Universe can not be described as huge, enormous or gigantic. It is all that, and more. To our senses, it truly is infinite. The scale of everything in the universe is huge, as you will shortly see.
GRAVITY:
But first, we need to understand the single most important force in the Universe, Gravity. Gravity is what keeps us grounded to Earth. But not only Earth, every big object exerts Gravity. Bigger a body, greater the gravitational force. This force not only keeps us from flying off to space, but also keeps the satellites around the planets, planets around the Sun, the Sun around the center of our Galaxy , and so on.
SOLAR SYSTEM:
All the ‘things’ in space – planets, stars, moons, etc. – are all collectively called heavenly bodies. The one we know best? Our Earth! Isn’t Earth big? So much of land, and then three times of that water. Well, if you consider the Sun, and the Solar System, Earth would actually come across as quite tiny.
Our closest neighbour in space is moon, Earth’s natural satellite, and about a quarter its size. The solar System has 8 ( earlier 9 ) planets.
In order of their distances from the Sun, they are:
1. Mercury: Closest, No moons, No atmosphere, Rocky Planet.
2. Venus: Hottest Planet, Thick Atmosphere, No Moons, Rocky Planet.
3. Earth: Only known life sustaining planet, At just the right distance from Sun, 1 Moon, Rocky, blue Planet.
4. Mars: Mild, Earth like Temperatures, Frozen Polar Cap water, 2 Moons, Rocky Red Planet.
5. Jupiter: Biggest Planet, 63 Moons, Gaseous Planet.
6. Saturn: Beautiful, Thin, Wide Rings, 34 Moons including Titan, Gaseous Planet.
7. Uranus: Spins on its side, 27 moons.
8. Neptune : A lot like Uranus, 13 moons, Ice Planet.
9. Pluto: Dwarf Planet, 3 moons, Icy.
Remember them by using the mnemonic:
My Very Educated Mother Just Showed Us Nine Planets.
There are also Asteroids, Meteors, Meteorites: Rocks flying around the space.
Comets: Icy core, Long Dusty Tail, Hailey’s comet every 76 years. Tail can either be in front or back of the core.
GALAXY:
Galaxies are a group of stars- billions of stars, huddled together, revolving around the center of the galaxy.
Solar System forms a part of our galaxy, The Milky way, which is a spiral galaxy.
The Sun and The Stars.
Sun, or Sol, is our star. But it is not exceptional in any way if one considers the Universe. Sun is a medium-sized star on one of the arms of Milky Way. Stars can be much smaller, or much bigger than the Sun.
Space consists of a lot of empty space, and interstellar medium made mostly of a gas called Hydrogen. This ‘cloud’ of dust and gas is called a Nebula. When a portion in the Nebula compresses, the gases heat up immensely, and a rotating gas globule is born. This rotating globule finally settles into a central core (the Star) and surrounding planets, asteroids, etc.
Stars don’t live forever. When their fuel runs out, they die. According to their sizes, they can become a White dwarf or a neutron star/ Black Hole following a supernova explosion.
THE START:
How did it all start? With a big bang, literally. All the galaxies in Universe are moving away from each other, like dots on an inflating balloon. It must have all, therefore, started with a super-huge explosion, often called as The Big Bang.
THE EXPLORATION:
How do we know all this? Astronauts have only gone as far as the moon. Then, how we know all that we know about the Universe? The scientists use a lot of equipments to ‘see’ space. Unmanned spaceships, probes, and Telescopes, all help to enhance our understanding of the space. Hubble Space Telescope, for example, has sent invaluable data about the space.
No comments:
Post a Comment