P16 - Space 2️⃣✅ Flashcards
What is the big bang theory?
The theory that the universe was created in a massive explosion, and that the universe has been expanding ever since
What is a black dwarf?
A star that has faded out and has gone cold
What is a black hole?
An object in space that has so much mass that nothing, not even light, can escape from its gravitational field
What is centrepedal force?
The resultant force towards the centre of a circle acting on an object moving in a circular path; it acts perpendicular to the direction of forward motion
What is a main sequence star?
A star that has reached the stage in its life cycle during which it radiates energy because of the nuclear fusion of hyrogen to heium in its nucleus
What is a neutron star?
The highly compressed core of a massive star that remains after a supernova explosion
What is a protostar?
The concentration of dust clouds and gas in space that forms an early star
What is a red giant?
A star that has expanded and cooled, resulting in it becoming red and much larger and cooler than it was before it expanded
What is a red supergiant?
A star significantly larger than the sun expanding and cooling and becoming what is essentially a red giant, but due to its siginificantly larger size, its known as a red supergiant
What is the Mnemonic for the planets in our solar sytem in order?
My
Very
Easy
Method
Just
Speeds
Up
Naming
(Planets)
What are the planets of a solar system in order?
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
(Pluto)
What are planets?
Planets are large rocky objects that orbit around a star (planets in our solar system orbit a star (the sun))
What are exoplanets?
Planets that orbit another star that isnt our sun
What is a comet?
A small cosmic snowball of frozen gasses, rock & dust that orbit the sun in an elliptical orbit (ellipse = squashed circle) - when it comes closer to the sun it heats up and the ice starts to melt (hence shooting stars)
What is an asteriod?
Floating lumps of rock
What is a metiorite?
An asterioid that has entered an atmosphere
What is a geostationary satelite?
A satelite that orbits at the same speed as the earth’s orbit so it will always be at the same place overhead
What is geosynchronous orbit?
When an object in orbit passes over the same spot the same time everyday as the orbit takes roughly 24 hours.
Why do weather satelites have a very low orbit?
So they orbit at quicker speeds
What is low polar orbit?
A ‘vertical’ orbit from the north to the south pole
What is a satelite?
A smaller object orbiting a larger object
What are the two most common types of orbits?
Circular & Elliptical orbits
What is instantanious velocity?
Velocity at one instant in time that is always perpendicular to the direction of force
What is a natural satelite?
A natural satellite is any body in space that orbits around a larger body
What is an artificial satelite?
An artificial satellite is a man-made body placed in orbit round the earth or another planet, commonly in order to collect information about it or for communication purposes
Complete this diagram for the life cycle of a star
What is a white dwarf?
White dwarfs are the remnants of averaged sized stars stars that have exhausted all of their nuclear fuel and have collapsed under their own gravity. They are incredibly dense, with a mass similar to that of the sun but a size comparable to that of Earth
What does an average main sequence star do to produce energy?
Undergo nuclear fuision of hydrogen atoms into helium which releases unfathamable ammounts of energy, significantly larger than nuclear fission
What happens when a star runs out of hydrogen atoms to fuse?
Fusion will stop and therefore the outwards pressure force the fusion produces also stops, rendering the balance between the outwards pressure force and inwards gravitational force unbalanced, causing the star to collapse inwards under gravitys inwards force. The increased pressure because of this will cause the star to become even denser and hotter, causing the helium atoms to fuse and produce elements like carbon. This reinistates the outwards pressure force due to fusuion reoccuring and resulting in the star expanding, forming a red giant
How are elements upto Iron produced?
For stars larger than the sun, after carbon, they will continue to fuse elements larger than the previous up until iron. When they reach iron, so much energy is produced in the core of the star that it causes a massive explosion - a supernova where enormous ammounts of heat and light energy are released.
How are the elements above Iron produced?
During the supernova explosion
What happens to a red supergiant after a supernova?
Depending on the size, it will become a neutron star (if smaller) but if siginifcantly larger star it will become a black hole
What will a red giant eventually become?
A white dwarf and then after 10s/100s of billions of years become a black dwarf
What are the forces that act on a star?
The force of gravity acts inwards towards the star whereas the energy/ pressure produced by the star’s nuclear fusion produced an outwards force, equal to the gravity, therefore leaving the star in balance
Why are low polar orbits used for spying?
Because they are lower, they produce higher quality images and can move quicker
How does red-shift imply/ support the big bang theory?
As red-shift insinuates that the universe its expanding in the present day, it is therefore implied that the universe was once small and at some point, tiny
What is red-shift?
It is a result of the space between the Earth and the galaxies expanding. This expansion stretches out the light waves during their journey to us, shifting them towards the red end of the spectrum. The more red shifted the light from a galaxy is, the faster the galaxy is moving away from Earth
What are 2 proposed theories for the origins of the universe?
- Big bang theory
- Steady state theory
What is the steady state theory?
Theory before the big bang that proposes that the universe is being pushed apart by matter that is being created to counteract its loss in density
What are 2 pieces of evidence to suppor the big bang theory?
- Red shift
- Cosmic microwave background information
What is cosmic microwave background radiation?
The accidental discovery of the cold remannts of the immense levles of radiation that would have been emitted during the big b bang; the radiation, originally would have been much larger and hotter, but over the years its cooled down into microwaves
