# It’s 5 times greater. It’s 10 times greater. It’s 20 times greater.

## Presentation on theme: "It’s 5 times greater. It’s 10 times greater. It’s 20 times greater."— Presentation transcript:

It’s 5 times greater. It’s 10 times greater. It’s 20 times greater.
How does the collecting area of a 10-meter telescope compare with that of a 2-meter telescope? It’s 5 times greater. It’s 10 times greater. It’s 20 times greater. It’s 25 times greater.

When we look at an object that is 1,000 light-year away, we see it…
as it is right now, but it appears 1,000 times dimmer. looking just the same as our ancestors would have seen it 1,000 years ago. as it was 1,000 years ago. as it was 1,000 light-years ago.

Where is the closest star to us?
In a certain solar system. In a globular cluster. In an open cluster. Outside the Milky Way.

The distances of nearer stars may be measured by observing their apparent motion as
the Earth orbits around the Sun. the Earth rotates on its axis. the Sun orbits around the center of the Galaxy. the planets cross their oath.

One point of light that is the blurred image of both stars.
Suppose that two stars are separated in the sky by 0.1 arcsecond. If you look at them with a telescope that has an angular resolution of 0.5 arcsecond, what will you see? Two distinct stars. One point of light that is the blurred image of both stars. The two stars will appear to be touching, looking rather like a small dumbbell. Nothing at all.

above Earth’s atmosphere.
The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is: larger. smaller. closer to the stars. above Earth’s atmosphere.

The stars in our sky twinkle in brightness and color because of ___________.
light pollution rapid changes in the brightness and colors of stars caused by changes in their spectra turbulence in the Earth’s atmosphere the bubbling and boiling of gases on the surfaces of stars

Star A is identical to Star B, except that Star A is twice as far from us as Star B. Therefore:
both stars have the same luminosity, but the apparent brightness of Star A is 4 times that of Star B. both stars have the same luminosity, but the apparent brightness of Star B is twice that of Star A. both stars have the same luminosity, but the apparent brightness of Star B is 4 times that of Star A. Both stars have the same apparent brightness, but the luminosity of Star B is 4 times that of Star A.

What is a white dwarf? A main sequence star, which tends to look white in color. The remains of a star that ran out of fuel for nuclear fusion. It is a type of star that produces energy by gravitational contraction. It is a star that follows a color-luminosity relation.

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