On Monday, April 18, I had the opportunity to hear a lecture by Stephen Hawking. I am currently taking a freshman seminar titled "How Did the First Stars and Galaxies Form?" and my professor, Dr. Loeb, arranged for Stephen Hawking to visit Harvard to discuss black holes.

Dr. Loeb is working on the Alpha Centauri project with Hawking, a project aimed at sending probes traveling at 20% the speed of light to the nearest star system. In a filled Sanders Theater, Stephen Hawking enlightened us all on the darkest parts of our universe by explaining that black holes aren't so dark after all.

Hawking's lecture focused on the information paradox, the theory that information that enters a black hole is lost. It is a theory that violates the belief that information about a system at one time can be used to understand its state at other times. Early theories suggested that the only information retained about an object entering a black hole is its mass, angular momentum, and charge.

Hawking, however, asserts that black holes store much more information than we know about. Based on the earlier theories, identical black holes could be made from infinite configurations of matter, an idea that violates the quantum mechanics principles suggesting that black holes can only be made of particles with particular wavelengths.

Unwilling to accept the dark nature of black holes, whereby not even light can escape from these extremely attractive bodies, Hawking explored emission of energy from black holes and found that a steady stream of thermal energy was in fact emitted from black holes. If black holes emit particles, they will eventually shrink and disappear. If the particles that fell into a black hole simply emerge randomly when the black hole disappears, that would strike at the principle of determinism and the predictability of the universe.

Because there is still so much to be learned about black holes, research is currently being conducted to explore the information paradox and understand whether matter is actually lost or encoded in the Event Horizon.

As someone who has limited knowledge about astrophysics beyond one freshman seminar on the early formation of the universe and its contents, Hawking's lecture was both engaging and accessible.

Stephen Hawking is an incredible teacher who can take the most complex topics and deliberately and eloquently explain them to a normal audience.

I'm somewhat of a space-junkie who gets way too excited at the subtle mention of supernovae, so sitting a mere 50 feet away from one of the greatest scientists and listening to him speak about one of my favorite topics was an unforgettable experience. Stephen Hawking has made incredible contributions to science, making him one of the most distinguished individuals of our time.

In high school I read one of Stephen's Hawking's papers on model-dependent realism. It was the first time I had encountered his work and I distinctly remember musing over his writing. Hearing his iconic voice, patiently waiting during the pauses as he types his sentences, and laughing at his absurd and witty jokes, however, is completely different from reading his thoughts on paper. His lecture made me appreciate to an even greater extent the discoveries he has made and the theories he has proposed because they have allowed us to think about the universe in revolutionary ways.

At 74 years old, Stephen Hawking is still an active researcher and teacher. As a man who has defied the odds, Stephen Hawking will continue to break the barriers of science and elucidate some of the mysteries of our universe.

"If determinism — the predictability of the universe — breaks down in black holes, it could break down in other situations. Even worse, if determinism breaks down, we can’t be sure of our past history either. The history books and our memories could just be illusions. It is the past that tells us who we are. Without it, we lose our identity."

- Stephen Hawking