8 ms·

Thanks, I think I added the link to the paper while you were writing this. From skimming it I can't tell the answer to my question though. How do they know wha

• LolWolf 8y ago
  If you observe a very wide band of light (e.g., EM radiation) and there is nothing received from those spots, then, for all intents and purposes, the region of that image is black. Now, if you're asking if, perhaps, the region isn't really black, but rather it's emitting some sort of small radiation relative to the bright region, it would be essentially impossible to know without much higher resolving powers (since it might even be indistinguishable from the background noise generated by the surrounding region). There is no way to really know if it's "perfectly black" vs. "orders of magnitude darker than the surrounding regions."
  • nonbel 8y ago
    Makes sense. So I guess they could probably tell us an upper bound on how bright it is.
    • LolWolf 8y ago
      Indeed! That’s for sure: it’s probably not hard to extract a bound on the magnitude of a part of the spectrum from this analysis.
      • nonbel 8y ago
        Any idea how bright it might be? Eg, could it be as bright as the sun? The moon?