Assertion: black hole | /r/HasProperty | difficult to see
Facets:
Source sentences:
text: Such black holes would be difficult to see if they’re simply floating quietly in space and keeping to themselves.
text: Black holes are difficult enough to understand, but it gets much worse: also known as an “impossible possibility”, a white hole is a hypothetical, celestial body that emits energy—in the manner of a time-reversed black hole.
text: Because light cannot escape from a black hole's event horizon (the point of no return), black holes are difficult to capture in images, as the objects simply appear black.
text: Black holes are so difficult to see that it would be difficult to see one if it were right beside the Earth.