5th Class Science Earth, Moon and Sun Our Universe

OUR UNIVERSE

FUNDAMENTAL

• Universe is all of space and everything having stars, planets & galaxies etc.
• Astronomy is branch of science that deals with the study of celestial bodies.
• A star is luminous sphere of plasma held together by its own gravity, the nearest star to Earth is the Sun.

SOLAR SYSTEM-SUN IS THE NEAREST STAR.

Planet is a celestial body made up of rocks, metals and gases, which revolve around a star. Sun has 8 planets orbiting around it.

OUTER PLANETS

These are four planets in solar system which are very far from Sun. These are Jupiter, Saturn, Uranus and Neptune.

INNER PLANETS

            These are four inner planets which are closer to the sun. These are mercury, Venus, earth and mars.

SOLAR ECLIPSE

This occurs when moon (which revolves around the earth) comes directly in between the earth and the sun and hides he sun partially or fully from the earth view. Solar eclipse can only happen during a new moon. Two to five solar eclipses occur in a year.

LUNAR ECLIPSE 

            It occurs when moon passes in the shadow of the earth. The moon may remain eclipsed for about an hour.

MOON                         

The moon is the only natural satellite of the earth,   so revolves around the earth. It does have any light of its own, it shines by reflected light of the sun.

We see different part of the moon while it orbits around the earth. The changing shapes are called phases of the moon. There are five major phases of the moon.

Moons gravitational pull is (1/6^th) of the earth. So it is very difficult to walk on moon. As the moon has no air or wind the astronaut's foot prints will remain there forever.

METEORS AND METEORITES

A meteor is a bright streak of light in the sky (a "shooting star" or a "falling star") produced by the entry of a small meteoroid into the Earth's atmosphere. If you have a dark clear sky you will       probably see a few per hour on an average night; during one of the annual meteor showers you may see as many as 100/hour. Very bright meteors are known as fireballs.

ASTEROID

Asteroids are rocky worlds revolving around the sun that are too small to be called planets. They are also known as planetoids or minor planets. There are millions of asteroids, ranging in size from hundreds of miles to several feet across. In total, the mass of all the asteroids is less than that of Earth's moon. About 35000 asteroids are orbiting around the sun.

COMETS

A comet is an icy body that releases gas or dust. They are often compared to dirty snowballs, though recent research has led some scientists to call them snowy dirtballs. Comets contain dust, ice, carbon dioxide, ammonia, methane and more. Astronomers think comets are leftovers from the gas, dust, ice and rocks that initially formed the solar system about 4.6 billion years ago.

CONSTELLATION

A group of stars forming a recognizable pattern that is traditionally named after its apparent form or identified with a mythological figure. e.g., Orion is a group of stars resembling a hunter (Orion means hunter)

Important constellations:

SPACE MISSION

• Laika, a dog was the first living organism who spend 7 days in space in sputnik 2
• Kalpana Chawla, Sunita Willium and Rakesh Sharma (Indian), are people of Indian origin who went in space.
• Russian Yuri Gagarin was first to orbit around the earth in small capsule called vostok - 1.
• Valentina Tereshkova was first woman to go to space in Vostok 6 in 1963.
• Sally Ride, first American woman to go into space in 1983.
• Alexey leonov took 10 minute space work 1965 in vostok 2.
• Neil Armstrong was the first person to step on the moon in Apollo 11 with Edwin Aldrin.
• Ham (The chimpanzee) was also another space traveler.
• There are three space shuttle in use today

            (i) NASA's Fleet leader (discovery)

(ii) Rounding out the shuttle program legacy - Atlantis

            (iii) NASA's good ship Endeavour.

• Challenger exploded in 1986 and Columbia shuttle enfolded on entering the Earths space Kalpna Chawla was one of the astronauts who died in that tragedy.
• Rakesh Sharma is an Indian who visited space.