Concept
Age of the universe
Related concepts (33)
Main sequence turnoff
The turnoff point for a star refers to the point on the Hertzsprung–Russell diagram where it leaves the main sequence after its main fuel is exhausted - the main sequence turnoff. By plotting the turnoff points of individual stars in a star cluster one can estimate the cluster's age. Red dwarfs, also referred to as classM stars, are stars of 0.08–0.40 solar masses. They have sufficient mass to sustain hydrogen-to-helium fusion via the proton–proton chain reaction, but they do not have sufficient mass to create the temperatures and pressures necessary to fuse helium into carbon, nitrogen or oxygen (see CNO cycle).
Baryon acoustic oscillations
In cosmology, baryon acoustic oscillations (BAO) are fluctuations in the density of the visible baryonic matter (normal matter) of the universe, caused by acoustic density waves in the primordial plasma of the early universe. In the same way that supernovae provide a "standard candle" for astronomical observations, BAO matter clustering provides a "standard ruler" for length scale in cosmology.
Timeline of the far future
While the future cannot be predicted with certainty, present understanding in various scientific fields allows for the prediction of some far-future events, if only in the broadest outline. These fields include astrophysics, which studies how planets and stars form, interact, and die; particle physics, which has revealed how matter behaves at the smallest scales; evolutionary biology, which studies how life evolves over time; plate tectonics, which shows how continents shift over millennia; and sociology, which examines how human societies and cultures evolve.