Space intro-Stars-Galaxies- Human history

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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.