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.
My second piece for BBC Future is up! I ask—and partly answer—the question, “Will we ever detect gravitational waves directly?” (And don’t worry if you don’t know what a gravitational wave is: I answer that one too!)
A major part of the problem is that gravity is weak: even the strongest gravitational wave will only nudge an atom by a tiny amount. Additionally, the wavelength of gravitational radiation – the distance over which a wave repeats itself – is often similar to the size of the objects emitting it. So, while radio waves from pulsars may have wavelengths measured in centimetres, the gravitational radiation emitted could have wavelengths measured in kilometres. Which means that you most likely need detectors of a similar size to detect them. [Read more…]
For those of you in the UK, you might need to use this link instead, due to weird issues with the BBC website.
Forgive me if I get excited for a moment, but…today marks my first contribution to BBC Future! The feature I contributed is part of the “Will we ever?” series, in which science writers ask some big questions about what research may or may not be able to answer in the future. My article pondered whether we’ll ever be able to identify dark matter: the mysterious substance that comprises more than 80% of the mass of the Universe. (The link for my UK readers is here.)
Right now, a far easier question to answer is what dark matter isn’t. First of all, the name is misleading: dark matter isn’t “dark” in any usual sense of the word. “Invisible matter” is a better term: light shining on dark matter from any source passes right through without being absorbed or scattered, regardless of the type of light. This means dark matter can’t be made of atoms or of their constituent parts; that is, electrons, protons and neutrons.
In fact, dark matter doesn’t correspond to anything in the Standard Model, the best explanation we have for how the universe works. [Read more…]