Life's thermal history

Lifes preservative against self-killing

in the "index of botanical names", where the medieval Latin designations take you to the main dictionary, for example to the items satirion and testiculus leporis, under which the Middle English names are listed, in the case of satirion indiscriminately with other possible identifications, such as Arum and Endymion. Admittedly, the difficulties of identification are considerable-one reason bein...

Universe: Thermal History

Hierarchies of Biocomplexity: modeling lifes energetic complexity

In this paper, a model for understanding the effects of selection using systems-level computational approaches is introduced. A number of concepts and principles essential for understanding the motivation for constructing the model will be introduced first. This will be followed by a description of parameters, measurements, and graphical representations used in the model. Four possible outcomes...

Week 3: Thermal History of the Universe

• T ∼ 10−4 eV, t ∼ 1010 yr: today; baryons and the CMB are entirely decoupled, stars and galaxies have been around a long time, and clusters of galaxies (gravitationally bound systems of ∼ 1000s of galaxies) are becoming common. • T ∼ 10−3 eV, t ∼ 109 yr; the first stars and (small) galaxies begin to form. • T ∼ 10−1−2 eV, t ∼ millions of years: baryon drag ends; at earlier times, the baryons a...

The thermal history of the intergalactic medium

At redshifts z2, most of the baryons reside in the smooth intergalactic medium which is responsible for the low column density Lyα forest. This photoheated gas follows a tight temperature-density relation which introduces a cut-off in the distribution of widths of the Lyα absorption lines (b-parameters) as a function of column density. We have measured this cut-off in a sample of nine high reso...