Category: luna

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Night sky just after sunset on March 24, 2012 …

Night sky just after sunset on March 24, 2012 with crescent moon and backlight, Jupiter, Venus and the Pleiades.

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Ritzelmut

In 40 million years, Mars may have a ring (a…

In 40 million years, Mars may have a ring (and one fewer moon)

Nothing lasts forever – especially Phobos, one of the two small moons orbiting Mars. The moonlet is spiraling closer and closer to the Red Planet on its way toward an inevitable collision with its host. But a new study suggests that pieces of Phobos will get a second life as a ring around the rocky planet.

A moon – or moonlet – in orbit around a planet has three possible destinies. If it is just the right distance from its host, it will stay in orbit indefinitely. If it’s beyond that point of equilibrium, it will slowly drift away. (This is the situation with the moon; as it gradually pulls away from Earth, its orbit is growing by about 1.5 inches per year.) And if a moon starts out on the too-close side, its orbit will keep shrinking until there is no distance left between it and its host planet.

The Martian ring will last for at least 1 million years – and perhaps for as long as 100 million years, according to the study.

The rest of Phobos will probably remain intact, until it hits the Martian surface. But it won’t be a direct impact; instead, the moonlet’s remains will strike at an oblique angle, skipping along the surface like a smooth stone on a calm lake.

This has probably happened before – scientists believe a group of elliptical craters on the Martian surface were caused by a small moon that skidded to its demise. (If this were to happen on Earth, our planet’s greater mass would produce a crash as big as the one that wiped out the dinosaurs, the researchers noted as an aside.)

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images: NASA/JPL,

Tushar Mittal using Celestia 2001-2010, Celestia Development Team.

The dazzling full moon sets behind the Very La…

The dazzling full moon sets behind the Very Large Telescope in Chile’s Atacama Desert in this photo released June 7, 2010 by the European Southern Observatory. The moon appears larger than normal due to an optical illusion of perspective.

Credit: G.Gillet/ESO | twitter: @astronomy_blog

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The diversity of worlds in our solar system (climate and geology)…

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The Great Red Spot is a persistent high-pressure region in the atmosphere of Jupiter, producing an anticyclonic storm 22° south of the planet’s equator. It has been continuously observed for 188 years, since 1830. Earlier observations from 1665 to 1713 are believed to be of the same storm; if this is correct, it has existed for at least 350 years. Such storms are not uncommon within the turbulent atmospheres of gas giants.

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With over 400 active volcanoes, Io is the most geologically active object in the Solar System. This extreme geologic activity is the result of tidal heating from friction generated within Io’s interior as it is pulled between Jupiter and the other Galilean satellites—Europa, Ganymede and Callisto.

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Europa has the smoothest surface of any known solid object in the Solar System. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably harbor extraterrestrial life.

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Neptune, the eighth and farthest planet from the sun, has the strongest winds in the solar system. At high altitudes speeds can exceed 1,100 mph. That is 1.5 times faster than the speed of sound. In 1989, NASA’s Voyager 2 spacecraft made the first and only close-up observations of Neptune.

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Ganymede  is the largest and most massive moon of Jupiter and in the Solar System.

Possessing a metallic core, it has the lowest moment of inertia factor of any solid body in the Solar System and is the only moon known to have a magnetic field. (Sounds of Ganymede’s magnetosphere).

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Saturn’s hexagon is a persisting hexagonal cloud pattern around the north pole of Saturn, located at about 78°N. The sides of the hexagon are about 13,800 km (8,600 mi) long, which is more than the diameter of Earth (about 12,700 km (7,900 mi)).

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Miranda’s surface has patchwork regions of broken terrain indicating intense geological activity in Miranda’s past, and is criss-crossed by huge canyons. It also has the largest known cliff in the Solar System, Verona Rupes, which has a height of over 5 km (3.1 mi). 

Some of Miranda’s terrain is possibly less than 100 million years old based on crater counts, which suggests that Miranda may still be geologically active today.

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Enceladus is the sixth-largest moon of Saturn. It is about 500 kilometers (310 mi) in diameter, about a tenth of that of Saturn’s largest moon, Titan. 

Evidence of liquid water on Enceladus began to accumulate in 2005, when scientists observed plumes containing water vapor spewing from its south polar surface, with jets moving 250 kg of water vapor every second at up to 2,189 km/h (1,360 mph) into space.

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Titan is the largest moon of Saturn. It is the only moon known to have a dense atmosphere, and the only object in space, other than Earth, where clear evidence of stable bodies of surface liquid has been found.

Triton is one of the few moons in the Solar System known to be geologically active (the others being Jupiter’s Io and Europa, and Saturn’s Enceladus and Titan). As a consequence, its surface is relatively young with few obvious impact craters, and a complex geological history revealed in intricate cryovolcanic and tectonic terrains. Part of its surface has geysers erupting sublimated nitrogen gas, contributing to a tenuous nitrogen atmosphere less than 1/70,000 the pressure of Earth’s atmosphere at sea level.

source: wikipedia~

image credit: data and images from NASA

Reflections of Venus and Moon Image Cred…

Reflections of Venus and Moon

Image Credit: Filippo Curti (Sanderphil Urban Observatory)

Total Solar Eclipse Timelapse by Frank Mille…

Total Solar Eclipse Timelapse by Frank Miller

Jupiter in Near-Infrared & Jupiter and …

Jupiter in Near-Infrared &

Jupiter and Ganymede in Near-UV and Blue

Image credit:

Judy Schmidt   twitter | instagram

Rhea and Saturn by Gordan Ugarkovic

Rhea and Saturn by Gordan Ugarkovic

Venus, Mars, and the Crescent Moon in Conjun…

Venus, Mars, and the Crescent Moon in Conjunction

Image credit:

Frank Miller