Space physics Flashcards
(19 cards)
What is the universe?
The universe is a large collection of billions of galaxies.
What is a galaxy?
A galaxy is a large collection of billions of stars.
Where is our solar system located?
Our solar system is in the Milky Way galaxy.
What does our solar system consist of?
Our solar system consists of one star (the Sun), eight planets, dwarf planets, and natural satellites (moons).
What causes the force of gravity close to the Earth?
The force of gravity close to the Earth is due to the gravitational field around the Earth.
What does gravitational field strength, g, indicate?
Gravitational field strength, g, tells us the amount of gravitational force on a 1kg mass.
How does gravitational field strength vary?
Gravitational field strength, g, varies due to the mass of the planet, star, or moon and the distance from it.
What is the effect of gravitational force?
Gravitational force causes moons to orbit planets, planets to orbit the Sun, artificial satellites to orbit the Earth, and comets to orbit the Sun.
What type of paths do comets and planets orbit on?
Comets orbit stars on elliptical paths, while planets and moons orbit on nearly circular paths.
What does the force of gravity do in a circular orbit?
The force of gravity acts towards the centre of the circular orbit and causes acceleration in that direction.
What happens if the orbital speed changes?
If the orbital speed changes, the radius of the orbit must also change.
What occurs in nuclear fusion?
In nuclear fusion, low mass nuclei can join together to make heavier nuclei, transferring energy from the nuclear potential store to the kinetic store.
What are the stages of a star like the Sun?
The stages are: nebula, star (main sequence), red giant, and white dwarf.
What happens to a star with more mass than the Sun?
It explodes in a supernova, and the core becomes either a neutron star or a black hole.
How are elements heavier than iron produced?
All elements heavier than iron are produced by supernovae, which spread the elements through the universe.
What is a star?
A star is a near perfect black body.
What is a perfect black body?
A perfect black body absorbs all electromagnetic radiation incident on it and does not reflect or transmit any radiation.
What affects the emission of electromagnetic radiation from objects?
The intensity and wavelength distribution of any emission depends on the temperature of the object.
What happens to radiation emission as an object gets hotter?
The intensity of every wavelength of radiation emitted increases, but the intensity of shorter wavelengths increases more rapidly.
