In 1924, Edwin Hubble Proved That the Andromeda Galaxy Lay

question 28

Multiple Choice

In 1924, Edwin Hubble proved that the Andromeda Galaxy lay far beyond the bounds of the Milky Way, thus putting to rest the idea that it might have been a cloud within our own galaxy. How was he able to prove this?

• A) By observing individual Cepheid variable stars in Andromeda and applying the period-luminosity relation
• B) He was able to measure the parallax of the Andromeda Galaxy.
• C) He found that the universe is expanding, and therefore concluded that Andromeda must lie outside our own galaxy.
• D) He was the first person ever to look through a telescope at the object we now call the Andromeda Galaxy.

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Definitions:

Hydrogen Bonding

A weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other.

Ice

Water frozen into a solid state, typically at or below 0°C (32°F).

Water Boils

The transformation of water from liquid to gas phase, occurring at 100°C (212°F) at sea level.

Hydrogen Ions

Positively charged atoms of hydrogen, which contribute to acidity when present in high concentrations in solutions.