Google Earth now works on all web browsers except Chrome. That is, it works on Firefox, Edge, Vivaldi and Opera.
A brief history of Google Earth: In 2004, Google acquired a company called Keyhole. One of the company's products, called Keyhole Viewer, featured Earth mapping data. Google launched Google Earth in 2005 and then began mapping the world.
In 2017, Google has introduced a new version of Google Earth. It was only available on Chrome and Android, with the promise of bringing it to other Web browsers in the future. After three years (only), Google Earth is finally available for browsers other than Chrome. This happened thanks to Google switching from Native Client (NaCl) to WebAssembly (Wasm).
There is another browser that Google Earth does not have access to, it is Safari for which Google is committed to making Google Earth work in as many browsers as possible and this promise includes Apple Safari.