Earth and Space Flashcards
Artificial Satellites
Man-made satellites that have been sent into space for purposes such as satellite imaging and communication
Circular orbits
The circular path that a satellite or planet may travel in. Since their direction is continually changing, their velocity is always changing. Gravity provides the required force for these orbits.
Comets
Objects consisting of rock, dust, and ice that travel in the universe at high speeds. When they approach the sun they vaporise and produce a trail.
Galaxy
A system containing billions of stars
Main Sequence Star
The stable state of all stars. The gravitational forces pulling the star together, and the pressure pushing outwards are balanced.
Milky Way Galaxy
The galaxy in which our solar system is located.
Natural Satellites
The moons that orbit planets.
Nebula
A cloud of gas and dust.
Orbital speed
A measure of how fast an object orbits. It is directly proportional to the radius of the orbit and inversely proportional to the orbital period.
Protostar
In this stage the star becomes hot enough for hydrogen nuclei to fuse.
Red Giant Star
When their hydrogen is used up and larger nuclei are produced by fusion, stars of a similar magnitude to the sun will expand to form a red giant.
Supernova
The explosion of massive stars distributes the element created by the fusion reactions in stars throughout the universe.
Universe
A large number of billions of galaxies.
Weight
The force of matter due to gravity. It is equal to the product of mass and gravitational field strength, and so varies depending on your location in the universe.
White Dwarf
When the fusion reactions in stars of a similar magnitude to the sun come to an end, the star will contract under gravity and cool down to form a white dwarf.
