What if you could travel back in time to learn about the era when galaxies were first starting to form? That’s what the James Webb Space Telescope—a collaborative project between NASA and the European and Canadian space agencies— will be able to do when it’s finished. Because of the way light travels, when we look at stars from our vantage point, we see them as they used to be, not as they really are now. From earth, we see the sun as it was eight minutes ago and the next closest star system, Alpha Centauri, as it was over four years ago. Astronomers believe that peering through a telescope to see light from the first stars and galaxies would effectively mean looking back 13.6 billion years into the past. But there’s a catch. By the time this light reaches us, it has shifted into red wavelengths that are invisible to the human eye. That’s why the Webb telescope, which will travel further outside earth’s orbit than any telescope ever has before, is designed to see the universe at infrared wavelengths. The Webb is a complex, ambitious project requiring entirely new systems—including a sunshield longer than two tractor-trailers. So, understandably, the project has hit some delays. Back in the 1990s, scientists thought it could be finished for only $500 million by 2007. They are now envisioning a 2021 launch and $9.66 billion total budget. For the project’s supporters, it’s worth every minute of work and every penny spent—because it means the chance to learn more about the universe’s history, understand how galaxies form, witness the birth of stars and explore whether other planets could support life.
