Space Flashcards
What is an Astronomical Unit?
Mean distance of the earth to the sun
What does the Big Bang Theory explain?
The universe originated as a small, dense and hot region that expanded and cooled
What is Cosmic Microwave Background Radiation (CMBR)?
Photons that propagated freely after the big bang, now redshifted to microwaves
What is the Doppler Effect?
Apparent change in the wavelength of a wave as the source moves relative to an observer
What happens to the wavelength when a source moves away from an observer?
The wavelength increases
What is Dark Energy?
An energy responsible for the acceleration in the expansion of the universe
What does Dark Matter explain?
Certain galaxies appear more massive than observable matter suggests
What does the Hertzsprung-Russell Diagram plot?
Luminosity against temperature
What is Hubble’s Law?
The speed of a galaxy moving away is proportional to its distance from us
What is a Light Year?
Distance travelled through space by a photon in a year
What does Luminosity refer to?
The total power radiated by a star
What is a Main Sequence Star?
A star that sits on the central band of stars on a Hertzsprung-Russell diagram
What is a Standard Candle in astronomy?
Objects of known luminosity used as references to measure other stars
What is Parallax?
The change in position of an object depending on the viewing angle
Define a Parsec.
Unit of distance equal to the distance to a star with a parallax angle of 1 arcsecond
What does Redshift indicate?
The shift in light of distant galaxies due to their movement away from each other
What characterizes a White Dwarf?
A dense star with similar mass to the sun but similar size to the earth
Fill in the blank: A White Dwarf is a _______ stage of a low mass star’s life with low luminosity.
final
List the four stages of the life cycle of our Sun
Stage 1 - Sun born in a cloud of hydrogen and helium
Stage 2 - Sun in the Main Sequence
Stage 3 - Runs out of fuel and swells to Red Giant
Stage 4 - Slowly cools and collapses into White Dwarf
