http://www.hindustantimes.com/news/5...2500000000.htm
Well ok pluto didn't disappear but today the International Astronomical Union has
declared that Pluto does not meet the requirements to be a planet. Here is why
Pluto was discovered in the 1930s. It is about 900 miles across and back then any object
orbiting the sun larger than 400 miles in diamater, and somewhat spherical if you squint
ur eyes a bit, would be considered a planet. It was until not too long ago more space
programs have been able to observe planet compositions orbits and Pluto fails to meet the
requirements of many other of our planets. Here is why
PLuto...
-Was not created at the time of our sun. It caught onto orbit AFTER the sun was created.
All other 8 planets were created at the time of the sun.
-Its planetary composition does not match those of a terrestrial planet (earth venus mars
mercury) or a jovian gas giant (Jupiter, Saturn, Uranus Mars)
Creation of our Solar system:
There are many theories as to the creation of our solar system. First it was believed
the planets were floating in the galaxy and caught on to orbit with the sun. This was
decided to be flawed, as all 8 planets orbit the sun in the same direction, all planets 8
planet's orbits are pretty circular, all planet's orbits lie on the same plane. The
chance that all planets would catch on orbit in the same direction shape and orientation,
seems highly unlikely.
The second theory of our planet creation was the sun and another star came very close to
each other and gravity scraped off some sun matter and then it condensed into planets.
This theory was also unpopular as stars virtually NEVER collide. The smallest and
largest stars are between 500,000 miles to 500,000,000 miles in diamater respectively.
Stars are separated by hundreds of lightyears (lightyear = 6 trillion miles) which is a
unit of distance thousands to millions of times larger than their diameters. Stars move
on the average about 50 to 200 miles per second so obviously their speeds are way too
slow to do any serious traveling in the galaxy or universe for that matter.
The last theory and the one that seems to be most correct today is planets condensed and
formed in the accretion disk of the star's gases during its creation. A Star is formed
by gases and interstellar medium condensing and pulled together by gravity. As the gas
starts to condense and form into a star, conservation of angular moment takes place. The
hot gases are compressed and starts to spin. When it spins, the gases of the soon to be
star "flattens out" due to centrifugal force and a gas disk is made (this is called an
accretion disk). Eventually the gases within the disk condesed into 8 planets and in the
middle of the disk is where the star forms. This theory is consistent with the fact that
all 8 planets, are circular (give or take but close enough) travel in the same direction
and are in the same plane.
Pluto's elliptical orbit is highly eccentric. So eccentric that every 268 years its
orbit makes it closer to the sun than neptune. Between 1978 and 1999 pluto was closer to
the sun than neptune. Its orbital plane is about 23 degrees tilted. The highly
eccentric orbit and tilted plane makes it inconsistent with the accretion disk theory of
the creation of the planet.
Planet composition
Terrestrial planets are very dense. Their composition from outer to inner is Atmosphere
(gas), Crust (Solid rock 10% of radius), Lithosphere/upper mantle (Solid rock and lava
17.5% radius), Mantle (lava 17.5% radius), Outer core (liquid metal 37.5% ), Inner Core
(Solid metal 37.5%). Mars and Venus has the same structure as well as the proportions
but Mercury has an exceptionally large solid metal inner core for its size.
Jovian PLanet composition, not dense at all, saturn could float in water. Its
composition is not a discreet transition either. If you were to enter Jupiter, the first
6 thousand miles you descend into its surface you would be amist hydrogen, water, helium
and traces other gases The temperature here varies from 100K to 300K which doesnt seem
too bad at the earth's standpoint. As you go deeper past 10% of the radius the humidity
will increase and eventually reach dew point and at about 15% you will hit the liquid
gases by now its unsurvivable the pressure exceeds thousands of atmospheres and the
temperature is thousands of degrees kelvin. AT this point the pressure is strong enough
to compress gas into a liquid. For the next 60% of the radius about 36,000 miles you
descend it is all liquid gas and the pressure will build phenomenally. Past 36,000 miles
is the solid gas which is even more compressed. The solid gas accounts for the remaining
5% of the Jupiters radius and at the dead center of Jupiter is a metal core the size of
earth. At the metal core the pressure is approximately 100,000,000 PSI and 20,000 Kelvin.
Pluto doesn't fit any of these. If you could crack this 900 mile diamater _____
(classification name needed here) in half, you will find its mosly made of ice. Frozen
Ammonia, (NH3), Methane, CH4 and water H2O. It has no metal core, mantle, or any other
structure similar to Jovian or terrestrial planets. It does have a surface similar to
the moon. Its overall composition resembles a really large comet or asteroid.
In addition there are at least 2 other _____ (classification name needed here) larger
than pluto orbiting our solar system. If pluto were a planet, then the newer "planets"
discovered in the last ten years would expand our solar system to about 11 planets.
Well pluto is out! Time to rework the education system on astronomy to the future kids.
I guess "My very educated mother just served us nine pizzas" no longer works as a
mnemonic for the planets. Hmm how about... Mature Videogames Ensues More Junior-High
Students Undergoing Negative-Behavior. Well negative behavior and Junior high isnt
really 1 word but at the very least the rest of the sentence makes sense. And I guess
its not hard to remember.
I wonder how this will affect stock prices?
Tim Yang
Solar system now only has 8 planets 
