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While I do agree and sympathize with you, technically, 300 km/h *is* hundreds of km an hour.
Yeah, we've used balloon-based telescopes for a looong time. What I'm thinking of is a bit more ambitions. Rather than a relatively small telescope up for a few months, what we could have would be a large (few meter) telescope that's basically a permanent emplacement in the sky.
We've had airborne IR observatories for a while but they've been, to my knowledge, all military in nature for tracking incoming ICBM warheads until now.
This has got me thinking. What about those high altitude giant balloon platforms that JP aerospace is working on? They might make an ideal platform for mounting large telecopes. Imagine a Hubble on the cheap. It should be fairly simple to mount a few 2m scopes on those platforms. At that altitude, most of the UV and IR bands should be usable and the atmospheric interference effects will be minimal.
Incidentally, yesterday, Gravity Probe B entered into the science collection phase. The only remaining hitch is a persistent unknown force that's causing the liquid helium to circulate more than anticipated. The movement is under the limits of the experiment but just barely.
GCNR - I agree, the chemistry/physics of the elevator is the big stopping point here. Honestly, I can't see CNTs lasting more than a few years in space before reactive gasses, micrometeors and radiation degrade the molecular structure to the point where it can no longer hold itself up.
The only solution I can think of is to haul a big CNT factory to the anchor and start making CNT rope continuously. Basically, the elevator would be a continuous cenveyor belt of CNTs that are constantly being lowered to Earth and recycled there. You'd haul carbon up to the anchor using the elevator itself. Of course, the downside is that the CNT will be the most degraded and the weakest at the base where the stresses are greatest. OTOH, as most failures will occur near the ground repair is easy, just wait a few days/weeks/months for the ribbon to reach the ground again.
Another problem would be that the in order for the ribbon to be turned over, say once a year, You've got to be able to churn out CNT ribbon at a rate of about 4 km/hr 24/7. Also, any rising elevators will also have their rate of ascent (and energy usage increased) by the same speed as well.
I didn't see any mention of this already so I'll pull up some old but interesting news. I was watchin NASA TV earlier tonight and there were two interesting things mentioned. One was that the brighter rings are of much higher purity ice that previously though, being at least 99% pure.
The other was some sort of large anamalous event that released a cloud of atomic oxygen about 3-4 planetary radii out from Saturn in January. Unfortunately, the event occurred while CAssini was too far away to see what triggered it. However, whatevey it was, it was big. The total mass of oxygen released is estimated to be as much as the entire micron particle mass of the E ring or about 100 millions tons of material. The lead scientist speaking on the matter had no suggestions as to how such a large amount of gas could have been generated in such a short period of time. (it appears to ahve been generated in a month or shorter time scale)
Two problems with that idea, I'm afraid.
The first is that while the ion density is higher in the radiation belts, it's still very low. The radiation belts are characterized by the high energy of the particles rather than any exceptional density. The particles density is not much higher than the normal vacuum in orbit. Present technology simply can't gather meaningful amounts of material from high energy, low density sources like this.
The second is that the vast majority of the ions in the radiation belts are protons. For an ion drive, you need heavy ions like Xenon or Krypton. Protons are simply too light. An ion drive using protons would be terrible inefficient and low thrust.
On Wednesday night, I was stuck on the side of the road in Canada heading up to Whistler, waiting for the road crews to finish some blasting work. Spent the 1.5 hours laying on the asphault, miles from city lights and was counting about 1 meteor about every few minutes.
Viewing conditions were good enough to see Andromeda by naked eye which is a first for me. The only drawback is that I hadn't packed my telescope.
Incidentally, the Genesis mission used a very interesting orbital trajectory that was touched on in the interplanetary transporation forum a few months back under the thread 'zero energy trajectory' or somesuch. Basically, it allows a space probe that is at one of the Lagrange points to travel around the solar system using almost no fuel.
Thanks for making us aware of the Everett interpretation. How would this interpretation explain the results of those experiments in "quantum teleportation" which have already been done and have been determined to be valid by replication?
But by looking at them you can predict with complete accuracy what the spin of the entangled "partner" particle must be? And, if you change the spin of a particle, and actually observe it's new spin, then you can also predict with perfect accuracy what the spin state of it's entangled partner must be?
If the above statements are both true, then we must be dealing with semantics about the meaning of "transferred". Since, if one particle's spin is determined to be "up", it's partner's is always "down" it looks like a NOT gate to me.
I don't know about "transfer" between particles, but somehow in the experiment as a whole there is a relation, and therefore a transfer of information, between the states of entangled particles and the rest of the experimental situation or else the previous experiments could not have been successfully performed and it would be absurd to talk about "quantum computing". Yet granting agencies seem to be taking this seriously.
Whew, now I'm really going round and round. I thought that the basis of entangled relations between particles was spin states. Are different spin states at different energy levels? Or are spin states just examples of the properties which can be involved in entanglement?
The Everett interpretation, AFAIK, has been entirely consistent with all observations of quantum events. Basically, it's just as successful as the Copenhagen interpretation and suffers far less from some of the logical inconsistencies and paradoxes. The only big argument against the Everett model is that it calls for the constant generation of new universes. However, this objection (which is suprisingly common even among physicists) is false as the actual Everett model doesn't call for the generation of parallel univeses. Instead, it simply posits that the quantum wave functions never collapse.
Changing the spin of an entangled particle after they are seperated has NO effect upon its entangled twin. What you've done is taken one entangled particled and interacted its spin with another particle's spin, changing it. If one takes the spin of the particle used to change the spin and knows the spin transfer dynamics of the interaction, you can deduce the spin of the entangled partner. Basically, if you had two coins that are both heads up and then flip one of them over, you don't change the fact that the other coin is still heads up. However, by knowing that the coin you have has been flipped, you know that the other is heads up and not tails.
Quantum conputing is an entirely different thing, although related. Basically, before the wave function collapse posited by the standard Copenhagen interpretation, a quantum particle explores all possible solutions to its wavefunction. By carefully setting up the interaction of different quantum objects, you can make a computer that can work on many aspects of a problem simultaneously. The transfer of information in these computers works much as you would expect except for the fact that it occurs in a parallel fashion that is imposible in classical mechanics.
IT's not just the spin state of a particles that's entangled - it's any quantum state that is comehow connected between two particles. It just happens that spin is a value that's easy to measure unambiguously. However, the articles talks about transferring power through the entanglement which is a clear violation of the conservation of mass-energy. Even though it's not as obvious, the transfer of spin or other quantum states through the entanglement link is also just as verboten.
Ah, Errorist, long time, no see!
Yes, the Van Allen radiation belts can basically be viewed as gigantic ion traps. They aren't very good radiation traps as the trapped ions eventually wander out but the sheer size of the magnetosphere enqures that it has a fair amount of radiation in it at any given moment.
http://www.esa.int/export/esaSC/120377_ … .html]here
This is a really cool mission the ESA is sending up in 2010. IT's a followup to Hipparcos. Like Hipparcos, it uses super precise star positioning to measure paralax distances to stars. However, it's 100 times as accurate as Hipparcos and will measure the distances to a billion stars to an accuracy of <10% as far out as the galactic core. It will also have very high accuract spectrometers which will allow the spectral characterization of all of those stars. This allows the creation a a catalog of the position and motion of a billion stars.
Furthermore, Gaia's capabilities allow for the detection of trans-Neptunian objects like small palentoids, asteroids and comets. They expect hundreds to thousand of new finds this way. Also, the Doppler shift motion sensors will allow the detection of hundreds of new planetary systems in nearby stars.
Ultimately, we need the ability to remote service stuff in orbit via robot. Given that a large portion of our manufacturing capability these days is robot driven, it's silly that we're stillusing expensive human labor for space repairs. I think that the development of a decent robotic repair capability is essential for our ability to get a real orbital presence.
I've thought a bit about the quantum entanglement drive and I'm now completely convinced the guy who wrote the article simply has a very poor grasp of the subject.
The best way to think of quantum entanglement is as follows:
If you have a reaction that produces two particles with matched spins (eg: one spin up, the other spin down) you can ascertain the spin of both particles by looking at only one of them. Classical physics says that both particles have a spin upon formation and that looking at one particles imply lets you know the spin of the other. Quantum physics (the Copenhagen interpretation, at least) states that neither particles has a spin. Rather, both have a mix of up and down spin until you look at one and then it suddenly gains a spin. The other particle then instantaneously 'gains' the opposite spin regardless of distance. Note that the Everett multi-world hypothesis nicely avoids this whole problem - the EPR effect is a direct result of the Copenhagen interpretation. Personally, I favor the Everett interpretation for this and other reasons.
No information is transferred between the particles. You can tell that entanglement occurs because of something called the BEll inequality. Basically, by carefully designing the experiment and looking at the proportions of the spins you see, you can prove that the particles don't have spins until you look at them.
It is impossible to use this to transmit information. Lots of people have looked at the EPR effect for FTL communication and the conclusion is that is is not possible. Since you can't transfer quantum states, the entanglement drive in the articles doesn't work.
If you need further proof, the entanglement drive violates the conservation of energy. If you apply energy to an entangled particles and the partner goes to the same energy state you have effectively doubled the amount of energy in the system, creating energy from nowhere.
Oh yeah, another cool toy on MRO is an Italian ground penetrating radar that should be able to map underground ice deposits up to 1 km underground.
The 9-12 months is to plan things. The actual repair mission doesn't go up for at least 3 years, unfortunately. Hopefully Hubble is still in a repairable state in that length of time.
Brin is a sci-fi author. His most famous book is Startide rising. Most of his books are set un a universe where humans are a small, rather backwards bit player in a huge galactic civilization. Sundiver was one of his early novels set in this universe about a joint human-alien mission that sends a spaceship into the photoshere of the sun.
Brin's a rather lousy writer but he comes up with some really good ideas, though.
Well, in a stunning departure from their usual head-up-ass policies of late, NASA finally buckled under the pressure and committed to repairing Hubble.
I'm dubious. From my understanding of the EPR effect, it's not so much the transmission of a quantum state but a consolidation of a quantum state. Meaning that both of the particles have to be quantum indeterminant and that they both choose one of the states upon observation of one of the particles.
I think that the author just has a poor understanding of EPR.
http://origins.jpl.nasa.gov/news/2004/0 … .html]here
A link to the official web page.
http://marsprogram.jpl.nasa.gov/mro/]here
Here's the homepage for MRO. IIRC, I posted some stuff on this a while back but I can't find the post. I'm more excited about this mission than most of the other Mars missions in the pipeline. The scientific instruments on this probe put our previous ones to shame. In addition, it represents a quantum leap in space probe technology. It's got a high bandwidth comm system that will end up transmitting more data than all of the other deep space probes in history put together.
The imaging camera alone is simply amazing. I was looking at the technical stats and the design for the thing is wonderfully clever. Furthermore, it will have the ability to see sub-meter objects on the surface. Perhaps we'll finally get to see where Beagle ended up cratering.
Also NASA is gearing up for future lander missions and manned missions by including an advanced tracking system that will help to guide landers to Mars with much greater precision so that they can land in an area defined in a few km rather than hundreds of km.
I suppose you could also takea page from David Brin and call it Sundiver.
Cool pic but the caption overstates things quite a bit. For one thing, there's still quite a bit of controversy about the origin of the Casimir effect. It turns out that there are alternate ways to explain the force using standard electrostatics and that zero-point energy is not necessary to explain things.
Eeek, the thought of playing chicken with a stream of projectiles moving at high suborbital velocities is not something I'd like to be anywhere near. The failure mode is when the pellet stream gets a tiny bit off axis and erases a part of the system in a big explosion.
What I want to know is who they're going to con into flying Wildfire? They haven't had anything even remotely resembling a full scale test of their technology and they've move their laungh date up with a pilot on the first actual test of the integrated platform.
I wish the team the best of luck but I'm afraid that they're going to need a spatula to recover the pilot after the first flight.