Al-Quazwīnī (ca. 1203-1283) The wonders of creation, 16th century Florence, Biblioteca Medicea Laurenziana, Ms. Orientali 45, f. 17v This encyclopædia, which contains a lengthy section devoted to cosmography, enjoyed wide circulation in the Islamic world. The compiler referred back to the Greek authors, in particular to Aristotle and Ptolemy. At folio 17v, the configurations of the Sun, Earth and Moon that give rise to eclipses. (via Al-Quazwini, The wonders of creation)
This was the view out the International Space Station’s cupola on Jan. 1, 2013, around 09:37 UTC, looking nearly straight down the gullet of Italy’s Mt. Vesuvius. Perhaps you’ve heard of it? Just a little more than 1,900 years ago, it blew its top in the most famous volcanic eruption in recorded history. About 16,000 people lost their lives that day due to pyroclastic flow—searing hot ash blasting outward from the stratovolcano’s maw.
The volcano has erupted many times since then, including in the 20th century. Got that? It’s still active. Now take another look at that photo, and let the volcano’s surroundings settle in to your mind. It sits just a few kilometers from Naples, and more than half a million people live in the volcano’s red zone—where destruction from a big eruption would be swift and brutal.
That’s why volcanologists consider it the world’s most dangerous volcano. Given all we’ve learned about volcanoes in the past few decades, I hope scientists would be able to give people a few days’ warning about an eruption. Science, after all, saves lives. (via Bad Astronomy)
Photo with 1 note
A double hemisphere world map invites graphic embellishments that take advantage of the sheet’s marginal curved spaces. Designers often responded to this challenge by including celestial charts or polar projections in the central sections. The other margins could serve as the arena for illustrating religious, cosmological, or astrological themes. The peripheral areas of this double hemisphere map by Visscher are adorned with personified seasons and their accompanying zodiacal signs: Aries, Taurus, and Gemini (spring) ; Cancer, Leo, Virgo (summer) ; Libra, Scorpio, and Sagittarius (autumn) ; and Capricorn, Aquarius, and Pisces (winter). The two figures at the intersection of the hemispheres represent the triumph of Christianity over pagan idolatry.
Transit of Venus: 2012
Excitement all day over this evening’s cosmic event!
Transits of Venus are among the rarest of predictable astronomical phenomena. Historically, witnessing these rare celestial events has helped scientists reach up and grasp the cosmos. In the ages of heliocentrism, 17th century astronomers Galileo and Kepler studied the planet’s position, or parallax, in order to triangulate Earth’s distance from the sun. In 1728, while searching for stellar parallaxes, James Bradley discovers the “aberration of starlight,” an apparent shift in a star’s position due to the finite speed of light and the motion of the Earth.
Today, observing Venus’ path between Earth and the sun allows astronomers to explore the worlds orbiting distant stars. Scientists study far-off planets by observing how the light dips as the planets moves in front of the sun. They will also use tonight’s rare planetary encounter to study the transparent layers of the Venusian mesosphere. Astronomers will be measuring a thin arc of light, called the aureole, whose brightness and thickness helps determine the density and temperature of Venus’ atmosphere.
Sights of Venus passing by the sun happen in pairs over a hundred years apart. Since the last one was in 2004, Venus’ next journey across the sun will not occur until 2117! To find out when to look into the sky check out http://www.transitofvenus.org/, or watch it live here.
Photo with 3 notes
Drawings of the 1769 transit of Venus by James Cook, observed in Tahiti.
Photo with 3 notes
Sep 28, 2011 - Violent Sunspot Group AR 1302 Unleashes a Flare.
Page 1 of 2