Annie Aquino's Quiz

Annie Aquino

Astronomy

Chapter 14

What does our galaxy look like?

-the Milky Way appears in our sky as a faint band of light in the sky.

-dusty gas clouds obscure our view because they absorb visible light

-this is the interstellar medium that makes new star systems

-consists of disk, bulge, halo, globular clusters

How do stars orbit in our galaxy?

-stars in the disk all orbit in the same direction with a little up and down motion

like a merry go round

-orbits of stars in the bulge and halo have random orientations

-the suns orbital motion tells us the mass within the suns orbit

How is gas recycled in our galaxy?

-the star gas star cycle recycles gas from old stars into new star systems

-high mass stars have strong stellar winds that blows bubbles of hot gas

-lower mass stars return gas to interstellar space through stellar winds and

planetary nebulae

-xrays from hot gas in supernova remnants reveal newly made heavy elements

-a supernova remnant cools and begins to admit visible light as it expands

-new elements made by supernova mix into interstellar medium

-multiple supernovae create huge hot bubblers that can blow out of the disk

-gas clouds cooling in the halo can rain back down on the disk

-gravity forms stars out of the gas in the molecular clouds completing the star

gas

star cycle

-radiation from newly formed stars is eroding these star forming clouds

Where do stars tend to form in our galaxy?

-ionized nebulae are found around short lived high mass stars signifying active

star formation

-reflection nebulae scatter the light from stars

-1. gas clouds get squeezed as thy move into spiral arms

2. the squeezing of clouds trigger star formation

3. young stars flow out of spiral arms

What do halo stars tell us about our galaxy?

-Halo stars contain heavier elements and are older stars

-stars were born in a cloud of gas and dust which began to contract and spin,

continuing to form the disk as the galaxy grows older

What lies at the center of our galaxy?.

- stars appear to be orbiting something massive and invisible, (black hole?).

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