First, you're setting up the problem so that EM forces will be stronger. How about the EM force between two uncharged objects that aren't chemically bonded? The gravitational force between them will undoubtedly be stronger.
Second, chemical bonding is a quantum mechanical effect of a charge in a potential well. If we're to talk about the classical coulomb interaction, as all of us have been discussing in previous posts (the 1/r potential), the chemical bond cannot exist. The force that makes a chemical bond is a purely QM effect of EM. A chemical bond requires a very specific setup of a potential well. In addition, a chemical bond does NOT have to be attractive, and can actually cause two nuclei to repel one another (an antibond), in which case it would be weaker than gravity of course. This effect is just as electromagnetic as the chemical bond. Antibonds are not rare and are crucial to chemistry, as they are what allow chemical reactions to occur.
Third, chemical bonding is not causing the nail to stay in the ground. The forces of friction are causing that, which are more macroscopic than chemical bonds. Chemical bonds are holding the nail together and the penny together. But if the nail were perfectly smooth all around, it wouldn't be a very good nail, because the forces of friction wouldn't hold it into place.
Here's an example of one instance in which the EM force is weaker than gravity: When that refrigerator magnet keeps falling off the fridge. Gravity in that case is overwhelming the magnetic force holding the thing onto the fridge. That's just as macroscopic as your example.
Actually there would have to be a change in the orbit. The masses are both moving away from you, so the force exerted by both of them is decreasing. Imagine the situation when the two halves of the sun are many light years away.
What won't change is the direction of that slowly diminishing force. It'll always point at the same spot that the sun was before it broke into two.
Now, the effect on our orbit would be the following: since the force is always pointing "inwards," and decreasing, the earth is going to spiral outwards from its current orbit. The degree of the spiral depends on the speed of the halves of the sun. I put "inwards" in quotes because inwards doesn't really have a precise meaning for a spiral. But you get my point.
Actually if I'm not mistaken, gravity and electromagnetic both exert a 1/r potential (1/r^2 force). So their distance range is the same.
So at short distances:
strong>weak>=electromagnetic>gravitationa l
but this isn't quite right because the strong force has two characteristics, a main force and a residual force. The main force is what keep quarks together in neutrons and protons. That's absurdly strong, and it's strength actually INCREASES with distance. However, the residual strong force is what keeps the nucleons together, and falls off really fast with distance, like the weak force.
At long distances things are a bit simpler:
Electromagnetic>Gravitational>strong>weak
The problem with this is that the electromagnetic and gravitational are relative. You can't go by the constants associated with the field, because they're defined by us (for example, what if mass were in terms of petagrams? Then G~10^19, and the force (in terms of petanewtons, I think) would skyrocket.)
Point is that it's all dependent upon the system you're talking about and the units you're talking about them in. We really can't compare them.
I don't think it's a huge waste of resources. We can approximate the mass of the universe by looking at rotation curves of galaxies, luminous matter, etc. It is precisely the fact that we can't see some of this mass which we know exists that makes the dark matter problem so interesting. We can detect it - that's easy - just look at rotation curves. The fact that we can't see it doesn't mean we can't detect it...
I have never heard of that rule, could you tell me where you learned it from?
Most people nowadays access journals online through search engines like SciFinder or Beilstein (sp?). Most of these journals publish their papers online as.pdf's or in html format, and they are either identical in all ways to the paper version, or they are actually scanned copies of the journal.
However, if the paper is not published in hard copy, that's when you do have to give the web address and such.
In any case, my standard practice is that I find it online, then print it out and read it. If I decide that want to cite it, I jump back on the webpage I got it from and copy and paste the citation into my paper.
I just pulled up Mathematica and ran some amusing stats:
Assuming that 2000 characters can fit on a 8.25 x 11 inch page, you can print 10 pages/second, a page is 1 micrometer thick, you can print 2000 pages/toner cartridge, and you can speak 2 numbers per second...
Printed pages: 6.2 x 10^8 pages (620 million) Printing time: 117.96 years (excluding leap years) Stack of printed paper: 62 km high Toner cartridges: 310,000 cartridges Time to speak the entire number: 19,660 years Length of a continuous-page printout (ala dot matrix): 170,500 km, which could go around the earth 4.25 time, or get us halfway to the moon.
Feel free to check my work, or to add stats to this:?)
1/6 g in meters is 1.63m/s^2 1/6 g in feet is 5.33ft/s^2
also, I timed the descent with a stopwatch, and I get 1.46 seconds for the entire jump, or 0.73 seconds for the descent on average. I did the measurement using 2 different video players and that's what I got. I also count 24 frames, not 21, which would make the time 0.72 seconds.
Assuming everything else correct, we now have:
d=0.5*5.33*0.72^2 = 16.6 inches on the moon, and d=0.5*32*0.72^2 = 99.5 inches on earth
So now it definitely looks like they were in 1/6g.
I don't see what you mean about the recoil in his knees. On the first jump his knees barely buckled when he landed, and on the second jump he landed on one foot.
So any research out there that doesn't show an immediate gain should be bagged?
There is very much that NASA has added to society. For example, their research into solar panels has created more efficient light-gathering capabilities. Their gobs of money towards searching for NEO's could save a lot of lives some day. Their research into aerogel has yielded one of the best insulators known to man. Their work with earth-observing satellites can provide us with information about the ozone, global warming, and other global issues.
That's just a few off the top of my head, and there are tons more.
Personally, I do want some of my tax dollars to go towards searching for black holes, neutrinos, and ET's. So although you may not want it, a lot of other people out there do, or else NASA wouldn't be funded.
"you could jump very high, and would probably end up stumbling a little."
They didn't try to jump and see how high they would go. However, look at the roostertails made by the relatively slow moving rover - they're big. Also, look at some of the more amusing movies from the Apollo, like where Schmitt (I think) fell over trying to put a pole in the ground, because he wasn't light to get enough traction to twist the pole. It's pretty amusing.
"I also got some of the NASA pictures up close, and could see very easily that they were photoshopped. In 1969, they didn't have access to the zooming, so it was unnoticeable."
And you think they had photoshop? They did in fact have access to zooming. It was called a magnifying glass.
Actually that's not right. Every telescope has a diffraction limit that is a function of the size of its lenses. Hubble's diffraction limit prevents it from seeing things smaller than a certain size on the moon, and that size is much larger than the width of the landers.
Also (I may be wrong on this), but I hear that one of the Apollo missions put mirrors on the moon to reflect laser light back (to get Earth-Moon distances). Anyone know if that's right? I suppose that would be meaningless to conspiracy theorists, anyway, right?
Re:What if they don't find the gravity waves?
on
Examining Gravity Waves
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· Score: 2, Interesting
I don't think we can compare the two considering that they come from completely different times , when "science", meant completely different things.
Would you still think Newton was a genius if I told you that his Principia was a mere fraction of what he spent his life doing, and in fact was a quite well-known alchemist? How about the fact that he believed that he could predict the future by reading scripture (see: Temple of Solomon). Or read the last bit of the Principia, where he believed that the tails of comets were what provided us with water and nutrients so that we could survive. His work in alchemy and scriptures comprised the vast majority of his life.
But let's remember that prior to Newton (and afterwards, for awhile) there was no such thing as an equals sign. Imagine doing calculus completely geometrically. Also remember that for the first time in history there was a theory that agreed completely with observation. And how about the fact that the Principia was the final nail in the coffin for the geocentricity.
Then there's Einstein, who was ardently opposed to the revolution that he began (Quantum revolution), and which has resulted in the most tested and highly tested theory in scientific history (note that I'm not saying it's correct). Or that as late as 1895 he may have believed in an ether.
Then again, Einstein did "kick off" quantum mechanics with the photoelectric effect. And the fact that he completely "jacked around" with the foundations of physics by redefining things like space, time, and even reality, indicates a view of the world unlike any scientist had before him.
I've listed all of this because what we define as important factors in determining who was greater is inherently and unavoidably biased by our view of the world and the history that we know. Both of these men were revolutionaries who changed the way that we look at the world. They saw a new paradigm that no one else did, and that is something that only happens, oh, every few centuries in physics.
Incidentally, Newton did NOT do away with absolute space, but adamantly believed there to be one (check out Definition 8, Scholium, in the Principia). Oh yeah, and he did account for the retrograde motion of Mars. Galileo did that first (successfully), though.
The fact that GR is a specialized field doesn't say much, considering that Newtonian mechanics has been around for over 300 years, while GR isn't even 100 yet. More time to mull over mechanics has given scientists more time to take avantage of it. Remember we may go to another star with the help of Einstein.
Things aren't so clean in the history of science. There never was, and probably never will be, a single leader in any science who heads up a revolution. To do so is completely unscientific, as science is a society, not a dictatorship. Newton didn't lead the Copernican revolution, and neither did Copernicus, or Galileo, or Brahe, or DesCartes, or Kepler. Einstein (definitely) didn't lead the quantum revolution, just as Bohr, Schrodinger, Pauli, Pauling, Dirac, or Heisenberg didn't. It evolved, it had it's bumps and bruises. Read Thomas Kuhn's "On The Structure of Scientific Revolutions" for more.
I've noticed a lot of people think "this person did this, and this person did this..." instead of "this person was a driving force in this thought, and this person contributed to this scientific program...". I guess that's just a personal thing, and I'm sure someone will argue with me over this, but concepts like calculus or GR aren't invented, they evolve, like animals evolve. And concepts die, too, to be replaced by bigger, more powerful and robust concepts.
That's just my take on science in general, and I'm sure I'll change it at some point, but I figured I'd voice it anyways.
I noticed a few people wondering how this would affect our planetary tides, orbit, etc. This would NOT affect the earth at all. Hell, it wouldn't even make that big of a crater if it hit us (why do I think I'm going to get flamed for that?)
The thing is 100 meters wide. Imagine a 100 meter (300 foot) wide ball. If we just grabbed it and brought it to earth's surface (gently), it still wouldn't affect our tides at all. It's small enough to fit in a stadium. It's the size of a big hill. The point is that it wouldn't affect us at all.
Also, the reason it wasn't seen that long ago was that it was too far away and too small to see with the naked eye. (we could barely see it with a scope).
"Radioactive materials can emit beta particles, alpha particles or gamma rays, the last two of which can carry enough energy to be hazardous."
Last time I checked, alpha particles couldn't even penetrate skin, and beta particles could, making them more dangerous. Isn't the penetration level series actually alpha then beta then gamma?
On a related note, this just occured to me: when a beta-emitter emits an electron, thus leaving the atom positively charged, how does it ever gain an electron again. That is, if I have a block of, say Thorium 234 (a beta-emitter) sitting on a table, will it just become more and more positive, until you have a very positive chunk of Palladium?
The Buckminsterfullerene (or buckyball) was not discovered by Buckminster Fuller. It was created by a graduate student in Dr. Richard Smalley's Lab at Rice U., after astrophysics professor Harold Kroto in the UK wanted to collaborate with him regarding the process of carbon nucleation (Smalley's experiment provided a nice approximation to deep space conditions).
The name Buckminsterfullerene was picked because Richard Buckminster Fuller created the geodesic dome, which is essentially what a half of a buckyball looks like.
Following the buckyball's discovery, people all over began to create other things: different-sized buckyballs, bucky-ears, bucky-heads, and the famous buckytube. The buckytube gradually became renamed "nanotube" and that's where we are today!
They discovered it in June, and then used other scopes to verify it, and then finally announced it.
This is not Planet X. Supporters of Planet X believe it to be a very large planet, and much farther out than this one. This is even said so in the article to which you link. This planet appears to be very small (smaller than Pluto) and in the Kuiper belt (relatively close as compared to the place of origin of many comets - the Oort cloud).
"It's said the way that leads to the juvenile jokes."
That is the pronunciation of the supernatural Uranus. While the planet was originally named after that god, the IAU recently changed it to a pronunciation where the emphasis was on the first syllable. I cannot find a link to anywhere that this is stated, but all of my astronomy profs (I'm an astro major) use that pronunciation.
If you want an official pronunciation, fish around on the IAU site and I'm sure you'll find it. But the fact that the god is pronounced that way does not necessarily mean that the planet is likewise named.
I agree with you - the watts/m^2 are the important thing, not just watts. I figured 5mm was a fairly common beam size. The beam spread is a problem, it'll be interesting how they find a way to overcome it. The unit mm*mrad takes both of those factors into account (mm = beam size, mrad = beam divergence)
I really don't know what you could use it for. I mean, it could be useful in air dogfights, but it'd be really stupid, seeing as how if you miss your target, there's now this beam going for tens of miles that could easily lop an arm off of a civilian.
I've looked up some stats on beam power needed to cut through metal. CW solid state lasers that output 4kW easily cut through 1/2" slabs of metal. So this'll be 25 times that (assuming the same beam diameter.) Could be pretty powerful. I still don't know about cutting through tanks.
"Sounds like somebody didn't read his Laboratory Safety manual."
Haha yeah I know...I'm sitting there working on the laser, and I smell an odor of burning plastic - my sweatshirt sleeve was hanging in the beam. The frustrating thing about waving your hand through the beam at >6W is that you dont even realize you did it until all of the sudden you have a blister. It happened to me once and now I'm really careful about it.
I work in a laser lab, were the laser we work with (an Argon Ion) puts out a maximum 15 watts of power (of multiple wavelengths of visible light) in a ~5mm diameter beam.
At 1/2 watt, it will blind you immediately if your eye passes in front of it.
At 3 watts, it will burn through a piece of paper.
At 6 watts, it's burning through my sleeve.
At 8 watts if I accidentally wave my hand through it, it will cause blisters to form several minutes later.
At 10 watts, our power meter starts smoking and our mirrors begin to get these ugly burn marks on them.
At 15 watts, it'll burn through an aluminum can.
This is for a continuous wave laser (one that doesn't pulse). Now you can imagine what 100,000 watts will do:). The question is, seeing as how this must be firing in pulses, what is the pulse length? Minutes? Seconds? Milliseconds?
I'm also curious what wavelength it is firing at. I didn't notice it in the article (but I definitely could have missed it). Anyway, I hope that helped answer your question. Maybe some other slashdotters out there have worked with more powerful lasers?
"We don't seem to have much luck with surface probes on the red planet, so maybe the only way to get anything done is send real astronauts."
For the record, I count (http://nssdc.gsfc.nasa.gov/planetary/projects.htm l) 11/14 U.S. missions successful:
Mariner 4 Mariner 6 Mariner 7 Mariner 9 Mars Global Surveyor 2001 Mars Odyssey Mars Pathfinder Viking 1 Orbiter Viking 1 Lander Viking 2 Orbiter Viking 2 Lander
The failed missions:
Mars Climate Orbiter (units, people, units!) Mars Observer ("uh, where'd it go?") Mars Polar Lander ("So *when* do we fire the landing thrusters?") with Deep Space 2.
Not bad, considering the distance these things had to travel. And the accuracy with which they had land.
With humans up there, not only will we be taking care of the little stuff (like for the Apollo missions), but if anything goes wrong, there won't be a 20 or 30 minute lag between when something goes wrong, and when a human can respond to the problem. This will make things like landing (and of course launching) much easier. On top of that, things like sample collections will be easier with a human doing it than a machine.
"So music stores do not sell music, they sell round peices of plastic?"
Yes, they do just sell a little piece of plastic, but it has someone else's intellectual property on it. Just like when I buy a book, the book store isn't selling me the property or thoughts of the writer, but the pieces of paper with the writer's thoughts on them.
"You are confusing the right to play/listen/share with the right to re-record/sell&profit."
I'm not talking about rights, because that brings up the issue of copyrights, which is a whole new can of worms. All I'm saying is that when you buy a CD, that music, which is intellectual property, is not yours. You merely own a copy of someone else's work, just like a book.
Who's music? Your music? Music that you wrote and recorded?
You may want to share music files, but don't be mistaken: it's *not* your music unless you're the artist that made it. If you buy the CD, then you own a little round piece of plastic, but you still don't own the music.
Slashdot Mirror
Three issues here:
First, you're setting up the problem so that EM forces will be stronger. How about the EM force between two uncharged objects that aren't chemically bonded? The gravitational force between them will undoubtedly be stronger.
Second, chemical bonding is a quantum mechanical effect of a charge in a potential well. If we're to talk about the classical coulomb interaction, as all of us have been discussing in previous posts (the 1/r potential), the chemical bond cannot exist. The force that makes a chemical bond is a purely QM effect of EM. A chemical bond requires a very specific setup of a potential well. In addition, a chemical bond does NOT have to be attractive, and can actually cause two nuclei to repel one another (an antibond), in which case it would be weaker than gravity of course. This effect is just as electromagnetic as the chemical bond. Antibonds are not rare and are crucial to chemistry, as they are what allow chemical reactions to occur.
Third, chemical bonding is not causing the nail to stay in the ground. The forces of friction are causing that, which are more macroscopic than chemical bonds. Chemical bonds are holding the nail together and the penny together. But if the nail were perfectly smooth all around, it wouldn't be a very good nail, because the forces of friction wouldn't hold it into place.
Here's an example of one instance in which the EM force is weaker than gravity: When that refrigerator magnet keeps falling off the fridge. Gravity in that case is overwhelming the magnetic force holding the thing onto the fridge. That's just as macroscopic as your example.
Actually there would have to be a change in the orbit. The masses are both moving away from you, so the force exerted by both of them is decreasing. Imagine the situation when the two halves of the sun are many light years away.
What won't change is the direction of that slowly diminishing force. It'll always point at the same spot that the sun was before it broke into two.
Now, the effect on our orbit would be the following: since the force is always pointing "inwards," and decreasing, the earth is going to spiral outwards from its current orbit. The degree of the spiral depends on the speed of the halves of the sun. I put "inwards" in quotes because inwards doesn't really have a precise meaning for a spiral. But you get my point.
Actually if I'm not mistaken, gravity and electromagnetic both exert a 1/r potential (1/r^2 force). So their distance range is the same.
So at short distances:
strong>weak>=electromagnetic>gravitationa l
but this isn't quite right because the strong force has two characteristics, a main force and a residual force. The main force is what keep quarks together in neutrons and protons. That's absurdly strong, and it's strength actually INCREASES with distance. However, the residual strong force is what keeps the nucleons together, and falls off really fast with distance, like the weak force.
At long distances things are a bit simpler:
Electromagnetic>Gravitational>strong>weak
The problem with this is that the electromagnetic and gravitational are relative. You can't go by the constants associated with the field, because they're defined by us (for example, what if mass were in terms of petagrams? Then G~10^19, and the force (in terms of petanewtons, I think) would skyrocket.)
Point is that it's all dependent upon the system you're talking about and the units you're talking about them in. We really can't compare them.
I don't think it's a huge waste of resources. We can approximate the mass of the universe by looking at rotation curves of galaxies, luminous matter, etc. It is precisely the fact that we can't see some of this mass which we know exists that makes the dark matter problem so interesting. We can detect it - that's easy - just look at rotation curves. The fact that we can't see it doesn't mean we can't detect it...
I have never heard of that rule, could you tell me where you learned it from?
.pdf's or in html format, and they are either identical in all ways to the paper version, or they are actually scanned copies of the journal.
Most people nowadays access journals online through search engines like SciFinder or Beilstein (sp?). Most of these journals publish their papers online as
However, if the paper is not published in hard copy, that's when you do have to give the web address and such.
In any case, my standard practice is that I find it online, then print it out and read it. If I decide that want to cite it, I jump back on the webpage I got it from and copy and paste the citation into my paper.
Square root of 9 to 500000 places? wouldn't that just be 3. with a string of 500000 zeros after it?
If that's the case, it can definitely be compressed!
I just pulled up Mathematica and ran some amusing stats:
Assuming that 2000 characters can fit on a 8.25 x 11 inch page, you can print 10 pages/second, a page is 1 micrometer thick, you can print 2000 pages/toner cartridge, and you can speak 2 numbers per second...
Printed pages: 6.2 x 10^8 pages (620 million)
Printing time: 117.96 years (excluding leap years)
Stack of printed paper: 62 km high
Toner cartridges: 310,000 cartridges
Time to speak the entire number: 19,660 years
Length of a continuous-page printout (ala dot matrix): 170,500 km, which could go around the earth 4.25 time, or get us halfway to the moon.
Feel free to check my work, or to add stats to this:?)
"E-mail addresses left in news groups and on Web pages were almost certain to receive spam, they found..."
"Internet users can forward spam for FTC investigation to uce@ftc.gov"
I wonder how many spammers are going to spam uce.ftc.gov now...
Freshen up on the units there.
1/6 g in meters is 1.63m/s^2
1/6 g in feet is 5.33ft/s^2
also, I timed the descent with a stopwatch, and I get 1.46 seconds for the entire jump, or 0.73 seconds for the descent on average. I did the measurement using 2 different video players and that's what I got. I also count 24 frames, not 21, which would make the time 0.72 seconds.
Assuming everything else correct, we now have:
d=0.5*5.33*0.72^2 = 16.6 inches on the moon, and
d=0.5*32*0.72^2 = 99.5 inches on earth
So now it definitely looks like they were in 1/6g.
I don't see what you mean about the recoil in his knees. On the first jump his knees barely buckled when he landed, and on the second jump he landed on one foot.
Hope that helps
JoeRobe
So any research out there that doesn't show an immediate gain should be bagged?
There is very much that NASA has added to society. For example, their research into solar panels has created more efficient light-gathering capabilities. Their gobs of money towards searching for NEO's could save a lot of lives some day. Their research into aerogel has yielded one of the best insulators known to man. Their work with earth-observing satellites can provide us with information about the ozone, global warming, and other global issues.
That's just a few off the top of my head, and there are tons more.
Personally, I do want some of my tax dollars to go towards searching for black holes, neutrinos, and ET's. So although you may not want it, a lot of other people out there do, or else NASA wouldn't be funded.
"you could jump very high, and would probably end up stumbling a little."
They didn't try to jump and see how high they would go. However, look at the roostertails made by the relatively slow moving rover - they're big. Also, look at some of the more amusing movies from the Apollo, like where Schmitt (I think) fell over trying to put a pole in the ground, because he wasn't light to get enough traction to twist the pole. It's pretty amusing.
"I also got some of the NASA pictures up close, and could see very easily that they were photoshopped. In 1969, they didn't have access to the zooming, so it was unnoticeable."
And you think they had photoshop? They did in fact have access to zooming. It was called a magnifying glass.
Actually that's not right. Every telescope has a diffraction limit that is a function of the size of its lenses. Hubble's diffraction limit prevents it from seeing things smaller than a certain size on the moon, and that size is much larger than the width of the landers.
Also (I may be wrong on this), but I hear that one of the Apollo missions put mirrors on the moon to reflect laser light back (to get Earth-Moon distances). Anyone know if that's right?
I suppose that would be meaningless to conspiracy theorists, anyway, right?
I don't think we can compare the two considering that they come from completely different times , when "science", meant completely different things.
Would you still think Newton was a genius if I told you that his Principia was a mere fraction of what he spent his life doing, and in fact was a quite well-known alchemist? How about the fact that he believed that he could predict the future by reading scripture (see: Temple of Solomon). Or read the last bit of the Principia, where he believed that the tails of comets were what provided us with water and nutrients so that we could survive. His work in alchemy and scriptures comprised the vast majority of his life.
But let's remember that prior to Newton (and afterwards, for awhile) there was no such thing as an equals sign. Imagine doing calculus completely geometrically. Also remember that for the first time in history there was a theory that agreed completely with observation. And how about the fact that the Principia was the final nail in the coffin for the geocentricity.
Then there's Einstein, who was ardently opposed to the revolution that he began (Quantum revolution), and which has resulted in the most tested and highly tested theory in scientific history (note that I'm not saying it's correct). Or that as late as 1895 he may have believed in an ether.
Then again, Einstein did "kick off" quantum mechanics with the photoelectric effect. And the fact that he completely "jacked around" with the foundations of physics by redefining things like space, time, and even reality, indicates a view of the world unlike any scientist had before him.
I've listed all of this because what we define as important factors in determining who was greater is inherently and unavoidably biased by our view of the world and the history that we know. Both of these men were revolutionaries who changed the way that we look at the world. They saw a new paradigm that no one else did, and that is something that only happens, oh, every few centuries in physics.
Incidentally, Newton did NOT do away with absolute space, but adamantly believed there to be one (check out Definition 8, Scholium, in the Principia). Oh yeah, and he did account for the retrograde motion of Mars. Galileo did that first (successfully), though.
The fact that GR is a specialized field doesn't say much, considering that Newtonian mechanics has been around for over 300 years, while GR isn't even 100 yet. More time to mull over mechanics has given scientists more time to take avantage of it. Remember we may go to another star with the help of Einstein.
Things aren't so clean in the history of science. There never was, and probably never will be, a single leader in any science who heads up a revolution. To do so is completely unscientific, as science is a society, not a dictatorship. Newton didn't lead the Copernican revolution, and neither did Copernicus, or Galileo, or Brahe, or DesCartes, or Kepler. Einstein (definitely) didn't lead the quantum revolution, just as Bohr, Schrodinger, Pauli, Pauling, Dirac, or Heisenberg didn't. It evolved, it had it's bumps and bruises. Read Thomas Kuhn's "On The Structure of Scientific Revolutions" for more.
I've noticed a lot of people think "this person did this, and this person did this..." instead of "this person was a driving force in this thought, and this person contributed to this scientific program...". I guess that's just a personal thing, and I'm sure someone will argue with me over this, but concepts like calculus or GR aren't invented, they evolve, like animals evolve. And concepts die, too, to be replaced by bigger, more powerful and robust concepts.
That's just my take on science in general, and I'm sure I'll change it at some point, but I figured I'd voice it anyways.
I noticed a few people wondering how this would affect our planetary tides, orbit, etc. This would NOT affect the earth at all. Hell, it wouldn't even make that big of a crater if it hit us (why do I think I'm going to get flamed for that?)
The thing is 100 meters wide. Imagine a 100 meter (300 foot) wide ball. If we just grabbed it and brought it to earth's surface (gently), it still wouldn't affect our tides at all. It's small enough to fit in a stadium. It's the size of a big hill. The point is that it wouldn't affect us at all.
Also, the reason it wasn't seen that long ago was that it was too far away and too small to see with the naked eye. (we could barely see it with a scope).
"Radioactive materials can emit beta particles, alpha particles or gamma rays, the last two of which can carry enough energy to be hazardous."
Last time I checked, alpha particles couldn't even penetrate skin, and beta particles could, making them more dangerous. Isn't the penetration level series actually alpha then beta then gamma?
On a related note, this just occured to me: when a beta-emitter emits an electron, thus leaving the atom positively charged, how does it ever gain an electron again. That is, if I have a block of, say Thorium 234 (a beta-emitter) sitting on a table, will it just become more and more positive, until you have a very positive chunk of Palladium?
The Buckminsterfullerene (or buckyball) was not discovered by Buckminster Fuller. It was created by a graduate student in Dr. Richard Smalley's Lab at Rice U., after astrophysics professor Harold Kroto in the UK wanted to collaborate with him regarding the process of carbon nucleation (Smalley's experiment provided a nice approximation to deep space conditions).
The name Buckminsterfullerene was picked because Richard Buckminster Fuller created the geodesic dome, which is essentially what a half of a buckyball looks like.
Following the buckyball's discovery, people all over began to create other things: different-sized buckyballs, bucky-ears, bucky-heads, and the famous buckytube. The buckytube gradually became renamed "nanotube" and that's where we are today!
JoeRobe
Have you read the article?
They discovered it in June, and then used other scopes to verify it, and then finally announced it.
This is not Planet X. Supporters of Planet X believe it to be a very large planet, and much farther out than this one. This is even said so in the article to which you link. This planet appears to be very small (smaller than Pluto) and in the Kuiper belt (relatively close as compared to the place of origin of many comets - the Oort cloud).
"It's said the way that leads to the juvenile jokes."
That is the pronunciation of the supernatural Uranus. While the planet was originally named after that god, the IAU recently changed it to a pronunciation where the emphasis was on the first syllable. I cannot find a link to anywhere that this is stated, but all of my astronomy profs (I'm an astro major) use that pronunciation.
If you want an official pronunciation, fish around on the IAU site and I'm sure you'll find it. But the fact that the god is pronounced that way does not necessarily mean that the planet is likewise named.
JoeRobe
I agree with you - the watts/m^2 are the important thing, not just watts. I figured 5mm was a fairly common beam size. The beam spread is a problem, it'll be interesting how they find a way to overcome it. The unit mm*mrad takes both of those factors into account (mm = beam size, mrad = beam divergence)
I really don't know what you could use it for. I mean, it could be useful in air dogfights, but it'd be really stupid, seeing as how if you miss your target, there's now this beam going for tens of miles that could easily lop an arm off of a civilian.
I've looked up some stats on beam power needed to cut through metal. CW solid state lasers that output 4kW easily cut through 1/2" slabs of metal. So this'll be 25 times that (assuming the same beam diameter.) Could be pretty powerful. I still don't know about cutting through tanks.
"Sounds like somebody didn't read his Laboratory Safety manual."
Haha yeah I know...I'm sitting there working on the laser, and I smell an odor of burning plastic - my sweatshirt sleeve was hanging in the beam. The frustrating thing about waving your hand through the beam at >6W is that you dont even realize you did it until all of the sudden you have a blister. It happened to me once and now I'm really careful about it.
We do wear cool-looking safety glasses, though:)
I work in a laser lab, were the laser we work with (an Argon Ion) puts out a maximum 15 watts of power (of multiple wavelengths of visible light) in a ~5mm diameter beam.
At 1/2 watt, it will blind you immediately if your eye passes in front of it.
At 3 watts, it will burn through a piece of paper.
At 6 watts, it's burning through my sleeve.
At 8 watts if I accidentally wave my hand through it, it will cause blisters to form several minutes later.
At 10 watts, our power meter starts smoking and our mirrors begin to get these ugly burn marks on them.
At 15 watts, it'll burn through an aluminum can.
This is for a continuous wave laser (one that doesn't pulse). Now you can imagine what 100,000 watts will do:). The question is, seeing as how this must be firing in pulses, what is the pulse length? Minutes? Seconds? Milliseconds?
I'm also curious what wavelength it is firing at. I didn't notice it in the article (but I definitely could have missed it). Anyway, I hope that helped answer your question. Maybe some other slashdotters out there have worked with more powerful lasers?
JoeRobe
oh yeah and please add to that list if i've missed anything
"We don't seem to have much luck with surface probes on the red planet, so maybe the only way to get anything done is send real astronauts."
m l) 11/14 U.S. missions successful:
For the record, I count (http://nssdc.gsfc.nasa.gov/planetary/projects.ht
Mariner 4
Mariner 6
Mariner 7
Mariner 9
Mars Global Surveyor
2001 Mars Odyssey
Mars Pathfinder
Viking 1 Orbiter
Viking 1 Lander
Viking 2 Orbiter
Viking 2 Lander
The failed missions:
Mars Climate Orbiter (units, people, units!)
Mars Observer ("uh, where'd it go?")
Mars Polar Lander ("So *when* do we fire the landing thrusters?") with Deep Space 2.
Not bad, considering the distance these things had to travel. And the accuracy with which they had land.
With humans up there, not only will we be taking care of the little stuff (like for the Apollo missions), but if anything goes wrong, there won't be a 20 or 30 minute lag between when something goes wrong, and when a human can respond to the problem. This will make things like landing (and of course launching) much easier. On top of that, things like sample collections will be easier with a human doing it than a machine.
JoeRobe
"So music stores do not sell music, they sell round peices of plastic?"
Yes, they do just sell a little piece of plastic, but it has someone else's intellectual property on it. Just like when I buy a book, the book store isn't selling me the property or thoughts of the writer, but the pieces of paper with the writer's thoughts on them.
"You are confusing the right to play/listen/share with the right to re-record/sell&profit."
I'm not talking about rights, because that brings up the issue of copyrights, which is a whole new can of worms. All I'm saying is that when you buy a CD, that music, which is intellectual property, is not yours. You merely own a copy of someone else's work, just like a book.
"...one must never share one's music..."
Who's music? Your music? Music that you wrote and recorded?
You may want to share music files, but don't be mistaken: it's *not* your music unless you're the artist that made it. If you buy the CD, then you own a little round piece of plastic, but you still don't own the music.