I have so far only one qualitative comment - the one regarding Rick's statement that the oncoming light is blue-shifted. This does not
necessarily mean, however, that the stars in front view will "go out",
because ALL frequencies undergo this shift, so as the stellar visible
spectrum (in the galactic rest frame) will shift into UV (in the frame
of the spaceship), by the same token some of the stellar IR-radiation
will be blue-shifted into the visible. Even if the ship's velocity
approaches c, there will always be a region of the stellar spectrum
(first IR, then radio) blue-shifted into the visible. One could say
that the stars in front will become invisible anyway due to the drop
in the intensity of the IR and especially radio-frequency of the
black-body spectrum; however, together with the blue-shift, the Lorentz
boost will increase the intensity of the oncoming light in the ship's
rest frame.
Which one out of these two opposing effects is stronger, I cannot say
right now. It needs some quantitative estimation.
Moses Fayngold,
NJIT
-----Original Message-----
From: Forum for Physics Educators on behalf of Rick Tarara
Sent: Tue 1/17/2006 8:38 AM
To: PHYS-L@LISTS.NAU.EDU
Cc:
Subject: The view from the Enterprise.
To return to some physics.....
I'm doing some updates on my animations and want to try and simulate the
view (both forwards and backwards) from a spaceship as is speeds up and
approaches the speed of light.
If I ignore (for a minute) the relativistic effects and consider only the
Doppler shift, I think what one would see is that ahead of you the light is
shifted towards blue--a bit more so in the center of view. As the speed
gets high enough, the light is shifted to the ultraviolet and the stars seem
to go out--starting in the center of view and spreading outwards--like a
hole opening and expanding. Behind, the light is shifted towards red, but I
think it takes higher velocities before being shifted to the infrared.
If that is more or less right--and please correct this if wrong--then what
happens when we add in time dilation and spatial contraction? How would
these effect what is seen by Kirk sitting on the bridge--viewing say a 60
degree arc of space in front of him (seeing for the most part stars in this
galaxy) as the ship (under 'impulse' power only) speeds up from rest to near
the speed of light?
[My 'classical' animation test works very nicely--but I'm sure it is too
simplistic since the purpose of the overall animation is to 'show'
relativistic effects. ;-( ]
Thanks,
Rick
*********************************************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, Indiana
rtarara@saintmarys.edu
********************************************************
Free Physics Educational Software (Win & Mac)
NEW: Updated MOTION animations.
COMING: Spanish language versions.
www.saintmarys.edu/~rtarara/software.html
Energy 2100--class project
www.saintmarys.edu/~rtarara/ENERGY_PROJECT/ENERGY2100.htm
********************************************************
_______________________________________________
Phys-L mailing list
Phys-L@electron.physics.buffalo.edu https://www.physics.buffalo.edu/mailman/listinfo/phys-l