How cold was the ice age? Researchers now know
A University of Arizona-led team has nailed down the temperature of the last ice age—the Last Glacial Maximum of 20,000 years ago—to about 46 degrees Fahrenheit (7.8 C).
A University of Arizona-led team has nailed down the temperature of the last ice age—the Last Glacial Maximum of 20,000 years ago—to about 46 degrees Fahrenheit (7.8 C).
Earth Sciences
Aug 26, 2020
47
3707
The latest images of Jupiter from the James Webb Space Telescope (JWST) are stunners.
Astronomy
Aug 22, 2022
0
863
The Atlantic meridional overturning circulation (AMOC), a system of ocean currents that carry warm water from the tropics into the North Atlantic and transport cold water from the northern to the southern hemisphere, is a ...
Earth Sciences
Oct 18, 2022
4
967
Many of us know the conventional theory of how the dinosaurs died 66 million years ago: in Earth's fiery collision with a meteorite, and a following global winter as dust and debris choked the atmosphere. But there was a ...
Evolution
Jul 1, 2022
11
1054
New research from the University of Massachusetts Amherst provides a novel answer to one of the persistent questions in historical climatology, environmental history and the earth sciences: what caused the Little Ice Age? ...
Earth Sciences
Dec 15, 2021
43
2052
The poles are warming several times faster than the global average, causing record smashing heatwaves that were reported earlier this year in both the Arctic and Antarctic. Melting ice and collapsing glaciers at high latitudes ...
Environment
Sep 16, 2022
52
587
For over 60 years, scientists have theorized that a person's body shape and size could be influenced by the climate of where they live. Now a new study from the University of Tennessee, Knoxville, suggests there's more to ...
Evolution
Aug 5, 2016
2
311
A new research paper finds that genetic material from Neanderthal ancestors may have contributed to the propensity of some people today to be "early risers," the sort of people who are more comfortable getting up and going ...
Evolution
Dec 14, 2023
0
4517
(PhysOrg.com) -- Flitting among the cool slopes of the Appalachian Mountains is a tiger swallowtail butterfly species that evolved when two other species of swallowtails hybridized long ago, a rarity in the animal world, ...
Plants & Animals
Sep 8, 2011
3
1
"A great fire appeared in the sky to the North, and lasted three nights," wrote a Portuguese scribe in early March, 1582. Across the globe in feudal Japan, observers in Kyoto noted the same fiery red display in their skies, ...
Astronomy
Mar 26, 2021
0
523
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees (marked with °). The equator has a latitude of 0°, the North pole has a latitude of 90° north (written 90° N or +90°), and the South pole has a latitude of 90° south (written 90° S or −90°). Together, latitude and longitude can be used as a geographic coordinate system to specify any location on the globe.
Curves of constant latitude on the Earth (running east-west) are referred to as lines of latitude, or parallels. Each line of latitude is actually a circle on the Earth parallel to the equator, and for this reason lines of latitude are also known as circles of latitude. In spherical geometry, lines of latitude are examples of circles of a sphere, with the equator being a great circle.
Latitude (usually denoted by the Greek letter phi (φ)) is often measured in degrees, minutes and seconds. The Eiffel Tower has a latitude of 48° 51′ 29″ N-- that is, 48 degrees plus 51 minutes plus 29 seconds. Or latitude may be measured entirely in degrees, e.g. 48.85806° N.
If the Earth were actually spherical, and homogenous, and not rotating, then latitude at a point would just be the angle between a vertical line at that point and the plane of the equator. Everywhere on Earth a vertical line would point to the center of the Earth. In reality the earth is rotating and is not spherical, so a vertical line — a line in the direction of apparent gravity — doesn't point to the center of the Earth (except at the poles and the equator). If the Earth were homogenous, then a vertical line would still point to some point on the Earth's axis, and latitude at a point would still be the angle between the vertical line there and the plane of the equator.
But the Earth is not homogenous, and has mountains-- which have gravity and so can shift the vertical line away from the Earth's axis. The vertical line still intersects the plane of the equator at some angle; that angle is astronomical latitude, the latitude you would calculate from star observations. The latitude shown on maps and GPS devices is the angle between a not-quite-vertical line through the point and the plane of the equator; the not-quite-vertical line is perpendicular to the surface of the spheroid chosen to approximate the Earth's sea-level surface, rather than perpendicular to the sea-level surface itself.
This text uses material from Wikipedia, licensed under CC BY-SA