Picture a globe. A map of the world. If you have one nearby, take a look. At the macro level, it's a picture of land and sea, outlines of continents as they meet the shores of the oceans. If you have a topographic globe, you can run your fingers over it and feel individual mountain ranges, the tactile signature of our home planet.
Now picture of a map of the universe. Imagine a massive black plane, all the macro pieces—galaxy clusters, nebulae, black holes—placed just so, the emptiness of space washing upon their ample shores. Zoom in, and you could see individual stars, planets, comets. Zoom in far enough, and you'd find our tiny globe.
A map of our universe today would be highly incomplete. We know a lot—a whole lot—but there is still a nearly endless expanse of black yet to be filled in. Our own globe used to be similarly lacking. In fact, early citizens of Earth named it so because they hadn't yet seen the seas. (Eventually, some thought to rename it Water, but alas, the name was stuck.) But thanks to millenia worth of gallant explorers, men who gave their lives to forge the oceans and map the world, we now know what our home looks like, and we're learning more every day.
Consider Powers of 10, a short video made in 1968 that's been preserved by the United States National Film Registry in the Library of Congress. The whole thing is worth a view, but for our purposes, stick with the first half, until about 4:40 in. The filmmakers have zoomed out from two picnickers in Chicago by powers of 10, and have reached 100 million light-years away, “the limit of our vision.”
Now, consider this Scale of the Universe, created in 2010. It too conceptualizes the scale of our world in a way that veers toward comprehensible. But what in 1968 was so much empty space, dotted only by galaxies and galaxy clusters, is today a colorful explosion of nebulae, black holes, exoplanets, quasars, and supersonic star jets. Nowhere in Powers of 10 do we see the Pillars of Creation, or the Tarantula Nebula, or even our own Kuiper Belt, referenced only as "a fringe of myriad comets too faint to see." (Though Gerard Kuiper first hypothesized a plethora of bodies at the edge of the solar system in 1950, it wasn't until 1992 that astronomers sighted the first Kuiper Belt Object.) And nowhere does the video hint at the vastness noted in the Scale of the Universe: That our universe is 14 billion years old, and so we have billions of cubic light-years to explore.
|The famous Hubble Deep Field|
Hubble is dying. We cannot go back and fix it, and even if we could, it's time to move on. And what's next is the James Webb. Astronomers at the Space Telescope Science Institute (STScI) in Baltimore began planning JWST in 1995, just five years after Hubble's launch, because they knew building it would be a challenge. And it has been one. JWST is criticized for poor management, poor planning, and poor budgeting. But what must be remembered is that nothing like JWST has ever been built before. As a prominent scientist (who requested not to be named) at STScI recently told me, this is not like building a car. We have made many millions of cars. We know how much they cost, how they fit together, how much time they take to build. But no one knew, when work began on JWST, just what problems to anticipate. And the initial schedule and budget were overly optimistic.
This is a problem, and no one is denying that. But the project's leadership has been entirely reworked. JWST is now its own division within NASA, rather than part of the astrophysics division. Everyone at the senior management level has been replaced. In fact, changes took place almost immediately following the release of an Oct. 29, 2010, Independent Comprehensive Review Panel (ICRP) report
|L2 - the "Gravity Well" where JWST will be parked|
But why are we building JWST? Let's consider the science. James Webb is designed to see in the infrared in order to capture light from the most distant objects in the universe. It can see through the dust and gas smearing the skies and watch stars and planets as they form. And it can test the atmospheres of distant bodies to search for signs of planets like our own, planets that future, more ambitious technologies could study, or maybe, one day, visit. We are poised to discover our own creation. We are set to unearth interstellar siblings. We are prepared to fulfill dreams that have existed since man first peered at the sky. And we stand to lose everything.
|Comparison of formation in Visible and Infrared|
And that's really the point. There is no if. There is no should. Exploring is simply what humans do. It's what we've always done, and it's what we will continue to do. If we've proven anything about ourselves, it's that we're not content with not knowing. Men and women through the ages have dedicated their lives to exploring our land, our seas, and our skies, and those are the men and women we still hold in admiration decades, centuries, and millenia after they've died. James Webb is simply the next step—and as long as we're still alive, it won't be the last.
For more information on JWST's status, see JWST Program Director Rick Howard's
For more about the quest to map our home planet, read the chapter on Earth in Dava Sobel