The universe is 13.7 billion years old, constantly expanding, and only 4% of it consists of atoms. So says NASA after accumulating one year’s worth of data from the Wilkinson Microwave Anisotropy Probe.

From that, astrophysicists could calculate the age of the universe with unprecedented precision. Earlier estimates had ranged from eight billion to 20 billion years, but in recent years they have narrowed to somewhere between 12 billion and 15 billion years. The new estimate of 13.7 billion years has a margin of error of only 1 per cent, compared to about 30 per cent for the best previous estimates.

The data strongly confirm the prevailing Big Bang theory and allow researchers to test various versions of the ‘inflation theory’, which holds that, even before the universe was one second old, it had expanded dramatically.

This has also enabled scientists to produce the most exact calculation ever of what the cosmos is made of today. It turns out that only 4 per cent of the universe is made up of atoms with known forces such as electromagnetism and gravity, the ordinary stuff that makes people, potatoes, porcelain and everything else that is known.

About 23 per cent of the universe is made from mysterious unseen material dubbed ‘dark matter’ because scientists know so little about it. The rest – 73 per cent – is made up of yet another poorly understood force called ‘dark energy’.