Greene believes science must be brought to general audiences in new and compelling ways, such as his live stage odyssey, Icarus at the Edge of Time, with original orchestral score by Philip Glass, and the annual World Science Festival, which he co-founded in 2008 with journalist Tracy Day.
Brian Greene, a professor of physics and mathematics at Columbia University, has focused on unified theories for more than 25 years, and has written several best-selling and non-technical books on the subject including The Elegant Universe, a Pulitzer finalist, and The Fabric of the Cosmos—each of which has been adapted into a NOVA mini-series. His latest book, The Hidden Reality, explores the possibility that our universe is not the only universe.
Murray Gell-Mann is been called "the man with five brains" -- and he has the resume to prove it. In addition to being a Nobel laureate, he is an accomplished physicist who's earned numerous awards, medals and honorary degrees for his work with subatomic particles, including the groundbreaking theory that the nucleus of an atom comprises 100 or so fundamental building blocks called quarks. Gell-Mann's influence extends well beyond his field:
He's a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and the Council on Foreign Relations. He also serves on the board of the Wildlife
Conservation Society and is a director of Encyclopedia Britannica. Gell-Mann, a professor emeritus of Caltech, now heads the evolution of human languages program at the Santa Fe Institute, which he cofounded in 1984. A prolific writer -- he's penned scores of academic papers and several books, including The Quark and the Jaguar -- Gell-Mann is also the subject of the popular science biography Strange Beauty: Murray Gell-Mann and the Revolution in 20th-Century Physics.
A kilogram isn't what it used to be. Literally. The original name for it was the 'grave', proposed in 1793 but it fell victim to the French Revolution like its creator, Lavoisier. So begins the tale of the most unusual SI unit. The kilogram is the only base unit with a prefix in its name, and the only one still defined by a physical artifact, the international prototype kilogram or IPK.
But the problem with this definition has long been apparent. The IPK doesn't seem to maintain its mass compared to 40 similar cylinders minted at the same time. The goal is therefore to eliminate the kilogram's dependence on a physical object. Two main approaches are being considered to achieve this end: the Avogadro Project and the Watt Balance.
The Avogadro project aims to redefine Avogadro's constant (currently defined by the kilogram -- the number of atoms in 12 g of carbon-12) and reverse the relationship so that the kilogram is precisely specified by Avogadro's constant. This method required creating the most perfect sphere on Earth. It is made out of a single crystal of silicon 28 atoms. By carefully measuring the diameter, the volume can be precisely specified. Since the atom spacing of silicon is well known, the number of atoms in a sphere can be accurately calculated. This allows for a very precise determination of Avogadro's constant.
