 Many of you probably know the song “Twinkle Twinkle Little Star” and some younger kids may think that all the things they can see in the sky are stars. Well, it is not true. There are many different objects in the sky. Do you know the solar system? The word “solar” means the sun and the term “solar system” is used to mean the sun and all the celestial bodies that orbit around it. The solar system includes the eight planets, five dwarf planets, 174 satellites plus countless fragments of leftovers called asteroids, meteors, and comets, excluding the stars. The solar system was formed 4.6 billion years ago after the explosion of a star supernova. The explosion produced a lot of dust and gases which combined to form the sun and other astronomical bodies. This whole incident is referred to as the Big Bang Theory. The solar system resides in the Milky Way Galaxy, about 28,000 light years away from its center.
The Sun
The sun is a large star that is located in the center of the solar system. The sun was created 5 billion years ago and has a total life of 10 billion years. The Earth is about 145 million kilometers from the sun. The light of the sun takes around 8 minutes and 17 seconds to reach the Earth. Because of its huge size and strong gravitational pull, the sun causes the planets to rotate around it. If you were to try to put the earth in the sun, you could put 109 earth sized planets into the sun. Its temperature ranges from 5505 degrees Celsius on the surface. Such high temperatures are caused by the fusion of hydrogen into helium. The sun is the most important source of energy for the Earth.
Planets
Planets are the celestial bodies that orbit around the sun. They do not have light of their own and reflect the light of the sun. There are eight planets in the solar system which revolve around the sun in fixed orbits. The solar system is basically divided into two sub-parts, the inner solar system comprising of Mercury, Venus, Earth and Mars, whereas the outer solar system consists of Jupiter, Saturn, Uranus and Neptune. Initially, Pluto was considered a normal planet but now it is known as a dwarf planet. In 2006, The International Astronomical Union had ruled that Pluto was not a planet because it’s too small, too far from the sun, not round enough, and mostly made of ice. Also, Pluto has an irregular orbit whereas all the other planets have regular orbits. Let’s take a look at the eight planets in more detail.
Mercury: Mercury is the smallest planet. It has the fastest revolution in the solar system which is only 88 days. Mercury has no atmosphere or satellite. Venus: Venus is known by the names “Earth’s Twin”, “Morning Star”, and “Evening Star.” Venus is the brightest and hottest planet in the solar system. Venus is also closest to the earth. The planet has no satellite and it rotates in a clockwise direction, unlike the other planets. Earth: The Earth, also known as the Water Planet, is the planet where you are living. It is the densest of all planets and rotates in the counter clockwise direction. The Earth takes 23 hours and 56 minutes to complete one rotation and, 365 days, 5 hours and 48 minutes to complete one revolution. It has only one satellite known as the moon. Mars: Mars is known as the Red Planet. The latest discoveries show the possibilities of existence of life there. It has two satellites, namely, Phobos and Deimos. Jupiter: The largest of all the 8 planets, Jupiter is known as the “Lord of Heavens”. It has the fastest rotation time in the solar system, which is 9.8 hours. It comprises of 63 satellites, the largest being Gannymede. The Red Spot on its surface is indicative of a huge storm. Saturn: Saturn is the second largest planet in the solar system. It’s a very pretty planet because it has three well defined rings. Saturn takes 29 years to revolve around the sun and 10.3 hours to rotate on it axis. It has the lowest density among all the planets and it has 31 satellites, among which Titan is the most famous. Uranus: Uranus rotates in the most peculiar way from north to south as it is inclined at an angle of 98 degree from its orbit. It is surrounded by 9 faint rings and it has 21 satellites. Neptune: The furthest planet form the sun, Neptune takes the longest time for revolution (165 years) and rotation (15.7 days). It has 13 satellites.
Sky Wonders
Have you ever seen a sky wonder? If you have seen a solar eclipse, a lunar eclipse, comets, asteroids or meteor showers, you have seen a sky wonder. Let’s learn more about them.
Solar Eclipse: A solar eclipse occurs when the sun, moon, and Earth are in the same straight line with the moon coming between the Earth and the sun. It casts a shadow on the Earth. A solar eclipse can be partial or total. Lunar Eclipse: A lunar eclipse occurs when the Earth, sun and moon are in a straight line with the Earth coming in between the sun and the moon. It casts a shadow on the moon. Comets: Comets are irregular small bodies with a head and a tail. A comet has a highly elliptical orbit with its tail appearing only when it gets closer to the sun. A prime example is the Hailey’s Comet, which can be seen every 76 years. Asteroids: Asteroids are the fragments left over after the formation of inner planets. Hundreds of thousands of asteroids have been identified and each year, thousands more are discovered. Meteor Shower: A meteor shower is a phenomenon in which a large number of meteors radiate from a particular point in the sky. Some of the meteor showers which can be seen in 2011 include the Quadrantids, Lyrids, Perseids, Draconids, and Leonids.
Constellations
Constellations are clusters of stars grouped together. They form patterns of various imaginary figures in the sky like the Great Dog, the Hunter, and more. Constellations are very useful for calculating or locating planets and other astronomical bodies. Here are some of the most famous constellations. Andromeda: This constellation is found in the Northern sky. It is named after a mythological princess who was tied to a rock and left to be eaten by Cetus, a sea monster. The Great Dog: Also known as Canis Major, this constellation is in the southern skies. One of Orion’s dogs, its brightest star is Sirius. Big Dipper & Little Dipper: The Big Dipper is a pattern of seven stars, which are the brightest in the Ursa Major. The Little Dipper refers to the tail of the Little Bear, which appears somewhat like the handle of a ladle. The brightest star, Polaris, or the North Star is a part of the Little Dipper. Gemini: Gemini is a constellation of the zodiac. Known as the Twins in Latin, it has two stars known as Castor and Pollux, which represent their heads. Scorpius: A constellation of the zodiac, “scorpius” means scorpion in Latin. Lying between Libra and Sagittarius, it’s located in the southern hemisphere. Taurus: Another constellation of the zodiac, “taurus” means bull in Latin. Located between Aries and Gemini, Taurus can be found in the northern hemisphere’s winter sky. Orion: Also known as the Hunter, this constellation is almost visible to everyone. This is one of the most popular constellations.
The Remaining Constellations Altogether, there are a total of 88 constellations which have been officially recognized. Some of the remaining constellations include Cancer, Aquarius, Lynx, Pegasus, Serpens, Virgo, and Piscis Austrinus.
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