Thursday, July 9, 2015

9th Rock From The Sun


Click the arrow to watch the briefing. Video source: NASA YouTube channel.

More than nine years after it launched from Launch Complex 41 at Cape Canaveral Air Force Station, NASA's New Horizons mission to Pluto is just five days away from its closest approach to that world.

When New Horizons launched, Pluto was still called a planet, but in August 2006 Pluto was demoted to a “dwarf planet” by the International Astronomical Union. The problem was the existence of worlds similar or larger in size than Pluto which had not been categorized in the past as a planet. According to the 2006 IAU resolution:

A planet is a celestial body that

  1. is in orbit around the Sun,
  2. has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and
  3. has cleared the neighbourhood around its orbit.

A “dwarf planet” is a celestial body that

  1. is in orbit around the Sun,
  2. has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape,
  3. has not cleared the neighbourhood around its orbit, and
  4. is not a satellite.

I suspect that the data returned from next week will reignite that debate.

For more information on the Pluto flyby, visit the official Johns Hopkins University Applied Physics Laboratory web site for the mission.


Watch the New Horizons launch on January 19, 2006. Video source: NASA New Horizons YouTube channel.

No comments:

Post a Comment