Question

When observing the light emitted from celestial objects, what evidence would we look for to make a claim that objects in the universe are moving toward the Earth, and what evidence would we look for to make a claim that objects are moving away from us?

A) Evidence of shorter wavelengths for objects moving toward Earth and longer wavelengths for objects moving away.
B) Evidence of longer wavelengths for objects moving toward Earth and shorter wavelengths for objects moving away.
C) Evidence of increased brightness for objects moving toward Earth and decreased brightness for objects moving away.
D) Evidence of unchanged frequency and wavelength for objects regardless of their motion in space.

Answer 1

The correct answer is A) Evidence of shorter wavelengths for objects moving toward Earth and longer wavelengths for objects moving away, due to the Doppler effect. A blueshift indicates an object is moving closer, while a redshift indicates it is moving away.

Step-by-step explanation:

When observing the light emitted from celestial objects, evidence of shorter wavelengths for objects moving toward Earth and longer wavelengths for objects moving away from us would be sought to make a claim about their motion relative to Earth. This phenomenon is due to the Doppler effect, which affects electromagnetic waves such as visible light.

If a celestial object, like a star or galaxy, is moving toward Earth, the light wavelengths will be crowded more closely together, resulting in a blueshift. Conversely, if an object is moving away from Earth, the light waves will spread out, leading to a redshift. Therefore, the correct answer to the question is A) Evidence of shorter wavelengths for objects moving toward Earth and longer wavelengths for objects moving away.

This effect is not related to the brightness of celestial objects, which can change due to other factors like size, temperature, and intrinsic luminosity. Additionally, the Doppler effect would result in wavelength and frequency changes, not a scenario where they remain unchanged regardless of motion, as mentioned in option D.