See it! Moon, Venus, Jupiter, comet

Source: Earth Sky

What a glorious western twilight sky on the nights of July 17 and 18, 2015! Waxing moon, brightest planets, and Comet C/2014 Q1 (PANSTARRS).

Venus (top left), Jupiter and the moon made a triangle as seen from some parts of the world on July 18, 2015. Aimilianos Gkekas submitted this photo to EarthSky. He caught the trio from a monastery known as Meteora – literally ‘suspended in the sky’ – in Thessaly, Greece.

Moon, Venus, Jupiter and Comet C/2014 Q1 (PANSTARRS) on July 18 by John Lafferty. 

 Venus, Jupiter and the moon setting on July 18 as seen from Porto, Portual. The star above the planets is Regulus in the constellation Leo. Photo submitted by João Pedro Bessa.

Moon and Venus on July 18, 2015 by John Ashley in Kila, Montana. If you view larger, you can see both worlds are crescents as seen from Earth now. Read why Venus appears as a crescent now.

Moon and Venus on July 18, 2015 by Billie C. Barb at Mutiny Bay, Freeland, Washington. 

Another view of the moon and crescent Venus on July 18, this one in daylight, from Spencer Mann in Davis, California.

Huge Saltwater Ocean Found on Jupiter Moon Ganymede

Artistic Impression of Ganymede (Largest Moon in the Solar System)

NASA has confirmed that Ganymede, one of the moons orbiting Jupiter, has a saltwater ocean lying below its icy exterior, making it a viable location for life to flourish.

The scientists studying the planet and its outlier moons through the Hubble Telescope shared the news in a statement Thursday, saying that the ocean may bear more liquid than all the water on Earth combined.

Ganymede is an anomaly among moons. It is the largest known moon in our solar system, and the only one that generates its own magnetic field. This attribute produces a phenomenon called aurorae—strips of radiant electrified gas that circle Ganymede’s poles. Because Ganymede is situated so close to its mother planet, any changes to Jupiter’s magnetic field directly affect that of its moon. So when Jupiter’s magnetic field shifts due to the planet’s rotation, Ganymede’s aurorae “rock” back and forth in a sort of cosmic mating dance.

Observing the interplay between the planet and its moon, scientists surmised that an ocean works against Jupiter’s magnetic pull, causing Ganymede to rock less violently than they had anticipated. Once they had observed the planet with the Hubble Telescope, the researchers built computer models that supported speculation that Ganymede has a salty ocean.

Researchers believe the subterranean ocean is 10 times as deep as Earth’s oceans.

Since water is necessary to sustain life, it’s possible that these oceans may confirm the long-suspected presence of life on other planets, or on moons such as Titan and Enceladus.

NASA has speculated since the 1970s that there was water on Ganymede. A 2002 Galileo mission confirmed that the moon had its own magnetic field, but the findings weren’t concrete enough to corroborate suspicion that Ganymede had a vast ocean beneath its outer crust—until now. In a statement, an assistant administrator of NASA’s Science Mission Directorate, John Grunseld, said, “A deep ocean under the icy crust of Ganymede opens up further exciting possibilities for life beyond Earth.”

Source:Newsweek.com

Jupiter's ‘one-eyed giant Cyclops’ captured by Hubble

A stunning event captured by NASA’s Hubble Telescope shows a big black eye staring back from Jupiter's Great Red Spot storm. In reality, it is shadow play on a planetary scale.

The image was captured by NASA’s Hubble Space Telescope as it tracked changes in Jupiter’s immense Great Red Spot storm – a storm that has been raging for over 300 years. The black eye is caused by the shadow of the Jovian moon, Ganymede, sweeping across the center of the storm.

“For a moment, Jupiter stared back at Hubble like a one-eyed giant Cyclops,” a NASA spokesman told the Daily Express.

The Great Red Spot, the largest known vortex in the Solar System at 10,000 miles wide, is a persistent anti-cyclonic storm just south of Jupiter's equator. It has been raging for between 300 and 400 years, blowing winds at 345 miles an hour – speeds that are beyond comparison with even an Earthly Category 5 hurricane, which can only maximize up to 200 miles.

Astronomers are only beginning to fully understand the complexity of Jupiter, a gas giant which has a mass 317 times bigger than Earth. The planet has 62 moons – including four large ones called the Galilean moons, first discovered by Galileo Galilei in 1610. Ganymede is the largest of these moons.