Astronomy has shown us that the fundamental laws of physics are the same everywhere in the universe.

• A. the same everywhere in the universe.
• B. only on Earth.
• C. diverge across galaxies.
• D. not yet tested.

Answer: (A)

Physical laws are universal; they apply the same way everywhere in the universe. This idea lets us trust Earth-tested physics when we study distant stars, galaxies, and cosmic phenomena. For example, the speed of light in a vacuum is the same constant no matter where we measure it, and gravity describes the motion of planets not just in our solar system but around other stars as well. Atomic spectra look the same anywhere, so chemistry and spectroscopy work the same in remote nebulae as on Earth. Because of this broad consistency, the statement that the fundamental laws are the same everywhere is well supported, making the answer that they are the same everywhere in the universe the best choice. The other possibilities would imply physics changes by location or have not stood up to the numerous tests conducted across the cosmos, which isn’t supported by current evidence.