Astrophysics 7.1 - 7.4 Flashcards
What is an orbit
An orbit is the curved path that a celestial body or spacecraft takes around another celestial body
What happens when the moons instantaneous velocity is less than the force of gravity that it experiences due to the earth
It will get pulled into the earth
Explain why the moon is always accelerating
It is always accelerating because any change in direction will result in a change in velocity. If you look at the formula a = v-u/t , the velocity value will be changing which means the acceleration will also change
How can smaller objects stay in orbit
They would need a greater instantaneous velocity to counteract the forces of gravity that it experiences
What is a solar system
A solar system is a collection of planets that orbit a central star
What is a galaxy
A galaxy is a collection of billions of stars that orbit the center of a galaxy
What is a universe
A universe is a collection of galaxies. The universe is filled with mostly empty space as the distance between each galaxy is unimaginable
What are satellites
Satellites are objects that orbit a celestial body
What are the two types of satellites
Man made and artificial
Name the 8 planets in the solar system
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
What are asteroids and where are they found in the solar system
Asteroids are basically a combination of rock and metal and are found between mars and jupiter in the asteroid belt
What are comets and where are they found
Comets are basically a combination of ice and dust and are found closer to neptune
Name and state each stage of the life cycle of a star
Nebula, protostar, main sequence star which can then take two paths:
Path 1: red giant, white dwarf, black dwarf
Path 2: red super giant, supernova, black hole or neutron star
Explain the process that takes place from a nebula all the way to the end stages of a star
Nebula which is dust and clouds gets pulled together due to gravity forming a protostar which then starts up nuclear fusion which causes the star to heat up and expand. This then forms a main sequence star like our sun which then continues the process of nuclear fusion until it’s hydrogen is depleted which will take a very long time. The star will then shrink due to the forces of gravity which pull it inwards because the outwards force that the nuclear fusion once provided is no longer there. After the star has shrunk, it begins nuclear fusion again which will form elements upto iron and repeats this process many times until it forms a red giant or a red super giant. A red giant will become unstable and expel its outer layers leaving behind a dense core which we call a white dwarf which will then deplete all its energy forming a black dwarf. If it was a red super giant, it’ll also become unstable after which it will explode in a supernova which will form elements heavier than iron. Two scenarios can now play out. If the star was very big, It’ll form a neutron star which is a dense core. If the star was massive, It’ll collapse in on itself forming a black hole
What elements do main sequence stars form
Helium
What elements do red giants and red super giants form
Elements up to iron on the periodic table
Elements heavier than iron are formed in
Supernovas
What is red shift
Red shift is the stretching of the wavelength of light which causes it to appear red
What is an absorption spectra
An absorption spectra is the visible light spectrum with black lines which indicate the wavelengths of light that have been absorbed
How does the absorption spectra of a planet moving away from us look like
It has black lines that are shifted towards the red end of the absorption spectra
What is the big bang theory
The big bang theory is a theory proposed by and agreed upon by many scientists stating that the universe was once tiny consisting of a single point so dense and so hot that contained all the matter in the universe now, that exploded and expanded and continuing to expand to this day
