The “Horrendous Space Kablooie” Theory, Art and Science Meet

"Baby picture" of the universe, isn't it cute?

I needed a break from war and politics, so for fun I have been studying the “Horrendous Space Kablooie” theory. The what? This is a science post, bear with me. I discovered that the name “Horrendous Space Kablooie” (often shortened to HSK) has actually gained some currency in the scientific world, at least informally. What is the HSK theory? Readers of Calvin and Hobbes of course already know, the “Horrendous Space Kablooie” is Calvin’s improved name for the Big Bang, the theory about the early moments of the universe.

Oddly enough the Big Bang theory was given its name by Fred Hoyle, and he meant it as a pejorative. The good Dr Hoyle was a proponent of the Steady State theory, he thought that the Big Bang theory meant the universe had a beginning, an idea the was uncomfortable with for philosophical reasons. And while the name caught on, it really wasn’t very accurate. “Horrendous Space Kablooie” actually captures its essence in a more nuanced fashion, for the Big Bang wasn’t an explosion in any normal sense of the word.

So what’s the Big Theory? Well, it’s easiest to understand if we approach how scientists arrived there. First, we have the universe, billions of galaxies as far as we can see in every direction. Does that mean space is infinite? No, that’s a common misconception, the universe is very large but it’s not infinitely large. There is some maximum distance apart that two objects can be in the same universe, some 93 billion light years is the best current guess. So that means the universe has an edge? No. If one travelled in a straight line long enough one would eventually come back to the vicinity of where one started. The best way to visualize this is to think of the universe as the surface of a sphere, if one heads in a straight line one eventually returns to where one started.

OK, where does the Big Bang come in? Well, astronomers studying the universe discovered a very curious thing. The further away other galaxies are from Earth, the faster they were moving away from Earth. And this acceleration was remarkably constant over distance and was the same in every direction we looked. This was very puzzling, and scientists could only come up with two possible explanations….

The first was that the universe was indeed rushing away from Earth, and that somehow Earth was at the centre of some huge event that had hurtled the galaxies away from us. This was unsatisfactory for two reasons. For one it meant that Earth was somehow uniquely positioned in the centre of  the universe, which didn’t really jibe with everything else we  know about our commonplace little sun. And secondly, such an event should have left telltale signs, signs that couldn’t be found.

So that left the second explanation … the universe is expanding. Expanding as in getting larger, so that the space between the galaxies and stars we see is constantly getting greater. To visualize this take our previously discussed universe on a sphere and stick dots on it to represent galaxies.  Then expand the sphere like blowing up a balloon, and the dots grow further apart. This is what our universe appears to be doing. And since scientists can calculate how fast the universe is expanding, they can extrapolate backward to see how it all started. And it turns out that the universe gets smaller and smaller until nearly 14 billion years ago the entire universe was a dimensionless point.

Not only did the Big Bang theory explain why the galaxies were moving away from us, various calculations about what the nature of the universe was like in its earliest seconds made predictions about what sort of evidence should remain. When the universe was only seconds old and the size of a grapefruit, it was so very very hot that we should still see the afterglow. And lo and behold, in 1964, the afterglow of the HSK was discovered, the cosmic microwave background radiation. This pretty much clinched it for most scientists, and further observations have  shown that no matter how much it doesn’t  “make sense,” the universe does appear to have been expanding for nearly 14 billion years from a universe smaller than the head of a pin. There was nothing outside this tiny point, there was no before this point. It hurts the head to think about, I know.

Science has also worked out in remarkable detail how the pure energy the universe started out as organized itself as it expanded and cooled. A time-line can be viewed here. Yes, it’s all Greek to me too. Basically normal matter didn’t appear until the universe was 3-20 minutes old, and it wasn’t until the universe was hundreds of thousands of years old that the first  atoms of hydrogen and helium form. When the universe was about 100 million years old (or older) the first stars began to shine.

The final point, scientists have a pretty good understanding down to when the universe was about 10⁻⁴³ seconds old, but before that it’s a mystery. Yes, 10⁻⁴³ seconds is a very small amount of time, in fact it’s the theoretical smallest unit of time that can be measured. The HSK theory doesn’t tell us what happened before then, nor does it tell us how the universe originated. The Big Bang theory is simply the best explanation of what we currently observe in the heavens. That’s all science is, finding the best testable explanation  for what we observe.

Cosmologists do have some speculation about how our universe came into existence, but that will have to wait for another blog. And indeed it will have to wait until I understand enough about it to even attempt to explain it.

(The above image of the CMB radiation is public domain as it was produced by a US government agency. Credit: NASA/WMAP Science Team. It’s the oldest light in the universe, having travelled for over 13 billion years. Coming soon, scientists carefully weigh tiny pebbles in an attempt  to prove God exists.)