DARK MATTER A NEW DAWN

A SCIENTIST SEARCHING FOR THE MISSING PART IN OUR THEORY OF THE UNIVERSE REVEALS HOW WE'LL FIND IT DO CRACKS IN THE STANDARD MODEL HINT AT THE ARRIVAL OF A NEW PHYSICS?

- ALEXANDRA AMON

Tiny, fuzzy blobs. I’ve spent a lot of time in the last few years looking at images of tiny, fuzzy blobs. They’re only ever a few pixels wide, like smudges on a photo, but they could be the key that unlocks the mystery of dark matter.

The blobs are galaxies: swirling pools of stars and planets suspended in space, millions of light-years away from Earth. The images were collected by an advanced camera with a 1m (3.3ft) lens mounted on the giant Victor M Blanco Telescope, 2,200m (7,200ft) up in the mountains of the Coquimbo Region of Chile. Astronomers have spent years using it to scan the sky, gathering images of the cosmos. I, and my colleagues in the Dark Energy Survey, have pored over these images of millions of tiny fuzzy blobs in the hope that they reveal a vital missing piece in our understanding of the Universe. We’re on the edge of our seats, because this piece fills the gaping hole in our understanding of the cosmos. It could even turn that understanding completely upside down.

AN INVISIBLE TRUTH

You might think that cosmologists have the Universe sussed. And it’s true that we have learnt a lot about it and how it works.

But there’s an elephant in the room: our theory of the Universe hinges on the existence of dark matter, and we have no idea what dark matter is. In fact, less than one-fifth of the matter in the Universe is made up of particles whose physics we understand.

Do you feel confident admitting that you only understand 20 per cent of something?

Yes, we can be proud that we’ve honed a standard model of cosmology: a physical and mathematical description of the Universe. It’s a major achievement. But, thanks to this dark matter elephant, we can’t be absolutely sure that it makes any sense at all.