Bigger Than Big - year 10 2025

the universe

all space and matter that exists

light year

an astronomical distance unit - 1ly is the distance light travels in a year

galaxy

a cluster of stars, dust, gas, matter, and often, planetary systems

star

a ball of hot gas (mainly hydrogen and helium) that produces it's own light, held together by its own gravity.

planetary system

a system of planets revolving around a star

what is the universe mostly made up of?

dark energy and dark matter - with less that 5% of it being ordinary matter; the majority of which is free hydrogen and helium and stars

dark matter

a hypothetical substance different from normal matter that doesn't reflect, emit, or obstruct light - it only interacts with gravity

dark energy

a hypothetical substance that fills the seemingly empty space in the universe - believed that it pushes the universe apart against the pull of gravity

elliptical galaxies

The most common galaxies in the universe. Most contain little gas and dust and cannot make new stars - the stars within them are very old and appear red

irregular galaxies

A galaxy that does not have a regular shape. makes up a quarter of all galaxies - uncommon

spiral galaxies

a galaxy with a bulge in the middle and arms that spiral outward in a pinwheel pattern - often has a black hole in the center

celestial object

any natural object found in space

planet

An object that orbits a star, is large enough to have become rounded by its own gravity, and has cleared the area of its orbit. can be solid, liquid, or gas

moon

A natural satellite that orbits a planet.

terrestrial planets

The name given to the four inner planets: Mercury, Venus, Earth, and Mars

jovian planets

the four outer planets - Jupiter, Saturn, Uranus, Neptune

dwarf planet

a celestial body resembling a small planet but lacking certain technical criteria that are required for it to be classed as such.

my very early morning jump starts unwanted nausea

mercury earth venus mars jupiter saturn uranus neptune

rotational period

the time it takes for an object to do a full rotation around it's axis

orbital period

how long it takes for an object to complete an orbit

3 trends of the solar system

1. planets closer to the sun have higher temperatures

2. smaller planets have longer rotational periods

3. planets closer to the sun have shorter orbital periods

extraterrestrial objects

objects in space smaller than stars and planets - like asteroids, comets, and meteoroids

doppler effect

the effect where the light from distant galaxies increases it's wavelength and shifts towards red as it travels towards earth - proving that these stars are moving away from us and that the universe is still expanding

cosmic background radiation

very low energy radiating in every direction throughout the universe - the 'afterglow' of the big bang

goldilocks zone

the perfect distance from the sun to sustain life - hold water in liquid form, not gas or solid.

astronomical unit

the average distance between the earth and the sun

steady state theory

1940s-60s

- the universe has always existed and always will, in the state it is in now

- expanding, but density remains the same

- this is because hydrogen gas 'bubbles' up into the universe

gravity

A force that pulls objects toward each other - every object exerts it and is impacted by it

escape velocity

how fast an object must be launched to escape something's gravity

evidence for the big bang theory

1. Doppler effect/redshift (galaxies are moving away from us)
2. Cosmic Background Radiation (implies everything was close together in a similar state in the past)
3. Abundance of Light Elements (amount matches with what the big bang would create)
4. Olbers Paradox (the universe has a finite age, so light from distant stars hasn't reached us yet)

when was the hubble space telescope launched

1990

where was the hubble space telescope launched

into low earth orbit

what was the hubble space telescope designed to do

to observe and explore the universe in visible, ultraviolet, and infrared wavelengths, providing clearer images of astronomical objects and phenomena than ground-based telescopes.

what has hubble helped discover

• the atmospheric composition of planets in other planetary systems

• dark energy

history of our solar system

1. molecular cloud - large cloud of gas and dust (mostly hydrogen)

2. rotation of the cloud + gravity makes hydrogen concentrate at the center - eventually the ball collapses in on itself, becoming the sun

3. protoplanetary disk (a spinning, flattened disk of gas and dust) is formed around the sun

4. the planets are formed from this disk - a long series of collisions occurred between small objects causing them to become larger and larger

5. orbits were cleared for the 8 planets - all other remaining debris congregated within the asteroid and kuiper belt