PHYSICS - Stars and Planets Flashcards by AceFlare .

Q

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

A

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

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Q

Name 4 “smaller objects” in the solar system

acronym:
darn, must ass come?

yikers D:

A

Dwarf planets, Moons, Asteroids, Comets

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Q

What are asteroids and where is it located?

Also why it no form a planet?

A

Could be remains of a smashed up planet/moon
Between Mars and Jupiter
Due to Jupiter’s gravity thought to keep em smeared out

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Q

What are comets?
Whats wrong with their orbit?

A

“Dirty snowball” contains rock and ice
Their orbits are highly elliptical, probably why their orbits are sometimes longer than Pluto’s

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Q

Name the 8 planets from smallest to largest

(ig sun is included)

acronym:

mister mayor, view earth nicely under some justifying sizes

A

Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, Jupiter, Sun

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Q

Desc. of a galaxy

A

A collection of billions of stars

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Q

Desc. of earth

A

Planet, object which orbits a star

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Q

Desc. of the sun

A

Burning ball of gas
Fuses hydrogen into helium

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Q

Desc. of the universe

A

A collection of billions of galaxies

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Q

Desc. of solar system

A

A group of planets and its stars

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Q

What is a light year?

A

The distance travelled by a light wave in one year

(1 ly = 9.5x10^15 metres)

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Q

When should km be used in terms of space measurements?

A

Diameters of planets

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Q

When should AU (Astronomical Unit) be used and what does it give us a good comparison with?

A

In the solar system, good comparison with earth

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Q

When should light year be used?

A

Distance between stars and galaxies

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Q

What is a parsec?

A

Sorry bro, look at pg. 12

bruh it says:

parsec = 3.3 light years

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Q

The life cycle of a star (omg so yummy we love this)

Nebula - what happens here

A

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

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Q

The life cycle of a star (omg so yummy we love this)

Protostar - what happens here

A

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

Q

The life cycle of a star (omg so yummy we love this)

Main sequence stars - what happens here

A

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

Q

The life cycle of a star (omg so yummy we love this)

SMALL MASS STAR
a) Red Giant - what happens here

A

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)

Q

The life cycle of a star (omg so yummy we love this)

SMALL MASS STAR
b) White Dwarf - what happens here

A

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

Q

The life cycle of a star (omg so yummy we love this)

SMALL MASS STAR
c) Black Dwarf - what happens here

A

Unfortunately, it has finally ran out of fuel
Cools into a black dwarf which doesn’t radiate energy
Sad star death :(

Q

The life cycle of a star (omg so yummy we love this)

LARGE MASS STAR
a) Red Super Giant - what happens here

A

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

Q

The life cycle of a star (omg so yummy we love this)

LARGE MASS STAR
b) Supernova - what happens here

A

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

Q

The life cycle of a star (omg so yummy we love this)

LARGE MASS STAR
c) Neutron Star - what happens here

A

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) 5. 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