Question

1. how did edwin hubble change our understanding of the universe?

Explanation:

Edwin Hubble made two key contributions. First, he used the Hubble telescope to observe cepheid variables in other galaxies (like the Andromeda Nebula), proving they were separate galaxies outside the Milky Way, ending the "island universe" debate. Second, he discovered the redshift - distance relationship (Hubble's law, $v = H_0d$, where $v$ is recessional velocity, $d$ is distance, $H_0$ is Hubble constant), showing the universe is expanding, which was crucial for the Big Bang theory and revolutionized cosmology.

Answer:

Edwin Hubble changed our understanding of the universe in two major ways: 1. He proved that "nebulae" like Andromeda were actually other galaxies (extragalactic astronomy), ending the idea that the Milky Way was the entire universe. 2. He discovered the cosmic expansion (Hubble's law, \( v = H_0d \)) showing galaxies move away from us, implying the universe has a dynamic, expanding nature, foundational for Big Bang theory and modern cosmology.