meta user
network profile
| bio | website | snowhare.com |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 1 year, 10 months |
| seen | Mar 26 at 15:19 | |
| stats | profile views | 46 |
|
Mar 5 |
answered | Is it (theoretically) physically possible to project an image into thin air? |
|
Jan 30 |
accepted | Could an ultra-relativistic particle tunnel directly through a stellar mass black hole? |
|
Jan 30 |
comment |
Could an ultra-relativistic particle tunnel directly through a stellar mass black hole? I'm not sure we aren't talking past each other. My question is about the quantum mechanical possibility of the particle quantum tunnelling 'past' the barrier posed by black hole without ever actually 'entering' it (ala the Klein Paradox). I'm happy either way - I just want a clear explanation of why it can or cannot. |
|
Jan 29 |
comment |
Could an ultra-relativistic particle tunnel directly through a stellar mass black hole? I'm not getting why the cross-sectional area of the horizon matters. We are talking about the probability of the particle tunnelling through a thin potential barrier. The size of the barrier in the directions perpendicular to the direction of motion would seem to be irrelevant. To put it another way - if I were to replace the black hole with a normal matter wall, how would that differ for the question of tunnelling a ultra-relativistic particle through it? |
|
Jan 29 |
asked | Could an ultra-relativistic particle tunnel directly through a stellar mass black hole? |
|
Oct 24 |
answered | Why are photons released from high-voltage electricity through a near vacuum? |
|
Oct 23 |
comment |
Why are photons released from high-voltage electricity through a near vacuum? What actual example of photons being generated in a vacuum by high-voltage electricity are you thinking of? |
|
Jul 3 |
awarded | Yearling |
|
May 12 |
awarded | Tumbleweed |
|
May 5 |
revised |
Temperature of the CMB when the Earth formed and the faint young Sun paradox Explaining why the idea doesn't work |
|
May 5 |
asked | Temperature of the CMB when the Earth formed and the faint young Sun paradox |
|
Apr 25 |
answered | Can you use a wormhole to travel through space not time? |
|
Apr 14 |
comment |
Will a hole cut into a metal disk expand or shrink when the disc is heated? Here is a way to think about it that makes the answer obvious. Replace 'cut a hole into with 'draw a circle on' and consider what happens to the drawn circle when the disc is heated. |
|
Apr 10 |
comment |
Is there a named unit that, when divided by 32, gives meters per second? It sounds like someone got a meters to feet conversion backwards. 10 meters is about 32.8 feet. Also, are you getting meters per second (velocity) or meters per second squared (acceleration)? 1 g is about 9.8 meters/(sec*sec) or 32.1 feet/(sec*sec). Another context where 32 shows up is in atmospheres of pressure. You get about 1 atmosphere of pressure for a water column 32 feet deep. Context would help a lot in guessing why 32 is showing up. |
|
Apr 6 |
comment |
Why does a coin falls faster when it's flipping as well? To extend on my remark about the difference in the fall distance of the center of mass: A difference of only 1.1 millimeters in the fall distance would change the fall time by 15 milliseconds. That is on the order of the thickness of a typical small coin. |
|
Apr 6 |
awarded | Commentator |
|
Apr 6 |
comment |
Why does a coin falls faster when it's flipping as well? You need to specify your experimental setup better. I can think of a few things that could be causing issues such as differences between the location and fall distances of the center of mass of the coin when dropped to make it flip vice dropped to not flip. You could be accidentally be effectively dropping the 'flipping' coin a shorter distance. You could also be having air flow effects caused by a nearby surface as the coin rotates. There are several possible sources of the difference, but they depend on your setup. |
|
Apr 1 |
comment |
If you place a spring on a neodymium hard-drive magnet, it appears to vibrate in slow-motion. Why is that so? Are you using a compact florescent light on your desk? If you are, you may be seeing a 'strobe' effect rather than a large physical change in the frequency. A small change in the oscillation frequency could produce a visual 'beat frequency' effect where it appears to vibrate much slower than the actual change in frequency would suggest. |
|
Mar 29 |
comment |
How do levers amplify forces? Here is a mental model that might help. Think of a series of balls connected in a straight line by very rigid springs floating in space with no external forces acting on it. When it is in its 'rest state' there are no stresses on it. Now give the ball at one end of the assembly a push at right angles from the line. When you do that the spring connecting it to the next ball bends a bit - transmitting the force to the next ball as it tries to straighten out the line. From there to the next ball, and so on. |
|
Mar 27 |
answered | Does a photon exert a gravitational pull? |
