The Cracks In Cosmology

In terms of our understanding of the Universe, some things just don’t add up. Which means either our measurements are wrong, or our theories are…

- Marcus Chown

The standard model of our Universe may be showing some cracks. Several fundamental cosmological observations are contradicting each other. For instance, the Universe appears to be expanding 10 percent faster than it should be, according to observations of the leftover heat from the Big Bang.

It’s perfectly possible that the contradictions will disappear as our estimates of cosmic parameters improve.

But it’s also possible that the contradictions won’t go away and that our fundamental picture of the Universe is about to undergo a radical revision, perhaps to include invisible, ‘dark’ components as complex as atoms, stars and galaxies.

ADDITIONAL INGREDIENTS

Cosmology is the ultimate science. It deals with the birth, evolution and fate of the Universe. The standard model consists of several ingredients: the Big Bang, dark matter, dark energy and inflation.

First, take the Big Bang. Astronomers can see that the galaxies – the basic building blocks of the Universe of which the Milky Way is one – are flying away from each other in the aftermath of a titanic explosion. They also observe that the Universe is permeated by relic heat – the cosmic background radiation. Together, these two observations tell astronomers that the Universe was smaller and hotter in the past. In fact, according to the standard picture, the Universe was born in a blisteringly hot fireball 13.82 billion years ago and has been expanding ever since, with the galaxies congealing out of the cooling debris.