The solar System

 

The Solar System is the gravitationally bound system of the Sun and the objects that orbit it. 

The largest of such objects form a planetary system of eight planets, in order from the Sun: four terrestrial planets, named Mercury, Venus, Earth and Mars; and four giant planets, including two gas giants, Jupiter and Saturn, and two ice giants, Uranus and Neptune. 

#MERCURY

Mercury is the smallest planet in our solar system and nearest to the Sun is only slightly larger than Earth's Moon. Its surface is covered in tens of thousands of impact craters.

From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as 11 times brighter.

Despite its proximity to the Sun, Mercury is not the hottest planet in our solar system that title belongs to nearby Venus, thanks to its dense atmosphere. But Mercury is the fastest planet, zipping around the Sun every 88 Earth days.

#VENUS 

Venus is the second planet from the Sun and our closest planetary neighbor.

Similar in structure and size to Earth, Venus spins slowly in the opposite direction from most planets. 

Its thick atmosphere traps heat in a runaway greenhouse effect, making it the hottest planet in our solar system with surface temperatures hot enough to melt lead. Glimpses below the clouds reveal volcanoes and deformed mountains.

#EARTH

Earth, third planet from the Sun and the fifth largest planet in the solar system in terms of size and mass. 

Its single most outstanding feature is that its near-surface environments are the only places in the universe known to harbour life. 

Earth’s name in English, the international language of astronomy, derives from Old English and Germanic words for ground and earth, and it is the only name for a planet of the solar system that does not come from Greco-Roman mythology.

Earth is part of the "observable universe," the region of space that humans can actually or theoretically observe with the aid of technology. Unlike the observable universe, the universe is possibly infinite.

#MARS

Mars is the fourth planet and the furthest terrestrial planet from the Sun. 

The reddish color of its surface is due to finely grained iron(III) oxide dust in the soil, giving it the nickname "the Red Planet".

Mars's radius is second smallest among the planets in the Solar System at 3,389.5 km (2,106 mi). 

The Martian dichotomy is visible on the surface: on average, the terrain on Mars's northern hemisphere is flatter and lower than its southern hemisphere. 

Mars has a thin atmosphere made primarily of carbon dioxide and two irregularly shaped natural satellites: Phobos and Deimos.

#JUPITER

Jupiter is the fifth planet from our Sun and is, by far, the largest planet in the solar system  more than twice as massive as all the other planets combined.

Jupiter's stripes and swirls are actually cold, windy clouds of ammonia and water, floating in an atmosphere of hydrogen and helium. 

Jupiter’s iconic Great Red Spot is a giant storm bigger than Earth that has raged for hundreds of years.

#SATURN

Saturn, second largest planet of the solar system in mass and size and the sixth nearest planet in distance to the Sun. 

In the night sky Saturn is easily visible to the unaided eye as a non-twinkling point of light. 

When viewed through even a small telescope, the planet encircled by its magnificent rings is arguably the most sublime object in the solar system.

#URANUS

Uranus is the seventh planet from the Sun and is a gaseous cyan ice giant. 

Most of the planet is made of water, ammonia, and methane in a supercritical phase of matter, which in astronomy is called 'ice' or volatiles. 

The planet's atmosphere has a complex layered cloud structure and has the lowest minimum temperature of 49 K (−224 °C; −371 °F) out of all Solar System's planets.

#NEPTUNE

Dark, cold, and whipped by supersonic winds, ice giant Neptune is the eighth and most distant planet in our solar system. 

More than 30 times as far from the Sun as Earth, Neptune is the only planet in our solar system not visible to the naked eye. 

In 2011 Neptune completed its first 165-year orbit since its discovery in 1846.

The terrestrial planets have a definite surface and are mostly made of rock and metal. The gas giants are mostly made of hydrogen and helium, while the ice giants are mostly made of volatile substances such as water, ammonia, and methane. 

In some texts, these terrestrial and giant planets are called the inner Solar System and outer Solar System planets respectively.

The Sun, Moon, and brightest planets were visible to the naked eyes of ancient astronomers, and their observations and calculations of the movements of these bodies gave rise to the science of astronomy. 

Today the amount of information on the motions, properties, and compositions of the planets and smaller bodies has grown to immense proportions, and the range of observational instruments has extended far beyond the solar system to other galaxies and the edge of the known universe. 

Yet the solar system and its immediate outer boundary still represent the limit of our physical reach, and they remain the core of our theoretical understanding of the cosmos as well. 

Earth-launched space probes and landers have gathered data on planets, moons, asteroids, and other bodies, and this data has been added to the measurements collected with telescopes and other instruments from below and above Earth’s atmosphere and to the information extracted from meteorites and from Moon rocks returned by astronauts. 

All this information is scrutinized in attempts to understand in detail the origin and evolution of the solar system a goal toward which astronomers continue to make great strides.