start and stop, and that some of the steps involve consuming resources that have to be replaced and retested once consumed.

The delta II uses different types of fuel. Some of them can last in the rocket for 3(?) days. Some last for shorter periods of time.

Re:The real reason for the launch delay.

[Anonymous Coward]

I work in the arms industry (unfortunately can not say much more than that), so what im about to say may not be entirely correct to space craft, but it should be close.

When you launch things into the air, where it can go kaboom and fall on people down on the ground, you have to make *very* sure it does not go kaboom. This involves testing, testing and some more testing and then testing to confirm that your testing worked.

Typically when you fire a rocket, you actualy start 'heating up' stuff beforehand. My knowledge of actual rocket propulsion is not that great, but things seem pretty volatile from down here, so assume the following would be close.

If you count down to, lets say 10 seconds, you will probably have opened up the fuel lines, to ensure that they work properly. This means you have exposed various parts to volitile, corrosive substances. Thus if you do not go through with the launch you have to replace those things. Im thinking of measuring equipment, seals, 'o-rings' and such stuff.

Now, once you have opened up the little baby, you have to be very carefull closing it up. Make sure you dont leave any loose spanners in there, and then test that everything is working again. This can be very time consuming. Im talking days of work for a team of people.

However if you shutdown at 300 seconds, then probably you would not have opened up the fuel lines, which means you dont have to replace stuff. Thus you can get of the ground quicker.

(I use the example of fuel and fuel lines here, but it applies to just about all the systems onboard.)

The decision the controller had to take probably was something like the following:
1) We downloaded the new flight plan, but its going to take at least 250 seconds, perhaps more, to confirm (it is not as easy as typing in 'version---' on the command line). Furthermore the people around here are still busy confirming that this new flight plan, compiled over a few minutes, is correct (normally this job is done by a team of people over several hours). Chances that we get the green light at T- 10 is 20%. If we abort at this time we will be grounded for a week, retrovitting the rocket.
2) We abort now (at T-300), take our time to work out and confirm the flight plan and try again in 24 hours.

Remember, grounded for 7 days is more PR work and more man hours(7*24*20). All of this converts to *money*.

Re:Faster than light ships?

[gilrain]

He still cannot accelerate to or past the speed of light. If he were enclosed in a box traveling at a constant velocity => lightspeed, then yes everything would appear normal to him, and it's only the stationary observer who would notice anything odd. However, assume that same box is ACCELERATING to lightspeed, and suddenly the man in the box is exposed to all of the effects that entails. Namely, mass going to infinity, and energy required to continue acceleration going to infinity.

Let me dig up a reference...

The Elegant Universe, by Brian Greene, PhD (from Oxford)

Page 52

"You may have wondered, for instance, why6 we can't take some object, a muon say, that an accelerator has boosted up to 667 million miles per hour -- 99.5 percent of light speed -- and "push it a bit harder," getting it to 99.9 percent of light speed, and then "really push it harder" impelling it to cross the light speed barrier. Einstein's formula explains why such efforts will never succeed. The faster something moves the more energy it has and from Einstein's formula we see that the more energy something has the more massive it becomes. Muons traveling at 99.9 percent of light speed, for example, weigh a lot more than their stationary cousins. In fact, they are about 22 times as heavy -- literally. .... But the more massive an object is, the harder it is to increase its speed. .... Since a the mass of a muon increases without limit as its speed approaches that of light, it would require a push with an infinite amount of energy to reach or to cross the light barrier. This, of course, is impossible and hence absolutely nothing can travel faster than the speed of light."

Re:Faster than light ships?

[AKAImBatman]

Actually, at the speed of light, traveling towards the arth from Alpha Centauri, light from Sol would be traveling at 600,000km/sec in relationship to him.

You're off by a factor of 2. Light travels ~300,000 km/sec to all observers.

Light originating from his ship would be travling at normal speed to him, but faster or slower in perspective to anyone (or anything) he was passing.

Nope. Light originating from his ship would travel ~300,000 km/sec to him and anyone else who might be watching.

So, the speed of incidence would be Pa + Pb, which to either photon would be rather high.

That's Newtonian physics, which Einstein disproved. The speed of the photon will always be Pb. Have you read "Elegent Universe" yet? It's the best explanation I've ever seen. In short, we're all traveling at light speed through four dimensions. By traveling faster through space, we travel slower through time. This scales so perfectly, that we will always measure light as going ~300,000 km per one of our current seconds. We may actually be reaching 99.9999% of the speed of light, but it will seem to us that light is still traveling at ~300,000 km/sec. If we manage to obtain light speed, our time dilation will become infinite and we will forever be frozen in time. Thus photons never age, because they expend their entire velocity in only 3 dimensions.

Scientists always wanted the project killed

[SpecialKae]

I was actually just talking to my advisor about this (astronomy chair) and the basic idea is this: the scientific communtiy has been killing this project constantly (he several times graphically depicted shooting something on the ground) just to have someone in congress decide to bring it back. It's the most illconceived experiment - they are trying to measure not only what has been completely PROVEN but also in the most inane manner. Just about everything else that affects the gyroscopes are larger effects, what they are trying to detect is so small. When this was first thought up, it was probably kind of novel, but we're beyond that (can you say strings) now and its just one messey experiment (would you want to do the math for that?).

So why not work on something useful like alternate propulsion systems or batteries that keep my mp3's coming for more than 10 hours....

Re:warp space?

[AKAImBatman]

When Kepler figured out the planetary orbits, he envisioned invisible brooms sweeping the planets towards the sun. When I read "gravity is just curved spacetime" I think of Kepler's brooms as they both seem to say about as much.

Think more like a bowling ball on a trampoline. The bowling ball will "warp" the trampoline, and objects placed on the trampoline will fall toward it.

As for planetary motion, I'm sure you've seen those funnels that you put coins in. The coin spins round and round. Friction eventually slows it down enough to fall toward the center. If your coin was in a vacuum and had sufficient velocity, it could keep going around the center forever. (e.g. The Earth keeps "missing" the Sun)

Just how does mass warp space? How does space know the mass is around?

We don't know the former yet. Space knows mass is around, because at a quantum level matter and energy are inbalances in the vacuum. "Empty" space is really a bunch of wild waves called "quantum foam" that all cancel each other out.

What particle is gravity's carrier?

Gravitons are only theoretical. At this point it looks like they don't exist. In other words, gravity waves are perpetrated in a vacuum instead of by a particle like the strong force's gluon.

If there is a gravity particle, how come planets don't speed up as they plow into them orbiting the sun?

If a planet heads toward the Sun (not a good thing) it *will* speed up. The trick is that a stable orbit implies having *just enough* speed to keep missing the object.

And how come it gets to escape black holes but no other particles can come out and play?

Because there's no particle. It's the nature of space-time. :-)

We can describe gravity's effects but we can't say how it does the trick.

General Relativity says gravity == acceleration. Therefore, the presence of matter and energy "slopes" space-time in such a way as to accelerate all other particles in the Universe.

Do photons have mass? Q/A

[Anonymous Coward]

http://www.usatoday.com/weather/resources/basics/w onderquest/photonmass.htm

Q: Do photons have mass? If not, why does the gravitational field of a star bend passing light?

A: No, photons do not have mass according the present definition of mass. The modern definition assigns every object just one mass, an invariant quantity that does not depend on velocity, says Dr. Matt Austern a computer scientist at AT&T Labs Research. Under this definition, mass is proportional to the total energy, Eo, of the object at rest.

Re:Faster than light ships?

[Muttley]

Correct. When a collegue of Einstein's suggested that it was impossible for an object with mass to reach light speed, Einstein felt compelled to point out that a photon has mass and it travels at light speed.

Photon's have zero rest mass. The only mass they have is a relativistic consequence of their velocity.

Not only frame dragging...

[Shivas Sitter]

...but also whethere or not mass bends space/time. The probe was designed to test for both, and includes a set of gyroscopes for this purpose. These contain the most spherical spheres ever constructed. The mass bending thing was to be tested by measuring the length of the orbit. If an inch is 'missing', mass bends space/time. Imagine if massy objects were placed on a sheet that was anchored along the edges. They sag into the sheet. An object orbiting one of these objects now has a shorter distance to travel than if the objects did not cause the sheet to sag.

Interesting Interview of Scientists on NPR

[HenryKoren]

This aired last Friday on public radio:

Talk Of The Nation Science Friday

Seek to 27:30 for the start of the audio program on Frame Dragging.

Re:NASA's near M$ like mistake!

[pediddle]

Everyone should be clear: the "software" that they couldn't verify was the flight plan for the launch vehicle, not the software on the satelite.

Variable high-altitude winds just prior to launch required them to update the flight control parameters, but they couldn't verify that the update was successful in the final 4 minutes before launch. Better safe than sorry, so they scrubbed it 'till tomorrow.

Re:NASA's near M$ like mistake!

[Mercenary_56]

They can't afford to launch a satellite only to discover there was a bug in the software and have it be worthless

If you look at Gravity Probe B's Site you will find that the software that they are referring to has nothing to do with the probe itself but rather there was insufficient time to confirm that the Delta II rocket had the correct wind profile loaded for the data from the final weather balloon.

They wanted to make sure that the rocket had the data from the last weather balloon and there wasn't enough time to make sure.

Re:Faster than light ships?

[bcmm]

If a photon had mass, it would appear to have infinite mass when travelling at the speed of light.

Infinity. Not good.