If you could build a time machine, what would it look like? Maybe, it should look like a telescope. American scientists are building a space telescope that they hope will look back over distance and time to show the universe close to its beginning. But this distant past will mainly be seen in infrared light which telescopes and cameras can see, but not the human eye. The American space agency, NASA, is now building the largest space telescope ever. The James Webb Space Telescope is named after NASA's second director. It will have a mirror seven times the size of the one on the Hubble Space Telescope. The mirror is six and a half meters wide, made of lightweight beryllium and covered in gold. But it will mainly study the universe in infrared light. We usually experience infrared light as heat. But, if you have ever used a TV remote control, you know there are many uses for it. The James Webb Space Telescope is a complex engineering project. It will be huge -- about the size of a passenger jet. And it will have to be super-cooled. Because the telescope studies infrared heat, its mirror must be kept very close to absolute zero. That is minus two hundred seventy-three degrees Celsius. NASA is building the Webb telescope at the Goddard Space Center, outside Washington. The agency hopes to launch it in twenty-fourteen.Jonathan Gardner is a project scientist for the telescope. We asked him how the device can look back in time. He says: "We can see back in time because light takes time to get from there to here. So, as we look further and further away, it takes longer and longer for the light to get from where it's emitted to here and we can actually see backwards in time." And if you look far enough, you start to approach the event that scientists believe gave birth to everything. As Jonathan Gardner puts it: "We're looking at the universe when it was much younger and we're looking back most of the way to the Big Bang."Jonathan Gardner says: "Any astronomer, at any university, in any country can write a proposal for what they want to do with the telescope." The James Webb Space Telescope should help scientists learn how the first galaxies formed and what they looked like. It may even show things scientists never predicted.

For VOA Special English, I'm Carolyn Presutti. You can watch a video about the James Webb Space Telescope and download an MP3 of this story at voaspecialenglish.com.