Our solar system consists of the sun, the eight planet namely: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. It also includes: the five dwarf planets, their 173 satellites or moons, thousands of comets, asteroids and interplanetary dusts. Just like our Earth that has extremes, the solar system takes pride of having its own extremes, below are some of them.

The Densest Planet

Earth, where millions of species including humans inhabit, is the only place in the universe where life is known to exist. Its outer surface is divided into tectonic plates, that slowly travel across the surface over periods of many millions of years. About 71% of the surface is covered with water, the remainder consisting of continents and islands.  Liquid water is, of course, essential for life as we know it. The Earth’s atmosphere is composed of 77% nitrogen, 21% oxygen, with traces of argon, carbon dioxide and water.

The Least-Dense Planet

Saturn is the second largest planet in the solar system and the planet with the least density. It has an equatorial diameter of 119,300 kilometers (74,130 miles). It would take 29.5 Earth years for Saturn to orbit around the sun and its day is 10 hours, 39 minutes long. Hydrogen with small amounts of helium and methane composed the planet‘s atmosphere. Its density is lesser than water, so Saturn would float in water if  a large ocean could be found.  The wind near the equator that blows mostly in an easterly direction could reach a speed of 500 meters a second (1,100 miles an hour). Its ring system makes Saturn one of the most beautiful objects in the solar system. The rings are divided into a number of different parts, that include the bright A and B rings and a dimmer C ring.  Saturn has 30 known satellites and more are being discovered. And lastly, Saturn is the most flattened planet in our Solar System; the difference between its polar and equatorial diameters is about 10%.

The Biggest Planet

Jupiter is the largest planet within the Solar System and the fourth brightest  object in the sky (after the Sun, the Moon and Venus). Would you believe that all the other planets in our Solar System could fit inside Jupiter. Jupiter has a mass of 1.9 x 1027 kg and is 142,800 kilometers (88,736 miles) across the equator. It has 28 known satellites that include: Callisto, Europa, Ganymede and Io. It has a simple ring system that is made up a main ring, an inner halo, and a Gossamer ring ( once taught to be a single ring but images send by the space probe Galileo tells it actually are two rings. Jupiter is primarily composed of hydrogen (90%)with a small proportion of helium about 10%.  It is also the planet where you would feel the heaviest. If you weigh 100 pounds on earth, you will weigh 254 pounds on Jupiter. It is also the planet with the Shortest Day: A day on Jupiter only takes 9.8 Earth hours! 

The Smallest Planet 

After Pluto was declared a dwarf planet in 2006, Mercury is now recognized as the smallest planet in the solar system measuring 4879 km along its equator. Mercury is bare and rocky, with many craters and consists of approximately 70% metallic and 30% silicate material. Mercury is extremely dense with a density of 5.4 grams per cubic centimeter. Mercury is also the planet with the shortest year: it only takes 88 earth days for it  to orbit the Sun.

Most Tilted Rotational Axis

Uranus is the third largest in the solar system. This huge, icy planet about 51,118 km in diameter, is covered with clouds and has at least 22 moons and 11 rings.  A day on Uranus takes 17 hours 14 minutes and it revolves around the sun once every 84.01 Earth years. Uranus is a frozen, gaseous planet where the atmosphere is consists of 83% hydrogen, 15% helium and 2% methane.
Uranus, whose axis is tilted 97.9 degrees on its side. Unlike other planets that rotate on an axis almost perpendicular to the plane of the ecliptic, Uranus spins on its side (along its orbital path), thus resulting to extreme seasons.

Orbit Most Inclined From the Ecliptic (Excluding Comets)

Pluto which was classified as a dwarf planet in 2006, is about 1,413 miles (2274 km) in diameter. Its mass is about 1.29 x 1022 kg (about 1/500th of the mass of the Earth). A 100 pound person on Earth would weigh only 8 pounds on Pluto because its gravity is too weak. Each day on Pluto takes 6.4 days on Earth, and would take 247.7 Earth years for it to orbit the Sun.  
Pluto has a very eccentric orbit; it is tilted 17.15 degrees from the ecliptic meaning it does not maintain a constant distance from the sun as it revolves around the sun. It also spin about its axis in the opposite direction from most of the other planets.

The Hottest Planet

Venus which is 12,100 km. in diameter is the hottest planet in our solar system. 95% of its atmosphere is carbon dioxide and nitrogen, sulfuric acid and other elements comprised the remaining 3.5%. At the surface, the temperature ranges from 900F+/- 50F (about 500°C +/- 32°C). Venus is covered with thick clouds that create a greenhouse effect that makes it very hot.   
Also, Venus is the planet with the longest day; orbiting the sun once every 224.7 days in a counterclockwise direction at an average distance of about 108 million km. A day on Venus takes 243 Earth days (called a sidereal day). Venus rotates very slowly that its sidereal day (one complete rotation on its axis) is longer than its year (224.7 Earth days).

The Coldest Planet with the Longest Year

Now that Pluto is considered as a dwarf planet, Neptune is now the coldest planet in  the solar system. Since it is the farthest planet from the sun, its outer atmosphere is one of the coldest places  making it’s temperature an icy -125 degrees Celsius. Neptune has a mass of 1.0243 × 1026 kg, and an equatorial diameter of 49,500 kilometers. radius of 24764 km. A day on Neptune is 16 hours and 6.7 minutes and orbits the Sun every 165 Earth years making it the longest year in the solar system. It has eight moons and  has a set of four faint and narrow rings. Neptune has the fastest and strongest winds on any planet that could measure up to  2,000 kilometers (1,200 miles) an hour.

The Biggest Moon

Ganymede is the largest moon in the solar system and also the biggest moon of Jupiter. It has a diameter of 5,262 km (3,280 miles)and is most likely made up of a crust of rock and ice with a mantle composed of  water/ice. It has mountains, valleys, craters and lava flows but has no known atmosphere.

The Only Two Moons With Atmosphere

Titan (photo above), a moon of Saturn and Triton, the biggest moon of Neptune, are the only two moons with dense atmosphere. Next to Ganymede, Titan is the second largest moon in the solar system that has a diameter almost 50% larger than Earth’s moon. It is largely composed of rocky material and water ice and its atmosphere is mainly composed of nitrogen, methane and ethane clouds.

The Biggest Storm

The Great Red Spot is one of the most identifiable features on Jupiter. It is an enormous storm that has been spinning around the planet for hundreds of years. It is about 17,000 miles (28,000 km) long and 9,000 miles (14,000 km).

The Biggest Volcano

Mar’s Olympus Mons is the solar system’s largest volcano. It is three times higher than Mount Everest and covers an area larger than the whole Hawaiian volcano chain. Olympus Mons slopes rise only a few degrees at a time so it would not be difficult to climb it.

The Largest Impact Crater

Valhalla is the largest impact crater in the solar system. It is found in  Jupiter’s moon Callisto that has a 600 kilometers across central bright spot and concentric bright rings that stretches to about 1500 kilometers from the impact center.

The Smoothest Object

Europa, a large and unique moon of Jupiter, is among the brightest and the smoothest object in the solar system. Its surface made up mostly of ice lacks heavily cratered appearance but instead has lines and cracks wrapping the exterior. Europa is roughly  3,160 kilometers (1,950 miles) in diameter.

The Most Eccentric orbit (Excluding Comets)

Nereid, a moon of Neptune has the most eccentric orbit in the solar system. It is about 340 kilometers (210 miles) in diameter and takes 360 days to orbit Neptune once. Its distance to Neptune varies from about 1,353,600 kilometers to 9,623,700 kilometers.

The Largest and Brightest Asteroid

Some years ago, Ceres with a diameter of 950 km was the largest asteroid in the solar system, but in 2006, the International Astronomical Union classified it as a dwarf planet. So today, Vesta is the largest asteroid in the solar system. It is about  530 km in diameter. Vesta is also the brightest asteroid.