P2f Flashcards
1
Q
What does the solar system consist of?
A
- sun
- inner planets (Mercury, Venus, Earth, Mars)
- asteroid belt
- outer planets (Jupiter, Saturn, Uranus, Neptune)
2
Q
How does gravity work in the solar system/universe?
A
- gravity pulls everything in the universe towards everything
- the bigger the celestial body, the bigger the pull of gravity
- pull gets smaller the further away you go (why the Earth orbits around the sun and not other larger suns)
- gravity makes things that are already moving change there course, often into circular or elliptical orbits (if the Earth wasn’t already moving it would be pulled by gravity to the sun)
3
Q
Where can asteroids be found and what are they?
A
- found between Mars and Jupiter
- piles of rubble and rock
- when Solar System was forming rocks between these two plants didn’t form a plant
- because of Jupiter’s large gravitational attraction interfered
- usually stay in their orbit but sometimes pushed or pulled into other ones
4
Q
What are meteorites?
A
- meteors are rocks or dust that enter Earth’s atmosphere
- burn up as they pass through the atmosphere
- sometimes not all burns up and part crashes into Earth as a meteorite (only rarely)
5
Q
How can we tell asteroids have collided with Earth in the past?
A
- big craters
- layers of unusual elements in rocks
- sudden change in fossils between adjacent layers of rock, as species suffer extiction
6
Q
What are comets?
A
- balls of rock, dust and ice that orbit the Sun in very elongated ellipses
- as comets approach Sun, ice melts, leaving a bright tail of gas and debris
- comets speed up as they approach the Sun, because the gravitational pull increases as you get closer
7
Q
What are NEOs?
A
- near-earth object
- asteroids or comets that might be on a collision course for Earth
- small NEOs burn up in atmosphere if they hit Earth
- if enough warning is received about NEO’s coming we can try to deflect them before they hit us
8
Q
How what is the collision theory?
A
- Moon formed when another planet (Mars size) collided side-on with Earth
- in the heat of the collision, the dense iron core of the two planets merged to form Earth’s core
- less dense material was ejected as really hot dust and rocks
- this orbits round Earth for a while before forming the Moon
9
Q
What evidence is there to back up how the moon was formed?
A
- Moon has lower density than Earth and doesn’t have a big iron core like the Earth
- Moon rocks contain few substances which evaporate at low temperatures, suggesting that the Moon formed from hot material (all water, etc. boiled away, as would happen in a collision)
10
Q
What is a centripetal force?
A
-force caused by circular motion
11
Q
What is circular motion caused by?
A
- by force (pull) towards the centre of the circle
- for things in an orbit the force is provided by gravity
12
Q
What happens if a meteor hits earth?
A
- fires can starts
- hot rock and dust thrown into air
- craters in ground
- dust and smoke from a large impact can block out sunlight for many months, causing climate change, which can cause cause species to become extinct
13
Q
How are NEO’s monitored?
A
-astronomers use powerful telescopes and satellites to search for and monitor NEOs
