Joe Bennett: The Big Bang makes the mind boggle

Arianespace's Ariane 5 rocket with NASA's James Webb Space Telescope onboard, lifts off on December 25. Photo / AP

The Big Bang has boggled me for years. And now a telescope has boggled me afresh.

The notion of the Big Bang first arose in the 1920s. It boggled everybody at the time and it wasn't until the 1960s that the majority of scientists came round to it. You can understand why.

It posits that 13.8 billion years ago the universe as we know it didn't exist. Instead, everything that would become the universe was compressed into a single infinitely dense thing called the Singularity. The Singularity didn't exist in a place because there were no places and it didn't exist in time because there was no time. Then came the Big Bang - were capital letters ever better earned? - and time and place began.

It sounds more like religion than science, and to the boggled layman it raises more questions than answers, but the physics holds together, apparently. And now, in order to learn more about the Big Bang, NASA has built the James Webb Telescope at a cost of about $10 billion - $10 billion is a lot of money, but the Americans spend more than that each week on their military - which is boggling in a different way.

Technicians lift the mirror of the James Webb Space Telescope using a crane at the Goddard Space Flight Cente in 2017. Photo / AP

The telescope left earth on Christmas Day bound for a point a million miles into space. It will take two weeks to get there. A million miles in two weeks is 500,000 miles a week, which is 70,000 miles a day, which is 3000 miles an hour, which is 50 miles a minute which is more or less a mile a second. So in the 30 seconds it may have taken you to read this paragraph the telescope has travelled 30 miles.

At take-off the telescope was folded tight for aerodynamic reasons but now that it's in the vacuum of space it's been unfurling in the manner of a butterfly emerging from a chrysalis. But whereas a butterfly unfurls two wings, the telescope has only one, and it's the size of a tennis court.

Its purpose is to act as a parasol and it consists of five separate layers of a substance called kapton. The outermost of those five layers is 0.05mm thick. The other four are each 0.025mm thick. So the aggregate thickness of this five-layer parasol is less than a quarter of a millimetre. Yet on the sunny side of the parasol it will be hot enough to fry a steak, while on the shady side, where the telescope lives and all the complex electronics, it will minus 200 degrees Celsius. That's within cooee of absolute zero. More boggling.

The James Webb Space Telescope is separated in space on Saturday, December 25. Photo / NASA

The point in space that the telescope is bound for is Lagrange Point 2. This is one of only five points in the solar system where the gravitational attraction of the sun and the gravitational attraction of the earth cancel each other out.

So once the telescope is parked there it will remain constantly in the same position relative to both objects. What I cannot tell you, or begin to guess, is how the boffins in charge calculate that position in four dimensional space, or how they know how to park the telescope once they get there. These boffins are proper boffins.

At the heart of the telescope is a mirror six and half metres across. It is made up of 18 hexagons of gold-plated beryllium and it is tuned to catch infrared light. And if I wasn't out of my depth already, here's where I drown.

The essential notion, as far as I understand it, is that light takes time to travel. For example, light from the sun takes eight minutes to reach us. So when we see the sun we are actually seeing it as it was eight minutes ago. It might since have blown up or gone out but we wouldn't yet know.

The James Webb telescope is looking for light that's a bit older than eight minutes. It's looking for light that was emitted not long after the Big Bang, photons that have been travelling through the vacuum of space at the speed of, well, light, for 13.79 billion years before happening to bump into a man-made mirror six and a half metres across. That ancient light, if the James Webb Telescope manages to catch any, will be like a postcard from close to the birth of the universe. It's time travel.

And if that doesn't boggle you, well, you're unboggleable.