:: La réparation du satellite Hubble !:Reparation of hubble!

Hubble has a problem so we sent some people to reparate it.

Hubble a un problem alors on a envoyer des gens pour le reparer.

Si vous voulez voir les plus belles images de l'opération, cliquez ici.
If you want to see some pictures, clic here.

:: Uranus

Uranus is the third Gaz Gigantic Planet And seventh from the sun.

Uranus is containd of: rock, different kind of ice, 15° helium, 83° hydrogene and 2° methane. It gaz gives its blue light.

• Diameter: 51 100 kms.
• Distance to the sun: 2,9 milliards of kms.
  
• Duration of rotation: 17 hours.Uranus looks like it is on its side and it turns in that orbit.
  
• Duration of revolution: 84 hours.

:: Jupiter

Jupiter is the fifth planet and the largest one in the solar system.

There is a ring system, but it is very faint and is totally invisible from the Earth.

Jupiter is the third shiniest after the sun!

Jupiter has been visited for the first time by the satellite Pioneer 10.

Jupiter has a great red spot (which is a storm), that has been observed 300 years ago.

The spot is big as 3 times the Earth!

The comet Shoemaker-levy 9 crashed into Jupiter. What we could see was incredible!

Jupiter is composed of gases caled hydrogen and helium, and other gases over a tiny rocky core.

Most other planets in other solar systems are a bit heavier than Jupiter but Jupiter is larger than them.

• Duration of rotation : 10 hours!
• Duration of revolution : 12 years!
  
• Diameter : 142,981 kms. 11 times the Earth!
  
• Distance from the sun: 779 million kms.
  

:: Venus

Venus is the second planet from the sun, and the seventh largest. It is Earth's neighbour and has been observed by satellites.We sometime call Venus the Evening star because at night (a long time ago) people thought it was a star and it was the first to shine. Now we know Venus is not a star but a planet.

Quick facts

• Moons: none
• Distance from the sun: 108 200 000 kms.
• Diameter: 12104 kms.
• Duration of revolution: 224,7 days.
• Duration of rotation: 243 days.

Venus's rotation is so slow that a Venus year is smaller than a Venus day.

At some point, astronomers thought Venus was divided in 2.

Surface

About 85% of Venus's surface is covered by volcanic plains covered by layers of lava. There are a lot of craters on Venus but still very few compared to Mercury and the Moon.

Spacecrafts

The first spacecraft to observe Venus was Mariner 2. Since then other spacecrafts have orbited Venus. A few landed on the planet's surface, were able to send a few pictures back to Earth and melted.

Orbit

Venus's orbit is the one that is the less elliptical. It is the only planet to turn in a different direction.

Atmosphere

Venus's atmosphere is composed of: 90.5 % carbon dioxide, 3.5% nitrogen and other gases.

Venus's clouds contain a little water vapor, but we have little reason to think that water in any form exists on the planet itself. We think that most of the water that initially existed on Venus evaporated, when the Sun started to get warmer, and moved up to the upper atmosphere. This created a greengas effect, making the planet even warmer.

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:: Jupiters : 63 moons !

Jupiter with its 63 moons.

Names coming from Zeus's servants etc...

Let me present the four mane ones, discovered by Galileo in 1610...

Europa

The latest discoveries show that there may be life on Europa, the ice field that covers Europa seem to hide a ocean, very exiting indeed but the possibilities of life are small.

Europa is smaller than The Moon but much brighter, in fact it's one of the brightest moons in the solar system. This is caused because of sunlight reflecting off a relatively young icy crust.

Europa is named after the gorgeous Phoenician princess, who (according to the Greek mythology) was gathering flowers when Zeus spotted her and instinctively fell in love with.

• Distance from Jupiter :670 900 kms.
• Diameter: 3 138 km.
• fourth biggest satellite from Jupiter
• Discovered by: Galileo

Io

A bit bigger than the moon, Io orbits around Jupiter from about the same distance as the moon is to the earth.

Active volcanoes are present everywhere on Io.

• Distance from Jupiter: 421 600 km
• Time to orbit Jupiter: 1. 77 days
• Diameter: 3 643km
• Discovered by: Galileo

Ganymede

Ganymede is the largest moon of Jupiter, as Callisto it is mostly composed of a rocky core with a water/ice mantle and a crust of rock and ice. It was formed with 60% of rock and 40% of ice.

• Distance of Jupiter: 1. O7 million km.
• Time top orbit Jupiter: 7.15 days
• Diameter: 5262 km

Callisto

As Europa, this satellite is brighter than the moon. Callisto is a bit smaller than Mercury but contains on third of its mass.

Callisto is surely the most heavily cratered object in our known solar system. Its largest crater is named Valhalla. Valhalla's diameter is 2 485 km.

• Distance from Jupiter: 1.88 million km
• Time to orbit Jupiter: 16.69 days
• Diameter: 4821km

:: Saturn moons

Main moons of Saturn:

Prometheus

Prometheus, the third known moon of Saturn, is small and potato-shaped and it orbits Saturn in the ring F. It has a few craters of about 20 km that are in diameter visible.

In the Greek mythology, Prometheus was a titan, it is known for stealing fire from Zeus and giving it to humans.

• Distance from Saturn: 139 353 km
• Diameter: 91 km
• Time to orbit Saturn: 0.61 days

Enceladus

Tenth moon from Saturn, Encelade orbits the Planet in the Ring E. This moon is the brightest object in the known solar system. It was discovered by William Hershel in 1789. This moon displays at least 5 different types of terrain.

• Diameter: 500 km
• Distance from Saturn: 238 020 km
• Time to orbit Saturn: 1.37 Earth days

Dione

Nice and round, Dione was discovered by Cassiny the same day as Tethys. It is an icy body and is one of the densest moons of Saturn. Its surface is heavily cratered. Some of its craters are more than 100 km.

• Distance from Saturn: 377 400 km
• Diameter: 1120 km
• Time to orbit Saturn: 2.74 Earth days

Titan

Titan, the size of Mercury, is the largest of Saturn's moons. Before the Voyager encounters, scientists thought a lot of things that are now known to be wrong.

Titan's surface temperature appears to be about -178°C.

• Distance of Saturn: 1.22 million km
• Time to orbit Saturn: 15.9 earth days
• Diameter: 5 150 km

There are much more important moons of Saturn but please don't expect me to write about them because there are... 61!! Only 34 are named though.

The diameters of Saturn's moons range from 2 to 5150 kms.

:: Saturn rings

What makes Saturn so beautiful is her rings. The rings of Saturn are much more elaborate than those of any other planets.

Saturn's rings are divided into 7: D, C, B, A, F, G and E. It is hard to see the F and G rings but A, B and C are visible with a telescope.

(the F and G rings are thin)

Whene Galileo observed the rings for the first time he thought they where moons.

The rings of Saturn are about the 4,000,000 kms wide!

The distance of Saturn to the rings is like the distance of earth to the moon.

They are composed of: icy snowballs or ice covered rocks.

(This picture shows the B ring)