On Feb. 18, NASA announced the Wide-Field Infrared Survey Telescope mission has passed the final stage of review and will launch as a successor to the Hubble Space Telescope in the 2020s. University of Illinois astronomy professor Ryan Foley, who is heading up one of the science investigation teams for WFIRST, talked with News Bureau physical sciences editor Liz Ahlberg about the upcoming mission and what it could teach us about the universe and its mysteries.
WFIRST will look at two of the biggest questions in astrophysics: dark energy and planets outside our solar system. Why are these two areas so pressing for scientists, and what could WFIRST tell us about them?
Both topics are fundamental to our understanding of our place in the universe.
Dark energy makes up roughly 70 percent of the universe, yet we know very little about it. It is driving the current expansion of the universe, and depending on what it is, the universe may expand forever or collapse back on itself. The fate of the universe literally depends on what dark energy is. WFIRST will observe thousands of exploding stars and millions of galaxies to measure how the universe has expanded and evolved, and with those data, precisely constrain the nature of dark energy.
Detecting and characterizing planets outside our solar system places our own solar system in context. With WFIRST, we will complete a census of what kinds of solar systems exist. We will be able to determine how commonly systems like our own exist, how the systems form, and the number of planets in our galaxy.
What can this mission tell us that the Hubble Space Telescope or the James Webb Telescope cannot?
WFIRST will have a camera that is 100 times bigger than those on Hubble and those that will be on James Webb. This allows us to truly survey the sky rather than just looking at small patches. What would have taken years of time with Hubble will be achieved in days with WFIRST.
You are heading up a team that’s looking at a particular type of supernova to learn about dark energy. What are these supernovas?
We are using Type Ia supernovas, a kind of exploding star that has a very standard brightness. Because of their standard brightness, we can precisely measure how far away they are. This is similar to when you can estimate how far away a car is at night based on how bright its headlights look. Since light from very distance objects also was emitted a very long time ago, we can use these distances to measure the expansion history of the universe.
As an astronomer, what are you most looking forward to about WFIRST? Do you think it could be as influential to our knowledge of space as the Hubble has been?
I'm extremely excited to discover thousands of supernovas and find out more about dark energy. WFIRST is designed exactly for investigating dark energy, and the results should be spectacular.
Hubble has set a very high bar – and it continues to do so. But WFIRST has significant capabilities that Hubble never will have. If WFIRST lasts as long as Hubble has and if smart astronomers continue to push the limits of the telescope, WFIRST has a chance at matching what Hubble has done.