By: Arabella-Cox - 3rd December 2002 at 05:39
RE: Whats the speed of Dark ?
Sorry, I didn’t finish what I meant to say about tidal forces.
The density of an object determines the so called tidal forces.
Tidal forces is merely the change in gravitational force over distance.
A super giant star like Beetlgeuce (spelling) if placed in our solar system would have its outer surface at about the orbit of Jupiter.
In other words it is rather large.
It is not however very dense… (obviously with such volume)
Its change in gravity is similar to Earths in that the difference in gravity over 1.5-2m (ie head to feet) is not noticible.
If it were to collapse to become a neutron star however things would be very different. Its density would change from roughly the same as syrup to hundreds of thousands of tons to millions of tons per teaspoon full… if you had a cup of it on earth in your hand (even ignoring the temperature and pressure) the cup would plunge down to the core of the earth and the earth might move a few cms up to meet it too!
If you were in a spaceship orbitting this neutron star you would not be very happy… the difference in gravity between you head and your feet might be 100g or even 1000g… ie fatal.
Ironically this applies to black holes too.
Although matter is completely destroyed by the infinite gravity of the singularity and therefore there is not very much mass inside most Black Holes as matter enters the hole gets bigger based on the amount of mass that enters it.
A 2.5cm black hole of the same mass as the Earth whizzing through our solar system on a collision course with earth.
Warnings might include planets orbits being influenced by this tiny earth, or asteroids disappearing or being nudged out of orbit.
When it finally reaches earth it will take some time to destroy it… like draining a pond through a plughole.
Energy will be released as matter heats up as it is crushed together as it passes the event horizon.
The black hole now with the adition of the mass of the earth will be slightly larger… say 2.8 or 3.0 cm across and now twice as massive.
The effect on the black hole’s path would be similar to that of two earths collideing but without the explosion and fragments and debris.
With the technology of star trek we might be able to save ourselves… but not with their phasers or photon torpedos… with the technology that allows the crew to stand upright in apparantly 1g in space…
By: Arabella-Cox - 3rd December 2002 at 05:21
RE: Whats the speed of Dark ?
“You cant compare event horizons to escape velocity. Escape velocity is the measured speed of orbit where an object will not fall back to earth and therefore maintain somekind of infine orbit. There is no escape velocity for any object leaving straight up from the surface of the earth, this force can be calculated by in infinate ratio”
The event horizon is defined as the distance from a mass where the speed an object (or photon) must be traveling at to escape perminant orbit or falling back to that mass due to its gravity is the speed of light.
As the Earth pulls me down, my mass also pulls the Earth up to me. My mass influences the movement of every star in the universe as does yours… just not very much… the latter comment being a rather enormous understatement.
Even points of infinite mass like a singularity… and there are claculated to be 100s of thousands in each galaxy have no practical influence on you or I… when you walk down the street you don’t make adjustments based on their positions.
ie you cannot escape their gravitational field, but you can escape their pull… several voyager and pioneer spacecraft have already done that for Earth and the Sun and our whole solar system.
“Center of gravity is measured at the center of mass, there would be no dectable difference in the force of gravity if you crushed the earth to the size of a marbel and maintained same altitude form center”
It is measured in the centre because that is where it should be strongest for that mass and is therefore the absolute measure of gravity for that mass… ie distance is the smallest you can get without crushing the mass.
You are also forgetting tidal forces.
Because the gravitational pull on an object by another object is defined by distance as well as mass. An infinitely massive object pulls you just as much as a 1kg object if both are on the other side of the universe… the difference would not be measureable… just as the actual force they applied to your mass due to the extreme distance would not be measurable for each object either.
On Earth the difference between the gravitational pull on your head and the gravitational pull on your feet is so small you don’t notice it.
This is due to the fact that the gravity of half of the Earth is 6,000km or more away from you.
Let me put it this way… how is a black hole created?
A normal star is a ball of hydrogen gas.
Hydrogen is a very light element but if you get the amount contained in a very large star then this has considerable mass.
This considerable mass generates high pressure and most importantly very high temperatures at the core of this mass.
A small mass of H may not be “heavy” enough and will form a planet like Jupiter… made largely of hydrogen but with a core temperature not high enough for fusion to start. (its distance from the sun and its still rather large gravity prevents its gaseous matter from being blown away by the solar wind.)
If you jump up in size to our sun then the critical temperature is reached. Fusion at the core greatly increases the heat generated and the mass becomes a star. The surface of our sun is not hot enough for fusion… fusion needs millions of degrees C temps and only occurs at the stars core. The heat raises the temperature of the surface and supplies an outward force that stops the sun from collapsing further into a smaller sphere.
The fusion process involves the collision of hydrogen atoms to form helium atoms. The process doesn’t stop there and hydrgoen atoms can collide with helium or helium with helium to create new atom types (types that we rely on here on earth to live like oxygen and carbon let alone build planes…). Of course at the core of the star the elements are in a state of matter called plasma… electrons flow freely.
There is a problem however when Iron atoms are created.
Iron is highly dense and very conductive (of heat as well as electricity). This leads to the fusion process slowing down and stopping in a star.
Without the heat and outward force of the fusion at its core the sun will collapse under its own weight.
The heat and pressure generated by this collapse is called a Nova.
The resulting explosion will blow matter out into nearby space and the core will be crushed. This crushing can create new materials like Uranium and other heavy elements. (There is no natural process on earth or any other planet that could created the heat and pressure needed to create Uranium.)
A white dwarf may be created, or a cold dark core of dense matter.
If the star is slightly bigger than our sun then more drastic things can be created like a neutron star where the pressure and heat is so great that protons and electrons are crushed together and form neutrons (ie the weight of a proton plus the weight of an electron equals the weight of a neutron. the Positive charge of the proton plus the negative charge of the electron result in a non charged neutron… of course magnetic forces of repulsion would have to be overcome so the forces would have to be enormous.)
If they are even greated they create something very dense… called a black hole.
What the Heck is my point????
My point is that the creation of a black hole by a truely enormous star collapsing involves an explosion called a supernova that is a process that results in a huge amount of mass being blown off into space and the core of the star being crushed down to a very small area by that enormous explosion.
If black holes are merely created by putting together a large amount of mass then every star should become a black hole before it becomes a star as it weighs more as a star than initially as a black hole.
The only difference is that our sun is rather large and a black hole with the same amount of matter as our sun would be about 20km across… just as a black hole with the same amount of mass as the Earth would be about 2.5cm across (ie rather larger than the marble size I mentioned).
“And your wrong about the space ship being shrunk and achieving infate mass at light speed. All that would be measured by an observer not the person insde the spaceship.”
The only reason Einstein talks about a difference between an observer and those on board the space craft is because those on board the spacecraft are being effected in the same way the spacecraft is.
Many mistakenly think this means that this is an observational effect and it doesn’t really happen… of course it does.
As you accelerate the length of the ship in the direction of travel is reduced. On board the spaceship you don’t notice this because all of your measuring devices are reduced in length by the same amount.
If you were to jump on the scales on board the ship then you would seem to weigh the same except if you used a tension based method of weighing yourself… ie on earth I weigh 110kgs. Let us say that on the moon I weigh 1/5th that, which equates to 22kgs… but if I took up scales and a 22kg mass the scales would not balance because the 22kg mass would also be 1/5th lighter and would equate to about 4 and a half kilos.
Equally travelling at a fraction of the speed of light if I weigh 5 times more then the balance weights I use to measure my weight will weigh 5 times more so I will still put the 100kg and the 10kg weight on the other side of the scale and my weight will balance that… if we are accelerating at 1 g of course… 🙂
The only proof of this that you could retrieve from the spacecraft after it had slowed down would be that the clock would have slowed down and measured time at a different rate, though time would have returned to the same speed for the spacecraft and the observer.
If the changes in velocity by the spacecraft are ONLY observable by the observer then all features should return to normal when it is at rest again… like water in a glass making a straw look bent or broken but the straw is not really effected… just our observation of it… when the straw is removed its observed shaped and features return to what they always were (though wetter).
Whe the spaceship stops therefore the clocks on board should jump back forward to the time displayed by the stationary clocks… and they don’t.
(Atomic clocks have been accelerated to orbit and compared to atomic clocks that have not been accelerated to high speed and there is a difference… a very very small difference of course as orbital speed is no where near light speed.)
By: mixtec - 2nd December 2002 at 20:20
RE: Whats the speed of Dark ?
“I have mentioned the event horizon (here and in a previous post about BHs).
The event horizon is the sphere in space around an object that marks a boundary.
As an example there is a similar boundary around Earth and it is determined by the escape velocity of the object.
The Escape velocity for earth is about 11km/s.
If you leave the surface of earth at less than this speed then no matter how high you manage to get you will not escape earths gravity and you will fall back to earth eventually.
Gravity is strongly influenced by distance.”
You cant compare event horizons to escape velocity. Escape velocity is the measured speed of orbit where an object will not fall back to earth and therefore maintain somekind of infine orbit. There is no escape velocity for any object leaving straight up from the surface of the earth, this force can be calculated by in infinate ratio
“If you are 1,000km above the earth then you are 1,000km from the surface on one side… at about 12,000km across you are therefore 13,000km away from all of the earth at 1,000km above one side.
If you crushed the Earth down to the size of a marble the its gravity at 1,000km above one side will be significantly greater. In fact to reduce the Earth to that size will create a black hole.
This takes me back to the event horizon.”
Center of gravity is measured at the center of mass, there would be no dectable difference in the force of gravity if you crushed the earth to the size of a marbel and maintained same altitude form center
And your wrong about the space ship being shrunk and achieving infate mass at light speed. All that would be measured by an observer not the person insde the spaceship.
Someone please look this up and prove Im right.
By: Arabella-Cox - 2nd December 2002 at 11:25
RE: Whats the speed of Dark ?
[updated:LAST EDITED ON 02-12-02 AT 11:47Â AM (GMT)]Boy oh boy…
Where to begin?
Well lets start with the flashlight thing.
SOC is almost right.
If you are travelling at 100km/h and you have your headlights on then the light from the bulbs travels at the speed of light… NOT the speed of light + 100km/h.
Of course as the car is travelling through the earths atmosphere the speed of light is actually the speed of light in the air which is slower than the speed of light in a vaccuum, but faster than the speed of light in glass or water.
If you pointed a flashlight out of a spaceship travelling at the speed of light + 2km/h then the light from the bulb would be left behind by the ship you are travelling in.
(Note Einsteins theories show it is impossible to travel at the speed of light in a vaccuum, because physical size, mass, and time readings on board the object become absurd… ie a spaceship would become a two dimensional infinitely massive object in which time stops.
Values at above an below the speed of light in a vaccuum are however normal and therefore assumed possible.)
Where SOC was wrong was in trying to suggest that matter acts exactly like a photon.
A bullet shell fired at 900mps from an SR-71 flying at 900mps will initially travel (ie at muzzle velocity)at 1,800mps relative to the ground and 900mps relative to the SR-71. Just as a Mach 2 missile fired from a mach 2.83 aircraft will travel faster and further than a mach 2 missile fired from a hovering helicopter.
Due to drag and other atmospheric factors the mach 2 missile will not necessarily fly at mach 4.83 when fired from a mach 2.83 aircraft as its maximum speed also depends of the velocity of its rocket exhaust and its aerodynamic shape.
Note Photons don’t Accelerate or decelerate. The change in speed of a photon of light that passes from a vaccuum to a piece of glass or the atmosphere is instantanous.
Particles of matter have been detected travelling at very close to the speed of light in a vaccuum. In fact their speed in a vaccuum exceeds the speed of light in our atmosphere and when these particles enter our atmosphere as they decelerate they glow with bright spiral patterns that are the light equivelent of the sound barrier.
In other words as the photons enter the atmosphere they instantly change speed. For the distance it takes for the fast travelling particles to slow down below the speed of light in the atmosphere they are travelling faster than the speed of light (in the atmosphere… not a vaccuum).
Of course firing a gun backwards is a problem as the velocity of the bullet has the speed of the aircraft deducted from it, so a tail gun firing at 800mps from a bomber flying at 200mps would result in the bullet travelling relative to the ground at 600mps at the gun muzzle.
In other words a photo of light will travel at one speed each medium.
A photon from a flashlight travelling at 1 km/h or 200 billion km/h will travel the same speed… ie the speed of light in the medium the light photon is travelling through.
Matter is effected by many forces and a bullet fired forward from a moving vehicle has the speed of the vehicle added to it, whereas a rearward fired bullet has that speed deducted from its initial speed relative to stationary objects.
Or to use a consistant example.
Two cars heading toward each other a 100km/h.
The relative speed of the two cars to each other is 200km/h.
Replace one car with a stationary torch and the speed of the light relative to the other car is the same as the speed of the light relative to the road and other stationary objects.
Regarding the speed of Gravity, this makes as much sense as trying to find the speed of Friction.
There are many theories that gravity is a wave emitted by mass.
This theory is supported by many ideas about event horizons in black holes.
“Your refering to terminal velocity which is caused by the atmosphere, in a vacume in would continue to accelerate indefinately”
Consider the only sensible test of this idea.
As gravity seems to be related to mass and distance then lets imagine an atmosphereless mass in the shape of a donut.
A donut has as its centre of mass empty space so it is ideal for this example.
Falling from space toward the centre of the donut you would accelerate toward the centre of the donut.
As you got closer to the centre of the donut your acceleration would increase as distance is a major factor in gravitys pull.
When you pass the gravitational centre of the donut you are at maximum graviatational acceleration and then when you pass the centre and start leaving the donut you start to decelerate… ie negative acceleration. All things being equal with no collisions or atmosphere or other gravitational influences you should stop on the other side of the donut at the exact same distance you fell from on the other side. Then of course you should start to fall back again in an infinite cycle if you ignore energy losses through the fact that both the object falling and the donut are not homogenous so energy will be lost in these distortions etc etc.
“darkness must be composed of particles, which are not allowed to radiate photon(light) particles/waves(dependng on which side of the fence you sit on). There must be somthing special about the particles which restrict this energy emission. Basically its because a particle does not receive enough energy to allow the emission of a photon.”
Darkness is merely an absense of photons.
“2. If a photon has no speed, do you see it when(if) it decays and irradiates light?”
A photon is a ray or single light element.
BTW back to light if you have a wee think about black holes it becomes a little clearer.
I have mentioned the event horizon (here and in a previous post about BHs).
The event horizon is the sphere in space around an object that marks a boundary.
As an example there is a similar boundary around Earth and it is determined by the escape velocity of the object.
The Escape velocity for earth is about 11km/s.
If you leave the surface of earth at less than this speed then no matter how high you manage to get you will not escape earths gravity and you will fall back to earth eventually.
Gravity is strongly influenced by distance.
If you are 1,000km above the earth then you are 1,000km from the surface on one side… at about 12,000km across you are therefore 13,000km away from all of the earth at 1,000km above one side.
If you crushed the Earth down to the size of a marble the its gravity at 1,000km above one side will be significantly greater. In fact to reduce the Earth to that size will create a black hole.
This takes me back to the event horizon.
The event horizon is the point or distance above a mass where the escape velocity is the speed of light in a vaccuum.
Outside that boundry light can escape, but once that boundry has been crossed and you are closer to the mass than the event horizon then you are in trouble as it is impossible for light to escape so your chances are not good either.
If you had crossed the event horizon and you got out your flashlight and shined it out toward space an observer would never see the light that leaves your bulb. From the outside it is the event horizon that looks black, not any mass that might be passing through.
Inside the black hole… in its centre there is a singularity… a point of infinite gravity. This cannot be seen from outside the black hole, nor fom inside as no light can reflect off of it to reveal its presence, nor can it emit light.
The light from your bulb travels at the speed of light but the distortions of local space means that everything around it and the photons themselves from the bulb of your flashlight are falling back with you faster than they are travelling away from the object you and your torch and the light from your torch are falling into… weird?
“Gravity is just the acceleration of mass relitive to space caused by the bending of space by mass. “
Gravity is a measure of acceleration… even when it is not gravitationally induced… turning a high speed jet induces “g” forces that have nothing to do with gravitiation… but being pushed into your seat by 2gs or twice the normal sea level gravitiation of Earth means more to most people than having xyz newtons or joules of force applied to your body.
If we can determine if gravity is a wave and we can create a machine to generate an anti wave then interstellar travel becomes very close… accelerate at any speed you like (the crew can be protected from acceleration, while the Earth, the sun, the solar system, and the galaxy and the universe can be used to push against to fly anywhere.
(Note of all the forces like nuclear bonding forces and electrical forces gravity is a very weak force… an object the size of the earth is required to stop our atmosphere floating away.)
Some of you may be wondering why this model of Black holes supports the idea that gravity might be a wave.
As I mentioned a black hole contains a singularity… a point of infinite gravity.
Infinite gravity would crush any matter out of existance, so except for matter that has crossed the event horizon but not yet entered the singularity a black hole contains no mass.
But from the outside it is rather obvious by the way it attracts matter and bends and distorts space around it like a massive object would that it does contain a lot of mass.
The problem of the event horizon (EH) is that nothing can cross it, so the gravity field around an object emitted in some form cannot be from the object itself and must be space’s reaction to the mass.
Because nothing can travel through the event horizon except one way the space outside the event horizon does not know the matter that was influencing it no longer exists. It continues to act like the matter is still there, so I guess the space around the EH does not need any emission from the mass itself for the gravity distortion effect to work.
This suggests that any anti gravity machine would work by fooling space into thinking that there is more mass in one place than there actually is.
First of course you have to find out how space determines that there is mass there in the first place…
Brain bending stuff eh?
By: coanda - 1st December 2002 at 23:26
RE: Whats the speed of Dark ?
the spaceship and everything in it is travelling at a constant speed, it is experiencing equilibrium conditions, i.e. it can be said to be not moving at all, if you are IN the spaceship. If your watching it, it’ll go past very quickly, but you will see everything inside it in slow motion (if i remember correctly) as everything inside it is either adding or subtracting to their individual constant speeds, those either slowing themselves down or speeding themselves up. and this fraction is tiny compared to the overall speed.
The light source can be travelling at a constant speed, and still emmit a beam, which travels at the speed of light, because the beam may as well be coming from a stationary object. now if you were accelerating and emmitting a light source in the direction of travel…….
If you watch a train go past, with a person walking up an isle, you will hardly see him move, even tho you KNOW that this person could be walking at about 1.5 m/s(in his equilibrium state…..or at the vtrain + vperson)
therefore, the light WILL be emitted at the speed of light, with no additional factor, in fact if you want to get into it that much, if your pointing your torch forwards it could be said that you are exerting a decelerative force on the whole equilibrium system.
coanda
By: SOC - 1st December 2002 at 18:58
RE: Whats the speed of Dark ?
I have actually studied both standard and particle physics. The spaceship and everything in it is travelling at light speed. Turning on a light won’t project anything in front of the spaceship, but a stationary outside observer will now see the characteristic flashlight beam.
I’ll dig up a textbook and get the details later as to why this works. Part of the problem I believe may be related to wave-particle duality, and the conversion of matter.
SOC
“Peace through kinetic solutions”
By: mixtec - 1st December 2002 at 17:29
RE: Whats the speed of Dark ?
Your wrong SOC, the flashlight in front of a spaceship will function perfectly normal for the person inside the spaceship. Its a person standing stationary (relatively speaking) outside who will see no light emitted from flashlight. Your cannon firing from a mach 5 fighter is not a good example because again were dealing with the atmosphere. In a vacume there would be no reduction at all of the bullets velocity due to the speed of the fighter.
C´mon folks, isnt there anyone here whos studied this in college? Ive never formally studied physicics and only have a general knowledge.
By: SOC - 1st December 2002 at 05:27
RE: Whats the speed of Dark ?
Since AFM is down I’ll amuse everyone here }>
If you are moving at light speed and turn on a flashlight, you will not see the beam. The bulb will get bright, but the beam will be moving at the same speed as you are, so you won’t see it travelling out in front of you. Similar concept-if you are flying at Mach 4 and try to fire an M61 cannon, you are going to put a hole in your aircraft as you will overtake any bullets you fire. Now if they’re tracers, you’ll leave a really cool contrail…
The speed of dark? Dark is defined as an absence of light. Therefore it cannot be measured. This is like trying to measure the mass of the absence of the apple from this room I am in. There is no apple; I can’t measure it. On the other hand, in a perfectly dark room, you could measure the volume of dark present, by measuring the volume of the room and subtracting the volume of anything in the room such as furniture. This suggests that dark is something that is quantifiable, meaning you should be able to figure out its speed. I’d say that the speed of dark is the same as the speed of light, as the dark has to exit an area as quickly as the light enters.
Who else’s head hurts?
SOC
“Peace through kinetic solutions”
By: mixtec - 1st December 2002 at 01:16
RE: Whats the speed of Dark ?
Merlin-
“I was always taught that, as somebody has already pointed out, gravity is a force.”
Its not a force inherent in mass itself, mass bends space, space is causing the force
“A mass is forced by gravity to the Earth.”
Two masses are attracted to oneanother by the inverse of their distance (the earth is merely a mass)
A mass will also be forced to the earth when it has fallen or is seperated from the earth. ie jumping off a building or from an aircraft.
Remember the atmosphere factors into this heavily with objects in relation to the earth, the atmosphere forces objects into simutaneous motion due to friction. An object never actually leaves the force of attraction of the earth. When an object leaves the so called gravitation of the earth, its really just being taken over by a larger more dominant gravitation of the sun. When an object leaves the so called gravitaion of the solar system, its really not leaving anything, it again is just being taken over by the larger overall “gravitation” of the galaxys orbit.
“A mass will accelerate and gain a maximum speed through the air because of the forced applied by gravity.”
Your refering to terminal velocity which is caused by the atmosphere, in a vacume in would continue to accelerate indefinately
“This would mean that gravity is a constant force and a mass travelling aided by gravity would gain a max speed and therefore a constant speed.”
constant in relation to what?
ink-
“So if a man with a torch is travelling at the speed of light past the earth and I’m standing on it watching him switch the torch on – do i see it emit a beam of light? Surely the speed of light is a constant and can never be increased? The light emited by the landing-lights on plane doesn’t travel at: 3×10^8 m/s + a bit, does it? It still travels at the speed of light.”
Yes the speed of light is constant just as the speed of sound is relitively constant at a given altitude. So when your on a train and you hear the sound of a traffic warning bell rise as you approach and fall as you move away, the speed of the sound has not actually changed, but it has changed in relation to you, hence- relativity, get it?
By: ink - 1st December 2002 at 00:13
RE: Whats the speed of Dark ?
Coanda,
So if a man with a torch is travelling at the speed of light past the earth and I’m standing on it watching him switch the torch on – do i see it emit a beam of light? Surely the speed of light is a constant and can never be increased? The light emited by the landing-lights on plane doesn’t travel at: 3×10^8 m/s + a bit, does it? It still travels at the speed of light.
By: Merlin3945 - 30th November 2002 at 22:03
RE: Whats the speed of Dark ?
Back to the speed of gravity for a sec.
I was always taught that, as somebody has already pointed out, gravity is a force.
A mass is forced by gravity to the Earth. A mass will also be forced to the earth when it has fallen or is seperated from the earth. ie jumping off a building or from an aircraft. A mass will accelerate and gain a maximum speed through the air because of the forced applied by gravity. This would mean that gravity is a constant force and a mass travelling aided by gravity would gain a max speed and therefore a constant speed.
makes sense the way I read it but there it is
Merlin
By: coanda - 30th November 2002 at 17:15
RE: Whats the speed of Dark ?
lol
coanda
By: Hellaid - 30th November 2002 at 17:09
RE: Whats the speed of Dark ?
There is no speed of dark because it is just an absence of light
By: coanda - 30th November 2002 at 11:44
RE: Whats the speed of Dark ?
well, the light being emitted, is being done so from an object in equilibrium, i.e. its travelling at a constant speed, or, you can suppose it is stationary…….so its not travelling faster than the speed of light, it is travelling at or below the speed of light….once again, its where you stand that makes the difference.
do you stand with the torch, or do you watch the torch go past??
coanda
By: geedee - 30th November 2002 at 11:22
RE: Whats the speed of Dark ?
So if I get this right, holding a torch while travelling at the speed of light, pointing it forward and switching it on would produce a beam of light from the torch ? So in fact the light emitted from the torch is actually going at twice the speed of light ?. Bit dangerous that…think of the recoil !!!
cheers
Gary
By: coanda - 29th November 2002 at 23:52
RE: Whats the speed of Dark ?
yeah, well thats a clue, as to the answer, the famous E=m(C*C) is not the complete version, and is pretty hopeless, mathmatically(in these situations), and really wouldnt be used in that form,by physicists). Of course it can be converted to anything you want, related to energy.
gravity is defined as being the acceleration felt by 1kg in one second thus g in units is kg/m/(s*s)
this you can see is made up mass, time, and velocity.
you need to experience some velocity to experience an accleration.
If a torch was stable at the speed of light, the light the torch produces would in fact emit as would be expected, because it is in a state of equilibrium.
this all depends on whether you are holding the torch, also travelling at the speed of light, or watching the torch shoot past you at the speed of light……..the example we were taught was someone shining a torch up and down a train, as you watched the train come past…….the same thing.
darkness must be composed of particles, which are not allowed to radiate photon(light) particles/waves(dependng on which side of the fence you sit on). There must be somthing special about the particles which restrict this energy emission. Basically its because a particle does not receive enough energy to allow the emission of a photon.
So, you have inherent energy and you have given energy..inherent energy produces an equilibrium state. given energy must produce a change in state, positive or negative.
You can then see that particles, not supplied with extra energy (i.e. heating) still travel at the speed of light, but they do not have the energy to irradiate photons.
so the answer is 300 000 000 m/s give or take a few. This is in a perfect vacuum, it reduces a bit if there is air resistance, but negligibly so…..
coanda
By: mixtec - 29th November 2002 at 23:16
RE: Whats the speed of Dark ?
E=MCsq is basically the “horsepower” of mass. Infact MCsq can be directly converted into newtons, juels, horsepower or whatever measurement you prefer.
By: coanda - 29th November 2002 at 23:04
RE: Whats the speed of Dark ?
A couple of questions to help shine a light into the pitch black.
1. Is gravity a vector quantity?
2. If a photon has no speed, do you see it when(if) it decays and irradiates light?
E roughly equals M(C*C)……right?
coanda
By: mixtec - 29th November 2002 at 22:38
RE: Whats the speed of Dark ?
scyth-
“Speed of gravity? That doesn’t make sense, it contradicts the very foundations of basic physics. Gravity is a force, and therefore provides accelaration, which means speed cannot be a constant”.
Actually there is no such thing as gravity. Gravity is just the acceleration of mass relitive to space caused by the bending of space by mass.
Hand87-
“It does make sense. Imagine that a massive object wouls appear in the galaxy , the effect of his mass won’t be instantaneous. This force would propagate through the space. If this effect was instantaneous, it would mean that this effect travels at an infinite speed which is non physical. Let’s wait and see ….”
There is no outer limit to “gravity” of a given mass. Its force extends infinitly. As to “darkness”, Im guessing whats really being refered to is space. Im not sure that space has been really measured because there is no constant to measure it too (hence relitivity). I think thats what Einstein was striving for in his attempt at a unified field theory in bringing all the forces of nature under one law.
By: sparky - 29th November 2002 at 21:19
RE: Whats the speed of Dark ?
If you had solar powered headlights wouldn’t that solve the problem with fog.Great idea about the bi-focals what about having it incorporated in with your double glazing as there is no chance of hitting the house next door.What about having the switches in cars marked in braille?
Sign In
November 29, 2002 at 8:25 am