Galaxies and the Universe Review

Which type of galaxy is an ELLIPTICAL Galaxy?

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Which type of galaxy is a BARRED SPIRAL Galaxy?

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Which type of galaxy is an IRREGULAR Galaxy?

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Which type of galaxy is a SPIRAL Galaxy?

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Tags

NGSS.MS-ESS1-2

Which type of galaxy is the Milky Way?

• Spiral

• Barred Spiral

• Elliptical

• Irregular

When you look at the Milky Way in the night sky, we know it's a barred spiral because it looks like

• A band of stars and dust across the sky

• a large, bright circular mass of lots of stars

• Stars evenly spread out throughout the sky

• We can't see the Milky way in the night sky

How do stars in a galaxy appear to move?

• Random directions

• In straight lines

• in an orbit around the center of the galaxy

• Stars don't move in a galaxy

Based on what you know about how stars orbit a galaxy, and on Kepler's laws of Orbital movement, how SHOULD stars be moving based on their location in a galaxy?

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Answer explanation

Based on Orbital mechanics (Kepler's Laws of Planetary motion) and gravity, stars moving closest to the center of the galaxy SHOULD move faster than stars at the edge of the galaxy. The graph shows the speed of each planet's orbit around the sun - an example of how stars should also move around a galactic center.

Tags

NGSS.HS-ESS1-4

Based on astronomer's observations, how are stars ACTUALLY moving based on their location in a galaxy?

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Answer explanation

Stars are moving at the SAME or even FASTER rate at the edge of a galaxy compared to stars near the galactic center. The graph on the right shows the expected movement (dashed line), and the observed movement (yellow and blue dots)

Tags

NGSS.HS-ESS1-4

What did astronomers call this unexplainable motion of stars in galaxies (HINT - there is more MASS than they expected!)

• Dark Energy

• Cosmological Constant

• Orbital Rotation

• Dark Matter

Tags

NGSS.HS-ESS1-2