Originally posted by smomofo Earth's "escape velocity" is roughly 11.2 km/s. This means that if an object is thrown upward at, say, 5 km/s it will fall back to the surface of the Earth. If the object is thrown upward at 7 km/s it will go higher, but still eventually fall back to the surface. If the object is thrown upward at 15 km/s, Earth's gravity will not be able to stop the objec ...[text shortened]... object is for it to be a black hole or not?
Are there any astronomers in the house?
I dont know much about black holes, but I do know physics! I think that the light could be seen under very specific conditions, maybe a controlled experiment. I think that the black holes escape velocity would have to be very close to that flashlights speed of light. The photon would act as the baseball in the earths case. The only difference is that the escape velocity is so much stronger it needs alot faster trajectory. Please correct me if I'm wrong. Where can I go to learn the basics about black holes? They seem very interesting.
There are a number of very good books about black holes available at Barnes & Noble, Borders and other book stores. Basically a black hole is a collapsed star of at least 3 solar masses. If a star has less mass at collapse, it will most likely form a neutron star of about 10km diameter. The black hole thought to be at the center of the Milky Way is theorized to be many millions of solar masses. The mass has no effect on the size of the black hole itself only the event horizon. The mass is concentrated in an infintessimal small volume but the larger the mass, the bigger the event horizon. Read Stephen Hawking's "A Brief History of Time "
Originally posted by Blouc I may be off by a lot here (thus is the peril of a passing intrest in physics), but because, A, a black hole is commonly considered to be a singularity; and B, a black hole is the maximum expression of entropy, there can be no set direction for the light to come from. The light would exist as part of the theoretical observer and would exist as something like a ...[text shortened]... as far as popular theory goes).
I hope I have not made a greavious error in my explaination.
Light and everything else in the universe exists in 4 dimensions not three, Don't forget about time. Just remember, time, space and mass are all malleable, mass changes how space curves and changes the way time flows. Big Al said that a hundred years ago!
Originally posted by sonhouse Light and everything else in the universe exists in 4 dimensions not three, Don't forget about time. Just remember, time, space and mass are all malleable, mass changes how space curves and changes the way time flows. Big Al said that a hundred years ago!
Originally posted by Mephisto 666 but light still has no mass and there is nothing in space to bend, so your comparisons dont make sense to me
I learned in my High School Physics class that light does have weight. Light can behave like a particle or a wave.
As for the next part of your statement, even in a vacuum you are still in a part of the space-time continuum.
Originally posted by Peter X I learned in my High School Physics class that light does have weight. Light can behave like a particle or a wave.
As for the next part of your statement, even in a vacuum you are still in a part of the space-time continuum.
Whoever told you that lied like a rug. Light has zero mass. zilch, nada. It has the property, however, of MOVING mass when it hits said mass. You may have seen the little 4 vaned device in an air evacuated sphere where the little vanes are on the ends of two little rods and balanced very well and free to rotate. One side of the vanes are white, the other black. When light hits the vanes, it imparts momentum to the vanes and they start to rotate about the common axis. But each photon if it were weighed, would come up to zero. It has energy and imparts physical momentum which is why rocket scientists can make solar sails to propel space craft throughout the solar system without needing fuel. A working model has yet to built but test mirrors have been flown in space, by the Russians.
Fundamental, or mental ?, If a small person were hurled by an incredibly strong individual at somewhere near the speed of light, themselves having been ejected from a (canon) at or near the speed of light, and the little person then hurled (or shone his torch) an object or beam of light - all in the one direction of travel with or without gravitational distortion, the sheer sum of velocities potentially creates a velocity greater than light, yet relatively - one to another, they are equal to or less than the speed of light.
Escape velocity and black holes
22 Jul '06 07:25
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