some notes on universe chapter
Answers
hey mate here is ur answer..
Universe is a huge space which contains everything that exists. The width or extension of universe is about 100000 light years.
The distance between the earth and sun is measured in astronomical unit.
1AU = 1.5*1011m
The distance travelled by the light in one year is called light year.
1 light year = 9.5*1015m
The distance at which mean radius of the earth sustends an angle of second of arc is called parsec.
1parsec = 3.1*1016m
Constellations are the group of stars having fixed shapes. Examples: Aries, Cancer, Aquarius, Leo, Libra etc.
Galaxy is the system of stars that consists star, star clusters, dust and gases held together by gravity.
Our solar system is in the distance of 30000 light years from the Milky Way galaxy.
Solar system is composed of the sun, eight planets including the earth, satellites, asteroids, comets, meteorites etc. The distance in the space is measured in the term of light year.
Planets
Planets are the heavenly bodies which revolve around the sun in elliptical path without being intersected by path of other planets.
There are major eight planets in the solar system.
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
The closest planet and the farthest planet from the sun is mercury and Neptune respectively
Mercury is the fast rotating planet.
Venus is the brightest planet.
Mars is red planet.
Jupiter is the largest planet.
Satellites
Natural satellites
Those naturally occurring satellites which revolve around the planet in their fixed orbit are called natural satellites.
Moon is the natural satellite of the earth.
Artificial satellites
Satellites made artificially on earth for the specific purpose are called artificial satellites.
Asteroids
Asteroids are the tiny planets made up of rocks and metallic substance which revolve around the sun between the Mars and Jupiter.
Comets
Comets are the non luminous body made up of chunk of gases, dust and ice . When comets come near to the sun, the ice particles in the comet starts to melt but due to the gravity of the comet it does not let the ice particles melt and the melting ice particles are attracted by the comet and as a result a tail is seen in comet when it approaches the sun.
The orbit of the comet is highly elliptical.
Meteoroids
Meteoroids are the small pieces of stony matter falling from the space to the earth due to the earth gravity. They are also called shooting stars and falling stars.
Stars: stars are the luminous bodies that produce the energy inside the core by nuclear fusion. There are large clouds of hydrogen gas called nebula and other materials. When the clouds and other materials attain a certain size, they start to contract due to effect of gravitation among them. Finally, these clouds are compressed to highly condensed mass. As a result, a protostar is formed. The protostar again condenses due to gravity and the clouds heat up and the pressure and the temperature also increases. At last, the core of protostar gains very high pressure and temperature and this results in the nuclear fusion reaction which provides enormous energy to the new star. This way, stars are formed.After a certain period; the hydrogen gas gets turned into helium gas. When helium gas cannot fuse with each other, there is inward gravitational pull, the star contracts continuously and temperature in the core further increases. This causes the expansion of the outer layer and size of star. The size increases considerably. A stage comes when the star becomes very large in size and red in colour. This red star is called red giant. A star remains red giant for million years. At the end of the stage, there is enormous release of energy which causes violent explosion called supernova. The star gets scattered and after some interval of time, its brightness finishes. This is called the death of star.
Black hole
Black holes are the remnant of stars so condensed that its gravitational force pull can even prevent light from escaping it. If the initial mass of the star is five times the mass of the sun, then the red giant of that star will form a black hole.
hope it may help u..
and thnxx for this wonderful question