Astronomy - Galaxies Test Review

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What is dark energy?

Back

Dark energy is a mysterious force that makes up about 71% of the universe and is responsible for the acceleration of its expansion.

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What did Edwin Hubble discover about galaxies?

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Hubble discovered that the farther away a galaxy is, the greater its redshift, indicating that the universe is expanding.

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What is the observable universe?

Back

The observable universe is the part of the universe that we can see and measure, which is constantly expanding.

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What is the significance of redshift in astronomy?

Back

Redshift occurs when light from an object is stretched to longer wavelengths, indicating that the object is moving away from us, which supports the theory of an expanding universe.

Front

What is the role of gravity in the universe?

Back

Gravity is the force that attracts objects with mass towards each other, playing a crucial role in the formation and structure of galaxies.

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What is the Big Bang Theory?

Back

The Big Bang Theory is the leading explanation for the origin of the universe, suggesting it began as a singularity and has been expanding ever since.

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What is a galaxy?

Back

A galaxy is a massive system that consists of stars, stellar remnants, interstellar gas, dust, and dark matter, bound together by gravity.

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What are the main types of galaxies?

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The main types of galaxies are spiral, elliptical, and irregular galaxies.

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What is the difference between a star and a planet?

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A star is a luminous celestial body made of plasma that generates energy through nuclear fusion, while a planet is a celestial body that orbits a star and does not produce its own light.

Front

What is the Milky Way?

Back

The Milky Way is the galaxy that contains our solar system, characterized as a barred spiral galaxy.