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Space intro-Stars-Galaxies- Human history
∞? ∞
What is a star system?o We call ours the solar
systemo has only one star, the sun.
But…o The majority of stars in our milky
way are groups of two or more starso two stars are called double stars or
binary.
Binary Star systemso Eclipsing binary
o When one star blocks the light from another
o Most binaries are found by observing the effects of gravity.
Our Milky Wayo It looks milky because:o It looks hazy because there are:
omany stars packed togethero Many clouds of dust and gas
Types of Galaxieso Spiral Galaxy
o Flat with arms that spiral outward like a pinwheel
o Eliptical Galaxieso Like a flattened ballo They have very little gas and dust
o Irregular shaped Galaxieso Who knows what they look
like?
Scale of the Universeo Light travels from the sun to
Earth in o 8 seco How long would it take for a
shuttle to travel at 100kpho140 years!
o It takes _______ for light to travel from the nearest star to Eartho 4 years
o the nearest star is therefore 4 light years away
Scale of the Universeo The nearest galaxy
o 1000s of light years awayo 25000 lightyears awayo Or over 200000 ly away
depends on your definition of galaxy
Uses for the skyo Have you ever heard of any
stories about using starso escaping slaves or mariners
MAYBE?
o Constellationso Group of stars in the same
part of the skyo They are Appear very close
togethero But are they…
Consider constellation: canis miniminor
o Fall o Spring
•Can you indicate which star is closest with a 1 beside it and so on, to 5.
•Canis minor as it appears from the Andromeda galaxy
looks totally different
Stars are not on a 2D plane butSpread from each other in 3D
Reflect….o Write down everything you
don’t know instinctively.