MICROWAVES ARRIVING AT EARTH TODAY

The microwaves that bathe the Earth today, as measured by the Planck satellite. The colours represent the temperature of the microwaves, which vary by only around 100- millionths of a degree. These tiny temperature variations are directly related to the d

Cosmology in five steps

1. Many cosmologists think that the Big Bang was preceded by a period of rapid expansion, called inflation. This inflation was caused by the energy stored within an all-pervasive field, called the inflaton field. 2. As the energy drained away from the inflaton field, the inflation ended and gave way to the Big Bang. At this time, almost 14 billion years ago, the Universe contained a hot, dense gas of elementary particles. 3. Quantum effects during inflation meant that these particles were not spread out with perfect uniformity. Instead, the gas was slightly denser in some regions than in others. 4. These density variations acted as the seeds out of which galaxies grew. Starting from these original seeds, cosmologists are able to compute today’s observed pattern of galaxies (and the cosmic microwave background). 5. It is possible that we live in a bubble universe which is just one of many in the entire Universe (the Multiverse). It is even conceivable that the laws of physics are different in each bubble universe.