Solar System

Take a look at this question that was asked previously about the upcoming planetary conjunction.

Uranus is not a particularly pleasant place to go! It is just a big ball of gas, mainly hydrogen, helium, methane and ammonia. It doesn't have a surface like Earth, you would just keep falling in until you got squashed by the pressure. It is also very very cold so you would need a way of keeping warm. Uranus rolls round its orbit which means that one side of the planet is facing the Sun for half a year, and the other side for the other half.

All systems including galaxies are supposed to be moving in orbits, what is the source of energy for this?

Would it be farfetched to compare all known space (galaxies) with all the atoms contained in one gram of material? Or would the atoms win out here?

The solar system formed when a huge cloud of gas collapsed to create the Sun and the planets around 5 billion years ago. As the gas collapsed it started to rotate faster and faster (like what happens when an iceskater pulls their arms towards their body to make them spin faster). This is why all the planets rotate the same way around the Sun. The reason they don't lose energy is because space is a vacuum, so there is no air resistance to slow down the planets as they move.

I suppose that the source of energy for the motion of galaxies is the Big Bang. At the beginning of time when the Universe started, there was a massive explosion. Galaxies are still moving away from eachother in all directions as a consequence of this.

As for the last part of your question, I assume you are comparing the numbers of galaxies to the number of atoms in one gram of material. The exact number of atoms depends on the type of material, but one gram of hydrogen would contain around 600,000,000,000,000,000,000,000 atoms, a much larger number than the number of galaxies.

I'm afraid that this is a little beyond the scope of the Virtual Solar System. Try looking at this site which answers some Frequently Asked Questions on Black Holes.

Because Venus is closer to the Sun than we are, it will always be near to the Sun on the sky when viewed from Earth. The picture below shows the maximum angle between Venus and the Sun:

The information in this site is mostly based on the astronomy I learnt during my degree, with additional information from an excellent book called 'Wanderers in Space'.

Gravity is indeed the answer. Billions of years ago, when the planets were forming from small lumps of rock, metal and ice the force of gravity pulled them together. Just as on Earth, objects fall down (towards the centre of the Earth) rather than up, these lumps of material would rather be close to the centre of the newly forming planet. With all the lumps fighting to be closest to the centre, the most natural shape for them to make is a sphere.

There is an excellent site called Moon-Watch which has plenty of easy to understand information about the moon, including an Ask Moon-Watch forum. I think that question 3 probably answers your query.

The reason that you cannot find any information about the surface of Saturn is because it doesn't have one. Saturn is a giant ball of gas which is held together by its own gravity. The gas gets more dense towards the centre but it doesn't form a surface. In fact, Saturn is actually less dense than water - it would float in the bath!

Perhaps your tourists could stay on one of Saturns many moons, which would give great views of the planet and its rings, I'd recommend Titan - apparently it has the best atmosphere!