太陽^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

太陽都計唔到重量,because 太陽太熱,任何物品靠近太陽都會熔化.

2008-06-26 10:14:58 補充：
and 因為地球嘅地心吸力先有重量.

yes, you are right.
the mass of sun is about 2 x 10^30 kg

in the view of physics,
mass can represent how mush matter an object has.
it is improtant to state that mass is independent of palcas ( in classical mechanics ), eg, the mass of an object in earth is totally equal to the mass of that object in outer space.

p.s. there are several definitions of mass when we focus on different topics, for example, special relativity : mass refers to the rest mass of an object.

weight is different from mass.
weight is a kind of force, define as W = mg
where m = mass , g = strength of the gravitational field
as the strangth of gravitational field may varies in different stars.
so, an object may has different weight in different stars, eg, the earth, the moon, etc.
or you can say force exist between two things with mass. this kind of force is known as gravitational force, which is one of the four fundamental forces in physics

2008-06-26 10:49:06 補充：
the SI unit of mass is kg, in Chinese 公斤
the SI unit of weight (i.e. force) is N

所有野都係因為地球嘅地心吸力先有重量,所以我想問下點計到...