Flashcards in Space Physics Deck (20)
How is a star formed?
-form from a cloud of dust and gas called a nebula
-force of gravity pulls the dust and gas together to form a protostar
-as star gets denser, temp rises and more particles collide with each other
-when temp is high enough, hydrogen nuclei undergo nuclear fission to form helium nuclei
-this gives out huge amounts of energy which keeps core of star hot
What is a red giant?
A small-medium star
What is a red super giant?
A large star
What is a main sequence star?
-when star enters a long stable period where outward pressure caused by nuclear fission that tries to expand the star balances the force of gravity pulling everything inwards
-typically lasts several billion years
-sun is in the middle of this stable period
What happens to the star when the hydrogen runs out?
-it will swell into a red giant(if it's a small star) or a red super giant (if it's a large star)
Why does a star become red?
-Because the surface cools
-fusion of helium and other elements occurs
-heavier elements (up to iron) are created in the core of the star
What happens to a small-medium star such as the sun?
(Like the sun)
-becomes unstable and ejects its outer layer of dust and gas
-this leaves behind a hot, dense, solid core (a White Dwarf)
What happens as a white dwarf cools down?
-it emits less and less energy
-when it no longer emits a significant amount, it is called a black dwarf
What is at the centre of our solar system?
The sun which is orbited by eight planets and other objects
What are the eight planets in the solar system?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto (dwarf planet)
"My Very Enthusiastic Mother Just Served Us Noodles!"
What is a planet?
Large objects that orbits a star
-there are 8 in our solar system
What is a Dwarf planet?
Planet-like objects that orbit stars but do not identify as planets
What is a moon?
-they orbit planets
-a type of natural satellite (not man made)
What is an artificial satellite?
-satellites that humans have built that are sent into space
-they generally orbit the Earth
Which galaxy are we a tiny part of?
The Milky Way Galaxy
What is the Milky Way Galaxy?
A massive collection of billions of stars that are all held together by gravity
What force creates orbits?
-gravitational force between the planet and sun or planet and its satellites
What does the size of the orbit depend on?
The objects speed
The stronger the force, the faster the orbiting object needs to travel at to remain in orbit
Why does the universe seem to be getting bigger?
All it’s galaxies seem to be moving away from each other. We know this as when we look at light from most distant galaxies, we find that the wavelength has increased (red shift)