1. How far away from earth, is space?
In fact, space is said to begin just 100km above the surface of the earth so if you were in a rocket then you would not need to travel for too long to hit space.
When you look in the sky to the moon for instance you actually only need to travel a tiny, tiny fraction of the way to the moon to enter space.
2. How does gravity affect life on Pluto?
Well, there is much less gravity no Pluto than there is on the planet Earth.
Therefore, it is easier to jump for instance a jump would take you much higher. Your body would also not need the robustness that it needs to deal with gravity here pushing down on your organs and so on, so might need to be less sturdy.
Clouds are formed as part of the water cycle. Effectively, warm air rises. Indeed, water vapor rises, as it is lighter than air.
However, as it rises through the sky, higher and higher up, the air is colder.
This causes the water vapor to condense and it turns to liquid droplets. This is what causes a cloud to form and condense.
When the density is high enough, the water escapes from the cloud and falls to earth as a cloud.
Theories abound. The most widely accepted thought at present is that some massive impact on earth in its very formative days was so violent that it sent a chunk of earth rock flying out into space, and this became the moon. Certainly if true, this was very fortuitous for life on earth in the end, as the moon has many effects on the earth that are beneficial for life, e.g. tides.
5. How can space expand faster than the speed of light?
Although nothing can travel faster than the speed of light, when space is expanding itself then things can move further than light does in a period - this is because it is not a particle that is traveling it is the fabric of space itself.
Space can expand at a rate that has not been determined but will not expanded to be bound by the movement of light or particles, so if the fabric of space itself expands then things can effectively be moved apart from each other at faster than light speed without themselves exceeding the limit.
In terms of size, Venus is the most like Earth, although not in terms of planetary conditions, climate, or hospitability for life.
Venus is 95% the size of earth. In terms of the density of the planet, it is very close to earth. It is 30% closer to the Sun than the earth is. It is also incredibly hot - around 880 degrees Fahrenheit at times, and sulphuric acid rain. The planet has a runaway greenhouse effect problem.
There is an edge to what we are able to see in the universe. The most distant galaxies we can now see are 10 or 12 billion light-years away. We could never see a galaxy that is farther away in light travel time than the universe is old, e.g. estimated 14 billion years. Thus, we are surrounded by a "horizon" that we cannot look beyond that. This horizon describes the visible universe-a region some 28 billion light years in diameter.
8. Does time stop at an event horizon?
You may have read that as you approach the event horizon of a black hole, time will stop for you.
Indeed, for any observers, it will appear that you go slower and slower and never quite reach it (ignoring the problems that you would be crushed to death by the gravity!)
However, if your watch were still to work, you would look down and perceive time to be passing as normal.
It is due to the immense gravity that the light you emit takes longer and longer to reach the external observer.
9. Does non-carbon based life exist somewhere in the universe?
No one can say no in answer to this, because we do not know what else is out there.
However, it seems likely that due to its chemical properties that life elsewhere would need to be based on carbon if it was of any size, although we cannot say for sure.
There are not that many elements that seem to have the flexibility that carbon does, the stability and abundance... however it is possible that something like silicon could perhaps be a candidate for life forms elsewhere; for very simple life forms there might be a larger range of candidate elements.
Of course we have no direct evidence of galaxies interacting but it does appear that they can and do, and are at this very moment, interacting.
Usually a violent and energetic affair, galaxies interacting will cause much destruction of existing material and then result in a product phase of much star formation and activity as the repercussions are felt throughout the galaxy.
11. Do black holes really exist?
As far as we can tell, they do exist, yes. Whilst no one has directly seen a black hole, they are of course dark objects so light cannot be seen; the effects of them can be seen.
Specifically the massive gravitational field and its impact can be observed at the centre of galaxies where the orbits of stars and matter do all sorts of crazy things from the intense gravitational pulls, so objects that behave consistently with the behavior of black holes at the centre of galaxies have had their predictions confirmed, yes.
12. Did water come from comets?
One interesting theory is that most of the water came to earth from comets.
The idea is that loads of small comets, about the size of small houses, come into the atmosphere every day.
They vaporize in the atmosphere, leaving their water behind.
The idea is that 10 of these very minute for billions of years over the course of the history of the planet would lead to virtually all the water in the oceans and atmosphere!
This would be significant, as it would give an alternative explanation for the standard idea that the water came from gaseous emissions from the crust of the Earth in the early days post its initial formation...
13. Describe the Venus atmosphere.
Venus has a very strange atmosphere, compared with the similar sized planet next to it - Earth.
The atmosphere is virtually all carbon dioxide - in the region of 9%. The rest is mainly made up of nitrogen. There is thick cloud made of not water but acids like sulphuric acid - nasty stuff indeed.
The pressure is massive in the atmosphere of planet Venus - indeed Venus would crush us, as it is 90 times that of earth!
The temperature on Venus is also massive, around 500 Celsius - even some metals would be liquid on the surface of Venus!
14. How far from earth, is the moon?
The Mean Distance of Moon from Earth is 238,712 miles (384,400 km).
The greatest distance is 252,586 miles.
The shortest distance is 221,331 miles.
Interestingly, the Moon used to be much closer to the earth, and may have had a pivotal role in the evolution of life on the planet and the whole history of the planet before us, that led to our creation.
The implication of this is also that the Moon will not always be with us - the Earth is slowly losing its grip on the Moon and at some stage long, in the future, the Moon will actually escape Earth's gravitational pull and out of Earth's gravitational grasp.
15. How fast is the solar wind?
A very interesting questions this about the speed of the solar wind. This depends on conditions in and around the sun and how particularly active it is at the time and therefore varies greatly. It moves between around 200 to 900 kilometers per second.
16. How have some stars had time to die since the universe began?
This often confuses people that there are stars that have been through their entire life cycle yet there are many stars still forming.
Well part of the answer is that a large star burns quicker and dies quicker so might have its whole life cycle in the fraction of the time a star as if our own Sun does which is perhaps mid sized.
Therefore, it might take a billion years for a large star to go through its lifecycle and if stars started to form around a billion years after the big bang, then after 2-3 billion years stars could have burnt out, thus they could have died already.
Saturn is like earth in the sense that it is one of the planets of the solar system.
Earth is also a planet. They also both are alike in that they go around the sun.
Also they both have moons, though earth has just one and Saturn has so many that we still don't know what they all are and more and more are being found around Saturn all of the time.
Therefore, in these ways they are similar.
18. How is Venus different to earth?
Venus is different to planet earth in quite profound ways. We focus, being alive, on the fact that Venus could surely not support life. This focuses us in on some massive differences between the two planets.
First, up, Venus rotates extremely slowly compared to earth.
It also has a magnetic field that is almost non-existent - not good for life! Of course, the temperature means it is so dry and there is hardly any water.
There is extreme pressure on the surface and temperature, and the atmosphere is very dense with a run away greenhouse effect.
Venus is like Earth in some ways, mainly cosmetic, but very different in others.
However until we studied Venus in general it was thought to be a sister planet but the reality is very different. In terms of similarities are the two main facts:
1) It is the closest to Earth in the solar system, very close indeed in planetary terms
2) The second thing is that it is a small rocky planet, of almost the same size as earth
However as you will see in the differences to Earth question I just answered, the differences between the two planets Earth and Venus are much more profound than the similarities.
20. How long is a day on Saturn?
A day on Saturn is hard to measure, however scientists now believe that the value of a day on Saturn in terms of length is around 10 hours and as such being ten hours compared to our 24 it is less hours than a day on earth.
21. How long is a year on Saturn?
Saturn is much further from the Sun than the Earth is. Therefore, for it to complete its orbit around the sun once takes much longer than for Earth due to the much wider circle it has to go around in order orbiting (well, ellipse).
Therefore, the length of a year on Saturn is approximately 29.5 Earth years.
So if you want to feel a lot younger and be a child again, define your age in Saturn years instead of Earth years!
22. How long is it until our solar system ceases to exist?
It is thought that the sun is approaching roughly the halfway point of its life.
In addition, the solar system - the system of the sun - lives and dies with its star, at least in turns of being active, because it is the heat and energy from the sun that sustains the reactions on the planets that are within the reach of its light and gravitational force.
The sun has several billion years to go yet until it cools and expands, so we are no immediate danger from the sun - in fact, we can guarantee that by the time the sun is big enough, nothing we recognize as human will exist.
23. How many black holes are there?
We do not know for sure, 100%, that there are any black holes. However, beyond reasonable doubt, when the compact object in an X-ray binary system is shown to be more massive than about 3 times the mass of the Sun, then this compact object is a black hole.
With regard how many there are in total, it is thought that many, perhaps most; galaxies contain a massive black hole in their centers. If this is the case, then there will be almost as many black holes as galaxies - a great number!
24. How many earths can fit into Jupiter s great red spot?
The great red spot is a storm on Jupiter that has been raging for around 300 years or so - that is when it was first spotted.
That is quite a storm really is not it, and we do not know when it will die out. It is also rather large as the question implies.
The answer is that it is estimated something in the region of two earths would fit into the great red spot alone, which gives some idea of the colossal scale of the gas giant that is Jupiter in comparison to the smaller ball of rock that is planet Earth.
25. How many moons do Ceres have?
Ceres is a big asteroid that has just become a wannabe planet in the new solar system, unbelievably, or at least is a pluton.
