Celestial Objects: Things like stars, planets, moons, etc. which are present within the space are referred to as celestial objects.

The Moon:
1. Phases of the moon:The different shapes of moon visible during various days in a very month are called as phases of the moon.


Different Phase of Moon

2. full-of-the-moon day: it's the day on which the total moon is visible.


3. new phase of the moon day: After the total moon day, the moon appears to become thinner and thinner. On the fifteenth day the moon isn't visible. at the present time is understood because the new phase of the moon day.


4. Why does Moon have different phases?
(i) Moon doesn't have its own light and truly it reflects the sunshine coming from sun which is accountable for various phases.
(ii) After new phase of the moon day, the visibility size of illuminated a part of moon seen from Earth keeps increasing and after full-of-the-moon day it keeps decreasing.


Moon is visible because of reflected sunlight

Positions of the moon in its orbit and its corresponding phases

5. The Moon’s Surface:
(i) The Moon’s surface is dusty, barren and has many alternative sizes craters thereon. Moreover, there are many big and little mountains.
(ii) The Moon has no atmosphere and water.


Surface of Moon

The Stars:
(i) These are objects which twinkle within the sky at nighttime.
(ii) Sun is that the nearest star to our planet which is approx 150 million km aloof from Earth.


Stars
Light Year:
(i) it's defined because the distance travelled by light in one year. And it's the unit to live large distances.
(ii) The speed of sunshine is about 300,000 km per second.
(iii) the gap of the Sun from the world is also said to be about 8 light minutes

Pole Star: it's the star which is situated within the direction of the earth’s axis.


Polar Star

Constellations:
The different known shapes that are formed by a bunch of stars, is understood as a constellation.


Some constallations within the night sky
1. Ursa Major:
(i) This constellation consists of seven stars.
(ii) it's sort of a big ladle or a matter mark. There are three stars within the handle of the ladle and 4 in its bowl
(iii) it's also referred to as Big Dipper, the nice Bear or the Saptarshi.
2. Orion:
(i) it's another well-known constellation visible during late evenings in winter.
(ii) It also consists of seven or eight bright stars. The three middle stars in Orion represent the belt of constellation and also the remaining four bright stars are arranged within the type of a quadrilateral.
(iii) Orion is additionally called constellation.


3. Sirius:
(i) it's the brightest star within the sky.
(ii) to seek out the situation of Sirius, imagine a line passing through the belt of three middle stars of Orion.


4. Cassiopeia:
(i) it's another popular constellation within the northern sky. it's visible during winter within the early a part of the night. it's sort of a distorted letter W or M.



The Solar System:
1. It consists of the Sun and other celestial objects present within the space revolving round the sun.The gravity between the Sun and these objects keeps them revolving around it. the assorted entities like planets, meteors, comets, etc. are a part of our scheme.
2. The eight planets in their order of distance from the Sun are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.


1. The Sun:
(i) The Sun is that the nearest star amongst all the celebs present within the universe.
(ii) it's the most source of warmth and lightweight for all the planets specially Earth.


Sun
2. The Planets: The planets are like stars, but they are doing not have light of their own. They merely reflect the daylight that falls on them. The planets keep changing their positions with relevancy the celebs.
These are the objects revolving round the sun in fixed path. This fixed path is termed as an orbit.
1. Period of revolution: it's the time taken by planet to finish full revolution round the sun.
2. Period of rotation: it's the time taken by planet to finish one rotation around its own axis.
3. Satellite: These are the celestial bodies present around other natural object. Example Moon may be a satellite of the world.
4. Artificial satellite: These are the man-made satellite present round the Earth.


Planets Revolving round the Sun:
1. Mercury (Budh)
(i) it's nearest planet to the Sun and also the smallest planet present in our scheme.
(ii) it's very difficult to look at it, as most of the time it's hidden within the glare of the Sun.
(iii) Mercury has no satellite of its own.


2. Venus (Shukra):
(i) it's nearest planet to Earth and it's the brightest planet visible within the night sky.
(ii) it's also called a morning or a night star, although it's not a star.
(iii) Venus rotates on its axis from east to west.
(iv) Venus has no moon or satellite of its own.


3. The Earth:
(i) it's the sole planet within the scheme on which life exists.
(ii) Earth appears blue green because of the reflection of sunshine from water and landmass on its surface.
(iii) The axis of rotation of the world isn't perpendicular to the plane of its orbit. the lean is accountable for the change of seasons on the world.
(iv) it's only 1 moon or satellite of its own.


4. Mars (Mangal):
(i) it's somewhat reddish and, so, it's also referred to as the Mars.
(ii) Mars has two small natural satellites.


5. Jupiter (Brihaspati):
(i) it's the most important planet of the scheme. It rotates very rapidly on its axis.
(ii) Jupiter includes a sizable amount of satellites. And also has faint rings around it.
(iii) it's about 1300 times larger than that of earth and its mass about 318 times than that of our Earth


6. Saturn (Shani):
(i) it's yellowish colored planet.
(ii) There are beautiful rings around this planet, which don't seem to be observed in the other planets.
(iii) it's the smallest amount dense among all the planets. Its density is a smaller amount than that of water.


7. Uranus:
(i) it's the one amongst outermost planet of the scheme.
(ii) the foremost quality of Uranus is that it's highly tilted rotational axis.


8. Neptune:
(i) it's the outermost planet of the scheme.



Some Other Celestial Members of the Solar System:
1. Asteroids:
(i) the little rocks like substances that are orbiting round the Sun are called asteroids.
(ii) it's found in large gap between the orbits of Mars and Jupiter.
(ii) they're visible only through large telescopes.


2. Comets:
(i) They revolve round the Sun in highly elliptical or circular orbits.
(ii) it's like as if it's a bright head with a protracted tail and it's been seen that the tail keeps growing in size because it keeps approaching the sun.


3. Meteors:
(i) These are small objects that sometimes enter the Earth’s atmosphere.
(ii) It occasionally enters the earth’s atmosphere with very high speed. because of friction of earth's atmosphere, It glows then evaporates quickly. that's why the brilliant steak lasts for a awfully short time.

4. Meteorite:
(i) These are the leftover object that reaches the world.
(ii) Meteorites help scientists in investigating the character of the fabric from which the scheme was formed


5. Artificial Satellites:
(i) These are the man-made satellites that revolve round the Earth.
(ii) Aryabhatta was the primary Indian satellite. another Indian satellites are INSAT, IRS, Kalpana-1, EDUSAT, etc.
(iii) they're used for forecasting weather, transmitting television and radio signals. they're also used for telecommunication and remote sensing.