## A Brief History of the Universe, Part II

So, a year and some change ago I did an absurdly wordy post that may have had slightly too many run-on sentances about the early history of the universe (If you didn't read it, here's A Brief History of the Universe, Part I). I then promised to follow it up with more history up until present day or so, and never did. Until now. And while you may think it took me a long time to follow up with a part II to that post, that time span is just peanuts to the universe. In fact, it's been around for about thirteen billion times longer than the wait between the first part of this series and this follow-up. So, cosmologically speaking, the delay was perfectly acceptable. Now, let's get on with it.

## Sonic (The Hedgehog) Speed

Sonic is a blue hedgehog from a series of SEGA video games (dating back to just after the Mario games came out) that collects rings and goes fast. In fact, going fast is the premise of most of the Sonic the Hedgehog games, with the primary goal of each level being getting from the beginning to the end as quickly as possible (and hopefully looking rad on the way). One of the level elements that appears many a time is a loop-the-loop, both to demonstrate how fast Sonic is moving, and to be a barrier which cannot be surmounted unless Sonic is moving at the necessary high velocities. So, this brings us to the question: how fast does Sonic need to go to complete a loop-the-loop without falling?

## LEGO Sun

On Fizzix Phriday, we sometimes endeavor to answer the questions other physics don't ask—nay, are too scared to ask. So today, I'm going to answer a question I am reasonably sure has never been asked. Is this because people were to scared of the answer, or because the question itself is simply nonsense? The solution is left as an exercise to the reader. The subject of today's Fizzix Phriday blog is: Could you build a star (similar to our sun) out of LEGO bricks? Let us take the mad journey to the answer to this bizarre question together.

## Shove in a Vacuum

Let's say you take two conducting plates, each one meter square or so, and put them in deep, deep space. Far enough away that nothing external should influence them, and they're sitting in the near-vacuum of interstellar space. Just to make things easier, we'll say this part of space lacks even the one hydrogen atom per cubic centimeter density of space, and is actually a perfect vacuum. Now, you make one place negatively charged, and the other positive. What do they do? Well, they attract due to electromagnetic forces. Obviously. So let's take away the charge. What do they do? Well, they attract due to electromagnetic forces. Wait, what?

## The Physics of The Flash, or Inertia is an Indomitable Scourge

This week, I just finished re-watching the first season of The Flash, and while it's a perfectly enjoyable show (Grant Gustin is great) that exists in the strange Hollywood land of nonsensical computer user interfaces and perfectly polished and machined electronic prototypes, the whole basis has a few serious flaws of the physical variety. So, in my quest to ruin all things that are good and fun, I'm going to examine the physics of the character The Flash himself, and how he would operate if the world the show was based in accurately reflected our own.

## Kepler Compendium

Today on Fizzix Phriday, it's time for some physics phistory (the p is silent). Let's take a jaunt back in time to the year 1571. Nicolaus Copernicus (born Mikolaj Kopernik) had published his revolutionary work, De revolutionibus orbium coelestium (in English: On the Revolutions of the Celestial Spheres) just 23 years ago, where he described, mathematically, a universe where the Earth was not the center, and all the planets revolved around the Sun, rather than the Earth. While this was a revolutionary idea, it was largely seen as incorrect or ignored, due in no small part to Copernicus's death around the time of its publication, and being therefore unable to defend his work from criticisms that arose from going against the established ideas in science and religion. Even worse, a note was prepended to his work before publication that basically said "everything in here about the Earth revolving around the sun and not the other way around is just a neat mathematical exercise..."

## The Tallest Tree

Often on Fizzix Phriday, it seems that I talk about things that are crazy far away in space, or so small you can't see them, or weird esoteric things, which, while super cool, aren't something you can go out and see yourself. So today, I'm going to talk about something that's probably near you, unless you life in a desert or grassland: trees. Now, I've been known to be upset and angry about how big trees can get, because the General Sherman tree (a Giant Sequoia) is just too big to be imaginable. But it's not the tallest tree out there. The tallest trees are the redwoods, which are also mind-bogglingly huge. I'd highly recommend seeing them at some point in your life. However, I'm not here to talk about how tall the California Redwoods are, I'm here to figure out how tall they are allowed to be. And that allowed means we're bringing in some physics.

## Echoes of the Big Bang

There are many things that we can observe about the universe which lead us to assert that it all started with a Big Bang. There is the velocity of galaxies further away from us being faster, or the fact that when we look back to a younger universe we see more primitive structures that would precede what our universe looks like now. But probably the best evidence of the Big Bang is called the Cosmic Microwave Background Radiation. Which sounds really cool, and totally is. So what exactly is it?

## Wormholes

Today we're going to discuss an interesting idea in general relativity (GR), but I'm going to try to do it without getting into any math. This will, unfortunately, limit us to a bird's eye (worm's eye?) view of it, however. In order to discuss the details of why some things are the way they are, you have to get into the nitty-gritty math of general relativity, so when I simply assert certain things to be true, you're going to have to trust me (or the physicists who said these things were true first, and proved it mathematically). So, let's talk about wormholes.

## Tidings of Tides

What exactly causes the tides? That question was something humanity wondered on and off for quite some time, though people did notice that it had something to do with the moon. In fact, Johannes Kepler was the first to suggest that an attractive pull from the moon caused Earth's tides (by observation and analysis of recorded data). However, it wasn't until about eighty years later that Newton pinned down what exactly was going on (with an actual physical theory of tides). Having described the mathematics of gravity and how it relates both to our attraction to the Earth and the movement of the planets, he tackled how the pull of the moon should create differing levels of water on the Earth. What he described was the Tidal Force, which is a force that results from gravitational attraction from a secondary body (the moon) on another body (the Earth) being unequal on all sides...