Making sense of modern cosmology.
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Journal Article↗
Biomedical subjects
P J Peebles
Publications and source records attributed to P J Peebles.
Galaxy formation.
It is argued that within the standard Big Bang cosmological model the bulk of the mass of the luminous parts of the large galaxies likely had been assembled by redshift z approximately 10. Galaxy assembly this early would be difficult to fit in the widely discussed adiabatic cold dark matter model for structure formation, but it could agree with an isocurvature version in which the cold dark matter is the remnant of a massive scalar field frozen (or squeezed) from quantum fluctuations during inflation. The squeezed field fluctuations would be Gaussian with zero mean, and the distribution of the field mass therefore would be the square of a random Gaussian process. This offers a possibly interesting new direction for the numerical exploration of models for cosmic structure formation.
Journal Article↗
The history of the galaxies.
Astronomical observations now reach far enough back in time, in enough depth and detail, to reveal the history of galaxies since their formation. The early Universe contained a network of gas clouds that filled much of the space between the young galaxies, where stars were forming at a high rate. Since then, intergalactic space has been swept clean, and galaxies have continued to convert the dwindling supply of gas slow into stars.
Astronomical Phenomena↗
The evolution of the universe.
Some 15 billion years ago the universe emerged from a hot, dense sea of matter and energy. As the cosmos expanded and cooled, it spawned galaxies, stars, planets and life.
Astronomical Phenomena↗