The height in the atmosphere as measured from the mean sea level.
An atmospheric phenomenon appearing as streamers or bands of light sometimes visible in the night sky, particularly in the northern or southern regions of the Earth. It is caused by charged particles from near Earth space following the Earth’s magnetic field and colliding with atoms and molecules in the atmosphere. The aurora responds to the strength of the solar wind and can strengthen during geomagnetic storms.
A narrow region or band around the Earth where aurora are most likely to occur. Both the northern and southern hemispheres have an auroral oval, and they are centered on the north and south magnetic poles. The ovals expand in width and toward lower latitudes during geomagnetic storms.
The very hot, outer atmosphere of the Sun.
A massive blast of magnetized plasma that creates a disturbance moving outward from the Sun’s hot, outer atmosphere (corona) through the solar wind.
Widely spread over a large area and having poorly distinguished edges.
Distinct, with well defined edges.
The time, twice a year, when the length of daylight and nighttime are equal for all places on Earth. This occurs around March 21 and September 22. During an equinox, the plane through Earth's equator passes through the center of the Sun.
A disturbance of the protective, magnetic bubble around the Earth (the magnetosphere). The disruption can be caused by a dramatic increase in the solar wind, due to a coronal mass ejection.
As the Sun emits the constant stream of plasma known as the solar wind, part of its magnetic field becomes trapped and is carried by the wind. This magnetic field travels out into interplanetary space with the solar wind and is known as the interplanetary magnetic field (IMF). Its orientation (direction) is important in the formation of geomagnetic storms.