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Light-year
A light-year or lightyear (symbol: ly) is a unit of measurement of length, specifically the distance light travels in a vacuum in one year. While there is no authoritative decision on which year is ... > more -
Mars Exploration Rover
NASA's Mars Exploration Rover (MER) Mission is an unmanned Mars exploration mission that sent two robotic rovers Spirit and Opportunity to explore the Martian surface and geology. Primary among the ... > more -
Earth's magnetic field
Earth's magnetic field (and the surface magnetic field) is approximately a magnetic dipole, with one pole near the geographic north pole and the other near the geographic south pole. The locations of ... > more -
Dark energy
In physical cosmology, dark energy is a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe. Assuming the existence of dark energy is ... > more -
Geomagnetic storm
A geomagnetic storm is a temporary disturbance of the Earth's magnetosphere. Associated with solar coronal mass ejections, coronal holes, or solar flares, a geomagnetic storm is caused by a solar ... > more
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