Tuesday, August 29, 2006

The day Pluto was murdered

The International Astronomical Union (IAU) General Assembly booted Pluto out of our solar system as a ‘planet’ in Prague on 24 August. They have reduced its celestial stature to that of a ‘dwarf planet’.

In plain language, to be a planet, a world must meet three criteria:

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

Worlds that meet only the first two criteria have henceforth been classified as "dwarf planets." An example of a planet would be Jupiter, which circles the sun supreme in its own orbit. On the other hand, Pluto, which shares the outer solar system with thousands of Pluto-like objects, has therefore been deemed a dwarf planet.

According to the IAU, the Solar System now consists of eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune; and at least three dwarf planets: Ceres, Pluto, 2003 UB313 (nicknamed 'Xena').

The Singapore Science Centre held a short ceremony yesterday to mark the symbolic change in the status of Pluto yesterday afternoon (28 August).

The Centre is also exhibiting a brilliantly made IMAX film, not on Pluto but on Mars, Roving Mars, in its Omi-Theatre. It is breathtakingly shot, with images shot by actual Mars Rovers, footage from Cape Canaveral rocket launches and landscapes of Antarctica doubling as Mars. Amazing! You must see it, if for nothing, than for the launch sequence, which is a combination of film footage and pixar animation.

You will see the lift-off, followed by the sequence of rocket stages falling away, and then the payload goes into a spin, and is finally shot into outer space like a bullet. The IMAX experience is great.

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