Parallel Worlds Probably Exist. Here’s Why

Prof. Sean Carroll https://www.preposterousuniverse.com His book, a major source for this video is 'Something Deeply Hidden: Quantum Worlds and The Emergence of Spacetime' I learned quantum mechanics the traditional 'Copenhagen Interpretation' way. We can use the Schrödinger equation to solve for and evolve wave functions. Then we invoke wave-particle duality, in essence things we detect as particles can behave as waves when they aren't interacting with anything. But when there is a measurement, the wave function collapses leaving us with a definite particle detection. If we repeat the experiment many times, we find the statistics of these results mirror the amplitude of the wave function squared. Hence the Born rule came into being, saying the wave function should be interpreted statistically, that our universe at the most fundamental scale is probabilistic rather than deterministic. This did not sit well with scientists like Einstein and Schrödinger who believed there must be more going on, perhaps 'hidden variables'. In the 1950's Hugh Everett proposed the Many Worlds interpretation of quantum mechanics. It is so logical in hindsight but with a bias towards the classical world, experiments and measurements to guide their thinking, it's understandable why the founders of quantum theory didn't come up with it. Rather than proposing different dynamics for measurement, Everett suggests that measurement is something that happens naturally in the course of quantum particles interacting with each other. The conclusion is inescapable. There is nothing special about measurement, it is just the observer becoming entangled with a wave function in a superposition. Since one observer can experience only their own branch, it appears as if the other possibilities have disappeared but in reality there is no reason why they could not still exist and just fail to interact with the other branches. This is caused by environmental decoherence.

The Race to Mars in 2020

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Mars is our next door neighbor, yet we almost never visit. But in July of 2020 humans are launching four separate missions to Mars. The missions are all launching in July 2020 because it is the ideal time to get a spacecraft to Mars while using the least amount of rocket fuel. But not because the two planets are at their closest, instead it has to do with something called a Hohmann transfer orbit—the most efficient way to send a spacecraft to Mars. This orbit is elliptical, and uses the sun as one focal point. The spacecraft’s launch is at the closest point to the sun, or perihelion, and it crosses Mars’ path at its farthest point from the sun, or aphelion. It is very important that Mars is actually there when the spacecraft arrives, but for that to happen the spacecraft has to be launched at just the right time. The time it takes a spacecraft to travel from perihelion to its aphelion in Mars’ orbit is approximately 259 days. During that time Mars will move about 136 degrees, since Mars is farther from the sun than Earth and takes longer to move the same angular distance. So in order to sync up the 180 degrees the spacecraft will travel while Mars moves 136 degrees, the spacecraft needs to launch when Mars has a 44 degree head start. This happens for a few weeks once every 26 months, and the next time it will happen is mid-July of 2020. And so, this time around a lot of space agencies are geared up for launch.