Catch Me If You Can, Said the Black Hole
It goes without saying that it is hard to observe something that we cannot perceive with our own eyes. Luckily, science and technology have come a long way in helping us to detect the unseeable.
Think of optical and atomic force microscopes showing how the Shewanella oneidensis bacterium extracts oxygen from toxic metals, mirrors and optical cavities that single out a rubidium atom, or spectrographs and telescopes revealing the presence of, among other chemical elements, neon in the hot gas cloud Omega Nebula, 52 million billion kilometres away from Earth.
Pricklier still is to discern something that does not send out any detectable information at all: a black hole.
What is a black hole, and how do we know it is out there if we cannot detect it?
A Star Is Born
The idea of a black hole originated in the 18ᵗʰ century, when John Michell and Pierre-Simon Laplace coined the conjectured phenomenon ‘dark star’.
In the latter half of the 20ᵗʰ century, divided global politics led independently to different names for the same object: physicists to the east of the Iron Curtain referred to ‘frozen stars,’ while those to the west spoke of ‘collapsed stars’.
