The theory of relativity usually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905 and 1915, respectively.<a href="https://en.m.wikipedia.org/wiki/Theory_of_relativity#cite_note-1" ]<1]<="" a=""></a><a href="https://en.m.wikipedia.org/wiki/Theory_of_relativity#cite_note-1" ]<1]<="" a=""> Special relativity applies to all physical phenomena in the absence of </a>gravity. General relativity explains the law of gravitation and its relation to other forces of nature.<a href="https://en.m.wikipedia.org/wiki/Theory_of_relativity#cite_note-londontimes-2" ]<2]<="" a=""></a><a href="https://en.m.wikipedia.org/wiki/Theory_of_relativity#cite_note-londontimes-2" ]<2]<="" a=""> It applies to the </a>cosmological and astrophysical realm, including astronomy.