Pluto is a dwarf planet,byebye to classical

Contemporary observations are changing our understanding of planetary systems, and it is important that our nomenclature for objects reflect our current understanding. This applies, in particular, to the designation 'planets'. The word 'planet' originally described 'wanderers' that were known only as moving lights in the sky. Recent discoveries lead us to create a new definition, which we can make using currently available scientific information.

The IAU therefore resolves that planets and other bodies in our Solar System be defined into three distinct categories in the following way:
(1) A 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, and (c) has cleared the neighbourhood 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, (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.
(3) All other objects orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".
The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.Insert the word "classical" before the word "planet"

previous define：
(1) the object must be in orbit around a star, while not being itself a star.
(2) the object must be large enough (or more technically correct, massive enough) for its own gravity to pull it into a nearly spherical shape. The shape of objects with mass above 5 x 1020 kg and diameter greater than 800 km would normally be determined by self-gravity, but all borderline cases would have to be established by observation.
if base on it,the 12 planets in our Solar System will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313.
随着科学技术发展，物质决定意识，9大行星概念从我们脑中抹去，其行星概念也需更新，不是9大，也不是12大行星，现在叫8大经典行星。
For more: http://www.iau.org/

Use a Wristwatch as a Compass

Hold a watch with the 12 o’clock at the leftmost part of your hand. Move your arm so that the hour hand points at the sun. The spot halfway between the hour hand and the 12 is south. [via 08.06 Wired magazine]

下面是一个小技巧，能让你用手表和太阳找出南方来：很简单：按上图把手表放在手掌上，让12点指向正左方，然后把时针指向太阳的位置，那么时针与12点方向形成的角的角平分线指向的就是南方。