2025 s2 Science exam Astronomy Terminology

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What is absolute magnitude?

Back

The actual brightness of a celestial object as it would appear if it were exactly 10 parsecs (about 33 light-years) away from the Earth.

Front

What is an absorption spectrum?

Back

A spectrum with lines missing from the pattern; the opposite of an emission spectrum because the element has absorbed its characteristic light wavelengths and removed them from the spectrum.

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What is apparent magnitude?

Back

The apparent brightness of an object in the sky as it appears to an observer on Earth.

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What is the Big Bang theory?

Back

A cosmological theory holding that the universe originated approximately 13.8 billion years ago from a violent expansion of matter.

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What is a black dwarf?

Back

The remains of a white dwarf after it has expended all of its energy and is no longer emitting detectable radiation.

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What is a black hole?

Back

An area of space-time with a gravitational field so intense that it doesn’t allow light to escape.

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What is blue shift?

Back

A decrease in wavelength of radiation emitted by a celestial body and is moving towards the observer.

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What is a constellation?

Back

A grouping of stars that make an imaginary picture in the sky.

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What is cosmic microwave background radiation?

Back

A form of electromagnetic radiation in the microwave spectrum left over from the formation of the Universe; evidence of the Big Bang theory.

Front

What is the Doppler Effect?

Back

The apparent change in wavelength of sound or light emitted by an object in relation to an observer’s position.