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

Of great weight; of great amount, quantity.

M.E. hevi; O.E. hefig, from P.Gmc. *khabigas (cf. O.N. hebig).

Sangin "heavy, weighty; stony, like stone, hard," from sang "stone, rock" (Mid.Pers. sang; O.Pers. aθanga-; Av. asenga- "stone" (related to Mod.Pers. âsmân "sky" → heaven); PIE *aken-) + -in adj. suffix.

In astrophysics, any → chemical element heavier than → helium. Such elements are also inappropriately referred to as "→ metals."

→ heavy; → element.

→ deuterium.

→ heavy; → hydrogen.

Water in which the hydrogen is replaced by → deuterium. Deuterium Oxide (D₂O).

→ heavy; → water.

A cataclysmic event in the history of the → solar system, estimated to have occurred 3.9 billion years ago (about 600 million years after the formation of the → terrestrial planets) during which → asteroid and → comet impacts with Earth were some 20,000 times more frequent than today. It is estimated that during this period the terrestrial planets were bombarded with an object 1 km in size every 20 years. This hypothetical event lasted 50 to 150 million years. Several explanations have been put forward, among which the occurrence of an instability in the outer solar system which caused → orbital migration of small bodies from the → Kuiper belt inward.

→ late, with respect to the formation time of the planets; → heavy; bombardment, noun from bombard, from Fr. bombarder, from bombarde "mortar, catapult" from bombe, from It. bomba, probably from L. bombus "a booming sound," from Gk. bombos "deep and hollow sound."

A star formation process in which → massive stars form more abundantly than that predicted by standard models, whereby the top end of the → initial mass function is significantly flatter than the canonical → Salpeter slope.

→ top; → heavy; → initial mass function.