The biggest planet??? The smallest planet???

最大：木星
最小：水星

木星是太陽系八大行星之一，按離太陽由近及遠的次序排列為第五顆。它也是太陽系最大的行星，自轉最快的行星。因為繞行天球一周為12年，與地支相同，所以中國古代用它來紀年，因而稱為歲星。它共有衛星63顆。木星表面有一個大紅斑，從東到西有40,000公里，從北到南有13,000公里，面積大約453,250,000平方公里。對於它是什麼目前仍有爭論，很多人認為它是一個永不停息的旋風，它的範圍可以吞沒3個地球。

水星是太陽系最內側與最小的行星，比月球大1/3；也是太陽系中運動最快的行星，環繞太陽一周只要88天。由地球上看水星的視星等亮度在-2.0至5.5等之間，但是因為距離太陽的最大角度（最大距角）只有28.3°：淹沒在日出前或日落後的暮曙光中，因此不太容易被看見。

biggest planet in the space
http://www.samtsai.com/p468

Here is the continuation of World Biggest Star Planet.
This visual film illustrates two stars that are even bigger than the almighty Antares. The video doesn’t show Uranus, though.

W Cephei; VV Cephei: 3,676,200,000 km (ie, 288194 x Earth)
My Cephei: 3,481,250,000 kim
Antares: 1,108,430,000 km
Beteigeuze: 905,125,000 km
Rigel: 86,335,000 km
Arcturus: 4,177,500 km
Pollux: 6,962,500 km
Sirius: 2,506,500 km
Sun: 1,392,500 km
Jupiter: 142,984 km
Saturn: 108,728 km
Neptune: 49,532 km
Earth: 12,756 km
Venus: 12,104 km
Mars: 6,794 km
Mercury: 4880 km
~~~~~~~~~~~

2008-04-09 14:54:51 補充：
smallest planet in the space


Smallest extra-solar planet found

The finding suggests Earth-mass planets may be relatively common
US astronomers say they have found the smallest planet orbiting outside our Solar System to date.

2008-04-09 14:55:05 補充：
The new world, which is about one fifth the size of Pluto, is the fourth planet to be discovered orbiting around a pulsar called PSR B1257+12.

A pulsar is a spinning neutron star producing powerful beams of radiation.

2008-04-09 14:55:19 補充：
The new planet is orbiting inside a large cloud of hot, charged gas that surrounds the pulsar and is some 1,500 light-years away from Earth.


Details of the work were announced at an astronomy meeting held in Aspen, US.

2008-04-09 14:55:27 補充：
Pulsars are formed from the collapsed cores of so-called "supergiant" stars that have exploded.

The discovery was made by Alex Wolszczan of Pennsylvania State University, US, and Maciej Konacki of the California Institute of Technology (Caltech).

2008-04-09 14:55:36 補充：
The orbit of the new planet is close to the average distance from our Sun to the asteroid belt.

The orbits of three planets discovered orbiting the same pulsar in 1992 were almost in exact proportion to the spacings between Mercury, Venus and Earth in our Solar System.

2008-04-09 14:55:41 補充：
Wolszczan and Konacki say the new planet could mark the fringes of the pulsar's planetary system, just like Pluto marks the edge of ours.

The new planet was discovered with the Arecibo radio telescope in Puerto Rico.