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Q:
WHEN I WAS 13, ME TEACHER WAS TALKING ABOUT LIGHT BEING BENT (General Relativity) BY A "Black Hole" AND SHOULD US A DIAGRAM OF THIS (star, black hole, and earth in a straght line with the star seen above the black hole)... I WAS THINKING ABOUT THIS THAT NIGHT AND IT HIT ME, ALL OF THE PICTURES AND DIAGRAMS WERE "2D" AND WE LIVE IN A "3D" UNIVERSE. SO INSTEAD OF THERE BEING 1 OR 2 STARS SEEN, SHOULDN’T WE SEE A RING OF STARS AROUND THE MASSIVE OBJECT BENDING THE LIGHT?
- Ryan (age 17)
Saunders Secondary School, London, Ontario, Canada
A:
Hi Ryan,
Good job working out the consequences of
bending light in a gravitational field! This is a great example of
exercising the scientific method: 1) formulate a hypothesis; 2) test
its predictions by performing an experiment or observing something in
Nature.
Your idea is correct. Here is an example of a ring of
images of a quasar behind a lensing galaxy, obtained with the Hubble
Space telescope.
This figure came from
this page at NASA.
If
the lensing galaxy were symmetrical around the line between us and the
quasar, and if it is centered right on that line, we'd get a complete
ring. As it is, the distributions are off-axis and nonuniform and so we
observe multiple "arcs".
Tom J.
(published on 10/22/2007)
Follow-up on this answer.
