Reviewing with River

Wikipedia is a goldmine of information, and NASA (and separately, JPL and the Goddard Institute for Space Studies) have a lot of information too. They are all free to access. Others space agencies (e.g. ESA, JAXA) also have useful websites.

Google is very powerful. Instead of typing a simple search term or question, you can use symbols (operators) to filter the search - quotes around a word or phrase for example, ensures the quoted text appears in the search results. Plus and minus symbols also act as filters on search terms, and you can limit searches to social media.

A list of the operators to filter or focus searches can be found here:
https://support.google.com/websearch/answer/2466433