You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "Who is regarded as one of the most important astronomers of all time, and invented a morphological classification scheme for galaxies?" whose answer is Edwin Hubble.
Each document should contain about 30 words, and these documents should contain useful information.

Query: Edwin Hubble contributions to astronomy
Useful Output:

Doc 1: In January 1925, Carnegie Science astronomer Edwin Hubble opened the doors to the cosmos by announcing his discovery that the universe existed beyond our own
Doc 2: American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is generally regarded as the leading observational
Doc 3: He created a system for classifying galaxies into ellipticals, spirals and barred spirals — a system called the Hubble tuning fork diagram, used
Doc 4: Hubble proved that many objects previously thought to be clouds of dust and gas and classified as "nebulae" were actually galaxies beyond the Milky Way. He used
Doc 5: In 1924, Hubble observed and studied the behavior of nebulae at the Mount Wilson Observatory using their reflecting telescope and came to the conclusion that