The famous Hubble deep field was first observed in 1995 when the telescope was pointed at a dark patch of the universe and stared for 10 straight days at a tiny patch of sky near the Big Dipper.
On July 11, 2022, the now-largest optical telescope in space, the JWST, released its own deep field image that is much bigger, more detailed, and more exciting than the one from Hubble and shows us a view of the universe as it was 4.6 billion years ago, at the same time the sun was being formed and the Earth was being born.
These first images included new images of the Carina nebula, a star-forming region of our galaxy; the Southern Ring, the site of the death of a star and its transition to a white dwarf stellar remnant; and amazing views of the interacting galaxies, Stephan’s Quintet.
The first release also included a detailed measurement of water in the atmosphere of the Jupiter-like planet WASP-96b, which orbits a completely different star. These observations were not novel, but just so much better than any measurements of the same fields and objects than ever before. And this is just the beginning of the era of JWST.
The JWST is the successor of the Hubble space telescope and was built in a collaboration between NASA and the Canadian and European space agencies. The telescope has a 6.5-meter mirror, as opposed to Hubble’s one-meter mirror. If you imagine that a telescope is a giant bucket for collecting photons, then a bigger mirror means we can collect more photons over the same amount of time. The mirror is so big that when the JWST was launched into space in December 2021, the mirror had to be folded like a flower. When it reached its destination at a distance of 1.5-million kilometres from us, the mirrors unfolded and operations began. The JWST is also special because it observes at infrared wavelengths. On Earth, we would think of it as night vision and, as such, the JWST will observe objects in space that are cooler in temperature and dimmer.
The mission of the telescope is to search for the first stars born in the universe and to look for signatures of life on planets orbiting other stars; exploring the birth, life and death of stars; and how galaxies form and evolve.
These topics are also central to astrophysics courses offered at Memorial: Physics 3150: Astrophysics I and Physics 3151: Astrophysics II. The first course will be taught in the fall 2022 semester; students will learn about the lives of stars and how they die, how telescopes like the JWST work and how scientists measure water on planets orbiting other stars from the change of light observed from a star when a planet passes in front of it.
Students will learn about how scientists interpret and learn from these amazing images. We are entering a new era of astronomy and space science. For those interested in a more general discussion, much of the science from those images will be discussed in Physics 2151: Stellar Astronomy and Astrophysics.