“It took less than an hour to make the atoms, a few hundred million years to make the stars and planets, but five billion years to make man!” -George Gamow
Earlier today, a video (from last month) was released where one of the members of the US House of Representative — a member who sits on the House Committee for Science, Space and Technology — proudly proclaimed the following:
“All that stuff I was taught about evolution, embryology, the big bang theory; all of that is lies straight from the pit of hell.” -Paul Broun
Well, if the Big Bang is a lie from the pit of hell, then the Universe itself is lying to us, and I’m a liar repeating those lies that it tells us about itself. Here’s why.
This is the night sky, our window into the deepest recesses of space itself. The points of light visible in this skyscape are stars and planets, but buried among them are faint, fuzzy structures whose structures were only revealed with the invention of the telescope.
Originally marked as this-is-not-a-comet, these nebulous structures were found to consist of a variety of star clusters, stellar corpses and remnants, and new star-forming regions. But there was another type of nebula among them, the spiral nebulae, with a distinctive structure and a very peculiar property.
These spiral nebulae may come in a variety of orientations and sizes, but they’re practically all moving very fast, and the ones that are moving fast are all moving very fast away from us. What am I talking about?
Every atom in the Universe absorbs and emits light at very specific frequencies: frequencies determined by the quantum mechanical laws of physics. Every atom of hydrogen in the Universe absorbs light at identical frequencies to one another, ensuring that when we see a pattern of spectral absorption lines, we can identify what atoms are present, and in what amounts.
But if those atoms are moving either towards us or away from us, or if the space between those atoms and ourselves is either contracting or expanding, those spectral lines will be shifted. Well, when we look out at those spirals in the sky, this is what we find.
The smaller and fainter one of these spiral nebulae appears, the faster it appears to be moving away from us! By making a variety of measurements, including those of individual stars present in these nebulae, we can not only determine their distances from us (placing them far outside of our own galaxy), but measure the relationship between their distance from us and their apparent motion away from us.
Although this was first done by Hubble back in the 1920s, modern measurements are far superior and extend billions of light years away from us.
So these spirals were not objects within our own galaxy at all, but rather “island Universes” unto themselves, or galaxies in their own rights. But if these spiral nebulae are galaxies, and these galaxies move away from us in proportion to their distance from us, then what does that tell us about our Universe?
It means that either the Universe had some type of explosion in the past, hurtling everything away from us, who just so happens to lie at the center of this cosmic explosion, or that the Universe itself is expanding.
Only the latter explanation is consistent with General Relativity, our experimentally verified best theory of gravity. (There are other alternative explanations for this one observation, such as tired light, Hoyle’s steady state theory, and Alfven’s plasma cosmology. Hang on and bear with me!) The idea that the Universe is expanding carries with it a number of staggering implications, first realized by George Gamow.
If the Universe is expanding with great spaces between the galaxies today, then in the distant past, things must have been closer together. Furthermore, because of how gravity works, it means if we look increasingly farther back in time, all the particles of light (photons) in the Universe should have had a shorter wavelength, which means they had a higher energy!
Well, if this picture of an expanding Universe that was denser in the past is true, then it must have been hotter in the past as well. At some point, in fact, it must have been so hot that the atoms themselves would have been blasted apart by the photons present. And at some point even earlier, before that, it would’ve been so hot that even atomic nuclei couldn’t have formed; the photons would have blasted everything apart into individual protons and neutrons!
So the Big Bang model — simply by stating the Universe obeys General Relativity and is expanding today — makes some very big predictions. Among them is the prediction that, based on the fact that it was very hot and dense in the past and has been expanding and cooling ever since, we should form the lightest elements in the Universe out of protons and neutrons when the Universe is only a few minutes old!
This includes deuterium, helium-3, helium-4, and lithium, in very specific proportions to one another, dependent only on the number of photons in the Universe.
This also means that, when the Universe finally cools enough to form neutral atoms, those photons left over from the Big Bang should still be there, omnidirectionally, in our Universe today. The only difference between then and now is that, because the Universe has been expanding and cooling, this radiation is not only no longer visible to our eyes, it isn’t even infrared anymore! It ought to have redshifted all the way into the microwave portion of the spectrum.
And what’s more than that, it ought to have a very particular spectral distribution, known as a blackbody spectrum. Well, this microwave-wavelength radiation was discovered back in the 1960s everywhere in the sky, and its wavelength was determined to an incredible precision to be blackbody in the 1990s by the COBE satellite.
And finally, it was only last year that the first absolutely pristine galaxies — made out of atoms that had never formed stars before — were found in the Universe. But this gas was indeed verified to have the right elemental abundances of hydrogen and helium, with no trace of any heavy elements that shouldn’t be there!
And with those three cornerstones in place — the expanding Universe from the recession of distant galaxies, the abundances of the light elements, and the cosmic background of microwave radiation — the Big Bang has been verified in a way that no alternative has. None of the other options proposed can give us these three things together: not the tired light model, not the steady-state model, not a plasma cosmology, nothing.
The Big Bang is the only model ever proposed that is consistent with these three pieces of data.
Of course, the Big Bang also gives us structure formation that matches galaxies and clusters in the Universe. Furthermore, it can actually be consistent with dark matter, dark energy and inflation, and every astronomical observation ever made and physical experiment ever performed. It’s not only the best theory out there for the physical Universe, it’s objectively, scientifically, an incredibly successful theory.
If it’s a lie, then the Universe itself is lying to us, and we’d be absolute fools not to repeat that lie. But Broun was right about one thing: considering the entire Universe was once so hot it had no neutral atoms, no atomic nuclei, and was entirely a furnace of ionized plasma, it did all come from the pit of hell!
At least, that’s one way of looking at it. Some of us, though, have a slightly more poetic name for the miraculous story of the origin of everything in our entire observable Universe.
We call it the Big Bang.