P1 - The Earth in the Universe Flashcards
Moons
Balls of rock which orbit planets
How many planet in our solar system are solid rock?
The four closest to the sun
How many planet in our solar system are gas giants?
The four furthest from the sun
Asteroids
Irregular lumps of rock, mostly in near-circular orbit between mars and Jupiter
Comets
Small objects made of rock and ice, with very elongated orbits around the sun
Dwarf planets
Small spherical lumps if rock in orbit around the sun
What percentage of the solar system’s mass is in the sun?
99%
Light year
The distance that light travels in a year
How far is a light year?
9.5 million kilometres
How fast does light travel in space?
3.0 x10^5 km/s OR 300,000 km/s OR 3 x 10^8 m/s
Relative brightness
How bright things seem
Real brightness
How bright something actually is
Nuclear fusion
When hydrogen nuclei are jammed together at such a high pressure that they combine to form helium nuclei
Nuclear fusion word equation
Hydrogen nucleus + Hydrogen nucleus -> Helium nuclei
Supernova
A large explosion where all the different chemical elements are made
When was the solar system made?
About 5000 million years ago
Redshift
The increase in wavelength from a galaxy moving away
The universe started expanding rapidly from a single point when?
About 14000 million years ago
When was the sun created?
About 5000 million years ago
When was the earth created?
About 4500 million years ago
What evidence supports the Big Bang theory?
The cosmic background radiation
Erosion
The wearing away of rock or other surface material
Sediments
Particles of rock in water that settle to the bottom
Fossils
Preserved evidence of a dead animal or plant. Mostly plastered in rock.
Geologists
Scientists which study rocks
Sedimentation
When eroded rock fragments are transported by wind, water and ice, broken up further and deposited on riverbeds and in the sea
What are the three types of rock?
Igneous, sedimentary and metamorphic
Name an example of each rock type:
Igneous: Obsidian, Granite
Sedimentary: Limestone, Mudstone
Metamorphic: Marble, Slate
Who thought of the theory of continental drift and when?
Alfred Wegener in 1915
Why didn’t geologists accept Wegener’s theory at first? 3 reasons
- They already had other, similar theories which explained some of his observations
- Nobody could explain or measure the movement of the continents
- Wegener was not a trained geologist and his theory was very different from the others
Sea floor spreading
The process during which the sea floor between continents moves apart and increases by a few centimetres each year
Tectonic plate
Huge slabs of rock which make up the crust and upper mantle
Plate boundaries
Where tectonic plates meet
What three directions do plates move in?
Apart, together or past each other
How are volcanoes formed? 2 ways
- When liquid magma is forced through cracks where tectonic plates are moving apart
- When one tectonic plate is forced under another heading towards it
How are fold mountains formed?
When two tectonic plates meet head on
Earthquakes
Releases of energy from tectonic plates sliding past each other
What layers make up the earth?
The crust, mantle, outer core and inner core
The crust
The relatively thin and rocky outermost layer of the earth
The mantle
Semi liquid rock which resides under the crust and moves slowly
The outer core
A layer of liquid nickel and iron about 2200km thick in the centre of the earth
The inner core
Solid nickel and iron about 1250km thick in the very centre of the earth
What are two types of seismic wave which occur when tectonic plates suddenly move?
P and S Waves
Properties of P-Waves:
- They move quickly through solid crust and liquid core
- Longitudinal waves
- Particles vibrates along the direction of motion of the waves
Properties of S-Waves:
- Only move slowly through the solid crust
- Transverse waves
- The particles vibrate at right angles to the direction of motion of the wave
Amplitude
The maximum height of the disturbance from the undisturbed position
Wavelength
The distance from one maximum disturbance to the next
Speed, distance, time formula:
Speed (m/s) = Distance (m) / Time (s)
Frequency
The number of vibrations of the source in one second
How many planets are in the solar system?
Eight
Oscilloscope
A machine that display waves on a screen
A loud sound has a … Amplitude
Large
A high pitched sound has a … Wavelength
Short
The Wave Equation:
Wave speed (m/s) = frequency (Hz) x Wavelength (m)
