Was the Big Bang actually the beginning?

The big question is what's inside the box? Is it the mushroom of true knowledge that makes us grow? Or is it a coin of incremental data that buys us a little more time before the goomba of unknowability stops our exploration?

The big question is what’s inside the box? Is it the mushroom of true knowledge that makes us grow? Or is it a coin of incremental data that buys us a little more time before the Goombah of unknowability stops our exploration?

I usually avoid the kinds of sexy big questions that often make cosmology books by Paul Davies or Stephen Hawking or Roger Penrose popular. The main reason for that is because those big questions may not be answerable, because they are beyond the reach of our telescopes or experiments. One such question—what, if anything, came before the Big Bang?—is cause for a great deal of speculation, and a good amount of nonsense. If memory serves, Pope John Paul II was the first pontiff to explicitly accept Big Bang cosmology, but he also forbade Catholic cosmologists from even pondering the question of whether anything came before.

However, BBC Future provided me a great opportunity to examine the meta-question: “Will we ever know what happened before the Big Bang?” That’s a question better suited to me: it’s not speculation, but pondering how can we know? And the answer isn’t clear:

First of all, the language we use to describe what we know and don’t know can sometimes be muddy. For instance, the Universe may be defined as all that exists in a physical sense, but we can only observe part of that. Nobody sensible thinks the observable Universe is all there is, though. Galaxies in every direction seem similar to each other; there’s no evident special direction in space, meaning that the Universe doesn’t have an edge (or a centre). In other words, if we were to instantaneously relocate to a galaxy far, far away, we’d see a cosmos very similar to the one we observe from Earth, and it would have an effective radius of 46 billion light-years. We can’t see beyond that radius, wherever we’re located. [Read more…]

Thanks again to Simon Frantz, my editor at BBC Future, who asked me to write the piece and helped turn it into something coherent, instead of Grumpy Matthew grumbling into his coffee.

Pascal the cat knows about particle physics.

Pascal the cat knows about particle physics.

It’s fundamental and natural to ask this question about an object: “how big is it?” For many things—most everyday objects, people, planets, stars—size is easy to measure. However, other things are more challenging, including the size of a proton: one of the three particles that make up every ordinary bit of matter. The major challenge is its tiny size, which precludes using light of any kind to measure it. To make matters worse, the size of a proton may depend strongly on what method you use to measure it, as I explained for Double X Science.

The simplest way to measure the size of a proton involves shooting electrons at it, and measuring the paths the electrons take as they feel the influence of the various forces. Because of those forces, in fact, the proton can’t be said to have a single size! Instead, physicists use three different size measurements, which are all pretty close to each other, but not exactly the same. The one most important to us for this post is the charge radius. Electron bombardment measurements found that to be about 0.88 femtometers.

However, electron bombardment only gets us so far; if we want better accuracy, we need another method. [Read more…]

How big is a proton?