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Stars:
They are large gaseous bodies in space which generate heat and light.
Light year:
It is the distance covered by light in one year and equal: 9.46 × 1012 km.
Galaxy:
It is a group of millions of stars and it is the biggest units of the universe.
Constellation:
A galaxy can be divided into small groups called "Constellations".
The most famous constellations are:
a- The ursa major (great bear)
b- Scorpion.
c- Gemini (the twin).
Astronomical unit:
It is the average distance between the sun and the earth equals 150 million kilometers (150 × 106 kms.)
The most important instruments used in exploration of outer space are:
a- Telescopes.
b- Artificial satellites.
c- Space ships.
The invasion of space:
It started on fourth of October 1957.
Types of telescopes are:
a- Refracting telescope.
b - Reflecting telescope.
Galileo:
He was the first scientist who proved that sun is the centre of the universe (solar system).
Stars:
They are large gaseous bodies in space which generate heat and light.
Light year:
It is the distance covered by light in one year and equal: 9.46 × 1012 km.
Galaxy:
It is a group of millions of stars and it is the biggest units of the universe.
Constellation:
A galaxy can be divided into small groups called "Constellations".
The most famous constellations are:
a- The ursa major (great bear)
b- Scorpion.
c- Gemini (the twin).
Astronomical unit:
It is the average distance between the sun and the earth equals 150 million kilometers (150 × 106 kms.)
The most important instruments used in exploration of outer space are:
a- Telescopes.
b- Artificial satellites.
c- Space ships.
The invasion of space:
It started on fourth of October 1957.
Types of telescopes are:
a- Refracting telescope.
b - Reflecting telescope.
Galileo:
He was the first scientist who proved that sun is the centre of the universe (solar system).
