http://www.hngn.com/articles/201039/20160622/earth-moon-second-moon-nasa.htm
http://www.astronomy.com/news/2016/07/hubble-gets-5-more-years-to-strut-its-stuff
http://www.space.com/33199-why-are-gravitational-waves-important.html
http://phys.org/news/2016-06-dark-gravity-phantom-energy-expansion.html
http://www.huffingtonpost.com/entry/milky-way-mass-700-billion-suns_us_574e1041e4b0757eaeb10024