Space Flashcards
What is the universe made up of?
Billions of galaxies
What does each galaxy contain?
Hundreds of millions of stars
What part of the galaxy is the solar system a part of?
Our solar system is a tiny part of the milky way galaxy
What is the solar system made up of?
●One star (the sun)
●Planets and dwarf planets (orbit sun)
●Asteroids and comets (orbit sun)
●Moons that orbit planets (called natural satellites)
What is a nebula?
Cloud of dust and gas
How was the sun formed?
The sun was formed from a nebula (cloud of dust and gas) which was pulled together by gravitational attraction
What happened when the sun was forming?
As the dust and gas were drawn together they collided increasing the temperature and creating a protostar
What happened after the protostar was formed?
More and more material was drawn together by gravity, these collisions increased until the temperature and pressure was high enough for hydrogen nuclei to fuse together forming helium and a main sequence star
How does the core of the sun stay hot?
Energy released by nuclear fusion keeps the core of the sun hot
What happened to the material that was not drawn into the sun when the solar system was forming?
The material remained in orbit around the new star (Sun) and formed the planets and other objects in our solar system
Is the sun still in its main sequence?
Yes, (main sequence= nuclear fusion, fusing hydrogen nuclei to form helium nuclei)
What is the sun’s stability due to?
*Fusion energy trying to expand the sun
*Gravity acting inwards trying to collapse the sun
What is life cycle of stars determined by?
Size
What happens to some of the different sized stars in their life cycle?
🌟 Small stars (like sun) end up as black dwarf stars
🌟Larger starsbecome neutron stars
🌟Largest stars become black holes
All stars began the same way as the sun, explain the process?
Clouds of dust and gas are drawn together by gravity to form a protostar and eventually a main sequence star
In the main sequence of a star, hydrogen fuses to create helium (like the sun) but what do larger stars create?
Lithium not helium
Where are elements heavier than iron produced ?
ONLY in a SUPERNOVA
Explain how the stars the same size as the sun change/age?
1) Main sequence star
2) Hydrogen begins to run out
3) Outward force due to fusion energy is less than the inward force due to gravity
4) Causes star to collapse inwards, temperature increase
5) Now helium nuclei fuse to create heavier elements
6) Star expands to form a red giant
7) Red giant stops fusing helium
8) Star shrinks = white dwarf
9) White dwarf, no fusion, cools
10) Stops releasing any energy, forms black dwarf
Explain the life cycle of stars larger than the sun?
1) Star runs out of hydrogen, leaves main sequence
2) Expand into red super giant
3) Helium nuclei fuse, produce heavier elements
4) Red super giant stops fusion
5) Star explodes, explosion=supernova
6) Temperature of supernova is high enough to produce elements heavier than iron
7) Elements distributed into universe
8) Remains of supernova are neutron Star and black hole
A supernova produces a neutron star, what is a neutron star?
Neutrons densely packed together
A supernova also produces a black hole, what is a black hole?
Has such a large gravity than nothing can escape it not even light!
What was the only element in the universe before stars?
Hydrogen
How was all the elements in the periodic table created?
Fusion processes in stars
What elements can stars fuse to create?
Can fuse up to and including iron
What do planets orbit?
The sun
What is an artificial satellite?
Moons are natural satellites, artificial satellites are man-made which orbit the earth
What is the use of artificial satellites?
Satellite TV and GPS systems
How do satellites and planets maintain circulation orbits?
Force of gravity
What is needed for an object to travel in a circular path?
There needs to be a force that acts towards the centre of the circle
For planets and satellites what is it that acts towards the centre so the object can travel in a circular path?
Force of gravity
What does an unbalanced force result in?
Acceleration towards the center
When an object undergoes circular motion what happens to acceleration?
*Acceleration doesn’t cause object to change speed
*Acceleration causes object to change direction
What happens to velocity when undergoing circular motion?
Velocity changes (vector quantity so has size and direction) but speed remains the same (scalar quantity so only has size)
What happens to instantaneous velocity (rate of change of position for a small time interval) when an object undergoes circular motion?
Instantaneous velocity is perpendicular (right angle) to the centripetal (moving towards center) force
As an object orbits, the force of gravity pulls the object in a curved path, what does this create?
Creates a centripetal (moving towards centre ) force
What happens if you change thr speed of an object when it’s in orbit?
Cause it’s orbit to change or cause it’s orbit to fail
What is happens when an orbit fails?
Spin off into space pr crash onto object it is orbiting
What is needed for an object to stay in a stable orbit at a particular distance from a large body (3D object) ?
To stay in a stable orbit, at a particular distance from a large body (3D object) THE SMALLER BODY MUST MOVE AT A PARRICULAR SPEED
What needs to change when speed changes?
If speed changes, RADIUS of the orbit must also change
For a stable orbit, the greater the radius, what happens to the speed?
The slower the speed
What happens when a source of waves is moving the waves it produces are?
*Squashed together as it moves towards a detector, reducing the detected wavelength
*Spread apart as it moves away from a detector increasing the decetred wavelength
*Known as the dopler effect
Where is the doppler effect noticeable?
Noticeable with sound waves made from cars, pitch seems to change if the car is travelling towards or away from the observer
What happens when a source of light is moving away from an observer?
The wavelength becomes longer and therfore redder
What happens the faster the source is moving away from an observer?
^The greater the observed increase in wavelength
^Greater the red shift
What is red shift?
Observed increase in the wavelength of light from distant galaxies, towards the red end of the spectrum
What does red shift tell us?
That galaxies are moving away from each other
What does red shift tell us?
Red shift tells us that GALAXIES ARE MOVING AWAY FROM EACH OTHER,
What happens when galaxies are moving away?
Light waves are atretched/wavelength is increased
Do galaxies that are further away have a bigger or smaller red shift?
Galaxies that are further away have A BIGGER RED SHIFT
If galaxies have a bigger red shift, are they moving away faster or slower?
THEY ARE MOVING AWAY FASTER
Do very distant galaxies have a very large or small red shift?
VERY LARGR RED SHIFT
Are very distant galaxies moving away very fast or very slow?
VERY FAST
How do scientists believe the universe began?
FROM A VERY SMALL REGION THAT WAS EXTREMELY HOT AND DENSE which expanded into the universe we see today
What is the name given to the way scientist believe the world started?
THE BIG BANG THEORY
What did astronomers assume would cause universe expansion to slow down?
GRAVITY
What did Supernovae show what was happening to the universe?
EXPANSION RATE WAS INCREASING
How did scientist explain how the universe is expanding?
Suggested UNIVERSE CONTAINS MATTER AND ENERGY WE CANT DETECT, DARK ENERGY AND DARK MATTER
What theory do red shift observations support?
red shift observations provide evidence that the universe is expanding and supports THE BIG BANG THEORY
