The James Webb isn’t just a $10 billion telescope: it’s a key. The most “largest and most complex key ever built”, yes; but a key after all. A key to regions of the Universe so deep, so far away, so old that it is hard for us to even imagine them. And it is that, while we look at the amazing images of the Webb, it is inevitable to ask ourselves: What do we really see when we look at deep space?
The most important photo of the Hubble telescope. Let’s back up a bit to get perspective. Hubble was launched in 1990 and took five years to take on what is still its most important photo today: the one we know as the ‘Hubble Ultra Deep Field’. It may not be the most popular (those are usually colorful nebulae or flashy stars), but it changed the way space astronomers used to work. Instead of focusing on a known object, Hubble set its detectors on… nothing.
Literally, too. The team led by Robert Williams searched for a point in the Universe that we knew nothing about, of which there were no previous observations; It was apparently empty. It was a colossal effort to see how deep Hubble’s gaze could see and, above all, how far back it could go in order to study the evolution of galaxies.
What came out of nowhere. On December 18, 1995, Hubble stared into space and over the next ten days the telescope took 342 pictures. And out of “nowhere” the telescope pulled dozens of galaxies – a fascinating picture that has confronted scientists with the origins of the Universe for decades. Because what Hubble brought to light was an unprecedented and razor-sharp perspective of the past.
It’s not a telescope, it’s a time machine. And is that when we talk about “deep space” we are talking about the history of the universe. All the waves (visible or not) that reach the Earth are echoes of things that happened billions of years ago. Specifically, Hubble has managed to go back 13.3 billion years in the past and capture light from stars that were formed 400 million years after the Big Bang. That is the number that the Webb and its infrared technology want to beat.
We are talking about the fact that, if all goes according to plan, the James Webb will be able to see stars formed 250 million years after the Big Bang. From our point of view it may not seem like much, but nothing like that. Those 150 million years are the difference between seeing the dawn of the first stars that emerged in the Universe or seeing how they give their last gasps. In other words, we are going to get very close to the limit that technology allows us to go back into the past. And all in the same way as Hubble: looking at nothing.
How will you get it? The key to reaching even further into the past is that while Hubble captures visible, ultraviolet, and some infrared light, James Webb contains the most sophisticated instrument ever sent into space to work in the thermal infrared range. Infrared light is, without going any further, the “oldest light” in the Universe. Or, put another way, in that infrared spectrum is the light of the objects that have moved the furthest from us due to the expansion of the Universe.
What awaits us? In general, for months, everything that has to do with the Webb generates a very important expectation. Almost too much. Until now it was relatively normal: the publication of the first color images of the telescope meant the culmination of the roadmap that had begun with takeoff. Now, once this initial phase is over, things get interesting.
It will not be immediately (remember that Hubble took five years to give us its most important photo), but little by little Webb will “give us light” to understand the origin of the Universe and will open the doors to new theories now that physics Modern society is in the midst of an existential crisis.
George is Digismak’s reported cum editor with 13 years of experience in Journalism