astrophysics Flashcards
definition - star (4)
an astronomical object consisting of a sphere of matter giving off heat and light, held together by its own gravity.
definition - solar system (1)
a star and all the natural objects that travel in orbit around it.
describe our solar system (what it consists of)
our solar system consists of the sun, eight planets and their natural satellites eg. moon, dwarf planets, asteroids and comets.
definition - galaxy
galaxies are groups of millions of stars held together by gravitational forces.
our galaxy? (2 - name, shape)
our galaxy is called the milky way and is a spiral galaxy.
why are light years used as an astronomical measurement of distance?
Astronomers use light years to measure the distances between stars because space is so big.
light year calculation
d = c x t
≈ 9.47 x 10^15m
≈ 9.47 x 10^12km
what is a fusion reaction?
the joining of 2 light nuclei to form a heavier one.
as this process occurs, mass is lost and is converted into energy according to Einstein’s equation.
the energy main sequence stars release is generated from nuclear fusion reactions involving hydrogen nuclei in the core of the star.
E = mc^2
4 - what each variable means, use
E - energy (J)
m - mass ‘converted’ into energy (kg)
c - speed of light (m/s) in an air vacuum
This formula is used to determine how much energy is produced during a nuclear fusion.
apparent and absolute brightness difference
apparent - the brightness of a star as measured from earth
absolute - the total energy radiated by a star per second (mass dependant). related to the mass of main sequence stars.
stars’ temperature based on colour
hottest to coolest:
blue -> white blue -> yellow -> orange -> red
the big bang? (3)
a model that scientists use to describe the evolution of the universe.
there is a rapid expansion and cooling of the universe from a hot dense concentration of matter.
accretion definition (3)
the coming together of matter under the influence of gravitation to form larger bodies. most astronomical objects are formed in accretion processes.
benefits of using instruments on board spacecraft (3)
- can obtain information about the astronomical body
- high resolution photographs without distortion from earth’s atmosphere
- travel close to the body
Australia’s involvement
Morrison government started a new budget of 1.16 billion to send out new satellites for earth observation to collect data for research.
