On April 10th, over 50 students and community members attended a lecture by Mike Gladders, an astronomy and astrophysics professor at the University of Chicago, on the topic of gravitational lensing.
Noella Dcruz, Ph.D., an astronomy and physics professor at Joliet Junior College, introduced Gladders to the audience and listed Gladder’s accomplishments such as receiving his PHD in astrophysics in 2002 and his extensive research experience also noting that Gladders is a member of the Kalvi Institute of Cosmological Physics.
His interest in astronomy was not known to him instantly. He didn’t explore the subject until he was kicked out of school for bad grades and placed on academic probation when he returned; since he was on academic probation, Gladders was forced to choose his classes last, and was stuck with astronomy being one of the only science classes still available. Little did Gladders know that taking that class would lead him to find a passion that would make him become the astrophysicist and the astronomer he is today.
“I hopefully have an interesting talk for you today.” Stated Gladders as he began his lecture. Gladders started his lecture on gravitational lensing by describing the physics of how optics work, from basic lens in our eyes to the advance mirrors on telescopes and how light travels through them.
“Light travels straight lines” explained Gladders. “However, objects with mass deviate the light from these straight paths. Gravity can change the direction of light.” Gladders demonstrated how objects with mass put a curvature in to the fabric of space-time which is the basis of Albert Einstein’s theory of relativity. Objects with a large amount of mass and gravitational pull such as stars and galaxies can bend photons towards the object which can distort the image of the object, this is called gravitational lensing.
Gravitational lensing was first discovered in 1919 which helped validate Einstein’s theory of relativity; since then, Einstein’s theory has been proven again and again. When light from an object is distorted by gravity, often you only get partial images or multiple images of the same object. The distortion of the image can be corrected and remapped by using mathematics. Astronomers can use gravitational lensing to measure the mass of objects whose gravitational pull causes the lensing.
The first gravitational lensing first observed by a galaxy was in 1979 and since then astronomers have been using galaxies and galaxy clusters to attempt to study gravitational lensing since galaxies and galaxy clusters are massive enough to have strong gravitational lensing. However, finding gravitational lensing is “hard to do” said Gladders who outlined the process of finding galaxies that would be good candidates to observe gravitational lensing. The process begins by cataloging and finding galaxies by taking pictures of them. After the galaxies are cataloged, astronomers must first find galaxies that are capable of gravitational lensing, this involves looking at over 300,000 pictures; this must be done by humans since computers can’t read images very well; Gladders exhibited this concept by relating it to the CAPTCHA tests that users always fill out when they register for something online. After examining images, the group was able to narrow the number of candidates to about 1000 galaxies. Now, the astronomers begin to observe the candidates and gather more specific data that verify or refute that a galaxy is a candidate for gravitational lensing, and once a galaxy is chosen, astronomers can observe and verify the lensing.
Gladders also gave the audience a peek into what new scientific technology is coming next such as the James Webb Space Telescope which is expected be launched in 2018 with the intent to replace the Hubble Space Telescope. Another new project noted by Gladders was the Giant Magellan Telescope expected to be constructed in 2019, which is a ground telescope that will be capable of shooting powerful light rays into the night sky so that astronomers can take clearer images not distorted by the Earth’s atmosphere.
Dcruz, who invited Gladders, commented that the event went well and explained that she always tries to have events like this on a diversity of astronomical topics. “I think that people have an interest in astronomy and the latest research, and like to learn it in a non-formal setting without all the specific details which is why I like to open these events to the general public.”
Gladders also shared this sentiment. “I feel like, it’s our job to educate people about science; if you do research and you don’t share those results than what is the point of doing research? We all value when we have a society of people who are scientifically literate and have intellect.”
Today, Gladders teaches the very subject that he fell in love with accidentally 22 years ago.