• Dec. 6, 1778 - French physicist & chemist Joseph Luis Gay-Lussac is born. Gay-Lussac is best known for the Gay-Lussac Law of gases, which says that pressure and temperature are proportional. He also published Charles' Law, based on previously unpublished work by Jacques Charles.
• Dec. 5, 1901 - Physicist and Nobel laureate Werner Heisenberg is born. Heisenberg was key in the development of quantum physics, with the development of the Heisenberg Uncertainty Principle. During World War II, he led German research in nuclear science.
• Dec. 5, 1932 - Albert Einstein is granted an American visa.
• Dec. 2, 1942 - Enrico Fermi's team on the Manhattan Project successfully initiates the first self-sustaining nuclear chain reaction.
• Dec. 7, 1972 - The last Apollo ship, Apollo 17, launches.
• Dec. 7, 1993 - German physicist and Nobel Prize laureate, Wolfgang Paul, dies. Paul was awarded the 1989 Nobel Prize in Physics for his co-discovery of the ion trap. (He should not be confused - as I did last year - with Wolfgang Pauli.)
• Dec. 3, 1999 - The Mars Polar Lander radio signal is lost by NASA as it entered the Martian atmosphere.

Dr. Stephen Hawking
NASA

The Perimeter Institute for Theoretical Physics was founded in the summer of 1999, when Mike Lazaridis - founder and CEO of Research in Motion, maker of the Blackberry (the cell phone, not the fruit) - decided to help foster physics research in Canada. The Perimeter Institute currently hosts 60 resident researchers, including their current Executive Director, cosmologist Neil Turok (appointed in May 2008).

In the announcement of Hawking's acceptance, Dr. Turok mentions that this is the first of a projected 40 such visiting research chair appointments, representing a new phase for the Perimeter Institute. It is hoped that this will help expand their growing interdisciplinary collaboration, by making the Perimeter Institute one of the research centers for some of the top minds in theoretical physics ... of which, Dr. Hawking most certainly qualifies.

Related Articles

• Perimeter Institute of Theoretical Physics (press release) - Stephen Hawking to Regularly Visit Perimeter Institute as Distinguished Research Chair
• PhysicsWorld.com - Hawking accepts post in Canada
• What Is Hawking Radiation?
• Book Review - Endless Universe: Beyond the Big Bang by Neil Turok and Paul J. Steinhardt

• Nov. 27, 1701 - Anders Celsius is born. The Swedish inventor and astronomer is best known for the Celsius temperature scale that he devised.
• Nov. 29, 1803 - Christian Doppler is born. The Austrian physicist is best known for the explanation of the Doppler effect in waves.
• Nov. 25, 1814 - German physicist and physician Julius Robert von Mayer is born. von Mayer is known as a founder of thermodynamics, especially for his early formulation of the law of conservation of energy in 1841.
• Nov. 29, 1849 - English electrical engineer and physicist John Ambrose Fleming is born. Fleming invented the diode for use in electronics. He also invented the right hand rule, used in mathematics when taking the cross product of two vectors.
• Nov. 25, 1867 - Swedish chemist, engineer, and inventor Alfred Nobel patents dynamite.
• Nov. 30, 1869 - Swedish industrialist Gustaf Dalen is born. Dalen was awarded the 1912 Nobel Prize in Physics for his invention of automatic valves, used in lights called the Dalen light. The valves had a darkened metal rod which expanded when sunlight came up, causing the valve to close. This cut off the flow of gas into the light, turning the light off during the day. It was used in lighthouses and buoys.
• Nov. 27, 1871 - Italian electrical engineer Giovanni Giorgi was born. He invented system of measurement called the Giorgi system, which was a precursor to our the SI unit system.
• Nov. 28, 1950 - American physicist Russell Alan Hulse is born. Hulse received the 1993 Nobel Prize in Physics for work in discovering the binary pulsar. He shared the prize with his doctoral thesis advisor, Joseph Hooton Taylor, Jr.
• Nov. 28, 1954 - Enrico Fermi dies. The Italian physicist won the 1938 Nobel Prize in Physics for his work on induced radioactivity, based on his work in the development of quantum physics. He is also known for his work in developing controlled nuclear reactions, which ultimately led to the construction of nuclear reactors. Fermilab, one of the most important centers for sub-atomic quantum research, is named after Enrico Fermi.
• Nov. 27, 2001 - The Hubble Space Telescope detects a hydrogen atmosphere on the planet Osiris, in the constellation Pegasus (approximately 150 light-years from Earth's solar system). This is the first atmosphere detected on an extrasolar planet.

The team, using some of the most powerful supercomputers in the world, has computed the masses for protons and neutrons, applying the principles of quantum chromodynamics (QCD) - the quantum theory governing the behavior of these particles.

Performing these calculations in the context of QCD has proven extremely difficult, taking the team over a year of computing to arrive at the determined masses. The new study calculates these masses from QCD directly, which involved (from Science News):

In their calculations, Hoelbling and collaborators approximated the continuum of spacetime with a four-dimensional crystal lattice composed of discrete points spaced along columns and rows. The researchers solved the equations of QCD on finer and finer lattices, and then extrapolated the results to the continuum, painstakingly accounting and measuring every approximation and uncertainty along the way.

Under the standard model of particle physics, both protons and neutrons are comprised of smaller particles called quarks which are bound together by other particles called gluons. The gluons act as the "glue" that binds these quarks together with what is called the strong nuclear force (or sometimes strong nuclear interaction).

The gluons, however, have no mass whatsoever and the quarks only account for about 5% of the mass of the protons or neutrons, so where is the other 95% of the mass located? The answer, according to Einstein's equation E = mc² is that the mass is in the form of the energy from the strong nuclear interactions between the quarks and gluons ... a prediction which appears to be confirmed by the new computations, which determined a theoretical mass within a 4% uncertainty of that obtained experimentally.

Related Articles:

• Science News - Standard Model Gets Right Answer for Proton, Neutron Masses
• ScienceNOW - At Long Last, Physicists Calculate the Proton's Mass
• Agence France-Press - E=mc2: 103 years later, Einstein's proven right
• Discover Magazine - Confirmed: Scientists Understand Where Mass Comes From