I have so far only one qualitative comment - the one regarding Rick's=
statement that the oncoming light is blue-shifted. This does not=
=20
necessarily mean, however, that the stars in front view will "go out"=
,
because ALL frequencies undergo this shift, so as the stellar visible=
=20
spectrum (in the galactic rest frame) will shift into UV (in the fram=
e=20
of the spaceship), by the same token some of the stellar IR-radiation=
=20
will be blue-shifted into the visible. Even if the ship's velocity=
=20
approaches c, there will always be a region of the stellar spectrum=
=20
(first IR, then radio) blue-shifted into the visible. One could say=
=20
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=20
black-body spectrum; however, together with the blue-shift, the Loren=
tz=20
boost will increase the intensity of the oncoming light in the ship's=
=20
rest frame.
Which one out of these two opposing effects is stronger, I cannot say
right now. It needs some quantitative estimation.
Moses Fayngold,=20
NJIT=20
-----Original Message-----
=46rom:=09Forum for Physics Educators on behalf of Rick Tarara
Sent:=09Tue 1/17/2006 8:38 AM
To:=09PHYS-L@LISTS.NAU.EDU
Cc:=09
Subject:=09The 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 a=
nd
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 li=
ght is
shifted towards blue--a bit more so in the center of view. As the sp=
eed
gets high enough, the light is shifted to the ultraviolet and the sta=
rs seem
to go out--starting in the center of view and spreading outwards--lik=
e 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 wo=
uld
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 i=
n 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