Space Exploration And Cosmology Flashcards
Planet
An object in orbit around a star
Satellite
An object in orbit around a planet
Moon
A natural satellite of a planet e.g. The Moon
Star
An object that shines due to nuclear reactions in its core (fusion)
Solar system
A collection of objects that orbit a star
Exo-planet
A planet that orbits another star outside or solar system
Galaxy
A group of stars, gases, gases and dust held together by gravity. (E.g. The Milky Way)
Universe
All existing matter and space considered as a whole
Sun
The star that Earth orbits in or solar system
Dwarf planet
Something resembling a planet that lacks criteria to make it one
Benefits of satellites
GPS - A GPS receiver determines its own location by measuring the time it takes for a signal to arrive at its location from at least four satellites
Weather forecasting - They give an improved view of the state of the Earth’s current weather patterns to improve forecast accuracy.
Communications - enable global telecommunications systems by relaying signals with voice, video and data to and from one or many locations.
Space exploration - Hubble telescope and ISS
Challenges of space travel + how they might be solved
Travelling large distances - attaining high velocity using an ion drive to produce a small force for a long time
-using a ‘catapult’ from a fast moving asteroid , moon or planet
Manoeuvring a spacecraft in a zero friction environment -
Maintaining sufficient energy to operate life support systems in a spacecraft - use solar cells with area that varies with distance from the sun
Risks of manned missions (radiation, gravity, isolation, distance from earth)
Risks of manned space exploration
Fuel load on take-off
Potential exposure to radiation
Pressure differential
Problems of re-entry to a planet’s atmosphere
Benefits of space exploration
Solar power
Robotics and nano-technology
Home insulation
Memory foam
CAT scans
Light years
The distance that light will travel in one year (in a vacuum)
One light year =
9.47 x 10^15 m
What does the big bang theory say
The universe began at a single point approximately 13.8 billion years ago and has been expanding ever since.
Evidence of the Big Bang
The expanding universe - Doppler effect and red shift of light from stars
Why the sky is dark at night - Olber’s paradox
Cosmic microwave background radiation the light left over from the big bang
abundance of light atoms like hydrogen and helium
What is the observable universe
The part of the universe that we can see. Light from distant galaxies hasn’t reached us yet.
What has happened to visible light from some very distant galaxies?
It has been stretched by the expansion of the universe, making it infrared so we can’t see it
Emission
When atoms of a hot gas release energy they produce light at specific wavelengths (colours)
Absorption
When white light passes through cold gas, the atoms of the gas absorb light of specific specific wavelengths (colours)
Emission and absorption lines are ______ in terms of the wavelengths produced
Identical
