PBS Space Time

There’s an absolute limit to our access to the universe beyond our own galaxy. So we’re going to figure out the absolute limit of our future view of the universe, and of the universe’s ability to influence us.

Black holes and dark energy being the same thing has received some recent hype in the press. So let’s see if it might actually be true.

Physics is the business of figuring out the structure of the world. So are our brains. But sometimes physics comes to conclusions that are in direct conflict with concepts fundamental to our minds, such as the realness of space and time. How do we tell who’s correct? Are time and space objective realities or human-invented concepts?

Physics progresses by breaking our intuitions, but we’re now at a point where further progress may require us to do away with the most intuitive and seemingly fundamental concepts of all—space and time.

Two protons next to each other in an atomic nucleus are repelling each other electromagnetically with enough force to lift a medium-sized labradoodle off the ground. Release this energy and you have a nuclear explosion. So how does it all hold together? Nuclei are held together by a quirk of nature, without which we would have no complex atoms, no chemistry, and certainly no labradoodles.

Perhaps you’ve seen videos of how the planets of the solar system move through the universe in this cool helix. Not only are these misleading, but the Earth’s real motion - YOUR motion through the universe, is way more complicated and way more interesting.

Life as we know it is carbon-based, but does it have to be this way? There’s another element on the periodic table that shares some of the key properties of carbon but is far more abundant on most planets. I’m talking about silicon. So is there silicon-based life out there?

Quantum phenomena have no subjective qualities and have questionable physicality. They seem to be completely describable by only numbers, and their behavior precisely defined by equations. In a sense, the quantum world is made of math. So does that mean the universe is made of math too? If you believe the Mathematical Universe Hypothesis then yes. And so are you.

Einstein once asked whether “the moon exists only when I look at it?". It was rhetorical objection to the idea that measurement in quantum mechanics causes reality to become real. But there was a time when the moon didn’t exist, and then hours later suddenly did. At least, according to the latest simulations of its formation.