Only about half of Americans are confident in the validity of the big bang. That’s a rather surprising number given that the big bang is not only well supported by the evidence, it is now a foundational concept in modern astronomy. There are, of course, several reasons for this lack of acceptance, but one I hear often in interactions with the public is the claim that the big bang (and astrophysics or cosmology in general) is not scientific because it is not falsifiable. After all, there is only one universe, and you can’t run that experiment again.
Money for Nothing
Although there is a great deal of evidence for the big bang, it does raise an interesting question. If the universe began with the big bang, what caused the big bang? One of the more popular answers is that the universe quite literally came from nothing.
Primeval Atom
The origin of the universe is often portrayed in popular science as a vast sea of darkness. Centered in this darkness is a bright point of light, which suddenly expands, filling your view with light, fading into a dance of galaxies. Of course this raises all sorts of questions: What did the universe expand into? What triggered the initial explosion? Where did all that matter and energy come from? The problem is, this isn’t how cosmologists see the big bang at all.
Echoes
Yesterday a research project known as BICEP2 announced important results regarding cosmic inflation. The result centers on what is known as B-mode polarization in the cosmic microwave background. This is pretty big news, but it is also pretty complex, so let’s look at what’s really going on here and why this matters.
To the Point
Popular science loves to portray the big bang as an explosion from a point. It was even portrayed this way in the new Cosmos series. The only problem is that isn’t how the universe began, and portraying it this way raises all sorts of misconceptions.
North of the North Pole
What happened before the big bang? You might ask what is north of the North Pole.
First Light
What’s truly amazing about this image is that it’s an observation of the first light of the universe. Within the first few minutes after the big bang, nuclei, electrons and photons formed, but for quite a while these were so hot that the light produced was quickly scattered or absorbed. Finally after about 380,000 years the electrons and nuclei formed atoms, and the light of the universe could finally travel freely through the universe.
Echo of the Big Bang
Evidence of an expanding universe doesn’t prove it began with a big bang. Claiming the observable universe was once smaller than an apple is a pretty crazy idea, so you’d be right to ask for more evidence before taking the idea seriously. Fortunately we happen to have a great deal of evidence. One of the earlier indications is known as the cosmic microwave background.
Hubble’s Constant
Hubble’s constant shows a relationship between the distance of a galaxy and the speed at which it moves away from us. Its discovery was the first evidence that the universe is expanding.
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