Astrophysics and Cosmology Flashcards
Define planets.
Objects with mass sufficient for their own gravity to force them to take a spherical shape, where no nuclear fusion occurs, and the object has cleared its orbit of other objects.
Define dwarf planets.
Planets where the orbit has not been cleared of other objects.
Define planetary satellites.
Bodies that orbit a planet
Define asteroids.
Objects which are too small and uneven in shape to be planets, with a near circular orbit around the sun.
Define comets.
Small, irregular sized balls of rock, dust and ice. They orbit the sun in eccentric elliptical orbits.
Define solar systems.
The systems containing stars and orbiting like planets.
Define galaxies.
A collection of stars, dust and gas. Each galaxy contains around 100 billion stars and is thought to have a supermassive black hole at its centre.
Define nebulae
Gigantic clouds of dust and gas. They are the birthplace of all stars.
How are protostars formed?
In nebulae, there are regions that are more dense than others.
Over time, gravity draws matter towards them and, combined with the conservation of angular momentum, causes them to spin inwards to form a denser centre.
GPE is converted into thermal energy, which heats up the centre. The resultant sphere of very hot, dense dust and gas is a protostar.
How are main sequence stars formed from protostars?
Describe how a low-mass main sequence star becomes a red giant.
Describe the evolution of a red giant to a white dwarf.
Describe the evolution of a high-mass main sequence star into a red supergiant.
Describe the process of the death of a high-mass star.
Describe the evolution of a red supergiant to a neutron star or black hole.
What does a Hertzsprung-Russell diagram look like?
Annotate the Hertzsprung-Russel diagram to show the Sun’s evolution.
Describe the process of electrons exciting in discrete energy levels.
All energy level values are negative. True or false?
What are emission line spectra and how are they formed?
What are continuous line spectra?
What are absorption line spectra?
What happens when an electron is de-excited?
What are diffraction gratings?
State Wien’s displacement law.
State Stefan’s law.
Define light year.
What is the Doppler effect?
What is Stellar parallax?
Define parsec.
What is the Cosmological principle?
What is red-shift?
State Hubble’s law.
Use Hubble’s law to estimate the age of the univurse.
Draw a simplified light curve for a binary star system.
What are quasars? What suggests that they are extremely distant objects?
What is the Big Bang theory? state evidence that lead us to believe this is true.
What is dark energy?
