Alien Solar System Much Like Ours 130
MrGort writes "Wired News reports that British astronomers say they found the first sun-like star with a giant gas planet in an orbit similar to Jupiter's, which leaves plenty of room for worlds like Earth and Mars. This system is a quick 90 light years away. The similar solar system to ours means that this gas giant could attract most of the debris, allowing smaller planets closer to the sun to develop like ours did!"
90 Million Light Years? (Score:1, Funny)
Of course the article said 90 light years, which is way too far to walk (or drive) anyway. (We are 8 light minutes from the sun, and it would take your whole life and part of your kids' to drive that far.)
Re:90 Million Light Years? (Score:1, Funny)
Pesky physics. (Score:2)
Anyways, who are we kidding? We are looking for planets like Earth not for life, which will evolve to suit nearly any environment, but to find possible colonization sites.
For that, a smelloscope would be much more useful.
patent (Score:4, Funny)
10 billion years of back license royalties... wehooo!
Re:patent (Score:5, Interesting)
But a repeating message has appeared, taking up more and more of the transmission. Our hero is summoned to a meeting where he learns that some of this repeating message has ben translated.
In summary, it reads: "Payment for service is overdue. Please remit immediately, or severe consequences will result."
The book plays out from this premise.
Let's hope we never have to deal with intergalactic IP issues.
Prior art Re:patent (Score:2)
Damnit!
This is not Star Trek (Score:5, Insightful)
This is the problem with the whole "is there life elsewhere in the universe" debate. I call it the "Star Trek Syndrome". People have gotten so used to movies and TV shows where space ships go zooming all over the galaxy that they have lost any understanding of the enormous distances involved.
There probably are planets out there with intelligent life -- maybe lots of them -- but they are so far away that it is impossible to have any contact with them. You can debate all you want about whether or not there's life out there, but you can't change the math.
If we could build a spacecraft capable of a speed of 16 Million Miles per Hour (which we can't -- that speed is far, far beyond any technology we have or have even dreamed of) you could reach Pluto in a few days, but it would take 360 years to reach that system that is only "a quick 90 light years away". Even trying to communicate via radio -- we would send a message and it would be at least 180 years before we got a reply.
Re:This is not Star Trek (Score:2, Funny)
'Eddies,' he said, 'in the space time continuum.'
'Ah. Is he? Is he?!
Re:This is not Star Trek (Score:4, Interesting)
We've dreamed of some pretty impressive things. For example, the Alcubierre drive (http://www.wikipedia.org/wiki/Alcubierre_drive). It has some [facetious]minor engineering problems like requiring negative energy density and more total energy than exists in the universe[/facetious], but it's a warp drive that satisfies the equations of general relativity. Faster than light, and physically legal.
Off topic, did the headline of this story strike anyone else as being like a headline from The Onion?
Re:This is not Star Trek (Score:2)
someone is sounding like a pessimist... tisk, tisk. 100 years ago, a couple guys were playing around with this idea of flight, that kinda took off didn't it? Space travael is a big step, give it time.
Re:This is not Star Trek (Score:4, Informative)
Re:This is not Star Trek (Score:4, Insightful)
The same applies to space flight now. We can dream it, but we can't figure out how to do it. Some day, a bunch of different people will come up with a bunch of theories on "super-luminal" travel, then set out to prove their theories. One of them will be proven.
Soon after that, someone will apply that "proven" law of physics (as the Wright brothers did), and a short time later interstallar travel will be like catching a plane is now - nothing out of the ordinary.
Unfortunately, it's not likely to be in our lifetime. (Oh, that it were!!)
Re:This is not Star Trek (Score:2, Informative)
Re:This is not Star Trek (Score:1)
Oh, that is were, indeed. We can console ourselves somewhat with things like SETI and the fact that with advanced nuclear technology we should be able to explore the Solar System. There must be so much there waiting to be discovered. I only wish those with the money and the brains would get on and do it!
Re:This is not Star Trek (Score:2)
Assuming Einstein was right with his theories of relativity, super-luminous travel or even travel at the speed of light is a major no-go: travelling at the speed of light means instant displacement for the traveller; for the traveller it takes 0 (zero) seconds to move any distance at the speed of light.
So Einsteins relativity doesn't keep
Re:This is not Star Trek (Score:1)
Re:This is not Star Trek (Score:1)
fair warning IANAP just a fairly well read interested spectator.
Mycroft
Re:This is not Star Trek (Score:1)
what i was basically trying to point out was that there are many theories that await to be discovered. If you would have asked someone 200 years ago how to get to the moon I am sure you would have just got a confused look. Admittedly, the "folding space" theory wasn't the best example but just becasue we cannot conceive of a way to travel to far off galaxies now does not mean it cannot happen.
Re:This is not Star Trek (Score:1)
uh, I hate to break this to you, but you're experiencing an acceleration of 1g right now, and you have been most of your life...
-calyxa
Re:This is not Star Trek (Score:2)
Exactly, the human body was "built" for 1g; you can't put humans in a spaceship and accelerate with 2g for 25 years or you'll arrive with a dead crew. Even if we had the technology to reach relativistic speeds; we can't accelerate human bodies a lot, so manned interstellar travel would still take generations (for the crews).
Re:This is not Star Trek (Score:2)
Yeah, but if we'ld have variable gravitation, we could use that as propulsion too: build two identical spaceships with such a gravity source. Starting with the two ships orbiting eachother, when one ship goes in the direction you want to travel, make it heavier (and the other ship lighter) s
The universe does not care what we dream. (Score:3, Insightful)
Why are you certain that one of them will be proven?
The universe is what it is, regardless of what we _want_ it to be. This may or may not include mechanisms for FTL travel, but we have seen no evidence of such phenomena occurring to date, and our
Re:The universe does not care what we dream. (Score:3, Informative)
The propagation speed of light in a medium has been reduced in the lab - not the speed of light in vacuum, which is the important number.
There are hints that the speed of light has varied slowly over the age of the universe, but this doesn't help us build space drives.
Re:This is not Star Trek (Score:5, Insightful)
With faster-than-light travel, we have a very different situation. He have actual scientific laws courtesy of that Einstein guy that show that you cannot accellerate an object up to the speed of light without consuming infinite energy . Those laws also indicate extreme difficulties with even the concept of something travelling FASTER than light (if you ever got going faster than light, it would take infinite energy to avoid travelling infinitely fast - and getting to a nearby star at infinite speed is MUCH harder than doing it at subluminal speeds.
Then, we also have no examples of super-luminal objects to point at and say "Ha! Those laws must be wrong".
That's an entirely different (and much more depressing) situation than the situation in the 1600's. They could look to a simple child's kite and imagine a hang-glider with a motor replacing the force provided by the kite-string. They could see birds doing that exact thing - taunting us with the ease of it all.
We have no similar thing to look towards - and one of the greatest minds of the last century showed us clear mathematical proof that this isn't going to be an easy matter.
Re:This is not Star Trek (Score:2, Insightful)
Re:This is not Star Trek (Score:2, Interesting)
The limitation on faster than light travel can be thought of as a requirement to preserve causality, if all reference frames (freely-falling ones, if you like) are regarded as equally good. Thus FTL travel would violate causality in the standard picture of relativity. But perhaps someone will show that a preferred frame exists. Even so, all alternative models I'm aware of which
I hate to rain on your parade... (Score:2)
In the 1600's, it was possible to make things go through the air. You can throw a rock through the air. Birds can fly outright. It, therefore, was somehow possible to do.
Supersonic flight was believed impossible, but mostly as an engineering challange (resisting massive pressures, etc.) not scientific law.
Superluminal speed is impossible from scientific law. We have never, EVER seen anything or made anything go faster than light. We may be able to get things moving AT the
Re:This is not Star Trek (Score:3, Insightful)
However, travel to other stars in less than a human life-time in our frame of reference will require super-luminal speeds. There is no physics known yet that will allow us to achieve this.
True, but it should be pointed out that for decades after that, most scientists thought it was physically impossible to break the speed of sound in an aircraft. There was no physics that allowed > Mach 1 speeds to
Re:This is not Star Trek (Score:3, Insightful)
Not true. Newtonian physics allows Mach 1 to be broken. Einsteinian physics does not allow c to be broken (or to be achieved with rest mass).
Re:This is not Star Trek (Score:2)
Re:This is not Star Trek (Score:1)
Can you document this? I'm aware of engineering studies showing what the difficulties would be in exceeding Mach1, and the valid concern that vibrations from the shock wave could damage improperly designed craft, but have never read a
Re:This is not Star Trek (Score:2)
I doubt that. In fact I doubt it so much that I challenge you for a citation.
Re:This is not Star Trek (Score:2)
The issue with "breaking the sound barrier" was largely an engineering problem, not a theoretical one.
Bullets, for example, had been supersonic for quite some time.
The trick was learning to design an _airfoil_ that could provide sufficiant lift at speed ranges that would allow subsonic takeoff/landing but yet still allow controlled supersonic flight.
It's all about the behaviour of air at high speeds - its material properties, if you will. But there was very little physics going on.
This is vast
Re:This is not Star Trek (Score:5, Insightful)
"The math" also says two things:
Communication occurs at the speed of light, so round-trip time to 90 light-years is 180 years, and one-way time is 90 years.
Modern humans have existed for about 30,000 years. Human civilization has existed for on the order of 6000 years, depending on who you ask and what you call "civilization". If the lifespan of an alien technological race is longer than this - and it will be, especially once it decentralizes (makes colonies not on the same easily-bombed planet) - then, of the stretch of their civilization's existence where they can hear and respond to us, the segment where they are more advanced than us is much longer than the segment where they are less advanced than us. This makes it likely that _if_ we find someone to contact, they're in the "more advanced than us" stage.
This makes communication, even with a multiple-lifetime time lag, worth it.
This discussion overlooks the impact of any future technology that would confer either extreme longevity, or the ability to store and reconstruct a human mind-state/personality. In the first case, slower-than-light travel between the stars becomes feasible because we have the patience for it, and it doesn't take that large a chunk out of our lives. In the second case, we can be sent at the speed of light as data, with no subjective time elapsing en route, to be reconstructed at the other end.
In conclusion, communication is both possible and worthwhile even without FTL travel or exotic technologies.
Re:This is not Star Trek (Score:2, Informative)
Re:This is not Star Trek (Score:4, Informative)
There turn out to be practical problems with this. Any craft that carries its own fuel with it - including the more practical breeds of antimatter drive - will be limited to a crusing speed of about 0.1-0.2C by the specific impulse of their fuel. The only thing that could approach speeds at which time dilation would be significant is a beamed core antimatter drive (that uses the charged particle shower from an antiproton annihilation as the reaction mass), but that requires unrealistic amounts of antimatter (positrons are easy to make, but antiproton synthesis is very inefficient, and will remain so unless new physics is discovered).
In principle, some kind of sailcraft driven by a stationary laser or maser array could reach relativistic speeds, but the array would be very expensive to build and very large (we need to focus on a planet-sized sail at a range of many light-years). It would also work wonderfully as a weapon capable of melting cities to slag at a range of hundreds of AU (or even light-years, depending on configuration), so I suspect non-proliferation agreements would prevent it from being built in the first place.
In short, the only hope for relativistic travel at less than colossal cost is new physics.
Re:This is not Star Trek (Score:1)
It's been far too long since I read a non-fiction book with spaceships in it, but can't you (in theory) propel a spaceship by shining a very powerful light out of the back, using the photons themselves as the reaction mass? Then could you get nearer to c?
Re:This is not Star Trek (Score:4, Informative)
You can, but the problem is generating the light in the first place, and the fact that light has a lousy ratio of momentum to energy (it has to be very, very bright to generate significant thrust).
Most light sources that are bright enough to move a ship at any reasonable acceleration (e.g. fusion bombs wrapped in other matter or just shining on a shield block that can tolerate gamma rays) waste matter - the energy to mass ratio of a fusion bomb is much worse than that of the photons you're driving the ship with. This means you'd be better off just using a magnetic bottle to deflect the plasma resulting from the fusion explosion, and you'd still end up with specific impulse too low for relativistic flight.
A light source that doesn't ablate or otherwise lose mass has to be relatively dim (either a hot block of solid matter or a confined plasma ball), which means getting anywhere will take an extremely long time.
The forms of light propulsion that I've seen considered involve generating the light somewhere else (e.g. a laser array) and just reflecting it off the craft's sail. You still have a drive that's horribly inefficient energy-wise, but the energy source doesn't have to travel with the craft.
For reference, power to thrust is 3e8 W/N for a photon drive (energy to momentum ratio is C for photons).
Re:This is not Star Trek (Score:3, Insightful)
That's, of course, not the only kind of craft: ramscoop ideas have been around for a while, and while they're not exactly "production quality" ideas, there's nothing fundamentally killing them. We'd just have to figure out how to do fusion much better than we do now - which is not exactly new physics - it's new engineering. We'd also want to get the hell past the heliopause, to interstellar space. Ramscoops
Re:This is not Star Trek (Score:1)
ramscoop ideas have been around for a while, and while they're not exactly "production quality" ideas, there's nothing fundamentally killing them.
Dialogues concerning the viability of ramscoops tend to follow a "death by a thousand cuts" pattern, mostly because whenever someone finds a reasonable obstruction to their practicality, someone else will propose a wildly unrealistic and ad hoc remedy, saying it could be plausible one day with future technology. Perhaps a better description of the situation w
Re:This is not Star Trek (Score:3, Informative)
Ramscoops are fundamentally killed by drag.
Consider a ramscoop to be a special case of a magnetic bottle. In a conventional magnetic bottle, matter leaks through "loss cones" at the pi
Re:This is not Star Trek (Score:2)
If it's fundamentally impossible to get it to fuse in flight, then it's always possible to contain the material, store it, process it, and fuse it la
Re:This is not Star Trek (Score:1)
Re:This is not Star Trek (Score:2)
This craft used a Bussard ramscoop. There have been multiple messages in this thread explaining why they turn out not to work. For practical field configurations, drag greatly overwhelms fusion-produced thrust.
Re:This is not Star Trek (Score:1)
Sorry for the misdirection.
Re:This is not Star Trek (Score:2)
Producing antiprotons efficiently requires new physics. Producing them _inefficiently_ is just a Small Matter of Engineering, and is already done on a semi-routine basis (though at quantities many orders of magnitude lower than would be needed for spacecraft fueling).
The problem is that when you create particle/antiparticle pairs, you get far more light ones than heavy ones. The fact that protons and antiproton
holy crap (Score:2, Funny)
You must get laid incredibly often with that schpiel
Re:This is not Star Trek (Score:2)
Re:This is not Star Trek (Score:2)
We are already broadcasting more than enough radio noise to be easily seen by any hypothetical aliens who are hunting down and destroying other races, so attempting contact does not substantially increase the risk of this scenario.
Furthermore, due to the vas
Re:This is not Star Trek (Score:2)
There is no proof of that. The whole hoping aliens are smarter than us is a bad assumption. If it took so long for life to evolve here, it would probably take just as long if not longer in other conditions.
Re:This is not Star Trek (Score:2)
There is no proof of that. The whole hoping aliens are smarter than us is a bad assumption. If it took so long for life to evolve here, it would probably take just as long if not longer in other conditions.
If anyone responds to us, then life has already evolved, so that issue is not relevant. The relevant question is, "given that someone is there who _ca
Re:This is not Star Trek (Score:1)
Re:This is not Star Trek (Score:2)
Having radios doesn't mean they are more advanced than us. We've had radios for a long long time.. What we are doing in regards to space exploration now could have been easily accomplished 20-30 years ago had space exploration been as big of a concern as say military weapons development.
Look at it another way.. Had we received transmissions from aliens 50 years ago, we probably could have replied, and I'm sure you'd agree that we are somewhat more ad
Re:This is not Star Trek (Score:1)
Are you seriously suggesting that a couple of centuries is a long time? Good grief man. I'm speechless.
Anyway, my point still stands that none of this has anything to do with how long it takes for life to evolve.
So you are con
Re:This is not Star Trek (Score:2)
Statements like that just show an ignorance of statistics. The odds of there being aliens more advanced than us is the same as there being aliens that are less advanced than us. Not to mention that you are using human intelligence as the metric for all intelligence. It is also just as likely that a civilization would have radio technology far better than our o
Re:This is not Star Trek (Score:1)
Ok, I think I see where you are coming from. I am equating how advanced a civilization is with time elapsed since the invention of radio. Granted, there are many other ways to measure "advancement".
Do you agree that an alien race with radio is likely to have possessed it for longer than we have?
I only wish you had expressed yourself more clearly in the first place instead of resorting to calling me ignorant.
Re:This is not Star Trek (Score:2)
No, I wouldn't even agree to that..there is nothing that would lead me to believe that an alien race within communication range of earth has had radio technology longer than we have. As I said, statistically, the odds of there being aliens more advanced than us are the same as there being aliens less advanced than us in regards to radio communication and otherwise.
It's one thing to assume there is intellig
Re:This is not Star Trek (Score:1)
What are these "statistics" you keep referring to? There are no statistics on alien races because we haven't yet even encountered a single one. What statistics are you talking about?
Re:This is not Star Trek (Score:2)
Statistics is a branch of mathematics, if you go to college you generally get a decent introduction to statistics. As I pointed out before, your statements show an obvious ignorance of statistics.
Re:This is not Star Trek (Score:1)
No, numbnuts, I mean what are the numbers that you're using? How did you decide that "statistically, the odds of there being aliens more advanced than us are the same as there being aliens less advanced than us"?
You're making it very hard for me to bel
Re:This is not Star Trek (Score:2)
No sir, it is you who is trolling me.
Re:This is not Star Trek (Score:2)
Re:This is not Star Trek (Score:2)
Old radio waves from the earth (Score:1)
Most of those radio waves are drowned in noise, alone by the fact that there are too many transmitters that share the same frequencies. All those powerful broadcasts for radio and TV are radiated into outer space, but from a long distance one would see a superposition of all those signals for different TV and radio stations, i.e. noise.
The exception is the short-wave radio band. Because one can receive a powerful
Re:Old radio waves from the earth (Score:1)
Re:Old radio waves from the earth (Score:1)
Let's try to estimate that. Consider the frequency range around 1 MHz, the MW AM broadcast band which has been in use for quite some time. The range is something like 0.7--1.5 MHz, or 200--400 m wavelength. I'm not so sure about the total power installed in the world; say 500 kW for every 200x200 km area of populated land. That is maybe 200 MW of total installed power (that feels like a high es
Re:Old radio waves from the earth (Score:2, Insightful)
Ummm, has someone told those SETI guys this? Maybe that's why we haven't found anything yet...
Re:Old radio waves from the earth (Score:2, Informative)
I think they're hoping to detect a transmission that is meant to be detected, in the range 1.4--1.7 GHz [216.239.37.100]. In that range, the thermal background of the sun is about 1e10 watt, so only a very directional narrow-band transmission has a chance to be noticed.
I remember that people have tried to send a message to a few nearby stars a few years ago with a powerful directional transmitter. The message was a series
Re:Old radio waves from the earth (Score:1)
Re:This is not Star Trek (Score:1)
Re:This is not Star Trek (Score:2)
>>This is the problem with the whole "is there
>>life elsewhere in the universe" debate. I call
>>it the "Star Trek Syndrome". People have gotten
>>so used to movies and TV shows where space
>>ships go zooming all over the galaxy that they
>>have lost any understanding of the enormous
>>distances involved.
>It's true, 90 light years is quite a distance
>for us to travel or communicate. But, compared
>to the re
Re:This is not Star Trek (Score:2)
I'm going to guess that the submitter actually knew that 90 light years isn't quick by any sort of standards we have for travel here on earth, but rather said that as a mix of tongue-in-cheek-humor, and some somewhat well-deserved optimism. It really could have been much, much farther, as far away as 90 light years really is.
Re:This is not Star Trek (Score:1)
Re:This is not Star Trek (Score:1)
Besides, considering the size of the galaxy, 90 light years is very, very close. I think it's clear that's all he was saying. He wasn't implying that we could drop by for a visit.
Cosmic Wonders! (Score:5, Funny)
Don't worry, kids, it's a NASA site!
we might be able to find intelligent life. (Score:3, Funny)
And one other detail, we have been mostly unsuccessful at finding intelligent life on earth, what makes us think we can find it somewhere else?
Re:we might be able to find intelligent life. (Score:5, Insightful)
We already have the technology that could get us there in around a couple of thousand years --- and only 1000 if you were happy with a fly-by mission. The 1970s Daedalus study by the BIS showed us how it could be done using only technology known at that time or reasonably expected to be available by the turn of the millenium. To this extent, it is indeed a minor detail.
There are two major details, IMO. The first is cultural: we no longer seem to want to embark on projects that are expected to have payback times measured in centuries, as the builders of the Egyptian pyramids and the European mediaeval cathedrals did. The other is economic: even if we wanted to do something like this, the cost would be enormous. OTOH, perhaps the cost might be no greater in societal terms than the price to the Egyptian economy almost 5000 years ago of building the great pyramids.
Paul
Re:we might be able to find intelligent life. (Score:2)
Perhaps you are right that humans have become too short-sighted to embark on any projects to further our species (look at the vast majority of government policies anywhere), but I don't think that we need build such a huge space ship just yet.
I think it will happen, but only after we have developed the technology to conquer our own galaxy. Then when we arive at the ne
Re:we might be able to find intelligent life. (Score:1)
Re:we might be able to find intelligent life. (Score:2)
One "problem" with the proposal was that if we sent such a probe, it might report back in 1000 years, but if we waited another century, we could send a probe that would get there in half the time, so we'd get the information in only 600 years.
Of course, in two centuries we'd be able to send a probe that could get there more quickly still, and maybe have the data less than 500 years from now. Of course there is a limit to thi
Re:we might be able to find intelligent life. (Score:2)
So I think it would at least be important to try to send probes, even though we hope that we could soon build faster ones.
"planetary system" (Score:1, Informative)
There is only one "Solar System," and that's the system of bodies orbiting our star, Sol.
The generic term for any other collection of planetary bodies orbiting some random other star is "planetary system." The planets therein are referred to as "extrasolar."
Read the original press release [aao.gov.au] and paper [arxiv.org]. You will see this usage reflected there.
Re:"planetary system" (Score:2)
(For that matter, we talk about Jupiter's "moons" a lot. Given that there is only one "the Moon", that shouldn't be, either. But it is, so just get used to it.)
Proof the Earth has 40 years to live (Score:1)
More info from New Scientist and others (Score:3, Informative)
A bit more info from a previously submitted post:
New Jupiter-like Planet Discovered in Sol-like system
A new Jupiter-like planet [newscientist.com] has been discovered in a circular orbit around a Sun-like star 90 light-years away in the constellation Pupis. What is remarkable about the discovery is that this system is the most like our own solar system discovered to-date. This development lends credence to the theory [ananova.com] that systems with small, rocky Earth-like planets are out there [ananova.com]. ''This is the closest we have yet got to a real Solar System-like planet [reuters.com] and advances our search for systems that are even more like our own,'' said UK team leader Hugh Jones of Liverpool John Moores University. Jones went on to say that, ''Jupiter's position is probably crucial to the distribution of other planets in the Solar System.'' Current thinking on planet-formation indicates a large, Jupiter-like planet in a circular orbit would allow the relatively undisturbed formation of an inner system of smaller Earth-like planets. The newly discovered planet is about twice the mass of Jupiter with an orbit equivalent to the asteroid belt [cnn.com] in our own solar system.
Giant ice cubes as space ships (Score:1)
The velocity was increased gradually by using the hydrogen as fuel. Of course, the book said that
Re: This is not Star Trek (Score:1)
Incorrect. The tapping is basically a vibration. And that vibration will travel no faster than the speed of light.
Re: This is not Star Trek (Score:2)
It's impossible to use a stick like that. (Score:1)
As the grandparent mentioned, it's a "vibration."
See this e2node [everything2.com] and the ones below it for a thorough debunking of the theory.
Re:It's impossible to use a stick like that. (Score:1)
Secondly, the faster something moves, the shorter it gets, due to relativistic effects. It's really tiny, like, the Apollo rockets got something like 0.0000001 mm shorter (haven't got the figures, you get the point) at maximum velocity, but this means as you move the stick the stick gets shorter, precise shrinkige a function of the speed you move it and the length of the stick.<br>
So, it could well
Re:It's impossible to use a stick like that. (Score:1)
no, it's not moving very fast, but it is rather long, and the shrinkage is a fraction of the total length. Someone reading this must know enough about relativity to do the math? Please??
I mean, reading other comments, I can get the whole speed-of-sound waveform thing, but wouldn't the relativistic-shrinking thing have some effect?
Re:It's impossible to use a stick like that. (Score:3, Interesting)
Re:It's impossible to use a stick like that. (Score:1)
huhuhuhuhuhu...
Shut up, Butthead! I said Shut up!
Re:It's impossible to use a stick like that. (Score:2)
There is no such thing as a perfectly rigid body.
Uhh.. what do think is responsible for the goatse.cx guy's [goatse.cx] condition?
Re:It's impossible to use a stick like that. (Score:1)
Re:It's impossible to use a stick like that. (Score:1)
Re:It's impossible to use a stick like that. (Score:3, Interesting)
If you shoved it "towards" Europa, for instance, then the stick would shrink slightly, but, if you're jiggling the stick back and forth, the stick would be shrinking, expanding, shrinking, expanding as you stop and start the motion. It's even worse than that as you're attempting to move a massively elongated object, so you get displacement waves rather than motion.
Plus the fraction that we're talking a
Re:It's impossible to use a stick like that. (Score:1)
There is no such thing as a rigi body the way you see it (that is, all its part move together 'instantly')
A rigid body is made of atoms tied up together by binding forces.
you apply a force at the start of the queue to move the stick, and you accelerate (imagining the stick is a just a long chain of atoms) the first atom toward the second, etc.. it's a "pushing chain" that propagate at about the speed of light
Re:It's impossible to use a stick like that. (Score:4, Informative)
(b) (I Am A materials scientist) "Solid" matter is composed of atoms bound together by electromagnetism. When you "push" a solid object, displacement waves (essentially sound waves), travelling from atom to atom inform the material that you are pushing it. For sufficiently fast pushes and short timescales, even a block of carbon steel looks like a wobbly jelly. This is important in impact engineering, for example, and mechanical engineers and materials scientists deal with stress waves in solids all the time (plastic torsion waves are the most "fun"). Nothing is perfectly solid.
Your "stick to europa" would have to have unphysical infinite rigidity for instantaneous transmission. In real life, assuming you could make a stick to europa (not in itself unphysical, just extremely unlikely), a wave train would travel down the stick when you displaced one end, displacing the material of the stick. This would happen at the speed of sound in the stick, which is always significantly lower than light speed (since it is determined by interatomic interactions, themselves subject to light speed) So yes, conceivably, the drum would make a sound, but the sound would come some time after you pushed the other end of the stick, since the stick would be acting like a wobbly jelly on such a scale, as all atomic matter must.
You can even see this in action - surely you've seen the high-speed movies of bullets hitting apples, with deformation waves crisscrossing the surface? All solids behave that way, it's just the waves travel very quickly (but not nearly as fast as light...) in some solids such as hardened metals.
Re:90 Million L.Y.? (Score:2, Insightful)