It's summer solstice time. What does that mean?
It's time for the start of summer—with a full moon to boot.
It's time for the start of summer—with a full moon to boot.
Planetary Sciences
Jun 19, 2024
0
17
Spring is here—officially, at least. The vernal equinox arrives on Tuesday, marking the start of the spring season for the Northern Hemisphere.
Planetary Sciences
Mar 18, 2024
0
28
Astrolabes serve two purposes. First, they are useful as an astronomical tool, especially for finding a ship's latitude. But second, they are works of art in themselves. Besides having to be precise, many are beautiful. They ...
Astronomy
Dec 13, 2023
0
27
Spring has sprung!
Earth Sciences
Mar 20, 2023
0
17
When animals experience a large injury, such as the loss of a limb, the body immediately begins a wound healing response that includes sealing the wound site and repairing local damage. In many animals, including humans, ...
Cell & Microbiology
May 19, 2022
0
177
Winter in the northern hemisphere and summer in the southern hemisphere are both coming to an end. That means the days and nights are becoming roughly equal in length, and the path the sun traces across the sky is changing.
Earth Sciences
Mar 22, 2021
0
12
Saturn is famous for its bright, glorious rings but in this picture, taken during Saturn's 2009 equinox, the rings are cast in a different light as sunlight hits the rings edge-on.
Space Exploration
Mar 19, 2019
0
11
From the Neolithic to present times, the amount of sunlight we see in a day has had a profound impact on human culture. We are fast approaching the winter solstice for the Northern hemisphere, which takes place on December ...
Astronomy
Dec 21, 2018
0
8
It's the time of the equinox or more specifically the spring equinox for us in the southern hemisphere.
Space Exploration
Sep 22, 2014
1
0
Captured on January 15, this narrow-angle Cassini image shows an outer portion of Saturn's A ring on the left and the ropy F ring crossing on the right. The thin black line near the A ring's bright edge is the Keeler Gap, ...
Space Exploration
Apr 25, 2013
0
0
An equinox occurs twice a year, when the tilt of the Earth's axis is inclined neither away from nor towards the Sun, the center of the Sun being in the same plane as the Earth's equator. The term equinox can also be used in a broader sense, meaning the date when such a passage happens. The name "equinox" is derived from the Latin aequus (equal) and nox (night), because around the equinox, the night and day have approximately equal length.
At an equinox, the Sun is at one of two opposite points on the celestial sphere where the celestial equator (i.e. declination 0) and ecliptic intersect. These points of intersection are called equinoctial points: classically, the vernal point and the autumnal point. By extension, the term equinox may denote an equinoctial point.
An equinox happens each year at two specific moments in time (rather than two whole days), when there is a location (the subsolar point) on the Earth's equator, where the center of the Sun can be observed to be vertically overhead, occurring around March 20/21 and September 22/23 each year.
Although the word equinox is often understood to mean "equal [day and] night," this is not strictly true. For most locations on earth, there are two distinct identifiable days per year when the length of day and night are closest to being equal; those days are referred to as the "equiluxes" to distinguish them from the equinoxes. Equinoxes are points in time, but equiluxes are days. By convention, equiluxes are the days where sunrise and sunset are closest to being exactly 12 hours apart.
This text uses material from Wikipedia, licensed under CC BY-SA