I am somewhat acquainted with astronomy and relativity. My
question is this: Quasar 3C273 has a jet moving at 9 times
light speed as seen from earth. This has been explained
away by science by saying that the angle of the jet towards
earth is just small enough to actually only give an illusion
of faster than light speeds relative to earth.
However there must be a counter-jet and I have been told by
an astronomer from Flagstaff, AZ that this is true. The
existence of a counter-jet showing the same relative speeds
would surely obviate the 'small angle' explanation and
would then prove that faster-than-light velocities do exist
in the universe relative to earth. This, then would
indicate that relativity is wrong in its assertion that FTL
relative to earth cannot be. Could you please tell me where
I'm wrong. It is a major stumbling block in my acceptance
of relativity. Thank you very much and could you, if
possible, indicate who is answering if I should have a
follow-up question. Again, thank you.
The Answer
I don't know offhand whether the counterjet for 3C273 has been seen.
http://www.cfht.hawaii.edu/Reference/Bulletin/Bull36/bulleti3.htm#764973 implies that it hasn't. It would be expected to be dimmer (since radiation
tends to be beamed in the direction of motion) and not show apparent
superluminal motion.
You are right that IF a superluminal counterjet were seen, that would mean
that something is very wrong with our understanding of the system or of
relativity.
I do know that the the 'microquasar' in our galaxy 1915+105, shows both
jets, and the one pointed towards us is apparently-superluminal while the
one pointed away is not.
David Palmer and Samar Safi-Harb
for Ask a High-Energy Astronomer
