CH 30 REview

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What is a spiral galaxy?

Back

A spiral galaxy is a type of galaxy characterized by a flat, rotating disk containing stars, gas, and dust, with spiral arms extending outward from the center. The nucleus typically contains bright stars and the arms consist of billions of young stars.

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What is a white dwarf?

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A white dwarf is a small, hot, extremely dense core that remains after a star has collapsed. It is the final evolutionary state of stars that are not massive enough to become neutron stars or black holes.

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Why do stars appear to move in the sky?

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Stars appear to move in the sky primarily because Earth is rotating on its axis and orbiting around the Sun, creating the illusion of movement.

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What are constellations?

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Constellations are recognizable patterns of stars in the night sky, often associated with mythological figures or animals, and the regions of space surrounding them.

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What are circumpolar stars?

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Circumpolar stars are stars that are located near the celestial poles and appear to circle around the pole star (e.g., Polaris) throughout the night, remaining visible all year round.

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What is the significance of Polaris?

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Polaris, also known as the North Star, is significant because it is located nearly at the north celestial pole, making it a key reference point for navigation in the Northern Hemisphere.

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What is the difference between a red giant and a white dwarf?

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A red giant is a late stage in the life cycle of a star where it expands and cools after exhausting its hydrogen fuel, while a white dwarf is the remnant core left after a star has shed its outer layers.

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What is the role of gravity in star formation?

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Gravity plays a crucial role in star formation by pulling together gas and dust in molecular clouds, leading to the collapse of these materials and the eventual birth of a star.

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What is a galaxy?

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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 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 non-luminous body that orbits a star and does not produce its own light.