The Solar System

Venus's orbit is the closest. I know because I have looked up the distances of both of them in a book. But how is that fact known? it goes back to Johannes Kepler in the early 1600s who formulated the laws of planetary motion.

Kepler probably noticed that the outer planets Jupiter and Saturn showed the least retrograde motion and he deduced that they therefore must have the largest orbits. Kepler scaled the orbits in terms of their time periods.

The absolute distance to Venus was later found by triangulation, measuring the position of Venus relative to the Sun from two different points on Earth during a transit of Venus. Because the size of the Earth was known, this method yielded the size of Venus's orbit, and then all the other orbits by Kepler's 3rd law. Probably the size of Mars's orbit was also measured by triangulation at some stage as a check.

Gravitational pull is less for Mercury, Venus, Mars and Uranus. And th eother planets have higher gravitational pull.

Because there are only 8 planets in our solar system.

As seen from the planet Earth, the two brightest bodies in the solar system are the sun and the moon. Number three is the planet Venus.

Technically speaking, Neptune is the planet with the lowest surface temperature; however, Neptune does not have a solid surface.

Our earth is considered as a unique planet in our solar system because of the following factors

Firstly, the distance of the earth from the sun results in such a climate which is best suited for the development of man and other forms of life on earth.

Secondly, it is a habitable planet it supports man and other forms of life by providing all the necessities of life.

Thirdly, its atmosphere is rich in Oxygen that makes life possible on this planet.

Fourthly, its atmosphere acts as a large cover to protect its surface from extreme cold and heat. Its mean temperature is 15 degree celsius, which is quite suitable for life to exist on earth.

Fifthly, on this planet water occur in vast quantities which makes life possible on the earth, as water is quite essential for all forms of life.

Generally I'd say Jupiter, but Uranus and Venus also have the same gaseous stripes as Jupiter. Take a look at some satellite pictures of the planets and decide for yourself

Pretty much nil. If there was a new planet, as opposed to a mini-planet such as Pluto, it would have an effect that would have already be recorded.

No. There is much more out there that is still to be discovered. The solar sytem consist of all sort of things, big and small, so there is more to be found.

Inside our Solar System distances are measured in Astronomical Units (AU) which is the average distance from the Earth to the Sun, or about 93 million miles. Jupiter is about 5.5 AU distance from the sun or around 500 million miles. Distances outside our Solar System are usually measured in Light Years.

You would go as fast as you could, which at the moment is round about 20 miles per second for spacecraft. At that speed you would get to the nearest star in 38,000 years.

In the time of the Tudors, 1485-1603, it was believed that what is stated in the Bible, about the Earth being at the centre of the universe, must be true.

Towards the end of that time, and in the Elizabethan era, Copernicus's theory that puts the Sun at the centre of the solar system was being discussed, and it was used by Kepler at the end of that era to show that all the planets including the Earth move in elliptical orbits round the Sun.

Final proof came when the Sun was found to be far more massive than the planets, but that didn't happen until the 18th century.

Exactly like ours? Not that we've seen yet. Are there solar systems orbiting other suns? Sure there are, not many with planets that could support life as we know it tho...

Outer: big, cold, gas giants (and lots of satellites)

Inner: small, rocky, warn (to hot).

The planet diameters in the Solar system are:

Mercury 4,878 kilometers (km)

Venus 12,100 km

Earth 12, 742 km

Mars 6,792 km

Jupiter 142,981 km around its equator, and

133,708 km around the north & south poles. Jupiter is made of gas, so its tremendously fast revolution time makes it bulge out around its equator.

Saturn 120,536 km at equator and 108,728 km around poles

Uranus 51,118 km

Neptune 49,500 km

There is a little bulge in Uranus and Neptune, but not really enough to report.

The planet Neptune is named for the Roman God of the Sea, the equivalent of the Greek Poseidon.

The Milky Way, parts of which we can see from Earth curving around us.

Just the one: good old Sol. Actually, lots of systems do have double, even triple stars. Our nearest stellar neighbor, Rigil Kentaurus, has two approximately Sun-sized stars (one a little bigger, the other a little smaller) plus a red dwarf that orbits them. Currently, this dwarf is at a part of its orbit which is closer to Earth than the other two, so we call it Proxima.

Some people claim that Sol also has a dwarf companion, orbiting at such a distance that it only comes by, rather like a comet, every 26 million years, and that this accounts of mass extinctions. This star, which some call Shiva and some Nemesis, has never been detected. Moreover, it's about 13 million years since the last big extinction, so even if it exists, it's way the heck out there and won't be seen anytime soon.

When Galileo observed that the planet Jupiter has moons which are in orbit around the planet, this made it more believable that planets orbit the sun, since it was already established that not everything orbits the Earth, as had previously been believed in the Ptolemaic system.

Four of the eight planets in the solar system do not have solid surfaces, unlike Earth. Compared with the other three terrestrial or rocky planets, there are three main differences. The most obvious ones are that Earth's surface is covered in liquid water and, with it, living organisms. A third difference that is not as obvious is that Earth's crust is broken up into several dozen technonic plates that slowly move, changing Earth's surface over the course of millions of years.

Originally the Earth was thought to be at the centre of the solar system. Religious teaching put the Earth at the centre and was opposed by Galileo, but he could not produce any proof and eventually recanted. It was not until Kepler's theory of planetary motion in the 16th century and Newton's law of gravity in the 17th were accepted that it was discovered that a better model would be achieved by assuming the Sun is at the centre.

Johannes Kepler

Saturn orbits the Sun like the other planets, it does not orbit anything else. One orbit for Saturn takes 29.4571 Earth years.