NASA's Great Observatories, four space-based missions designed to conduct astronomical studies over many wavelengths
As an astronomer, I have many tools at my disposal to study the universe and tackle tough questions. There are hundreds of ground and space-based telescopes that we point to the cosmos, powerful computers that analyze the images, and a wealth of knowledge on the internet and in libraries that both describe our current understanding and provide the mathematical framework to solve problems.
While the current suite of tools will continue to enable new research on a wide range of astronomical questions, history teaches us that major discoveries and breakthroughs come about when we apply new technologies to create unprecedented resources. For these reasons, I can hardly wait to see the first images from the James Webb Space Telescope.
Almost 100 years ago, astronomers built the first large, modern telescopes on the ground. Telescopes like the Hale and Hooker telescopes at Mt. Wilson Observatory, with their 60” and 100” mirrors to capture faint light, provided a new level of clarity in characterizing nearby stars in our galaxy, and led to the breakthrough discovery that our Sun is not located near the center of the Milky Way galaxy. These technologically advanced telescopes also enabled Edwin Hubble to prove that our galaxy itself was not alone in the universe, and that others like it were also wandering in space.
As astronomers produced larger and stronger telescopes, our ability to push beyond the Milky Way increased greatly, and we began to understand the vast nature of our universe and the diversity of galaxies within it.
NASA enabled a new leap forward in our understanding of the universe by developing the first big telescopes in space, such as Hubble and Spitzer. This Great Observatories program represented a bold new vision to expand our astronomical discoveries.
Hubble, launched over 20 years ago, has revolutionized almost every field of astronomy and planetary science, reshaped our knowledge of the universe and our role within it, and brought enthusiasm about space science to the general public, students, and educators. I personally owe a big thanks to Hubble. When I started my postdoctoral researchship in Santa Cruz, CA, in 2004, I was awarded a “Hubble Fellowship.” This research grant allowed me extreme flexibility and resources to pursue the research that I wanted, and was a great springboard for launching me to my career path.
Nowadays, I use Hubble both for my own research and to educate the public about the amazing discoveries that it has brought forth. Just a few weeks ago, I was showing pictures from Hubble to 500 kids in Long Beach, CA. It is one of the reasons that I love astronomy so much.
In the next few years, all of the Great Observatories may reach their limits. Astronomy is a science that is limited by the quality of the observations, and those observations are limited by how much light our telescope’s mirrors can collect. Hubble and Spitzer have demonstrated that many of the most important questions that we face in astronomy today can be answered by designing a powerful new telescope that combines Hubble’s razor-sharp vision with Spitzer’s infrared sensitivity.
To enable this next leap forward in telescopes, NASA has teamed up with the European Space Agency (ESA) and the Canadian Space Agency (CSA) to build the successor to the Great Observatories, the James Webb Space Telescope (JWST). As both an astronomer and as the Deputy Project Scientist for this mission, I feel very fortunate to be a part of this important scientific and technological achievement.
JWST, or “Webb” as we call it, will significantly overlap with Hubble and Spitzer in the range of wavelengths it sees, (red optical, near infrared, and mid infrared), and, most importantly, be more than 100 times as powerful as these Great Observatories. JWST includes many different types of cameras, spectrographs, and coronographs, to enable a diverse range of scientific investigations for astronomers. It is exactly what we have been waiting for!
Astronomers like myself have been excited about JWST for over a decade, and the project has now completed several important milestones. All 18 of the primary mirror segments of JWST (which span 21 feet when put together) are completed. All of the science instruments on the telescope are also making excellent progress. The telescope will soon enter a phase of assembly and testing, where all of the various completed parts are put together and tested as a whole. This ensures that everything works correctly in space, since astronauts will not be able to “service” JWST as they did for Hubble.
Once JWST launches in 2018, astronomers will embark on several new scientific projects that have not been previously possible. In my opinion, some of primary science goals of JWST for astronomers are intimately tied to fundamental questions that humankind has asked itself for centuries.
I grew up in a small town called Quesnel in central British Columbia, Canada, about 8 hours north of Vancouver. We had a beautiful view of the night sky. When I would stare up at the cosmos, I would ask myself how the universe began, how it came to be littered with all of these stars and galaxies, and whether there is life elsewhere on another planet.
JWST will reveal the first stars and galaxies in the infant universe, will teach us how these galaxies evolved to form beautiful systems like the Milky Way, will uncover newborn stars and planets in our own galaxy, and will examine the atmospheres of planets outside our solar system for the signatures of water vapor. Where there is water, there may be life!
And yet even with those goals, if Hubble is any example, JWST’s most amazing discoveries will actually be things that we cannot even imagine today.
Read all about the history of ground and space-based telescopes at our Amazing Space site “Telescopes from the Ground Up.”
