December 29, 2000 – Dear Friends and Students of NEOs:

As we approach the beginning of the new millennium on Monday, I remind you that this will also be the bicentennial of the discovery of the first asteroid or minor planet. At approximately 8 pm local time on January 1, 1801, the asteroid Ceres was discovered at Palermo, Sicily, by Giovanni Piazzi. Piazzi, like many astronomers of his day, believed there was a missing planet between Mars and Jupiter, in the "gap " first noted by Johannes Kepler two centuries previously. Piazzi followed the motion of the new "planet" for 41 days, providing enough information to demonstrate that it was orbiting the Sun within this gap. It was subsequently named Ceres for the patron goddess of Sicily in the ancient Roman pantheon. And yes, Ceres is "as big as Texas", with a diameter of nearly 1000 km. Today tens of thousands of asteroids have been identified within the asteroid belt between Mars and Jupiter, but Ceres remains the largest by a considerable margin. These main-belt asteroids are also the source of most of the near earth objects (NEOs) that interest us, in part for their potential to impact our planet.

Like the beginning of the new millennium on January 1, 2001, this anniversary does not seem to have captured very much public interest. However, there will be a celebration at the Palermo Observatory. As part of that event, MIT planetary astronomer Richard Binzel will be delivering an address at 8 pm on January 1 to commemorate the discovery. His address: "Asteroids Come of Age" is already published in Science 289, page 2065.

Best wishes for the twenty-first century and the third millennium.

David Morrison
NASA Ames Research Center

website: http://space.arc.nasa.gov
website: http://astrobiology.arc.nasa.gov
website: http://impact.arc.nasa.gov