Formation and Motion of Galaxies

Front

Universe Noun

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[yoo-nuh-vurs]

Back

Universe

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All of existing matter, energy, space, and time, which together constitute everything that is known and unknown to us.

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Example: This image shows the universe's expansion from the Big Bang, highlighting key stages like galaxy formation.

Front

Big Bang Theory Noun

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[big bang thee-uh-ree]

Back

Big Bang Theory

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The leading scientific theory that the universe began from a very hot, dense single point and has been expanding ever since.

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Example: The image shows the universe expanding from a single point, illustrating the Big Bang Theory.

Front

Matter Noun

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[mat-er]

Back

Matter

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Any substance that has mass and takes up space by having volume; the physical substance that makes up the universe.

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Example: The image shows matter as solids, liquids, and gases, each with different particle arrangements.

Front

Redshift Noun

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[red-shift]

Back

Redshift

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The stretching of light to longer, redder wavelengths, which occurs when a celestial object is moving away from an observer.

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Example: Light from a galaxy shifts from blue to red as it moves away from Earth, illustrating redshift.

Front

Steady State Theory Noun

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[sted-ee steyt thee-uh-ree]

Back

Steady State Theory

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A disproven theory that the universe is always expanding but maintains a constant density by continuously creating new matter.

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Example: New galaxies form as the universe expands, keeping density constant.

Front

Density Noun

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[den-si-tee]

Back

Density

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The measure of how much mass is contained in a given unit of volume, indicating the compactness of a substance.

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Example: Different liquids form layers based on density, with denser liquids at the bottom.

Front

Electromagnetic Radiation Noun

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[uh-lek-troh-mag-net-ik rey-dee-ey-shuhn]

Back

Electromagnetic Radiation

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A form of energy, including visible light and radio waves, that travels through space in wavelike patterns at high speeds.

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Example: The image shows the visible spectrum of light, illustrating electromagnetic radiation with labeled colors and wavelengths.

Front

Light-Year Noun

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[lahyt-yeer]

Back

Light-Year

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The distance that light travels in one year, approximately 9.5 trillion kilometers, used to measure vast distances in space.

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Example: The image shows light traveling from the sun to a distant star, representing a light-year.

Front

Wavelength Noun

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[weyv-lengkth]

Back

Wavelength

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The distance between two consecutive peaks or troughs of a wave, such as a wave of light or sound.

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Example: The image shows the distance between two peaks of a wave, labeled as 'wavelength'.

Front

Remote Sensing Noun

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[ri-moht sen-sing]

Back

Remote Sensing

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The science of gathering information about objects or areas from a distance, typically using satellites or aircraft-mounted instruments.

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Example: A satellite in space gathers data about galaxies, demonstrating remote sensing.