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Saturday, 24 October 2015

Cassini to fly through Enceladus' plumes, tracking hurricane Patricia from space....

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Cassini to sample Enceladus' ocean

Although Mars gets all the headlines (and cool movies) there are locations in the solar system that have much more life bearing potential - they're just a lot harder to get to. Enceladus,  a moon of Saturn which is only as big as the British isles, is one such place: Beneath it's shell of ice there is an ocean that scientists are itching to explore. The ice shell makes for a formidable barrier to exploration, but luckily Enceldus' ocean is jetting into space through geysers at it south pole.... and we ave a spaceship zooming around the Saturn system of rings and moons that can fly right through those geysers! The Cassini mission is set to make the second of its last three flyby's of Enceladus before the mission is decommissioned in 2017 - and that will be it for exploring the Saturn system, maybe for decades given how far away it is.
This will be the deepest flight through the plumes, and Cassini scientists hope it will give them one last round of insights on how the plumes work -  and what the ocean beneath them is like.

Above: A simulation of the Flyby, courtesy of NASA/JPL. 

"There's really no room for ambiguity," said Sascha Kempf, a CDA team co-investigator at the University of Colorado at Boulder. "The data will either match what our models are telling us about the rate at which the plume is producing material, or our concept of how the plume works needs additional thought."

Specifically, Cassini has three goals:

1. Confirm presence of molecular hydrogen, which would reveal how much hydrothermal activity is going on in the ocean.

2. Understand the ocean's chemistry: Cassini may detect new, more complex organic molecules (albeit with not enough resolution to confirm if they are biological in nature).

3. Determine the nature of the plume sources. Is the plume made up of tight, column-like jets or curtain-like eruptions that run along the length of the tiger stripe fractures (or both)? How much icy material are the plumes actually spraying out?
NASA will be having press conference on Monday 26th [EDIT: That's today J.F 26/10/2015] with more details (follow the title link for more information)

The International Space Station and fleets of weather satellites track the most intense hurricane in history

Hurricanes are the Dr-Who monsters of weather: Gigantic, self organising storm systems, feeding off the energy stored in the oceans. Hurricane Patricia has pulled itself together with incredible speed, and the storm has become the most intense ever recorded, as well as the strongest ever in the western hemisphere. With unprecedented sustained winds of over 300 km/h, Patricia is being tracked by fleets of satellites - and the international space station - to give people enough warning to take cover or stay out of its path.
Luckily the source of a hurricanes power  - the ocean - means they loose energy very quickly over land. Patricia struck the Mexican coast this morning, and is now weakening as it looses contact with the ocean. Even so, if you're in that part of the world, please stay safe.

Above: The ISS passes over Hurricane Patricia. Courtesy of NASA.

Above: Footage from weather satellites shows the storm approaching the Mexican coast.

Immense magnetic fields lurk inside stars

We can now take films of the surfaces of other stars (see this post) but what about finding out what goes on inside them? That might seem impossible, but a team of astronomers have found a way to'ultrasound' the core of some stars, using their own natural vibrations. Their results reveal magnetic fields in these stars cores are over 10,000,000 times stronger than Earth's.
"In the same way medical ultrasound uses sound waves to image the interior of the human body, asteroseismology uses sound waves generated by turbulence on the surface of stars to probe their inner properties," says Caltech postdoctoral researcher Jim Fuller.

Above: Artists impression of the supermagnetic core of a giant star. Photograph from AIA/SDO/Caltech

Asteroid probe undergoing final test

Asteroids and comets are a big deal at the moment - far from being dead chunks of rock... well OK most of them are.... but we know from studying them that they used to be part of protoplanets that had internal heat, liquids seeping through their rocks, even pre-biotic chemistry. NASA's ARM mission is going to actually retrieve one and put it into orbit about the Moon, and NASA is also launching the OSIRIS-REX mission, which will capture a sample of asteroid and bring it directly to Earth. The OSIRIS- REX spaceship is built and ready - it just started undergoing its 'environmentl tests' which simulate the conditions it will encounter on its journey and check it will be OK.

 Above; OSIRIS REX undergoing inspection. Courtesy of NASA.

Last Moon of Pluto imaged

Pictures, taken by the New Horizons spacecraft of Pluto's moon Kerberos, have finally come down, and they carry a bit of a surprise: They show that Kerberos has a double-lobed shape, with the larger lobe approximately 5 miles (8 kilometres) across and the smaller lobe approximately 3 miles (5 kilometres) across. Science team members speculate from its unusual shape that Kerberos could have been formed by the merger of two smaller objects, which would make it a relative of the comet currently being explored by ESA's Rosetta spaceprobe. 

Above: A familly portrait of Pluto's moons. Courtesy of NASA/JPL.

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