NIST's quantum logic clock returns to top performance

The quantum logic clock—perhaps best known for showing you age faster if you stand on a stool—has climbed back to the leading performance echelons of the world's experimental atomic clocks.

Flickering sky islands generate andean biodiversity

A new video shows how climate change connected and disconnected Andean "sky islands" during the past million years. The innovative mathematical model used to make the video was based on fossil pollen records and shows how ...

Understanding and preparing for wildfire season

The recipe for disaster is simple. Throughout Western North America, millions of people live in high-risk wildfire zones thanks to increasingly dry, hot summers and abundant organic fuel in nearby wildlands.

Feeling heat on the roof of the world

The Tibetan Plateau, also known as the "roof of the world," is getting hotter. This process is especially fast in places marked by retreating snow, according to new research by scientists from the University of Portsmouth ...

page 1 from 15


The elevation of a geographic location is its height above a fixed reference point[citation needed], most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic system, vertical datum). Elevation, or geometric height, is mainly used when referring to points on the Earth's surface, while altitude or geopotential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit, and depth is used for points below the surface.

Less commonly, elevation is measured using the center of the Earth as the reference point. Due to equatorial bulge, there is debate as to which of the summits of Mt. Everest or Chimborazo is at the higher elevation, as the Chimborazo summit is further from the Earth's center while the Mt. Everest summit is higher above mean sea level.

This text uses material from Wikipedia, licensed under CC BY-SA