Mr. Mac’s Earth Science Classroom Galaxies - Group of stars, gas, and dust. - There are over 40...
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Mr. Mac’s Earth Science Class Galaxies - Group of stars, gas, and dust. - There are over 40 billion galaxies universe! - 1000 to 1,000,000 light years wide
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Transcript of Mr. Mac’s Earth Science Classroom Galaxies - Group of stars, gas, and dust. - There are over 40...
Mr. Mac’s Earth Science Classroom
Galaxies
- Group of stars, gas, and dust.- There are over 40 billion galaxies in the universe!- 1000 to 1,000,000 light years wide.
Mr. Mac’s Earth Science Classroom
New Vocab Worddddd….
Light Year (ly): distance light travels in one year.
A light year is not a measure of time. Light travels 9.5 trillion kilometers in one year. That’s a lot!
Star: 4.3 ly away It will take light 4.3 years to reach our eyes. (Proxima Centauri)
Mr. Mac’s Earth Science Classroom
What is a galaxy?
Mr. Mac’s Earth Science Classroom
Spiral Galaxies
Mr. Mac’s Earth Science Classroom
Elliptical Galaxies
Mr. Mac’s Earth Science Classroom
Elliptical Galaxies
Most are tiny
Mr. Mac’s Earth Science Classroom
Irregular Galaxies
D. Hunter (Lowell Observatory), Z. Levay (STScI)
Mr. Mac’s Earth Science Classroom
Irregular Galaxies
These galaxies are not spiral or elliptical. They are irregularly shaped.
They contain lots of gas and dust which means that lots of stars are forming.
D. Hunter (Lowell Observatory), Z. Levay (STScI)
Local G
roup Galaxies S
urvey Team
, N
OA
O, A
UR
A, N
SF
Mr. Mac’s Earth Science Classroom
The Milky Way
“face-on” view
“edge-on” (looking from the edge)
view
25 kpc = 25 kiloparsecs = 25,000 parsecs
75,000 light-years
8.5 kpc (2/3 of the way out)
Mr. Mac’s Earth Science Classroom
The Big Bang Theory: 10 billion to 20 billion years ago:
An expansion of space from a single point..
Mr. Mac’s Earth Science Classroom
The Big Bang Theory: 10 billion to 20 billion years ago:
• Over time the universe has cooled, but is still expanding today.
(What proof do we have?Stay Tuned!) …
• After about 1 billion years, the first stars and galaxies started to form….
The galaxies are expanding WITH space!!!
The Big Bang Theory: 10 billion to 20 billion years ago:
Mr. Mac’s Earth Science Classroom
The Big Bang Theory: 10 billion to 20 billion years ago:
The “raisin bread” analogyraisins galaxies, dough space
Mr. Mac’s Earth Science Classroom
The Big Bang Theory: 10 billion to 20 billion years ago:
The “raisin bread” analogyraisins galaxies, dough space
Mr. Mac’s Earth Science Classroom
The Big Bang Theory: 10 billion to 20 billion years ago:
The “raisin bread” analogyraisins galaxies, dough space
Note: raisins are not moving through dough.
Rather, blobs of dough are expanding, and
pushing the raisins farther apart.
Note: galaxies are not moving through space.
Rather, blobs of space are expanding, and
pushing the galaxies farther apart.
