Gravitational Lensing to Observe Ancient Earth
1–10 of 66 posts
Re: Gravitational Lensing to Observe Ancient Earth
#2This is sweet. I can imagine this being woven into some great stories.
Re: Gravitational Lensing to Observe Ancient Earth
#3Ha, that was the plot line of Paycheck [1], but seeing the future, not the past.
Re: Gravitational Lensing to Observe Ancient Earth
#4I'm not so much into physics but based on what I understand - ok, we might get just enough photons reflected back by MACHOs if we build a massive new telescope.
But then how do we separate them from other photons - ie the ones not reflected back? Do photons reflected by MACHOs have a specific signature on their EM wave ??
Re: Gravitational Lensing to Observe Ancient Earth
#5I'm not so much into physics but based on what I understand - ok, we might get just enough photons reflected back by MACHOs if we build a massive new telescope. But then how do we separate them from other photons - ie the ones not reflected back? Do photons reflected by MACHOs have a specific signature on their EM wave ??
the photons "reflected" back would appear at specific locations around the edge of the MACHO, so you'd see expect to see something with Sun-like spectra at that radial location. lots of image processing would be required to un-warp the collected image.
Re: Gravitational Lensing to Observe Ancient Earth
#6I'm not so much into physics but based on what I understand - ok, we might get just enough photons reflected back by MACHOs if we build a massive new telescope. But then how do we separate them from other photons - ie the ones not reflected back? Do photons reflected by MACHOs have a specific signature on their EM wave ??
That is exactly the problem. The author talks about the photons that get turned 180 but the reality of the situation would be similar to seeing our sun reflected in a piece of glass a few thousand light years out (no need for a MACHO). The reflection is there but so is all the background noise, so just like trying to look the reflection on a clear piece of glass, the light mixing would be killer.
Re: Gravitational Lensing to Observe Ancient Earth
#7You need to read 'The Light of Other Days', detailing the use of microscopic wormhole lenses to observe ancient earth: http://en.wikipedia.org/wiki/The_Light_of_Other_Days
Re: Gravitational Lensing to Observe Ancient Earth
#8Ha, that was the plot line of Paycheck [1], but seeing the future, not the past. [1] http://www.imdb.com/title/tt0338337/
Greg Egan had a short story ('The Hundred Light Year Diary') in his collection 'Axiomatic' which dealt with people be able to send messages to the past (and thus becoming aware of their future).
Re: Gravitational Lensing to Observe Ancient Earth
#9You need to read 'The Light of Other Days', detailing the use of microscopic wormhole lenses to observe ancient earth: http://en.wikipedia.org/wiki/The_Light_of_Other_Days
Good book. I still have the paperback on my shelf.
Re: Gravitational Lensing to Observe Ancient Earth
#10The practical limitation isn't just magnitude, but resolving power. Atmospheric disturbance makes it difficult to resolve anything smaller than a meter from orbit, and the diffraction limit means the further are away from the thing you want to observe, the wider your telescope needs to be. Since the distortion effects near a black hole are near-asymptotic, the features we want to see have very small subtended angles, and we need much higher resolving power to "see" recognizable features.
Stars? Definitely feasible. Planets? Much harder. People? Certainly not with available optics.