Space Flashcards
List the planets in our Solar System in order
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
What are satellites?
Objects that orbit planets
What are Artificial Satellites?
Made by humans
What are Natural Satellites?
Not made by humans
Why do objects stay in orbit?
Gravity pulls them towards the centre of the orbit. Their sideways motion forces them to move in an ellipse
What is Pluto?
A dwarf planet
What are galaxies?
Collections of hundreds of billions of stars. Humans have never been to other stars
How do stars begin?
Nebula - a huge cloud of hydrogen and some other gases and dust. Over millions of years, the gravity in the cloud forms Protostars inside the Nebula.
What happens to Protostars?
When the Protostar gets big enough, its gravity can cause fusion of hydrogen into helium in the core by making the hydrogen hot and dense enough. The Protostar then becomes a Main Sequence Star
When stars are in their main sequence, they are very hot and bright. The forces outwards from the core are balanced by the force of gravity pulling inward so the star remains stable
What is the life cycle of stars?
Cloud of Gas and Dust -> Protostar -> Main Sequence Star -> (Red Giant -> White Dwarf -> Black Dwarf) / (Red Super Giant -> Supernova -> (Neutron Star) / (Black Hole) )
What is Red Shift?
When objects move away from us their wavelength increases. This shifts them to the red end of the spectrum so they appear more red.
What is the Big Bang Theory?
Initially, all the matter in the universe occupied a very small space. This tiny space was very dense and so was very hot
Then it exploded causing expansion
When are stars in Equilibrium?
When the Outward Pressure is balanced to the Inward Gravitational Force
What is the Steady State Theory?
The Universe is expanding but new matter is being made in order for the density of the universe to stay the same. Suggests the universe has no beginning and no end and that its appearance has always been the same and will always remain the same.
What is CMBR?
Cosmic Microwave Background Radiation - Electromagnetic radiation that fills the universe
What is Centripetal Force?
Force that will keep something in orbit
What is the Droppler Effect?
Waves get stretched as the source moves away, and squashed as they move towards
This means light from galaxies moving away from earth look redshifted and light from galaxies moving towards earth look blueshifted
Why are all galaxies redshifted?
They are moving away from earth. The further away from earth a galaxy is, the faster it is moving.
This proves the galaxy is expanding
How does a star similar to our sun’s size end its lifecycle?
Swell up to become a Red Giant as they run out of fuel
They lose their outer layers and leave behind a white dwarf
They cool to become a black dwarf
How does a star bigger than our sun end its lifecycle?
Swell up to become a Red Supergiant as they run out of fuel. They fuse heavier elements up to iron
Collapse in a supernova explosion which fuses elements heavier than iron. This can make a new nebula from which new stars can be born
A Supernova will leave behind either, a Neutron Star, or a Black Hole
