Biology- Planet Earth And Beyond Flashcards
Which is bigger , a galaxy or a solar system?
Galaxy - there can be many solar systems in a galaxy.
The name of our galaxy?
Milky Way galaxy
What is the closest star to earth?
The sun
The nearest visible star to the sun?
Alpha Centauri
How many planets orbit the sun?
8
What are some other things that are part of our solar system besides the planets and the sun
Meteors, asteroids, comets, the moon, balls of gas and rock
- most found in Kuiper belt and neptunes orbit
What is dark matter?
Does not produce light but know it is there because of the strong gravitational pull. 90% of milky way is dark matter
3 different shapes of galaxies
Spiral- Milky Way
Spherical
Irregular
Where is our solar system in the milky Way?
One of the spiral arms towards edge of milky way
Why is the milky way called the milky way?
The Greeks said it looked like spilled milk
2 types of telescopes that have helped in understand our galaxy
Why are they more effective than optical telescopes?
Infrared
Radio
Longer wavelengths that go through dust and debris,
Everything in the galaxy orbit around…?
The centre of the galaxy- like an invisible disc of dark matter
True or false…our sun is at the centre of the milky way galaxy?
False
In one of the spiral arms
Sunspots
Formed from magnetic storms on surface of sun
Explosions on surface of sun called?
Sun flares
Explain how the sun can be harmful as well as useful?
The strong rays of the sun are harmful , but the earths atmosphere filters them through the ozone layer. Humans are destroying the ozone layer through carbon dioxide gases
Know the mindmap diagram ‘sun is our main source of energy’
- We use energy from sun for cooking and heating
- Wind is caused by the sun hearing the earth , hot air rises, cools
- Wind causes waves
- Sun keeps water cycle moving …evaporation, precipitation, condensation
- Plants use sun energy to make food - photosynthesis
- We use this energy when we make fire( from potential energy in wood)
- Coal, gas, oil - fossil fuels come from plant material
- Humans and animals get energy from eating the plants
Closest neighbouring star system
Alpha centauri made up of three stars
Centauri A
Centauri B
Proxima
From where on earth can alpha centauri be seen? What constellation is it a part of?
Southern Hemisphere
Southern cross
How fast does light travel?
300,000km per second
Distances between galaxies are measured in
Light years
Our solar system is measured in
Light hours
The distances between planets or between planets and the sun is measured in
Light minutes
Name of a different galaxy close to the Milky Way ?
City of stars
The group of galaxies that the Milky Way and city of stars are part of is called
The local group
What is a merger?
When galaxies start coming together - change from spiral to a bigger spherical larger galaxy combined
Some facts about our universe that we have learned through radio and infrared telescope
The universe is expanding
It was hot when created and is cooling as it ages
Huge part of universe is made up of things we cannot see
The universe does not have a centre, galaxies a moving away from each other
Elliptically
Curved course of an object around the sun
Nearest star to earth
Proxima
Study of the stars
Astronomy
2 people who contributed to the study of stars
Ptolemy
Aristotle
Civilisations that studied the stars
Egyptians
Babylonians
Greek
Romans
EarlyAstronomers arranged stars into
Consolations
Name some other constellations
Orion
Scorpious
Taurus
Names of the constellations were linked to stories, name a story
Khoisan people have a story about a girl child who had such strong powers that when she looked at a group of lions they were turned into stars ( the three stars on onions belt)
Why were the skies , sun , moon , stars important to ancient civilisations
They realised that the sun was a source of life and many had a sun god . They believed that what happened in the heavens was linked to what was going on on earth, that is why many priests were also astrologers
In San legend what is the moon?
A man angered by the sun who cuts off a piece of the moon until there is only a tiny piece left, then it grow agAin.
Constellations seen in the SouthernHemisphere in the winter
Hercules
Sagittarius
Cygnus
Constellations seen in the SouthernHemisphere in the spring
Aquarius
Capricorn
Constellations seen in the SouthernHemisphere in the autumn
Cancer
Crater
Constellations seen in the SouthernHemisphere in the summer
Orion
Taurus
Constellations seen in the SouthernHemisphere all year round
Southern cross
Centaurus
Ancient civilisations named constellations after …(3)
Gods
Mythical heroes
Animals
Which part of the Southern cross points south?
The bottom part of the kite
Who made the first telescope?
Galileo
When Galileo looked at the milky way what did he see?
He didn’t see the stars any bigger, but he did see more stars than he was able to see with only his eyes
He could see craters on the moon
He could see moons around Jupiter
How does a telescope work?
Like our eyes….collects light ,
Focus on the object giving off the lights so as to see it better
Parts of a refractive telescope
Objective lens - at the end of the telescope - takes in the lights and refracts it to focus on one spot
Eye piece lens- nearest your eye- magnifies so that you can see image bigger
Reflection telescope how does it work?
Instead of refracting ( bending) light, mirrors are used to reflect the light
Which is better, refractive or reflective?
Reflective
Calculate magnification of a telescope
Magnification= Focal length of telescope / focal length of lens
What is South Africa’s largest optical telescope called ?
SALT
Southern Africa large telescope- it is a reflecting telescope
Why do people send telescopes into space?
Atmosphere doesn’t obstruct view, clearer
Famous space telescope
Hubble
How do radio telescopes work?
Large metal dishes , gather information - radio waves that objects in space send out .
Lots of radio telescopes put together called an array can collect more info
South African radio telescopes
KAT7 part of the Meerkat array being built
SKA square km array being built in Karoo
Best conditions for optical telescopes
Clear weather - no clouds
Air above telescope should be still - no wind
Air above telescope should be dry - no rain or humidity
Sky must be dark, no light polution
Altitude- higher the better
Galaxies
Dense collection of Stars grouped together by string gravitational forces
