Some physics help?
Jun. 20th, 2003 10:26 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
gridloreWe have a nutjob in alt.atheism who keeps claiming that he's disproved galactic expansion and is the only one who understands Einstein. Behind the cut tag is some of his ramblings. Could someone with more hard physics point out exactly where he's screwy?
"An event, wherever it may have taken place, would be fixed in space
with respect to K by the three perpendiculars, x,y,z on co-ordinate
planes, and with regard to time by a time-value t." (Relativeity, the
Special and General Theories, A. Einstein, p. 32)
"A light signal is sent along the positive x-axis, and this
light-stimulus advances in accordance with the equation x=ct i.e.
with the velocity c."
Now we take what Einstein said here and apply it to light emitted
in a distant galaxy. A photon is emitted in the distant galaxy and a
million years later reaches earth. x in Einstein's equation x=ct is
the displacement of the photon when it reaches earth from the point
where it is emitted. What the equation is saying is that when the
light was emitted, it spread outward from the point where it was
emitted as a sphere with a radius of ct, where t is time at the point
where it was emitted.
Now we consider some scientists on earth who observe the light
from the distant galaxy. These scientists have university degrees,
peer reviewed journals, state of the art equipment, and pro-abortion
advocates have to believe whatever they say. So they measure the
light, notice that there is a red shift, measure the speed of light to
be c, and conclude that the distant galaxy is moving away from earth.
What they neglected in their analysis was that c is the same in
their equation as it was for the equation at the distant galaxy. The
speed of light they measure is the magnitude of c, the velocity of
light that was observed when the light was emitted. Velocity of light
measured displacement of a photon, but the photon did not travel a
straight line in reaching earth.
"According to the general theory of relativity, a ray of light
will experience a curvature of its path when passing through a
gravitational field, this curvature being experienced by the path of a
body which is projected through a gravitational field." p. 127
So if we write an equation for the total distance the photon
traveled,
d=c(t2)
then d is a longer distance than x, the distance from the point in the
distant galaxyu where the light was emitted to earth, and t2 is a
longer time than t the time on a clock at the distant galaxy.
Therefore, relative to the light, a clock on earth is running
faster than a clock at the distant galaxy, and the light will appear
red shifted according to a clock on earth.
If we consider light from the sun, a clock at the distant galaxy
is running faster than a clock on earth, and scientists at the distant
galaxy will see the light from the sun red shifted. That is just what
the equations show.
"An event, wherever it may have taken place, would be fixed in space
with respect to K by the three perpendiculars, x,y,z on co-ordinate
planes, and with regard to time by a time-value t." (Relativeity, the
Special and General Theories, A. Einstein, p. 32)
"A light signal is sent along the positive x-axis, and this
light-stimulus advances in accordance with the equation x=ct i.e.
with the velocity c."
Now we take what Einstein said here and apply it to light emitted
in a distant galaxy. A photon is emitted in the distant galaxy and a
million years later reaches earth. x in Einstein's equation x=ct is
the displacement of the photon when it reaches earth from the point
where it is emitted. What the equation is saying is that when the
light was emitted, it spread outward from the point where it was
emitted as a sphere with a radius of ct, where t is time at the point
where it was emitted.
Now we consider some scientists on earth who observe the light
from the distant galaxy. These scientists have university degrees,
peer reviewed journals, state of the art equipment, and pro-abortion
advocates have to believe whatever they say. So they measure the
light, notice that there is a red shift, measure the speed of light to
be c, and conclude that the distant galaxy is moving away from earth.
What they neglected in their analysis was that c is the same in
their equation as it was for the equation at the distant galaxy. The
speed of light they measure is the magnitude of c, the velocity of
light that was observed when the light was emitted. Velocity of light
measured displacement of a photon, but the photon did not travel a
straight line in reaching earth.
"According to the general theory of relativity, a ray of light
will experience a curvature of its path when passing through a
gravitational field, this curvature being experienced by the path of a
body which is projected through a gravitational field." p. 127
So if we write an equation for the total distance the photon
traveled,
d=c(t2)
then d is a longer distance than x, the distance from the point in the
distant galaxyu where the light was emitted to earth, and t2 is a
longer time than t the time on a clock at the distant galaxy.
Therefore, relative to the light, a clock on earth is running
faster than a clock at the distant galaxy, and the light will appear
red shifted according to a clock on earth.
If we consider light from the sun, a clock at the distant galaxy
is running faster than a clock on earth, and scientists at the distant
galaxy will see the light from the sun red shifted. That is just what
the equations show.
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no subject
Date: 20 Jun 2003 22:33 (UTC)no subject
Date: 20 Jun 2003 23:10 (UTC)He's going to sue us for making donations to Planned Parenthood in his name.. just as soon as we send him all the evidence.
Re:
Date: 20 Jun 2003 23:35 (UTC)Re:
Date: 20 Jun 2003 23:39 (UTC)no subject
Date: 20 Jun 2003 22:56 (UTC)light was emitted, it spread outward from the point where it was emitted as a sphere with a radius of ct, where t is time at the point where it was emitted.
No. The t in x=ct is the elapsed time from the time it was emitted to the time it reached earth, t=tn-t0. tn == "now." t0 is the time it was emitted. He's trying to say t = t0, which is incorrect.
The next paragraph is an absolute mish-mash. I can't make sense of it. I suspect he doesn't understand how the doppler effect acts on EM radiation.
For the rest, yes, light encounters twisting from gravitational effects. Gravitational lensing is well known. In fact, measuring the angular differences seen in gravitational lensing provides information on the distance to far away galaxies.