Space Flashcards
Where does the sun lie in our solar system?
In the centre
What is the sun?
A star which takes up 99% of the mass of the solar system
How many planets are there in our solar system?
8
What are the 4 rocky planets in our solar system?
Mercury, Venus, Earth and Mars
What are the 4 gas planets in our solar system?
Jupiter, Saturn, Uranus and Neptune
What are moons?
Natural satellites
Apart from planets, what also orbits the sun?
Asteroids
They are small rocky objects
Where is the asteroid belt?
Between Mars and Jupiter
What are comets made of?
Dust and ice and orbit the sun in a different orbit to planets
The ice melts when the comet approaches the sun forming the comets tail
Where is our planet?
In a small part of the milkyway
What does our milkyway have
Billions of stars
Some of the stars have planets which orbit them
How is the sun formed?
The sun is formed from massive clouds of dust and gas called nebula
The gravity pulled this cloud together in a giant ball
As the nebula collapsed the centre of this ball got very hot and dense and began to rotate
Eventually, nuclear fusion could begin and formed a protostar (our sun)
What are stars held together by?
A balance of inward forces (gravity) and outward forces (pressure)
The pressure force is exerted from the expanding hot gases inside of the stars
Gravity is an attractive force which pulls the outer layers inwards
What is meant by the star being in equilibrium?
When the outward pressure force and the inward gravity forces are equal to each other.
What happens if the temperature of the star increases?
The outward pressure will increase causing the star to expand
What happens if the temperature of the star decreases?
The outward pressure will also decrease causing the star to contract
(The temperature may drop due to nuclear fusion slowing down)
How have all naturally occuring elements been formed?
By nuclear fusion in stars
ONLY HYDROGEN HASNT BEEN FORMED THIS WAY.
What is nuclear fusion?
When two light nuclei join at a high speed to form a larger nucleus
For example when two hydrogen nuclei fuse they form helium
The process of nuclear fusion releases heat and light energy
As only elements lighter than iron can be formed in nuclear fusion, how is iron formed?
They are formed in supernovae explosion
A supernovae occurs at the end of a stars life
When the star explodes it release very large amounts of energy and neutrons
ALL THE ELEMENTS THROWN OUT OF THE EXPLODED STAR COMBINE TO FORM ELEMENTS HEAVIER THAN IRON
1st Stage of a stars life
NEBULA
Stars form from a giant cloud of dust and hydrogen gas called nebula