Theoretical physicists Stephen Hawking (L) and John Ellis are pictured after professor Hawking gave a lecture on the creation of the Universe at the European Organization for Nuclear Research (CERN) in Meyrin near Geneva September 9, 2009.

Theoretical physicists Stephen Hawking (L) and John Ellis are pictured after professor Hawking gave a lecture on the creation of the Universe at the European Organization for Nuclear Research (CERN) in Meyrin near Geneva September 9, 2009.

Getty Images 3 months ago

WASHINGTON - AUGUST 12: U.S. President Barack Obama presents the Medal of Freedom to Steven Hawking during a ceremony at the White House August 12, 2009 in Washington, DC. The Medal of Freedom is the highest civilian award in the United States.

Getty Images 3 months ago

WASHINGTON - AUGUST 12: U.S. President Barack Obama (R) presents the Medal of Freedom to physicist Stephen Hawking during a ceremony in the East Room of the White House August 12, 2009 in Washington, DC.

Getty Images 3 months ago

WASHINGTON - AUGUST 12: U.S. President Barack Obama (R) presents the Medal of Freedom to physicist Stephen Hawking during a ceremony in the East Room of the White House August 12, 2009 in Washington, DC.

Getty Images 3 months ago

WASHINGTON - AUGUST 12: U.S. President Barack Obama (R) presents the Medal of Freedom to physicist Stephen Hawking during a ceremony in the East Room of the White House August 12, 2009 in Washington, DC.

AP Photo 2 months ago

British theoretical physicist Stephen Hawking, Professor at the University of Cambridge, delivers a lecture on "The creation of the universe" on the 450th anniversary of the University of Geneva, in Geneva, Switzerland, Tuesday, Sept. 15, 2009.

AP Photo 2 months ago

British theoretical physicist Stephen Hawking, Professor at the University of Cambridge, delivers a lecture on "The creation of the universe" for the 450th anniversary of the University of Geneva, in Geneva, Switzerland, Tuesday, Sept. 15, 2009.

Theoretical physicist professor Stephen Hawking is pictured before his lecture on the creation of the Universe at the European Organization for Nuclear Research (CERN) in Meyrin near Geneva September 9, 2009.

Theoretical physicist professor Stephen Hawking is pictured during his lecture on the creation of the Universe at the European Organization for Nuclear Research (CERN) in Meyrin near Geneva September 9, 2009.

Theoretical physicist professor Stephen Hawking is pictured before his lecture on the creation of the Universe at the European Organization for Nuclear Research (CERN) in Meyrin near Geneva September 9, 2009.

Theoretical physicist professor Stephen Hawking is pictured before his lecture on the creation of the Universe at the European Organization for Nuclear Research (CERN) in Meyrin near Geneva September 9, 2009.

AP Photo 3 months ago

Stephen Hawking waits as President Barack Obama prepares to give him a 2009 Medal of freedom during ceremonies in the East Room of the White House in Washington, Wednesday, Aug. 12, 2009.

Getty Images 7 months ago

Professor Stephen Hawking gives a lecture entitled 'Why We Should Go Into Space' during the 50 Years of NASA lecture series at George Washington University in Washington, DC, on April 21, 2008.

Getty Images 7 months ago

World famous British scientist Stephen Hawking gives a lecture at the Bloomfield Museum of Science in Jerusalem on December 10, 2006.

British physicist Stephen Hawking delivers a lecture on "The Origin of the Universe" at the Heysel conference hall in Brussels in this May 20, 2007 file photo.

Stephen Hawking, the British physicist and best-selling author famed for his work on time and space theory while confined to a wheelchair, answers questions during an interview in Orlando, Florida in this April 25, 2007 file photo.

Getty Images 7 months ago

LONDON - (FILE) Professor Stephen Hawking delivers his speech at the release of the 'Bulletin of the Atomic Scientists' on January 17, 2007 in London, England. According to Cambridge University, April 20, 2009 the 67-year-old physicist is "very ill" in hospital.

U.S. President Barack Obama presents the Medal of Freedom to scientist Stephen Hawking during a ceremony in the East Room of the White House in Washington, August 12, 2009. Obama presented the nation's highest civilian honour to 16 recipients during the ceremony.

U.S. President Barack Obama presents the Medal of Freedom to renowned physicist Stephen Hawking during a ceremony in the East Room at the White House in Washington, August 12, 2009. The medal is the country's highest civilian honor.

AP Photo 3 months ago

President Barack Obama applauds after presenting the 2009 Presidential Medal of Freedom to Stephen Hawking, the renown theoretical physicist and Cambridge University professor, during ceremonies at the White House in Washington, Wednesday, Aug. 12, 2009.

AP Photo 3 months ago

President Barack Obama holds the 2009 Presidential Medal of Freedom to be presented Stephen Hawking during presentation ceremonies in the East Room of the White House in Washington, Wednesday, Aug. 12, 2009.

AP Photo 3 months ago

FILE - In this April 21, 2008 file photo, Professor Stephen Hawking makes remarks at George Washington University in Washington.

Professor of mathematics at Cambridge University Stephen Hawking discusses theories on the origin of the universe in a talk in Berkeley, California on this March 13, 2007 file photo.

AP Photo 7 months ago

FILE ` In this April 21, 2008 file photo, Professor Stephen Hawking of the University of Cambridge, makes remarks at an event marking the 50th anniversary of NASA, at George Washington University in Washington.