The universe is big, but it’s peanuts compared to the eternally inflating multiverse. But just how many universes are there? What are they like? And most importantly, what can they tell us about … aliens?
This video is about Bell’s Theorem, one of the most fascinating results in 20th century physics. Even though Albert Einstein (together with collaborators in the EPR Paradox paper) wanted to show that quantum mechanics must be incomplete because it was nonlocal (he didn’t like “spooky action at a distance”), John Bell managed to prove that any local real hidden variable theory would have to satisfy certain simple statistical properties that quantum mechanical experiments (and the theory that describes them) violate.
One of the most startling possibilities is that our 3+1 dimensional universe may better described as resulting from a spacetime one dimension lower – like a hologram projected from a surface infinitely far away.
Imagine a universe in which the most elementary components are stripped of all properties besides some binary notion of existence or non-existence. Like, if the tiniest chunks of spacetime, or chunks of quantum fields, or elements in the abstract space of quantum-mechanical states can either be full or empty. These elements interact with their neighbors by a simple set of rules, leading to oscillations, elementary particles, atoms, and ultimately to all of the emergent laws of physics, physical structure, and ultimately the universe.
But… is the universe actually made of stuff? An increasing number of physicists view the universe – view reality as informational at its most fundamental level. But how big a memory bank would you even need to compute a universe? Seriously, let’s figure it out.
Accuracy, precision and reproducibility. These are the foundations of science that make our progress possible. How do these play into a scientist’s daily activities? And just how precise can we get with our measurements?
On this Space Time Journal Club we look at how gravitational waves can be used to search for extra dimensions of space!
There’s this idea that beauty is a powerful guide to truth in the mathematics of physical theory. String theory is certainly beautiful in the eyes of many physicists. Beautiful enough to pursue even if it’s wrong?
Some see string theory as the one great hope for a theory of everything – that it will unite quantum mechanics and gravity and so unify all of physics into one glorious theory.