On December 11, the James Webb Space Telescope (JWST) was finally placed atop the Ariane 5 rocket that will lift it from French Guiana and into orbit “no earlier than Dec 24,” according to NASA’s latest update (at the time of this writing). The rocket is now fueled for flight and all that remains (along with numerous final checklists) is for the telescope to be wrapped in its specially-designed fairing before launch. For astronomers, this would make for a Christmas gift that has long occupied the wish list, representing more than 30 years of development and $10 billion in costs. 1 I’ve followed along as a planetary scientist studying exoplanet atmospheres, eagerly anticipating what new things JWST can tell us about the chemistry, clouds, and weather on planets orbiting other stars.
The Webb telescope represents the successor to the extraordinary Hubble Space Telescope (HST), launched into orbit in 1990. Sporting a 2.4-meter (7 ft. 10 in.) diameter mirror and orbiting above the obscuring clouds and air of the Earth’s atmosphere, Hubble has had an enormous impact on astronomy, including providing unprecedented views of distant galaxies and new clues about the early history of the cosmos.
“…JWST will be able to see some of the first stars and galaxies that formed following the birth of the universe.”
For comparison, the 18 hexagon-shaped and gold-layered mirror segments of JWST add up to a diameter of 6.5 meters (21 ft. 4 in.). 2 Moreover, a key design feature of JWST is its ability to see infrared wavelengths well beyond that of visible light (and beyond what Hubble can see). 3 Astronomers are expecting these increased capabilities to be nothing short of revolutionary— not only for our understanding of planetary systems around other stars, but especially to peer even deeper into our universe’s past.
Indeed, because light travels at a finite velocity, we are looking into the past every time we observe something—that sunlight you feel on your skin, for example, left our star about eight minutes earlier. 4 The Webb—like all telescopes—thus serves as a sort of time machine: the further it can see into deep space, the further back it can look into deep time. And its particular design makes JWST one of the most powerful time machines ever constructed, sensitive to the light from distant galaxies that has been stretched to redder wavelengths from the ongoing expansion of spacetime. This means that JWST will be able to see some of the first stars and galaxies that formed following the birth of the universe.
As excitement (and anxiety) builds around the launch of JWST and the anticipated advent of a new era of cosmological exploration, we’re reminded again of the revelatory nature of creation: the way in which it serves as its own witness to its history, laid “before our eyes like a beautiful book.” 5 In this way, JWST will let us see clearer and further into the ancient and beautiful story of creation.
“…we can never see something God has not made.”
In these encounters, we also begin to realize not only the sheer scale, majesty, and beauty of the creation, but the power of the One who spoke it into existence. We’re reminded of the fact that as we build ever-more powerful tools for exploring creation—revealing what that no human eyes have yet seen—that we can never see something God has not made.
In the meantime, we can hope for a successful launch and look forward to whatever amazing new stories creation will tell us about its own beginnings.
So, this year, all I want for Christmas is a time machine.
Given its large size and cooling requirements, JWST has to be origami-like folded to fit within the rocket fairing. Fully deployed, the JWST sunshield would cover an area roughly the size of a tennis court. ↩
JWST is sensitive to wavelengths up to 28 microns; HST is sensitive to wavelengths of up to about 2 microns; The Spitzer Space Telescope, launched in 2003, can observe a broader range of infrared wavelengths than JWST, but with less sensitivity. ↩
Belgic Confession, Article 2; Ps 19:1-2, 97:6, 104; Rom 1:19-20, Heb 11:3, Acts 14:15-17, Job 38ff ↩