Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Gravitational wave wikipedia , lookup
Big Bang nucleosynthesis wikipedia , lookup
Weak gravitational lensing wikipedia , lookup
Astronomical spectroscopy wikipedia , lookup
Outer space wikipedia , lookup
Cosmic microwave background wikipedia , lookup
First observation of gravitational waves wikipedia , lookup
Non-standard cosmology wikipedia , lookup
Shape of the universe wikipedia , lookup
To escape the effects of gravity on this planet you have to reach a minimum of 11.2 km s-1 Less than that, you will fall back to the surface. More than that, the spare kinetic energy will propel you out of the gravitational well and you will continue into space. Bearing this in mind, if we calculate the mean density of the universe, we can work out what will happen to the Universe we live in. If we assume the Universe is homogenous, and we divide the total mass of all of the galaxies by the current volume of the Universe, we get a value of 10-27 kg m-3 . Consider then, instead of something trying to escape the confines of the Earths gravitational well, but the gravitational well of a galaxy and all surrounding galaxies. In order to do so, the Ep of a galaxy would have to equal the Ek of the same galaxy. Substituting H0 in (v = H0r) into the equations, we get a value ρc = 9.5 x 10-27 kg m-3 . At present, calculations of density are of the same order of magnitude as the critical density. It is, however, too close to call as to the outcome of the Universe.