The Cosmic Stretch: Red Shift Expanding Universe Quiz

If a light source moves away from an observer, then the waves it emits are stretched. If the wavelength of visible light is stretched, then it moves toward the longer, redder part of the spectrum. Therefore, this phenomenon is called Red Shift.

If a galaxy moves toward Earth, then the light waves are compressed into shorter wavelengths. If shorter wavelengths correspond to the blue end of the spectrum, then approaching objects are Blue Shifted. Therefore, objects moving away must be Red Shifted, making the statement false.

If every element has a unique "fingerprint" of spectral lines, then those lines appear at fixed wavelengths in a lab. If we see the same pattern of lines from a galaxy but they are all moved to the right, then we know a shift has occurred. Therefore, stationary lab samples act as the control for comparison.

If Edwin Hubble graphed the distance of galaxies against their velocity, then he found a straight-line relationship. If this means the expansion is uniform across the universe, then v=H0​d. Therefore, the answer is Hubble's Law.

If we see galaxies moving away from each other now, then if we "rewind" time, they must have been closer together. If we go back far enough, then everything must have been concentrated into a single point. Therefore, Red Shift is primary evidence for the Big Bang.

If the universe is expanding, then the fabric of space itself is stretching between galaxies. If space stretches, then the light waves traveling through it are stretched as well. Therefore, it is the expansion of space, not the "engine" of the galaxy, that causes Cosmological Red Shift.

If a siren moves toward you, the sound waves are squashed (higher pitch); if it moves away, they are stretched (lower pitch). If light behaves like a wave just like sound, then it should experience a similar shift in frequency. Therefore, the Doppler Effect is the physical principle behind Red Shift.

If the visible spectrum is arranged by wavelength, then violet is at the short end and red is at the long end. If a shift occurs toward longer wavelengths, then it is moving toward the red end. Therefore, the color is red.

If Red Shift is proportional to the speed of recession, then a greater shift means a higher velocity. If Hubble's Law is correct, then this also means Galaxy A is likely further away than Galaxy B. Therefore, a larger shift indicates a faster receding speed.

If the universe expanded from a hot point, then we should see stretched light (Red Shift), a leftover glow (CMB), and a specific mix of light elements. If the Moon's rotation and Earth's gravity are local solar system effects, then they don't prove the universe is expanding. Therefore, A, B, and D are the correct choices.

If the universe is expanding, then most distant galaxies are moving away. However, if a few nearby galaxies (like Andromeda) are gravitationally bound to us, then they can be moving toward us. If they move toward us, they show a Blue Shift. Therefore, the statement is false.

If the wavelength (λ) of light increases because it is stretched, then the frequency (f) must decrease because they are inversely related (c=λf). If the frequency decreases, the energy of the light also decreases. Therefore, Red Shift involves a drop in frequency.

If the expansion rate is the slope of the line on a velocity-distance graph, then it is a specific value denoted as H0​. If this value helps us estimate the age of the universe, then it is a fundamental cosmological number. Therefore, it is the Hubble Constant.

If the material of the balloon expands, then the distance between any two dots increases. If no matter where you sit on the balloon, every other dot seems to be moving away, then there is no "center." Therefore, the balloon is a 2D analogy for how 3D space expands.

If a galaxy is moving away extremely fast, then the light is stretched significantly. If the shift is large enough, then the original visible light wavelength becomes so long that it enters the infrared range. Therefore, we need infrared telescopes (like JWST) to see the most distant galaxies.

If light travels at a finite speed, then it takes time to reach us. If a galaxy is 1 billion light-years away, then the light we see today left that galaxy 1 billion years ago. Therefore, as we look further into the expanding universe, we are looking back in time.

If light is in a vacuum, then its speed (c) is always constant. If the wave is stretched, then its wavelength, frequency, color, and energy all change as a result. Therefore, B, C, D, and E are the correct answers.

If H0​ tells us how fast the universe is expanding, then the inverse tells us how long it has been expanding since it was a single point. If current measurements are accurate, then this gives us a value of about 13.8 billion years. Therefore, the answer is age.

If the early universe was extremely hot, then it emitted high-energy gamma rays. If the universe has expanded 1,000 times since then, then those waves have been stretched 1,000 times. If they have stretched into the microwave range, then the CMB is the ultimate Red Shifted signal. Therefore, B is correct.

If the universe expands uniformly, then an observer in any galaxy would see all other galaxies moving away. If every point sees the same expansion, then no point is special or central. Therefore, Red Shift proves expansion, not a center.