
O.k. here you see the terrestrial planets
plus Pluto. Terrestrial planets are made of silicates and they have a
metal core.
This means that they are quite dense. Did you know that Mars is so much
smaller than the Earth? It's radius is about the half of the Earths one.
Now the so called giant or gaseous planets. They are made of light
elements in the form of gas, liquid or solid compound like water,
carbon
dioxide,
ammonia, methane, etc. They often have an 'icy' core and a very low
density (e.g. Saturn would float on water). The volume of Jupiter is so
big that
all other planets could fit comfortably into it.
The Sun is a star, thus it's way bigger than any imaginable planet. Its
mass
is more than 99% of the total mass of the Solar system.
So, why does it look so small in the sunny sky? 'Cause it is about 150
milions chilometers away form the Earth.
Here
you can compare the size of the Sun with other popoular stars. Yes, the
Sun ain't that big. It is in fact a small star, it's a main sequence
star,
spectral type G2. For example, Arcturus is an orange-red giant star,
type K 1.5. Its diameter is about 26 times the Suns.
In
this pic the sun has a 1 pixel size. The two 'monsters' are two red
supergiants. The diameter of Antares is 800 milions chilometers, that
of the Sun is
about 1.4 milions chilometers.
So, could you image that our Earth is that small? And what about the
Sun, its size is negligible when compared with Antares.
More questions about planets and stars?
contact me
For people who likes videos at best, I suggest to take a look at one of
these links:
The
biggest star know to man
Largest star know to man
and even more spectacular:
the REAL size of the universe
what? you like more 'dynamic' stuff? Well, then
space
phenomena
If you scrolled until here, you deserve a gift! Here it is:
Pistol star, 600 times larger than the Sun. And just imagine, there
might be
another star, named Canis Mayor VY, that might be 2'100 times larger
than the Sun, i.e. 3.5 times larger then Pistol star ! Amazing !!!
I've made a sketch for eye comparison: on the left 'Pistol Star' on the
right 'Canis Mayor VY'.
Confused and dazed? Well, try to figure out this: draw a circle with 1
mm diameter (0.04 inches), so this represents the Earth. Canis Mayor VY
would
be represented by a circle with a diameter of 200 meters (656 feet)
