physics gcse 10 edexcel astronomy

what is the order of planets in relation to distance from the sun

mercury, venus, earth, mars, jupiter, saturn, uranus, neptune

what is a way to remember the order of planets in correlation to distance from the sun?

My

Very

Educated

Mother

Just

Made

Us

Nachos

what is red-shift?

when planets are moving away from us their absorption spectrum shifts towards red. The faster they are moving away, the more red-shifted they are

what evidence tells us the universe is expanding?

all/most things are red-shifted

what is the lifestyle of a star like our sun

nebula \rightarrow protostar \rightarrowmain sequence star \rightarrow red giant \rightarrow shell of gas \rightarrow white dwarf

describe the lifecycle from nebula to (massive) main sequence star

• the gas and dust in a nebula is pulled together by gravity.

• as it gets smaller it heats up and becomes a protostar

• gravity continues to pull it inwards until the pressure and temperature inside it are high enough to start fusion reactions.

• the hot gases cause an outwards pressure that balances the forces of gravity still trying to pull the material in the star together.

• the star is now a (massive) main sequence star

what is a protostar

a hot cloud of gas not quite hot enough for nuclear reactions

what is the lifecycle of a star much bigger than our sun (larger mass)

nebula \rightarrow protostar \rightarrow massive main sequence star \rightarrow red supergiant \rightarrow supernova \rightarrow neutron star OR blackhole

what is a shell of gas

gas thrown off a star when it finishes its red giant phase

what is a nebula

a cloud of dust/gas

what is a main sequence star

a stable star using hydrogen in fusion reactions

what is a white dwarf

a small, cooling star in which fusion reactions have finished

what is a red giant

a star that has used up most of its hydrogen and expanded greatly

how do planets orbit the sun

elliptical

what are the two factors that affect the gfs (N/Kg) of a planet/moon

• radius (km)

• mass (kg)

what is the key word for the effect that makes sounds from a moving object appear to change

doppler effect

describe sound or light in a moving object

• sound or light from a stationary object has the same wavelength and frequency in all directions

• if the source of the waves is moving, the waves in front of it get closer together

• the wavelength gets shorter and frequency gets higher

• the waves behind get further apart

• the wavelength gets longer and their frequency gets lower

• for light, if an object is moving away from us the wavelengths get longer

• we say the light source has been red-shifted

what is pitch

how high or low a sound is

what is frequency

the num of waves per s

what is wavelength

distance from one wave to the next on a fixed point