The Universe - 2023

what is a star

a large celestial body composed of gas and emits light

what is a galaxy

stars grouped together in a structure

what are galaxies made up of

large collection of stars, gas, and dust

list the 6 types of galaxies

barred spiral, irregular, spiral, peculiar, elliptical, lenticular

estimate amount of galaxies

100 billion

what does the universe contain

space and all the matter and energy

what is the ozone layer

layer in the atmosphere which absorbs harmful solar radiation + other gases (keeps the earth toasty)

what is a solar system

collection of stars and small bodies that orbits our sun

another name for bodies

planets

what is a planet

a spherical body which orbits the sun

name the terrestrial planets

mercury, venus, earth, and mars

qualities of the terrestrial planets

orbit nearest to the sun - rocky, dense, and relatively small

name the gas planets

jupiter, saturn, uranus, neptune

qualities of the gas planets

orbit farthest from the sun - thick, gaseous atmosphere; small, rocky cores; ring system of ice, rock, and dust

what are most stars made of

hydrogen and helium

life cycle of the star

RAHHHHHH

name the process which energy produced in the core of a star

nuclear fusion

what are galaxies

large collection of stars, gas and dust held together by gravity

how many stars do dwarf galaxies contain

few billion stars

how many stars do giant galaxies contain

hundreds of billions

where is our solar system located

Milky Way

why type of galaxy is the milky way

spiral galaxy

spiral galaxy

shaped like a pinwheel, central bulge which two or more spiral arms extend

elliptical galaxies

looks like spheres or ovals and do not have spiral arms

irregular galaxies

splotchy, irregularly shaped - blob

what is period of rotation

the amount of time taken for an object to rotate once (1 day)

what is period of revolution

the time taken for an object to revolve around the sun once (1 year)

what is gravity

a force that pulls all objects towards each other

what is inertia

the tendency of an object to stay either at rest or in motion along a straight path

what would happen if inertia was stronger than gravity

the objects would stay on their straight path and fly off into space

what would happen if gravity was stronger than inertia

the objects would crash into the earth

what do inertia and gravity do

work together to keep the moon orbiting the earth and to keep planets orbiting the sun

what is a comet

small body made out of dust, rock, gas, and ice

name parts of comets

nucleus, coma, ion tail, dust tail.

what are astroids

large pieces of space rock with irregular shapes

where do most asteroids orbit

sun in the asteroid belt located between mars and jupiter

what is a meteoroid

pieces of rock or dust that are smaller than asteroids

what is colour a clue about a star

the stars tempurature

what is a binary star

pairs of stars, pulled together by gravity, that orbits each other

what are binary star use to

determine the stars property

light year

units used to express stellar distance → distance light travels in one year

apparent magnitude

a stars brightness as it appears on earth

absolute magnitude

how bright a star actually is

what does the Hertzsprung-Russell diagram show

the relationship between the absolute magnitude and temperature of stars

what is Cepheid variable

a stars whose brightness varies periodically because it expands and contracts

list the ways a star can be classified

size, temperature, brightness and magnitude

size meaning (star)

how massive the star is

what colour do cooler stars have

red stars

what colour do warmer stars have

blue stars

what colour do medium stars have

yellow

what does a H-R diagram do

compares the temperature, colour and luminosity of a star on a graph

where is the temperature on the H-R diagram

horizontal (bottom axis) - hotter at left, cooler at right

where is the brightness on the H-R diagram

vertical axis (left side) - brightest near top, dimmer near bottom

name the two most common measurement for distance

* astronomical unit - AU
* light year

what does the astronomical unit measure

the average distance from the earth to the sun (used when discussing distance within **our** solar system)

who discovered redshift

Edwin Hubble

what did Hubble’s discovery tell us about the universe

almost all galaxies were moving away from each other

how does redshift work

shows how light moves towards longer or shorter wavelengths as galaxies and stars move closer or farther away

what does it mean if a star is moving closer to the red side of the spectrum

it is moving farther away from the earth

what does it mean if a star is moving closer to the blue side of the spectrum

it is moving closer to the earth

what is cosmic microwave background radiation

shows that when the universe was young it was very hot and as it expanded it grew cooler

who discovered the composition of the universe

Cecilia Helena Payne

what did Payne discover

stars were mostly made of hydrogen and helium

who discovered dark matter

Fritz Zwick

what are space technologies used for

to enter and retrieve objects or life forms from space

name the 3 present day space technologies

* hubble space telescope
* curiosity rover
* kepler spacecraft

name the 3 future space technologies

* antimatter-powered rockets
* laser and microwave-powered rocket
* sun powered rocket

what did Sir Isaac Newton discover

gravity, laws of motion, and the light spectrum

what is gravity

an invisible force that pulls everything towards the centre of earth

how is gravity measured

metres per second squared

how is mass measured

measured by how much matter is in an object

what is weight

weight is the force of a mass pushing down on the surface on which it is standingho

how is weight neasured

in newtons