![]() ![]() The Equator, at 0° latitude, receives a maximum intensity of the sun’s rays all year. Due to atmospheric refraction, we are able to see the sun minutes before it actually rises and sets. Atmospheric refraction is a result of increasing air density, which decreases the velocity of light through the air. Atmospheric refraction describes the way light seems to bend or deviate from a straight line as it passes through Earth’s atmosphere. This is largely due to atmospheric refraction. (The solar terminator is the shadowed line indicating daylight and sunlight on a globe.) A true equinox would indicate 12 hours of both day and night.Īlthough the equinoxes are as close to this phenomenon as happens on Earth, even during the equinoxes day and night aren’t exactly equal. This is the December solstice.Īs its name suggests, an equinox indicates equally illuminated hemispheres, with the solar terminator equally dividing Earth from north to south. Around December 21, the subsolar point hits the Tropic of Capricorn (23.5°S). After the September equinox, the subsolar point continues to move south as the Southern Hemisphere tilts toward the sun. This is the June solstice, after which the subsolar point begins to migrate south. Around June 21, the subsolar point hits the Tropic of Cancer, (23.5°N). After the March equinox, the subsolar point migrates north as the Northern Hemisphere tilts toward the sun. ![]() Only during an equinox is Earth's 23.5° axis not tilting toward or away from the sun: the perceived center of the Sun’s disk is in the same plane as the Equator.īefore and after the equinox, the subsolar point migrates north or south. The subsolar point is an area where the sun's rays shine perpendicular to Earth's surface-a right angle. (The Equator, of course, is 0° latitude.) So, equinoxes are the only times of the year when the subsolar point is directly on the Equator. Solar declination describes the latitude of Earth where the sun is directly overhead at noon. The September equinox is the autumnal equinox in the Northern Hemisphere and the vernal in the Southern.ĭuring the equinoxes, solar declination is 0°. The March equinox is the vernal equinox in the Northern Hemisphere, and the autumnal equinox in the Southern. On Earth, there are two equinoxes every year: one around March 21 and another around September 22. Sometimes, the equinoxes are nicknamed the “ vernal equinox” (spring equinox) and the “ autumnal equinox” (fall equinox), although these have different dates in the Northern and Southern Hemispheres. The equinoxes are the only time when both the Northern and Southern Hemispheres experience roughly equal amounts of daytime and nighttime. Active&Fit Direct and ChooseHealthy are trademarks of ASH and used with permission herein.An equinox is an event in which a planet’s subsolar point passes through its Equator. ![]() ChooseHealthy, Inc., and ASH Fitness are subsidiaries of American Specialty Health, Inc. The Active&Fit Direct program are provided by American Specialty Health Fitness Inc., (ASH Fitness). *The ChooseHealthy program is provided by ChooseHealthy, Inc. Sign in below to access this special Active&Fit Direct rate. The Active&Fit Direct program is not available at this time to Medicaid members. To confirm eligibility, please call Member Services at 80. It is also available to select Medicare Advantage Plus members. The Active&Fit Direct program is available to all Commercial members. Participating gyms may include Gold’s Gym, Curves, Anytime Fitness, and more. When Kaiser Permanente members sign up for an Active&Fit Direct gym membership, they can visit any of the 11,000 participating fitness centers in the nationwide Active&Fit Direct network. ![]() Get access to more than 11,000 gyms with one membership. With the ChooseHealthy® program*, you also have access to contracted fitness centers in the Active&Fit Direct network. ![]()
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