Astronomy - Gr.9 Flashcards
What is a solar system?
A solar system is a group of planets circling a star.
How did the planets begin to form?
Planets formed from the gases and other left over matter after the sun formed.
How are distances measured in a solar system?
Astronomical unit (Au) which is aprox 150 million km (average distance between earth and sun)
What are planets?
Planets are large, round, celestial objects that travel around a star.
What are the planets in order?
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
What are the terrestrial/rocky planets?
Mercury
Venus
Earth
Mars
What are the gas giants/ gaseous
Jupiter
Saturn
Uranus
Neptune
What are Dwarf Planets?
Dwarf Planets are celestial objects that oribit the sun, has a sphereical shape but does** not dominate its orbit.**
What does an object have to be to be cosidered a planet?
- Be in orbit around a star
- Have enough mass be pulled into a stablespherical shape by gravity.
- Dominate its orbit ( its mass must be greater than anything else that crosses its path)
What are two naturally occuring objects that orbit the sun?
Asteroids and Meteors
Obit the sun but too small to be planets
What are asteroids?
They are giant irregular shaped rocks that are full of rock and metal.
Called planetoids ot minor planets
What is the asteriod belt?
Millions of asteroids culmped in a ring orbiting in the gap between mars and jupiter.
2-6 years to orbit around the sun.
What is the largest asteroid?
ceres 952km in diamter
What are meteorids
small bodies that travel through space.
Most are smaller than dust particles
Most meteoroids are broken peices of asteroids that colide with each other.
What is a meteor?
A meteoroid that has entered the earths atmosphere
shooting star
As a meteor enters the earths atmosphere, it burns up. if the meteor doesnt completly burn up we call it a ______
meteorite
Did you know?:
asteroids are leftover rocks from the creation of our solar system. (peices that didnt get used to creating planets)
yes or no?
a very intense meteor shower is called a meteor storm
What is a comet made up of?
solid ice, gas, dust, water vapour and gases
What do comets orbit?
The sun, but libve in an area called the Oort cloud beyond pluto.
Did you know?
Comets are only visible when they are near the sun, their tails always point away ftom it.
The sun is a huge shpere of mostly ________
hydrogen gas
The sun emits energy in the forrm of _______________
Electromagnetic radiation (EM)
How many days does the sun take to rotate?
25 days
Name the layers of the sun
- Core (where nuclear fusion occurs)
- Radiation zone
- Convection zone
- photosphere (the lower atmospher and what we see)
- Chromosphere (an orange red layer of atmosphere)
- Corona ( the upper most part of the atmosphere)
What happens at the convection zone?
Heated materials rise, reaches the surface, cools and sinks back inside
What happens at the photosphere?
surface looks like boiling water and at this layer, radiation escapes.
What is the sun made up of?
Chromosphere (inner atmosphere)
Corona (outer atmophere)
What is nuclear fusion?
Within the suns core, high temperatures and pressures causes particles to collide and fuse.
this process emits enormous amounts of heat making the core the hottest.
What is a sunspot?
Dark, cooler areas in the photosphere.
Caused by disturbances to suns magnetic field.
What is a solar flare?
Gases and charged particles expelled above an active sunspot.
lasts only a short time
WHat is a solar prominence?
Slow, low-energy gas eruptions that travel through the corona.
solar wind ?
solar wind stream energized, charged particles flowing outwards from the sun.
-caused by solar storms
-can disrupt satellite communications
What is a stellar nebula?
A giant cloud of dust and gas in space
What is a white dwarf?
A dense, compact remnant from a low to meduim mass stars core.
T/F:
A star 100 times bigger than the sun becomes a black hole.
T
Why is the sun important? four reasons.
- sun drives weather
- makes plant life possible
- ## provides heat and light
T/F
A solar eclipse can be veiwed in a small part of the earth while a lunar eclpise everywhere
T
T/F
Warmer/hotter stars emit scattered wavelenghths of light, resulting in more btightly coloured stars.
F
Why do seasons exist?
Due to the tilt of the Earths axis relative to its orbit around the sun.
What is rotation?
How long it takes to complete a rotation?
The earth’s rotation on its axis causes the sun to appear to be moving in the sky.
24 hours.
Spinning on its axis
The act of rotating around an axis or center
How are the planets not floating away?
They are held onto their path by the attraction of the sun.
This is called the gravitational force or gravity.
What is Revolution?
The act of orbiting another object.
When is it winter?
when the earths axis points away from the sun
What changes the phases of the moon?
Monthly lunar orbit.
The moon does not generate its own light. reflects the sun
How long does it take the moon to orbit the earth?
28 days.
Why does the moon only show one side?
Because the moons time of rotation and revolution is 28 days. Because they are the same we only see one side.
What are the eight phases of the Moon?
- New moon 🌑
- Waxing cresent 🌒
- first quarter 🌓
- waxing gibbous 🌔
- Full moon 🌕
- waning gibbous 🌖
- third quarter 🌗
- waning cresent 🌘
What phase is this? 🌔
waxing gibbous
What phase is this? 🌗
thirdquarter
what phase is this? 🌒
waxing cresent
What are eclipses?
eclipses happen when one celestial object darkens, or blocks the veiw of another.
What is a solar eclipse?
Happens when the sun is blocked by the moon
Be able to draw a diagram
What is a lunar eclipse?
It happens why rge earth is positioned between the sun and the moon casting a shadow on the moon.
4 characteristics of stars?
- massive
- Gaseous
- spherical
- gives off light
Objects that are closer appear _________
brighter
what is luminosity?
The total amount of radiation produced by a star per second.
stars luminosity are compared to the sun which has the luminosity of 1
Why do objects that are closer appear brighter?
When the source is farther away, the light spreads out over a larger area. When the source is near the light is condensed/focused in a smaller area to appear brighter.
What is absolute magnitude?
Brightness of stars as if they were all located at 33ly away.
the smaller the number, the brighter
what is appart magnitude?
Brightness of stars appearing from earth
the smaller the number, the brighter
Why do we use absolute instead of apparent magnitude?
Because stars are found at different distances, it makes it diffcult to compare which stars emits more light. Therefore we use absolute magnitude.
How hot are blue stars
yellow
red
- 20000 35000 C
- 6000C
- 3000 C
What do scientists use to determine what elements make up stars?
A spectograph
(barcode line patterns matching)
does the life of a star sepend on its mass
yess
Low mass stars (red dwarf stars) use up their hydrogen slowly and can last up to a _______.
100 billion
What happens when a red dwarf star uses up its hydrogen
they end their lives as small, dim but hot white dwarf stars.
T/F
Intermediate mass stars like our sun use up their hydrogen more quickly-last 10 billion years
T
When hydrogen is used up, what happens?
the temperature rises and the outer layers of the star expand.
these cooler outer layers have a red color so they are called red giants
what happens to red giants as they age?
they get smaller, cooler and dimmer becoming a white dwarf then a black dwarf
What happens to high mass stars when they use their hydrogen.
High mass star use up their hydrogen quickly and last for millions f yea
When nearing the end of its life, the core of a high mass star collapses in a powerful explosion called a supernova.
*for very high mass stars the core contracts even further resulting in a dense neutron star
How is a supernova created.
When high mass stars collapse in a powerful explosion called a supernova.
What is a black hole how is it created?
The core of extremly massive stars contract into a super-compact, dense object.
the force of gravity is so great that not even light can escape it
What are the death of:
small to meduim star
Large
Extremly large
- core shirnks, becomes hot, dense white dwarf star
- core collapes and outer layer explodes as a supernoza
- core collapes and outer layer explodes as a largersupernoza
What are the remains of:
small to meduim star
Large
Extremly large
- white dwarf cools and fades
- core becomes neutron star
- core becomes black hole
bright but cool
red and super giants
dim but hot
white dwarf
*
What are three types of galaxies?
- elliptcal ( egg)
- barred spiral (beyblade)
- irrgular
our galaxie is spiral shaped
