Discuss what Physicists mean by dark matter and explain why an understanding of dark matter is
When physicists refer to dark matter they are talking about the apparent ‘missing mass’ within the universe. When the sum of the mass of visible matter is measured, it is found that around 90% of the mass required for our standard model of the universe cannot be accounted for. ... Due to the absence of emitted radiation this mass can be said to be truly dark, deriving the name ‘dark matter’. In this paper I will attempt to discuss the arguments that propose the existence of such matter and if found to be true, the implications it would have on the eventual fate of the universe. The most compelling evidence for just the mere existence of dark matter is present within the structure of galaxies, especially rotational ones such as our own. ... This provides a strong argument for the possible presence of dark matter between stars, or more commonly suggested, as a halo surrounding each star, keeping them rotating at this relatively fast velocity in respect to their distances from the centre of the galaxy. More evidence that leads to the believe that dark matter is present is the effect, predicted by Einstein, known as gravitational lensing. ... It is when this brightening of a star occurs with no visible object in between that leads physicists to believe that large bodies of dark matter exist. ... These are objects that consist of baryonic, or if you like ‘ordinary’ matter, such as protons and electrons.