11.1 Flashcards Preview

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Flashcards in 11.1 Deck (10):
1

Dark dust clouds are what?

Cool regions of gas that emit no visible light and absorb it from stars behind them and emit radiation primarily in the radio and infrared parts of the electromagnetic spectrum.

2

Emission nebulae are what?

Hot regions of gas surrounding new born stars

3

Emission nebulae emit what kind of light ?

Visible

4

Emission nebulae are often found where?

In dark dust clouds in which stars are forming

5

The interstellar medium

The matter between stars composed of gas and dust

6

Can light from the stars penetrate the density accumulations of dust?

Not anymore than a cars headlights can penetrate the fog

7

A beam of light can only be absorbed or scatter by particles with what diameters?

Diameters comparable or larger than the wavelength of the radiation involved

8

The obscurantism (absorption or scattering) increases how?

With decreasing wavelength

9

Obscuration

Absorption and scattering

10

Typical diameter of an interstellar dust particle or dust grain ?

10^-7 m