GCSE AQA Physics - Topic 8 - SPACE PHYSICS Flashcards
Nucleus
The central part of an atom, containing protons and neutrons.
Main sequence star
A star during the main part of its life cycle, where it is using hydrogen as a fuel.
Black hole
The core of a red supergiant that has collapsed. These are formed if the remaining core has a mass more than three or four times the mass of the Sun. It is so dense that light can’t escape it.
Protostar
The earliset stage in the lifecycle of a star They are formed when the force of gravity causes clouds of dust and gas to spiral together.
Red giant
A star that has expanded and cooled, resulting in it becoming red. It has used up all the hydrogen in its core and is now using helium as a fuel.
Fusion reaction
When nuclei join together and release energy.
Red supergiant
A star that has used up all the hydrogen in its core and has a mass much higher than the Sun.
Supernova
An explosion produced when the core of a red supergiant collapses.
White dwarf
A star that has collapsed from the red giant stage to become much hotter and denser than it was.
Neutron star
The core of a red supergiant that has collapsed but can can be seen.
Stable period
Time during which the radiation pressure from fusion reactions is balanced with the gravitational force
Nebula
A cloud of dust and gas
Orbit
The path on which one object moves around another
Big bang theory
The idea that the universe began from a small, very hot and dense region of space, which exploded and has been expanding ever since
Black body
An object that absorbs all the electromagnetic radiation that hits it. It is also the best possible emitter of radiation
Dwarf planet
A planet-like object in space that orbits a star but doesn’t match all the rules of being a planet
A Moon
A natural satellite which orbits a planet
The Moon
The Earth’s natural satellite
Planet
A natural object in space which orbits a star
Orbit
The path on which one object moves around another
Red-shift
The shift in observed wavelength of light from a source moving away from a stationary observer. The wavelength is shifted towards the red end of the spectrum
Satellite
An object which orbits a second more massive object
Theory
A hypothesis which has been accepted by the scientific community because there is good evidence to support it
Orbital speed
How quickly an object orbits another object. The smaller the radius, the higher the speed.
Dark matter
An unknown substance which holds galaxies together, but does not emit or interact with electromagnetic radiation
Dark energy
Thought to be responsible for the accelerated expansion of the universe
Our solar system is a very small part of our galaxy:
The Milky Way
The Solar System contains one star:
The Sun
The eight planets that orbit around the Sun, in order from closest to farthest away, are:
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Earth’s Moon, and all moons that orbit other planets are types of Natural…
Satellite
A cloud of dust and gas is called a…
Nebula
The Sun was formed from a nebula pulled together by…
Gravitational attraction
Early in a star’s life-cycle the dust & gas of a nebula, brought together by gravity, takes a roughly spherical shape. We call this a…
Protostar
Eventually, a protostar will accumulate more mass and experience gravity strong enough to cause…
Nuclear Fusion
Nuclear Fusion happens when light nuclei fuse to form…
Heavier nuclei
Protostars are not massive enough to instigate…
Nuclear Fusion
Nuclear Fusion reactions within the star create an outward…
Expansion
The mass of a star experiences an inward gravitational…
Collapse
Throughout much of a star’s lifetime (Main Sequence stage) the gravitational collapse and nuclear fusion expansion are held in…
Equilibrium (balance)
The life cycle, and ultimate fate of a star, is determined by it’s…
Mass
Life Cycle of a low mass star begins with a…
Main Sequence Star
Life Cycle of a low mass star begins with a Main Sequence star, then expanding to a…
Red Giant
Life Cycle of a low mass star begins with a Main Sequence star, then expanding to a Red Giant, before expelling outer layers to leave behind a…
White Dwarf
Life Cycle of a low mass star begins with a Main Sequence star, then expanding to a Red Giant, before expelling outer layers to leave behind a White Dwarf, and finally cooling to become a…
Black Dwarf
Life Cycle of a high mass star begins with a…
Main Sequence star
Life Cycle of a high mass star begins with a Main Sequence star, then expanding to a…
Red Super Giant
Life Cycle of a high mass star begins with a Main Sequence star, then expanding to a Red Super Giant, before exploding in an event called a…
Supernova
Life Cycle of a high mass star begins with a Main Sequence star, then expanding to a Red Super Giant, before exploding in an event called a Supernova, leaving behind either a…
Neutron Star (or Black Hole)
Life Cycle of a high mass star begins with a Main Sequence star, then expanding to a Red Super Giant, before exploding in an event called a Supernova, leaving behind either a Neutron Star, or a…
Black Hole
Fusion processes in stars produce all of the naturally occurring…
Elements
Elements heavier than iron are produced in a…
Supernova
The explosion of a massive star (supernova) distributes the elements throughout the…
Universe
What provides the force that allows planets and satellites to maintain their circular orbits?
Gravity
As velocity is a vector, an object in a stable orbit can change it’s velocity without changing it’s…
Speed
As velocity is a vector, an object in a circular orbit, at constant speed, will…
Accelerate
Any object that accelerates must experience a resultant force. For orbiting objects, that force is…
Gravity
For a stable orbit, the radius must increase if the speed…
Decreases
For a stable orbit, the radius must decrease if the speed…
Increases
Red-shift is an observed increase in the __________ of light from most distant galaxies.
Wavelength
The further away the galaxies, the bigger the observed increase in wavelength (red-shift) and the ______ they move away (recede).
Faster
The observed red-shift of distant galaxies provides evidence that space itself (the universe) is…
Expanding
The observed red-shift of distant galaxies supports the…
Big Bang theory.
The Big Bang theory suggests that the universe began from an extremely…
Hot & dense region
Since 1998 onwards, observations of supernovae suggest that distant galaxies are…
receding ever faster.
Red-shift is measured by comparing stellar spectra to…
Spectra from earth-based experiments
The evidence that a galaxy’s rate of recession is proportional to its distance from Earth proves that the universe is…
Expanding
Red-shift observations prove an expanding universe. Logically then, in the distant past all galaxies will have been much closer together. Therefore supporting the…
Big Bang theory.
Much of the universe is still not understood, for instance…
Dark Energy & Dark Matter.
