Astrophysics Flashcards
How does the orbit of a comet compare with the orbit of a planet?
-A comet’s orbit is more elliptical (Oval shaped)
-Comet’s orbital speed varies
-Planets have a star in the centre of the orbit
-Different orbital radius
Describe two pieces of evidence that support the big bang
-Cosmic microwave background radiation (CMBR) appears to be everywhere in the universe
-Implies all parts of universe were in contact at one point.
-The galaxy is constantly moving away from Earth due to red-shift
-The further away the greater the red-shift meaning they move further away.
-Which implies expansion from a single point since the big bang
How has the size and temperature of the universe changed since the big bang?
-The universe has expanded and the universe has cooled.
What is absolute magnitude
It compares the brightness of stars as if they were a fixed distance from earth.
Life cycle of a low mass star
Nebula, Protostar, Main Sequence, Red giant, White dwarf
Life cycle of a higher mass star
Nebula, Protostar, Main Sequence, Red supergiant, Supernova, Neutron star
Characteristics of a star that has a higher mass
-Higher inner core temp
-Higher pressures
-Higher density
-Shorter life
Describe how a main sequence is formed from a nebula
-A nebula consists of gas clouds
-Eventually it becomes hotter
-Gravity causes the nebula to collapse creating a protostar
-Fusion occurs in the core of protostar forming main sequence.
Describe how a main sequence star becomes a white dwarf
-Main sequence core temperature increases then expands to form a red giant
-This red giant then runs out of hydrogen and its temperature decreases
-A white dwarf is formed when helium fusion stops in the core.
Which side of the Hertzsprung-russell diagram has the highest temperatures
-The left hand side as it’s blue.
Location of White dwarfs, main sequence and red giants in H-R diagram
White dwarf: bottom left
Main Sequence: Top left to bottom right
Red Giant: Top Right
What is red-shift
When wavelength increases due to a galaxy appearing to be moving away from Earth.
