An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Pertaining to or existing at or from the very beginning.

From L.L. primordialis "first of all, original," from L. primordium "the beginning," from primus "first" + stem of ordiri "to begin."

Bonâqâzin, from bon "basis; root; foundation; bottom" (Mid.Pers. bun "root; foundation; beginning," Av. būna- "base, depth," cf. Skt. bundha-, budhná- "base, bottom," Pali bunda- "root of tree") + âqâzin "pertaining to the beginning," from âqâz "beginning" (Proto-Iranian *āgāza-, from prefix ā- + *gāz- "to take, receive," cf. Sogdian āγāz "beginning, start," pcγz "reception, taking").

The relative amount of a light element (e.g. deuterium, lithium, helium) synthesized in the early Universe.

→ primordial; → abundance.

A black hole formed following the Big Bang event due to incredibly violent turbulence that squeezed concentrations of matter to high densities. These black holes, first suggested by Stephen Hawking, are expected to have a mass comparable to that of a mountain and a size as small as an atom. Same as → mini black hole.

→ primordial; → black hole.

In cosmological models, the phenomenon that is supposed to seed the → cosmic microwave background anisotropies and the structure formation of the Universe.

→ primordial; → curvature; → perturbation.

A high redshift, metal-deficient galaxy that formed very early in the history of the Universe.

→ primordial; → galaxy.

The helium element created in the → early Universe, around 3 minutes after the → Big Bang, when the temperature dropped to 10⁹ degrees; in contrast to the helium being synthesized in stars. Based on observations of helium → emission lines in → H II regions of metal-poor dwarf galaxies (→ metal-deficient galaxy), the primordial ⁴He → chemical abundance (by mass) is estimated to be Y_P = 0.24672 ± 0.00017. Moreover, using observations of a near-pristine → intergalactic cloud, a value of 0.250 ^+0.033_-0.025 has been reached (Cooke & Fumagalli, 2018, Nature Astronomy, 2, 657). The theoretical He abundance predicted by → Big Bang nucleosynthesis is 0.24709 ± 0.00017 (Pitrou et al., 2018, arXiv:1801.08023).

→ primordial; → helium.

The formation of → chemical elements in the → early Universe, between about 0.01 seconds and 3 minutes after the → Big Bang, when the nuclei of primordial matter collided and fused with one another. Most of the → helium in the → Universe was created by this process. Same as → Big Bang nucleosynthesis

→ primordial; → nucleosynthesis.