How big is the Universe?
Astronomers say that the universe is without an end and that it is expanding!
Proxima Centauri is the nearest star to the Sun. It is only about 43.000.000.000.000 kilometres away.
Our galaxy, the Milky Way is 100.000 light years across. (1 light year is 10 million million kilometres.)
How old is the universe?
How did it come into being?
Many astronomers belive in the "big bang theory". It says that all the matter we can find in the universe today was once packed together. About 15.000 million years ago all this exploded and was thrown out into space. That is also the reason why the universe is still expanding.
The Solar System
The Sun is the centre of the Solar System. It is a medium sized star. It has a temperature of about 6.000 C at the surface.
Mercury is the second smallest planet and is about the same size as the Moon. It is the planet closest to the sun. The temperature can go up to 400 C. It takes Mercury 88 days to go around the Sun.
Venus can often be seen in the morning and in the evening here on earth. It looks like a star. Venus is the hottest of the planets. The temperature can go up to 500 C. The surface is rocky and covered with craters.
Earth is the fifth largest planet. From the space it looks bluish. The temperature varies from 60 C to -90 C. Most of the surface (75%) is covered with water.
Mars has a reddish colour on the surface and it is very rocky. It has a volcano that is 25.000 m high. There are no "little green men" on Mars. The planet is too freezing cold for anyone to live there.
Asteroids are lumps of rock of different sizes. Some astronomers belive that they are traces of a planet wich has exploded. Between Mars and Jupiter there is a belt of asteroids.
Jupiter is the largest planet. It is more than 1.300 times the size of the Earth. It is mostly made up of gas and ice crystals. You can recognize Jupiter beacuse of its "red eye". This is an enormous hurricane that has been active for thousands of years.
Saturn is the second largest planet. The most typical thing about it is the rings. They consist of blocks of ice which circle around the planet.
Uranus is a blue-green planet quite a long way from the centre of the centre of the solar system. There are nine rings which circle the planet. Some areas of Uranus have daylight for 42 years followed by 42 years of "night".
Neptune is 4.497 million kilometres from the Sun (Earth is 149 million kilometres way). The light from the Sun does not give Neptune much heat. It is therefore a cold planet covered with ice.
Pluto is the smallest of the planets and the one furthest away from the Sun. It takes Pluto over 248 years to go around the Sun. Not much is known about Pluto but it is thought to have no atmosphere and to be covered with ice.
-to correct you on some of your info the universe is estimated at about 13+ billion years..-1 light year is a little over 6 trillion miles.-venus is atmosphere is also ver y toxic as well with sulfuric acide and CO2.-earth is the only planet with known life on it.-aliens do not exsist-and its impossible to search the entire universe.-mars also has the the larget known moutain region in the known universe called Olympus Mons.-uranus and neptune are both covered large amounts of methane and ammonia and hydrogen-pluto infact is just a giant ice ball since it so far away fro mthe sun, also some people don't consider pluto to be even a planet at all.
how...many accurate data about universe,interesting description.we were eager to know where we were in and from when mind was available.we are so chickenshit comparing with the space and time.universe is too vast to imagine how it is.in addition,through more researches in the solar system only earth can breed lives...no convinced evidence to prove only 9 planets in solar system till now,because to many secondary planets can become a member of solar system at any moment.however we are sure that only earth have the living condition to maintain living.
When you look at the night sky and make a wish upon your favorite star, you may not be wishing on a star at all. What most of us perceive with our eyes to be stars are sometimes much much more. Some of the objects in the night sky are actually just the planets in our solar system reflecting the sun's bright sunlight. Other objects may be comets or a whole galaxy of stars. Though these objects seem close together in the sky, we know that they are actually a great great distance apart.To get a better picture of the immense size of the universe we study many of the objects in space and the distances between them.
That one question always makes me wonder. Is there other life out there? Not that we know of but there could be. SM the definition alien, someone from a foreign country or someone that doesn't fit in so there very well could be aliens out there. We just don't know of them. They probably don't look like the ones little kids think of with one eyeball and green but you never know. You can't really say there is none because we haven't explored the whole universe and probably never will. We would have to be able to travel the speed of light to catch up with things. I personally believe that there probably once was life on mars or some type of life but I guess I'll have to wait and see.
It is quite possible extraterestial aliens will be green. If their planet originates closer to their sun or the sun has higher energy output, it might be beneficial to harvest energy directly from sun to body even for larger massed beings. Also, your wrong about using speed of light to catch up. Our telescopes already see light traveling at the speed of light, and the hubble very deep field has seen objects some eleven billion light years away. The universe also expands faster then the speed of light and in actuality it could be some twenty-six billion light years wide.