Stephen Hawking: A Physics Icon Remembered in Photos

Weightlessness

The world-renowned theoretical physicist experiences zero gravity during a flight aboard a modified Boeing 727 aircraft owned by Zero Gravity Corp. Founder of Zero Gravity Corp Peter Diamandis rotates Hawking's weightless body. Hawking's aide and nurse practitioner Nicola O'Brien kneels below Hawking. During the celebration of his 65th birthday on Jan. 8, 2009, Hawking announced plans for a zero-gravity flight to prepare for a sub-orbital spaceflight in 2009 on Virgin Galactic's space service.

String theory

Hawking attends a Q&A session at the 2006 International Conference on String Theory on June 21, 2006 in Beijing, China. Alongside Hawking were: physicists Andrew Strominger, David Gross, E. Witten and Chinese mathematician Shing-Tung Yau, a professor at Harvard University.

The universe will end

Hawking, shown here at the Center of Mathematical Sciences, University of Cambridge, proposed during his career that since the universe has a beginning (the Big Bang), it will likely have an end. In fact, working with cosmologist Roger Penrose, he demonstrated how Einstein's general theory of relativity suggests space and time began with the birth of the universe. As for where they end? Hawking proposed within black holes.

Teaching kids about the universe

Hawking with his daughter Lucy and Christophe Galfard, a theoretical physicst at Cambridge University, pose for photographs in Hawking's office at The Centre for Mathematical Sciences in Cambridge, on Sept. 3, 2007. At the time, Hawking had just published his first children's book "George and the Secrets of the Universe," a kid-friendly look at theories on space and black holes. He wrote the book with his daughter and Galfard.

Contributions to the world

South Africa former President Nelson Mandela meets with Hawking in Johannesburg on May 15, 2008. Hawking visited the country for a $75 million plan for Africa's first postgraduate centers for advanced math and physics. Scientists and entrepreneurs stepped up to financially back the plan after the British government declined to provide funding.

Medal of Freedom

U.S. President Barack Obama presents the Presidential Medal of Freedom to Stephen Hawking during a ceremony in the East Room at the White House on Aug. 12, 2009. Obama awarded 16 individuals the medal that year.

At the opera house

Hawking attends the EE British Academy Film Awards at The Royal Opera House on Feb. 8, 2015, in London, England.

Breakthrough Starshot

Hawking attends the New Space Exploration Initiative "Breakthrough Starshot" announcement at One World Observatory on April 12, 2016 in New York City. The $100 million project aims to build the prototype for postage stamp-sized spacecraft. The light-propelled probes would be built to visit the nearby star Alpha Centauri after a journey of just 20 years.

Starmus science

Hawking is shown here during a press briefing on May 19, 2017, at The Royal Society in London previewing the Starmus science and arts festival that took place in Norway. From left to right: Claude Nicollier, Hawking, Edvard Moser, Omega president Raynald Aeschlimann and Garik Israelian.

Death notice

A notice announces the death of Professor Stephen Hawking outside Gonville and Caius College, Cambridge, England.