An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 2 Search : reverse
reverse
  وارون، واگرد   
vârun, vâgard (#)

Fr.: contraire, opposé   

Opposite or contrary in position, direction, order, etc.
Acting in a manner opposite or contrary to that which is usual. → invert = vârun (وارون).

M.E. revers from O.Fr. revers "reverse, cross," from L. reversus, p.p. of revertere "to turn back," from → re- "back" + vertere "to turn," cognate with Pers. gard "to turn," as below.

Vârun "inverse, upside down," from vâ- "back, backward, again, re-," variant of bâz-, from Mid.Pers. abâz-, apâc-, O.Pers. apa- [pref.] "away, from;" Av. apa- [pref.] "away, from," apaš [adv.] "toward the back;" cf. Skt. ápāñc "situated behind."
Vâgard, from vâ-, → re-, + gard present stem of gardidan, gaštan "to turn, to change" (Mid.Pers. vartitan; Av. varət- "to turn, revolve;" cf. Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend").

reverse shock
  تش ِ واگرد   
toš-e vâgard

Fr.: choc en retour   

A → shock front in a → supernova remnant (SNR) arising from the interaction of the → supersonic  → forward shock wave with the → interstellar medium (ISM) material. The reverse shock forms as the high pressure gas behind the forward shock wave expands and pushes back on the stellar ejecta. Reverse shock propagates into ejecta, starting from outside.

reverse; → shock.