How big is the universe? One estimate is 92 billion light years in diameter.
So even travelling close to the speed of light—186,000 miles a second—it would still take you almost 50 billion years to reach its edge.
However since it is expanding at a speed faster than light, you could never reach its outer limits anyway.
Next imagine something as small as an atom. These tiny entities are less than a nanometre, or one billionth of a metre, in diameter.
Yet according to current scientific thought, our universe was originally the size of an atom, yet expanded after a huge explosion—the “Big Bang”.
This happened just under 14 billion years ago. Yet the crucial events—those that formed the building blocks of our universe—all happened within the first three minutes.
Sounds far-fetched? Well, last month scientists announced important new evidence for the rapid expansion that followed the Big Bang.
The new findings also confirm an idea first proposed by Albert Einstein almost a hundred years ago—that gravity makes waves in spacetime that can be measured.
Isaac Newton first recognised the force of gravity. But he provided no explanation of the material basis for this mysterious force.
It was left to Einstein to do this as part of his famous theory of relativity.
According to this, gravity is merely a reflection of the fact that any object of mass will deform the space around it, pulling smaller objects towards it.
And if a massive object is moving, its effects are not confined only to its immediate vicinity, but will also spread out as waves.
So if our universe really did begin with a Big Bang, this should have generated gravitational waves.
And it is evidence of these waves that scientists now claim to have detected.
The discovery further confirms the power of science in revealing the material basis of the natural world.
It shows that far from requiring supernatural explanations for how our world came into being, those based on matter alone are sufficient.
By studying these gravitational waves in detail scientists hope to gain new insights into what might have come before the Big Bang.
They also hope to better understand how the subatomic world—which is composed of the tiny particles that make up atoms—and the whole universe are connected.
This might seem abstract. Yet our understanding of the subatomic world already forms the basis for computer hard-drives, CD players, and medical scanners.
Who knows what important new technologies may await as a consequence of new insights.
Of course previous insights also led to the horrors of Nagasaki and Hiroshima, so how do we stop such horrors in the future?
Here I am always inspired by the example of Einstein himself.
Throughout his life Einstein backed the struggle for a better world. He opposed the First World War, sympathised with the Russian Revolution and backed the black Civil Rights Movements in the US.
His essay ‘Why Socialism?’ is a brilliant account of why we need a society run according to the needs of the majority, not the profits of the few.
It shows that scientific progress means little while millions continue to die from starvation and war.