It is possible to derive the age of the universe given the value of the hubble constant and the distance to a galaxy, again with the assumption that the value of the hubble constant has not changed since the big bang. consider a galaxy at a distance of 400 million light-years receding from us at a velocity, v. if the hubble constant is 20 km/s per million light-years, what is its velocity? how long ago was that galaxy right next door to our own galaxy if it has always been receding at its present rate? express your answer in years. since the universe began when all galaxies were very close together, this number is a rough estimate for the age of the universe.

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.

Fitness is the ability to perform only very light levels of physical activity.