Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 23/09/2016 11:53:01
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Luke Pullar asked the Naked Scientists:
If we pointed a telescope at the same point in space for a few/many years, would we see "new" (to us) stars as the light eventually reaches us from increasingly distant places?
What do you think?
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Disclaimer: I am not a professional =)
If the rotation of the galaxy and solar system was taken into account. I don't see why would couldn't view new stars. If telescopes are similar to camera shutters. The longer the shutter stays open more light seen. If you could factor in the rotation of the solar system with the rotation of the galaxy. You should be able to have the telescope trained on one spot in space. hold the shutter open and hope to see more stars.
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If we pointed a telescope at the same point in space for a few/many years, would we see "new" (to us) stars?
Yes, the Hubble Deep Field exposure totaled about 140 hours, staring at the same patch of sky, and revealed many galaxies that were invisible with shorter exposure times.
Of course, demand for observation time on Hubble is so great, and the number of potentially interesting astronomical subjects are so numerous that the committee allocating Hubble observation time could not possibly allocate years on this unique resource to a single observation.
See: https://en.wikipedia.org/wiki/Hubble_Deep_Field#Observations
...as the light eventually reaches us from increasingly distant places?
The Hubble Deep Field exposure occurred over a 10 day period, so at best we could see galaxies from just 10 extra light-days due to this mechanism.
However, light becomes fainter with an "inverse square law", so a 100x longer exposure time is able to reveal the stars of galaxies at 10x greater distances, adding perhaps a billion light-years to the observation distance.
There are limits to how far the Hubble telescope can see, since the expansion of the universe red-shifts the light from distant galaxies into the infra-red.
- The Hubble telescope was not optimized for infra-red astronomy.
- However, the upcoming James Webb telescope is optimised for infra-red astronomy (and has a much greater light-collecting area), so it should be able to detect galaxies at far greater distances than the Hubble Deep Field exposure - by perhaps another billion light-years or so.
See: https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Infrared_astronomy