PHYSICS - Stars and Planets Flashcards
Name 8 planets orbiting the sun from closest to furthest
acronym =
may venus enter mars just slightly under nobody?
lol even some of it is in there
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Name 4 “smaller objects” in the solar system
acronym:
darn, must ass come?
yikers D:
Dwarf planets, Moons, Asteroids, Comets
What are asteroids and where is it located?
Also why it no form a planet?
- Could be remains of a smashed up planet/moon
- Between Mars and Jupiter
- Due to Jupiter’s gravity thought to keep em smeared out
What are comets?
Whats wrong with their orbit?
- “Dirty snowball” contains rock and ice
- Their orbits are highly elliptical, probably why their orbits are sometimes longer than Pluto’s
Name the 8 planets from smallest to largest
(ig sun is included)
acronym:
mister mayor, view earth nicely under some justifying sizes
Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, Jupiter, Sun
Desc. of a galaxy
A collection of billions of stars
Desc. of earth
Planet, object which orbits a star
Desc. of the sun
- Burning ball of gas
- Fuses hydrogen into helium
Desc. of the universe
A collection of billions of galaxies
Desc. of solar system
A group of planets and its stars
What is a light year?
The distance travelled by a light wave in one year
(1 ly = 9.5x10^15 metres)
When should km be used in terms of space measurements?
Diameters of planets
When should AU (Astronomical Unit) be used and what does it give us a good comparison with?
In the solar system, good comparison with earth
When should light year be used?
Distance between stars and galaxies
What is a parsec?
Sorry bro, look at pg. 12
bruh it says:
parsec = 3.3 light years
The life cycle of a star (omg so yummy we love this)
- Nebula - what happens here
- Dust and gas (hydrogen & helium) in space collect to form a gas cloud called nebula
- Gravity causes them to attract each other
- Gravitation energy of the particles converts to kinetic energy
The life cycle of a star (omg so yummy we love this)
- Protostar - what happens here
- As hydrogen and helium collapse in on each other, they start to collide
- During collisions, kinetic energy of particles converts to heat energy
- Centre of nebula heats up and becomes protostar
The life cycle of a star (omg so yummy we love this)
- Main sequence stars - what happens here
- After centre of protostar reaches 15 mil degrees, hydrogen fuses to produce helium
- Once that starts, star produces its own energy, so it’s in its main sequence
- During this, inward force of gravity is balanced by outward forces of gas pressure + electromagnetic radiation
(fun fact - our sun is half way through this stage)
WOW I’M SO INFORMED
The life cycle of a star (omg so yummy we love this)
- SMALL MASS STAR
a) Red Giant - what happens here
- Stars only enter this stage when hydrogen runs out
- Star starts shrinking
- Centre heats up, causes heavier elements to fuse
- Star then increases in size forming a red giant
- Happens cuz outwards radiation and gas pressure greater than inwards gravitational pull
- Small stars would produce elements up to carbon and oxygen
If this happens to our sun, it’ll consume inner planets like our earth
(OMG NOOOO)
The life cycle of a star (omg so yummy we love this)
- SMALL MASS STAR
b) White Dwarf - what happens here
- Nuclear fusion stops
- Due to temperatures not high enough to fuse heavier elements
- Outer layers of red dwarf ejected as a planetary nebula, leaving core of star
- Star will still emit light due to thermal energy still being given off
- Thermal energy eventually stop = white dwarf –> black dwarf
The life cycle of a star (omg so yummy we love this)
- SMALL MASS STAR
c) Black Dwarf - what happens here
- Unfortunately, it has finally ran out of fuel
- Cools into a black dwarf which doesn’t radiate energy
- Sad star death :(
The life cycle of a star (omg so yummy we love this)
- LARGE MASS STAR
a) Red Super Giant - what happens here
- Quite similar with Red Giant however
- This one produces more energy as it uses its fuel up at a greater rate
- And also elements up to Iron (most stable element) can be produced
The life cycle of a star (omg so yummy we love this)
- LARGE MASS STAR
b) Supernova - what happens here
- Due to fast fuel consumption
- And also technically when it produces iron
- Core contracts centre
- Heats soo much that
- Explodes, flinging rest of star into space
(Elements up to Uranium (heaviest naturally occurring elements) formed in this phase
The life cycle of a star (omg so yummy we love this)
- LARGE MASS STAR
c) Neutron Star - what happens here
- Explosion causes core to be compressed
- A very small object called a ‘Neutron Star’
- Spins and gives off EM radiation of the form of pulsars
The life cycle of a star (omg so yummy we love this)
- LARGE MASS STAR
d) Black Hole - what happens here
- Due to some massive stars causing large super novas
- May allow core to shrink even further to create a ‘black hole’
- Gravity very strong = no light can escape from that hole in space
How does a star obtain energy?
Nuclear fusion
- Fusing light nuclei (isotopes of hydrogen), into heavier nuclei (helium)
What causes star to begin nuclear fusion?
- Large mass of star creates extremely large gravitational force
- ^^^ seeks to squeeze star into smaller volumes
- Force resisted by gas particles colliding, pushing outwards
- ^^^ creates an outward gas pressure
- Squeeze effect creates heat, right conditions for nuclear fusion :0000
What are the conditions for fusion?
High pressure
* Very high density, little room for space, higher chance of collisions
(Density of gas gotta be greater than the metal lead)
High temperatures
* High speed allowing positive hydrogen nuclei to overcome repulsion force to fuse
* ( Approx 10 million degrees needed in star)
How is a star considered stable?
When internal forces are in equilibrium
Outward EM Radiation Pressure + Outward Gas Pressure = Inwards Pull of Gravity
Explain stable phase of star
- Remains in this for billions of years
- As supply of fuel runs out, rate of fusion decreases
Explain shrinking phase of star
- If rate of fusion falls
- Outwards pressure drops
- Star shrinks under the larger gravitational force
Explain expansion phase of star
- If rate of fusion increases
- Outwards radiation pressure increases
- Star expands
What are the name of the 3 forces acting on a star?
Gravity & pressure & EM radiation
Explain in terms of forces what happens when a star becomes a red giant?
Gas pressure + Em radiation > gravity
What are the “3” elements present before the birth of anything larger in the Universe?
1) Hydrogen (approx 75%)
2) Helium (approx 25%)
3) Light nuclei such as Lithium (Less than 1%)
Whats the heaviest element that can be produced from a small star like the Sun?
Carbon & Oxygen
Up to what element can be made inside a red supergiant?
Iron
If Uranium is found in Earth, what does this suggest bout’ our solar system?
Issss created from a supernova
Our solar system classed as a 2nd gen, what this mean?
1 star died creating our solar system
Idk but if u want, look at pg 23
I mean, really is your choice
Now this is important, look at page 27.
This is what happens when you don’t fucking got access to images on brainscape
