Thank you for all your kind replies! Its so great to see that space-stuff still excites many.
Just a few images have come back,and it has left scientists scratching their heads and ready to throw their current theories into the dustbin.
Pluto turned out to be absolutely nothing like they imagined!
Pluto is extremely cold. Situated at the far reaches of the Solar System,it doesn't get as much heat from the Sun,as does Earth. The Solar flux decreases double for every single unit of distance. Hence,these distant icy bodies were thought to have formed around cores of rocks which got clumped together while the Solar System was forming and then got covered with ice.
But its not ice as we know,because the surface temperature of Pluto is around -220 Celsius! So its not only too cold for water-ice but the surface is actually made of solid nitrogen. And clumps of solid methane.
So its a planet covered with nitrogen ice.
Now since Pluto's orbit is very eccentric,ie,its not perfectly circular(it comes closer to the Sun than Neptune during a part of orbit),it was theorized that a part of that surface nitrogen would sublime and rise up to become a tenous atmosphere,and would freeze and solidify as it goes farther away from the Sun.
So as far predicting Pluto's surface geology,it was thought to be quite ancient and covered with craters. Craters are a great sign of an ancient surface because that indicates the lack of any surface weathering or active geological process to erode them. Greater the crater count,more old the surface.
Ancient cratered surface of the dark side of the moon.
The Pluto,from that picture,has totally stumped scientists. As you can see,there is not a single sign of a crater.
Instead what you can see are those giant icy mountains. Those mountains are said to be 3-4 kms tall,jutting straight out of the surface. What a sight it must be if anyone is standing on the surface and looking up at it.
And beside the mountains you can see a flat plain which looks like it has been created out of a liquid flow. And you can see some canyons,cliffs and escarpments surrounding it. This shows that it is a very geological active world. And the scientists are pretty flummoxed as to what is causing it. Bear in mind that when people say its geologically active,these features are said to be not more than 100 million years old,which in planetary geology is like yesterday.
Our planet has something which has yet not been found on any other planetary body as of yet and that is active tectonic plates. The radioactive decay of the core of our planet gives off tremendous amounts of heat and energy which keeps the crust very active. The plates move out about,clashing with each other,getting consumed back into the Earth at the subduction zones and is constantly replenished and kept active. Thats why the surface of the Earth is so young and it creates mountains,canyons,continents and keeps weathering processes like the water cycle going on.
A smoothed crater in the Martian desert
Other planets also have interesting and active geology but not on the level of Earth. Surface of rocky planets like Mars is very old and is not troubled much by its thin atmosphere. Its core far cooler than Earth to allow tectonics. Venus,although it is a hellish place thanks to its incredibly dense atmosphere,it has no active tectonics to keep on shaping its land.
Sand Dunes on Mars.
The outer moons though are surprisingly active.
Volcano erupting on left.
There is the Jupiter's volcanic moon Io(Mustafar from Star Wars
).It has probably more volcanoes than earth and it spews out molten sulfur 500km up in the air.
Jupiter's moon Europa,which is said to consist of a planet encircling liquid water ocean underneath its frozen surface.
Largest sea on Titan,called 'Kraken Mare'
There is Saturn's rockstar moon called Titan,which is like a mini-Earth.It has a thick atmosphere,it has something analogous to our water cycle but since it is very cold so the water is replaced by methane. There are methane clouds,it rains methane and there are lakes and seas on Titan.
Geyser's of Enceladus
And Saturn's moon Enceladus,which has these huge rows of water geysers which throws water straight into space.This water is said to come from an underground ocean like Europa and gets heated and comes out on the surface.
Young surface of Enceladus
These moons dont have a radioactive core to supply them heat,so how come they have such active meteorology? The answer is the Gas Giants they orbit around. Jupiter and Saturn exert immense gravitational forces on their moons. The forces are so strong that they kind off pull and push on these moons,a rhythmic stretching and squeezing. These forces give rise to something called 'Tidal Heating'. And it is this tidal heating that allows water to exist in liquid form under the surface and also keeps the surface young.
But Pluto doesnt orbit a gas giant.Although it has an extremely large moon called Charon,relative to its own size,Charon is not large enough to cause tidal heating.So scientists are not sure what is keeping Pluto's surface active.
Much to learn.
BTW a splendid picture of Charon has come too.
Look at that deep cut on the top right-side,where you literally look through and see the other side. Its said to be a few kms deep.
PS: Excuse me for any scientific inaccuracies.I am just writing what i know from mucking around in space related stuff whenever i can.Please do look up wiki and other places to get a more accurate picture.