An Etymological Dictionary of Astronomy and Astrophysics

A rise in a planet’s surface → reflectivity between red → absorbance and → near-infrared reflection due to → vegetation. The red-edge is one of the possible signs of life on distant → habitable  → exoplanets.

Its presence is attributed to the chlorophyll molecule and leaf structure. The leaves of land plants reflect sunlight much more efficiently long-ward of this edge than they do in the visible.

Although the red-edge position for Earth’s vegetation is fixed at around 700-760 nm, that for exoplanets may not necessarily be the same (Takizawa et al., 2017, Nature Scientific Reports 7, Article number: 7561).

See also: → red; → edge.