U of Arizona professor discusses replacement for Hubble Space Telescope

Wednesday, February 26, 2020 - 10:05pm

Dr. Marcia Rieke discusses the successor of the Hubble Space Telescope for Mohler Prize Lecture at the Michigan League Wednesday evening.

Dr. Marcia Rieke discusses the successor of the Hubble Space Telescope for Mohler Prize Lecture at the Michigan League Wednesday evening. Buy this photo
Hannah Yoo/Daily

Marcia Rieke, regents’ professor of astronomy at the University of Arizona, spoke about the James Webb Space Telescope (JWST), the upcoming successor to the Hubble Space Telescope, in a talk in the Michigan League on Wednesday. 

The lecture was part of Rieke’s reception of the department of astronomy’s Mohler Prize, which is awarded for excellence in research on astronomy and astrophysics, and named after Orren Mohler, former head of University of Michigan observatories. Approximately 70 people were in attendance.

Rieke began by talking about the current Hubble and explaining why a new space telescope was being developed. According to Rieke, the Hubble is not big or powerful enough to see the most distant galaxies. This is because it can only see a small part of the infrared spectrum. Rieke explained infrared light is important for seeing distant objects because of a phenomenon called “redshift.”

“The more distant an object, the more its light output is shifted to red wavelengths and it gets to the point where you can’t just rely on visible light, you have to go to longer wavelengths to the part of the spectrum beyond the red, called infrared,” Rieke said.

Because of redshift and the discovery that the rate at which a galaxy moves away from earth is proportional to how far away it is from the earth, scientists can figure out the age of galaxies from light.

“So if we measure a spectrum … we know the velocity and therefore we know how far away the galaxy is and we know what its age was when the light was made,” Rieke said.

While the Hubble in its current form can see objects formed up to 13.4 billion years ago, the new JWST, with its advanced infrared capabilities, will allow scientists to see even further into the past, giving them greater ability to figure out when the first stars were formed.

Besides aiding scientists in figuring out when the first stars were formed, the increased infrared abilities of the JWST will also help scientists analyze the atmospheres of exoplanets, which are planets orbiting other stars, to see if they contain water and other important chemicals and could support life.

Rieke then described the technical specifications of the telescope. It is designed for a five-year timeline but will carry enough supplies to last up to 14 years. Additionally, the telescope will be cooled to the “low” temperature of -388 degrees Fahrenheit. Cooling the telescope this low is necessary to prevent the radiation from the telescope’s own heat from damaging the images it produces. 

Besides cooling the equipment, another engineering challenge in producing the telescope was fitting it into a rocket. The telescope could not fit into a rocket the way it was meant to operate so it will be folded up and then get into position, Rieke explained.

“You can see the cutaway of a nose cone of a rocket,” Rieke said “You can kind of see that there’s a telescope…(it) doesn’t fit in very well. Well, how do you solve this problem? You turn your telescope into a piece of origami and you fold it up so it will fit inside the nose cone and that is part of what makes this mission challenging.”

Another difference between the Hubble and the JWST is the JWST will not be repairable like the Hubble was since it will be orbiting the sun about one million miles from the earth. Rieke said this isn’t a problem but just requires the team to conduct many tests to ensure the equipment functions properly. 

“It’s not really a big problem if you take the appropriate steps,” Rieke said. “Appropriate steps mean you need to design for a long lifetime and test it thoroughly. I have spent a lot of my recent lifetime testing part of this, testing some of that — (it) was exciting and fun, some of it was scary, some of it was boring.”

After tests in three different locations, the JWST will be launched into orbit from a rocket in French Guinea. Rieke asserted the rocket is one of the most reliable large rockets around and underscored that it will be the right kind for a mission of this gravity. 

“Nearly $9 billion worth of stuff will be going on a reliable controlled explosion,” Rieke said. “It’ll all work.”

Though the tests occurred here on Earth, they involved extensive processes and were not without their own complications. A portion of testing in Houston happened during Hurricane Harvey, and though the telescope was safely secured, the hurricane almost caused the team to run out the liquid nitrogen they were using to cool the telescope. 

If all goes to schedule, the JWST is set to be launched into orbit by the end of this year.

Rackham student Matt Patrick, who studies gamma-ray detection, regularly attends talks from the Department of Astronomy. He said another thrill of the JWST coming into operation is the bold investment in science and research that it represents.

“The engineering is really exciting (and so is) the willingness of the government and the science institutions to place a bet on these huge technologies — some of them not really proven yet,” Patrick said.

LSA junior Rhiannon Singer, who majors in astronomy and extensively discussed the JWST in her astrophysics class, was excited to come to the event to hear about the new capabilities of this telescope.

“I think that the biggest thing is … that we will be able to look back farther in time so we will be able to get more detailed information about the earliest galaxies, the earliest formed structures of our universe,” Singer said. “We may be able to see some of these early structures we’ve never seen before and that will give us a lot of information about how the universe actually came to be the way it is.”

Contributor Carter Howe can be reached at tcbhowe@umich.edu