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Several Questions About the James Webb Space Telescope

-- Craig Koch | January 8, 2022

Question:

Does it matter which direction the JWST telescope is aimed to obtain an image of the universe not long after the Big Bang? Would it “see” the same image regardless of the direction, away from earth, that the telescope is aimed? My hunch is that the telescope will see the same thing, with light traveling 13+ billion years to arrive, regardless of the direction it is aimed. If so, does that relate to a “flat universe?”

I understand the concept of L2. I understand the concept of an accelerating expansion of the universe. I know that the universe is thought to be flat (but other than the ballon analogy I don’t really understand it).

Also, for objects relatively much closer, how can the telescope maintain a stable, time compensated image for long duration images during it’s rotation around the sun?

-- Craig Koch

Answer:

To your first question, the James Webb Space Telescope (JWST) will see different things when it points to different directions in space. The “flatness” of the Universe relates to its expansion rather than to its distribution of matter. Regarding how the telescope can produce images when it is orbiting around the Sun and the gravitationally-stable L2 position, the telescope has a very sensitive attitude control system which allows it to control the position to which it is pointing very accurately. This system includes thrusters and gyroscopes which allow for very fine adjustment of the telescope during measurements.

-- Jeff Mangum

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