There are some WMAP data in which the low quadrupole moment of the CMB patterns suggests that the universe might, in fact, be finite. But it's REALLY iffy in my opinion, and other than that, there's no evidence (AFAIK) for a finite universe, despite ubiquitous claim.
The value in Hz gives you the scaling frequency of the universe. It makes sense to talk about the inverse of this frequency, which is in seconds, which is the time it takes for the universe to grow to e times its former size.
Universe expansion will create causal separation in the future, but not the past. It doesn't limit how far away you can see something, because you are looking at something in the past, but it does prevent you from going there. Because looking backward in time, the universe is shrinking, and you can see more and more of the universe going back. Looking forward in time, everything is getting more separated, and, for far regions of space, the rate of separation is higher than light can catch up to.
In the scenario of big rip, the acceleration of the expansion continues to increase until the future light cone of every particle is separated from the future light cone of every other particle. The past light cones still intersect.
Balloon can only reach an elevation where it matches the buoyancy of the air. The article doesn't say, but I presume that the structure will be heavier than air. For that to work, you need something holding you up from the bottom, or a space elevator.
Motion is relative. You can always transform to a frame where the black hole center of mass is not moving. I'm not sure about this, but I suppose a moving black hole is length-contracted like in SR. Gravity waves might exhibit a headlight effect, which makes gravity stronger in front (??? I'm way out of my league here). But it will still be impossible to escape the length-contracted EH.
1. Everything is moving relative to everything else. There is no stationary reference frame, so unless you happen to move at the same velocity as the BH, it will appear to move. 2. Black holes aren't necessarily all that massive. The ones in the centers of galaxies are super massive, but black holes created by supernovae could be around 2 solar masses, which is not very massive on cosmological scales. If it sucks in another solar mass, it just sucked in a huge influx of momentum, which isn't going to disappear. 3. Gravity accelerates things regardless of how massive it is. A black hole will orbit a gravitational center just like a star will.
Black holes are a bit weirder than your typical Newtonian gravity well, if you get really close. Light can orbit the black hole at 1.5 Schwarzschild radii. Closer than that, light will get "sucked in" unless it's pointed outward. Farther outside, you can drop an object with sufficient angular momentum and it will stay in orbit, but too close it will get sucked in.
Anything that gets too close to the black hole gets sucked in. But on the outside of the event horizon, there is still the possibility of escape. Anything that falls near a black hole gains huge kinetic energy which can't just disappear (conservation of energy). When these things collide with each other, they emit x-rays, much of which will escape.
Probably a joke, but if there are free-floating black-holes flying around, and we happened to be unlucky enough, we could be gone just like that, and there ain't nothing we could conceivably do about it.
The initial Tuesday night report said incumbent Ron Kroeger received 49.96 percent of the vote, short of the 50 percent plus 1 vote re-election requirement. The recount found he actually received 51.8 percent, more than enough to secure his seventh term over challengers John Roberts and Steve Rolinger.
Doesn't anyone think that 49.96%, short of 50% is too perfect for a random error? Most software errors will cause the numbers to explode, either to 0 or some gigantic number.
Good point. AFAIK, these precocious kids usually become less extraordinary when their peers have had time to catch up in adulthood. They usually peter out at some slightly above average ability, and don't continue to advance beyond mortal powers.
I don't think there's a well-established standard for characterizing genius. It's just a subjective word, like tall. If someone says someone is tall, you don't say, no, he's not tall. He's 6'4" and the definition of tall is 6'6" or higher.
Just because he was one of the major participants in its discovery doesn't mean that he didn't shun it. But the story is actually more rich, as shown by the Bohr-Einstein debates. http://en.wikipedia.org/wiki/Bohr-Einstein_debates
The surface of a sphere is 2D, and the surface of the Earth is very close to 2D (but probably fractal). When we talk about the dimensionality of a generalized volume, we generally aren't interested in the dimensionality of the Cartesian space it is embedded in, but rather how many parameters we need to define a point. If a particle moves in 3D but has a single holonomic constraint (in the case of a sphere, fixed radius), the surface it moves through is 2D. (more generally, we could use the fractal dimension).
Now, in modern physics, Cartesian coordinates aren't regarded as especially holy. You are considering Earth as 3D because you are saying that Cartesian coordinates are what really exists and polar coordinates are a human construction. But when you study enough physics, you realize that physics is just a tool to model how the universe behaves, and one cannot assume various intuitive concepts represent the ultimate reality. The 3D Cartesian space seems so natural because it fits well with our personal experiences, but, at a more fundamental level it's not necessarily better than some other system of generalized coordinates.
There has been talk of how string theory is 10 or 26 dimensions or something, and this concept hasn't been effectively communicated to the layman.
In physics we often describe a system of N (spinless) particles as 6N dimensional, because each particle has a position and a momentum, so there are 6N degrees of freedom. The reason we can pick out that there's actually 3 space coordinates rather than 3N is because many particles will interact if their position coordinate is close to the position coordinate of other particles, so they actually must be somehow in the same space. But if the particles don't interact due to distance, there's no way to show that these dimensions are the same thing. Now, if there are more complicated interactions, there might be some way to show that there's actually 2 space coordinates because the 3rd is redundant. I kinda doubt that, but I think that's what they are getting at.
Slashdot Mirror
I don't think this will be used on a large enough scale to seriously affect the environment
There are some WMAP data in which the low quadrupole moment of the CMB patterns suggests that the universe might, in fact, be finite. But it's REALLY iffy in my opinion, and other than that, there's no evidence (AFAIK) for a finite universe, despite ubiquitous claim.
That makes no sense. Thank you for playing. Maybe you mean a circle has an infinite number of points?
The value in Hz gives you the scaling frequency of the universe. It makes sense to talk about the inverse of this frequency, which is in seconds, which is the time it takes for the universe to grow to e times its former size.
Universe expansion will create causal separation in the future, but not the past. It doesn't limit how far away you can see something, because you are looking at something in the past, but it does prevent you from going there. Because looking backward in time, the universe is shrinking, and you can see more and more of the universe going back. Looking forward in time, everything is getting more separated, and, for far regions of space, the rate of separation is higher than light can catch up to.
In the scenario of big rip, the acceleration of the expansion continues to increase until the future light cone of every particle is separated from the future light cone of every other particle. The past light cones still intersect.
Balloon can only reach an elevation where it matches the buoyancy of the air. The article doesn't say, but I presume that the structure will be heavier than air. For that to work, you need something holding you up from the bottom, or a space elevator.
I don't think the idea is to make it lighter than air, but just use air to provide some physical structure to it.
I bet he has some handsome scholarships in line.
What's your trick?
Parents. Plus, he's still living in the basement.
Maybe I'm an anomaly, but I'm only getting a degree to earn more.
Please, go to a trade school and stay out of the universities.
Motion is relative. You can always transform to a frame where the black hole center of mass is not moving. I'm not sure about this, but I suppose a moving black hole is length-contracted like in SR. Gravity waves might exhibit a headlight effect, which makes gravity stronger in front (??? I'm way out of my league here). But it will still be impossible to escape the length-contracted EH.
1. Everything is moving relative to everything else. There is no stationary reference frame, so unless you happen to move at the same velocity as the BH, it will appear to move.
2. Black holes aren't necessarily all that massive. The ones in the centers of galaxies are super massive, but black holes created by supernovae could be around 2 solar masses, which is not very massive on cosmological scales. If it sucks in another solar mass, it just sucked in a huge influx of momentum, which isn't going to disappear.
3. Gravity accelerates things regardless of how massive it is. A black hole will orbit a gravitational center just like a star will.
Wow, someone actually used the phrase spacetime continuum outside of Star Trek! And it makes sense, too!
Black holes are a bit weirder than your typical Newtonian gravity well, if you get really close. Light can orbit the black hole at 1.5 Schwarzschild radii. Closer than that, light will get "sucked in" unless it's pointed outward. Farther outside, you can drop an object with sufficient angular momentum and it will stay in orbit, but too close it will get sucked in.
Anything that gets too close to the black hole gets sucked in. But on the outside of the event horizon, there is still the possibility of escape. Anything that falls near a black hole gains huge kinetic energy which can't just disappear (conservation of energy). When these things collide with each other, they emit x-rays, much of which will escape.
Probably a joke, but if there are free-floating black-holes flying around, and we happened to be unlucky enough, we could be gone just like that, and there ain't nothing we could conceivably do about it.
The initial Tuesday night report said incumbent Ron Kroeger received 49.96 percent of the vote, short of the 50 percent plus 1 vote re-election requirement. The recount found he actually received 51.8 percent, more than enough to secure his seventh term over challengers John Roberts and Steve Rolinger.
Doesn't anyone think that 49.96%, short of 50% is too perfect for a random error? Most software errors will cause the numbers to explode, either to 0 or some gigantic number.
Actually, software CAN glitch, due to memory corruption from cosmic rays and such. But more often the problem is in the programming.
Good point. AFAIK, these precocious kids usually become less extraordinary when their peers have had time to catch up in adulthood. They usually peter out at some slightly above average ability, and don't continue to advance beyond mortal powers.
I don't think there's a well-established standard for characterizing genius. It's just a subjective word, like tall. If someone says someone is tall, you don't say, no, he's not tall. He's 6'4" and the definition of tall is 6'6" or higher.
Or, maybe he realizes he's special, but is wise enough not to flaunt it.
Just because he was one of the major participants in its discovery doesn't mean that he didn't shun it. But the story is actually more rich, as shown by the Bohr-Einstein debates. http://en.wikipedia.org/wiki/Bohr-Einstein_debates
The surface of a sphere is 2D, and the surface of the Earth is very close to 2D (but probably fractal). When we talk about the dimensionality of a generalized volume, we generally aren't interested in the dimensionality of the Cartesian space it is embedded in, but rather how many parameters we need to define a point. If a particle moves in 3D but has a single holonomic constraint (in the case of a sphere, fixed radius), the surface it moves through is 2D. (more generally, we could use the fractal dimension).
Now, in modern physics, Cartesian coordinates aren't regarded as especially holy. You are considering Earth as 3D because you are saying that Cartesian coordinates are what really exists and polar coordinates are a human construction. But when you study enough physics, you realize that physics is just a tool to model how the universe behaves, and one cannot assume various intuitive concepts represent the ultimate reality. The 3D Cartesian space seems so natural because it fits well with our personal experiences, but, at a more fundamental level it's not necessarily better than some other system of generalized coordinates.
There has been talk of how string theory is 10 or 26 dimensions or something, and this concept hasn't been effectively communicated to the layman.
In physics we often describe a system of N (spinless) particles as 6N dimensional, because each particle has a position and a momentum, so there are 6N degrees of freedom. The reason we can pick out that there's actually 3 space coordinates rather than 3N is because many particles will interact if their position coordinate is close to the position coordinate of other particles, so they actually must be somehow in the same space. But if the particles don't interact due to distance, there's no way to show that these dimensions are the same thing. Now, if there are more complicated interactions, there might be some way to show that there's actually 2 space coordinates because the 3rd is redundant. I kinda doubt that, but I think that's what they are getting at.
It's what 4 (in general) should ahve been from the start.
That's what people said about 4.1.
Well, the users fucked up and the editors fucked up by not catching it.