News from the World of Science
Japan installs the world’s first nationwide earthquake-detector system
Because Japan experiences some of the most powerful earthquakes on a regular basis, it has been at the forefront of the science of earthquakes (seismology). One of the goals of this science has always been to predict earthquakes in time to allow people to move to safe places. The Japanese feel prepared to attempt this, using a network of seismometers (instruments that measure the shaking of the earth) and a way to alert scientists when a particular type of shake is felt, one that often precedes a powerful quake. If it works, it could save thousands of lives. But if it creates false alarms, it may not help. The ability to predict powerful earthquakes is not yet completely certain, so time will tell if the system will work.
Reference: Discover Magazine, September, 2006, p. 14.
Links for more information:
ABC News Report on Japan’s New Earthquake Detection System
A Japanese Earthquake Model from 1887
Historic Developments in the Evolution of Earthquake Engineering
Earthquake Prediction
Award-winning Japanese Seismologist Hiroo Kanamori
John Milne: The father of modern seismology
Pluto Reclassified as a Planetary Dwarf
Until August 24, 2006, Pluto had been listed as one of the nine planets in our solar system. On this date, the International Astronomical Union, made up of professional astronomers from around the world, voted on a new definition of a planet, in order to better classify a host of new bodies being discovered orbiting the sun in the vicinity of Pluto and further out. After much discussion, the following definitions were voted on (quoted from Wikipedia):
(1) A "planet" [1] is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit.
(2) A "dwarf planet" is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape [2], (c) has not cleared the neighborhood around its orbit, and (d) is not a satellite.
(3) All other objects [3] except satellites orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".
By this definition, Pluto and three other bodies are dwarf planets, leaving just eight planets. So in one sense, Pluto has been demoted, but it has gone from being the last and most insignificant planet, singled out as an oddball, to being the first of the new classification. It was almost honored by giving its name to the new classification, that of Pluton or Plutonian, but dwarf planet was decided on in the end.
Beyond the controversy, the process demonstrates the scrupulously democratic process by which science proceeds and the willingness of scientists to change long established ideas to better fit new developments, data, and theories. At the time Pluto was discovered, no comparably sized bodies were known, so it was added to the growing list of planets. But with better telescopes and a lot of hours of hard work, science is ready to allow the distinction of planet to be made on the basis of a set definition rather than the happenstance of the discovery process.
Links:
New York Times, August 24
Discover Magazine article: Beyond Pluto
Latest Facts about Pluto
An overview of the Solar System
Interested in a career in Astronomy?