An eminently quotable quote, the principle for which I have applied here is …
“Always get rid of the difficult bit in the title – it does less harm there than in the text” – Sir Humphrey Appleby
Now that we have gotten past that one, let me tell you what these guys were talking about the other day. Made little sense to me, and maybe even less to them. But the topic was about black holes and quantum gravity. Now quantum gravity means all things to all people, but these guys were talking about Loop Quantum Gravity.
So what is Loop Quantum Gravity and what were these guys talking about? This is the principle of quantum gravity in which space-time is seen as being quantized. In other words, space-time isn’t a smooth continuum, rather, it’s a series of looped quanta of space-time. This has implications for black holes, according to some researchers. The reference was to this article.
The idea is quite simple. As the black hole shrinks, at some point it reaches the dimension of the space-time quantum. From here, the black hole doesn’t have anywhere to go, and the singularity of Einsteinian general relativity is avoided by this quantum. This is because this quantum being the lowest possible unit of space-time, nothing can be smaller. At this stage, the black hole converts into a white hole, according to researchers.
The next question is how long this conversion takes. According to researchers, this conversion could take only a fraction of a second. But this should mean observers should be seeing black holes popping into white holes all the time. Why this doesn’t happen is because of time dilation. What is a fraction of a second to a black hole seems to the outside observer to be billions of years because of time dilation. In fact, at a point of infinite density, this fraction of a second would actually be infinite time to the external observer.