3 ms·

Name me one thing which has no beginning.

ceejayoz 8y ago
We see all sorts of weirdness with time, like delayed choice experiments: https://www.scientificamerican.com/article/quantum-eraser-delayed-choice-experiments/ https://www.scientificamerican.com/article/quantum-eraser-de... The entire concept of time starts to break down in spots, like within a black hole: https://phys.org/news/2015-09-law-implies-thermodynamic-black-holes.html https://phys.org/news/2015-09-law-implies-thermodynamic-blac... It also breaks down when you start talking about pre-Big Bang cosmology. It's not clear there is such a thing as a "beginning" outside of the universe.
- linsistine 8y ago
  What does this even mean?
  - ceejayoz 8y ago
    "Time is a weird concept even in our universe at times. It breaks down entirely outside of the known universe."
    - linsistine 8y ago
      Yes...but what does this mean?
      - ceejayoz 8y ago
        That the idea that "things must have a beginning" may not be the case when talking about physics outside the known universe. Sure, that's hard to wrap your head around, but so's quantum entanglement and the double slit experiment. Doesn't change the fact that the universe works in very, very weird ways sometimes. Here's Stephen Hawking on the weirdness of all of this: http://www.hawking.org.uk/the-beginning-of-time.html http://www.hawking.org.uk/the-beginning-of-time.html > Quantum theory introduces a new idea, that of imaginary time. Imaginary time may sound like science fiction, and it has been brought into Doctor Who. But nevertheless, it is a genuine scientific concept. One can picture it in the following way. One can think of ordinary, real, time as a horizontal line. On the left, one has the past, and on the right, the future. But there's another kind of time in the vertical direction. This is called imaginary time, because it is not the kind of time we normally experience. But in a sense, it is just as real, as what we call real time.

We see all sorts of weirdness with time, like delayed choice experiments: https://www.scientificamerican.com/article/quantum-eraser-delayed-choice-experiments/ https://www.scientificamerican.com/article/quantum-eraser-de... The entire concept of time starts to break down in spots, like within a black hole: https://phys.org/news/2015-09-law-implies-thermodynamic-black-holes.html https://phys.org/news/2015-09-law-implies-thermodynamic-blac... It also breaks down when you start talking about pre-Big Bang cosmology. It's not clear there is such a thing as a "beginning" outside of the universe.

linsistine 8y ago
What does this even mean?
- ceejayoz 8y ago
  "Time is a weird concept even in our universe at times. It breaks down entirely outside of the known universe."
  - linsistine 8y ago
    Yes...but what does this mean?
    - ceejayoz 8y ago
      That the idea that "things must have a beginning" may not be the case when talking about physics outside the known universe. Sure, that's hard to wrap your head around, but so's quantum entanglement and the double slit experiment. Doesn't change the fact that the universe works in very, very weird ways sometimes. Here's Stephen Hawking on the weirdness of all of this: http://www.hawking.org.uk/the-beginning-of-time.html http://www.hawking.org.uk/the-beginning-of-time.html > Quantum theory introduces a new idea, that of imaginary time. Imaginary time may sound like science fiction, and it has been brought into Doctor Who. But nevertheless, it is a genuine scientific concept. One can picture it in the following way. One can think of ordinary, real, time as a horizontal line. On the left, one has the past, and on the right, the future. But there's another kind of time in the vertical direction. This is called imaginary time, because it is not the kind of time we normally experience. But in a sense, it is just as real, as what we call real time.