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The practical limitation isn't just magnitude, but resolving power. Atmospheric disturbance makes it difficult to resolve anything smaller than a meter from orb
by aphyr 14y ago
The 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.
- pkrein 14y agoAperture synthesis (several widely-separated telescopes looking at one object) is often used to increase the resolving power. http://en.wikipedia.org/wiki/Aperture_synthesis http://en.wikipedia.org/wiki/Aperture_synthesis
- mikemoka 14y agoyes but if we manage to do everything (including unwarping the earth's reflection in the image) we would only see how our planet looked like 6 light years ago (3 for the light to arrive to the black hole and 3 to go back) and we won't be able to discern anything but the earth's surface, is that right?
- pkrein 14y agooh -- yeah seeing what people are doing on Earth via a black hole is totally out of the question technologically. that's pretty much the conclusion of the article.
- privong 14y agoTo be technical, you could still see an object that is smaller to than your resolving power (this happens essentially every time we observe individual stars). The issue is what is called the "confusion limit" - the point at which you can't be confident that what appears to be a source is not just the summed emission from a bunch of fainter background objects. But you are right that increased resolution is key. The higher resolution helps you beat the confusion limit by working to resolve the faint background sources into individual objects, so you can separate them. So, if you wanted to be certain that what you were seeing was the refracted light from Earth, you would need the high resolution to be sure that what you were seeing was actually that reflection, and not just a superposition of fainter background sources. More on the confusion limit: http://coolwiki.ipac.caltech.edu/index.php/Confusion http://coolwiki.ipac.caltech.edu/index.php/Confusion
- derekp7 14y agoThis reminds me of the "Picture Zoom" sketch from "Red Dwarf -- Back to Earth". Youtube clip here: http://www.youtube.com/watch?v=KUFkb0d1kbU http://www.youtube.com/watch?v=KUFkb0d1kbU