Jupiter’s moon Io is the most volcanically active world in the Solar System, with hundreds of volcanoes, some erupting lava fountains up to 250 miles high. However, concentrations of volcanic activity are significantly displaced from where they are expected to be based on models that predict how the moon’s interior is heated, according to NASA and European Space Agency researchers.
The two planets will appear side-by-side in western skies for the next two evenings – offering a dazzling spectacle. So where and how can you best see them?
After the moon, they are the two brightest objects in the night sky, and for the next few evenings they will appear side-by-side in western skies in a dazzling heavenly spectacle.
Though Jupiter is seven times farther from Earth than Venus, the planets’ orbits bring them into close approach on Tuesday evening, when they will appear only three degrees, or a few finger-widths, apart…. Continue reading Venus and Jupiter: how to spot them
Jupiter map realised in 2011, between October 10th and October 15th at the Pic du Midi Observatory
Jupiter observed with the 1 meter Telescope at the Pic du Midi observatory, and a Basler Scout Camera. Crédit : S2P / IMCCE / OPM / JL Dauvergne / Elie Rousset / Eric Meza / Philippe Tosi / François Colas / Jean Pajus / Xavi Nogués / Emil Kraaikamp
Nasa says it has found evidence of a vast salt water lake just under the icy crust of Jupiter’s moon Europa – a potential location for alien life
Lake of slush hidden under floating ice cap on Jupiter’s moon Europa ‘could harbour life’
By ROB WAUGH
- Slushy lake may be hidden by a ‘lid’ of floating ice
- Salty water lake could lie 3km below the surface
- Would contain as much water as American Great Lakes
- Nasa considers mission with ground-penetrating radar
Scientists have often speculated that Jupiter’s moon Europa might contain hidden oceans – and thus the potential for life.
But lakes buried too deep beneath the surface would be sterile.
Now, computer simulations based on scans of ‘chaos terrain’ on the aurface suggest that an ‘ice cave’ might be buried near enough the surface to support life, with a floating ‘cap’ leading to a cave of salty slush.
It would contain as much water as the American Great Lakes.
The salty lake is thought to be locked within Europa’s icy outer shell a few kilometres from the surface.
Other large pockets of liquid water are also likely to exist on the moon, it is claimed.
Scientists are excited by the discovery, which offers one of the best hopes yet of finding life beyond the Earth.
Evidence for the ice-covered lake in Europa’s Thera Macula region is seen in the shape of the terrain above it. The site appears to be marked by a fractured and collapsing lid of floating ice.
On Earth, similar features in the Antarctic are caused by briny seawater penetrating and weakening ice shelves. They are also present in Iceland, where glaciers are heated from below by volcanic activity.
Scientists have long suspected that a liquid or slushy ocean exists under Europa’s surface, warmed by the tidal forces of Jupiter’s powerful gravity.
Theoretically, a liquid water ocean could provide a suitable habitat for life – but only if it was not too far from the surface.
Experts disagree about how thick the layer of covering ice is. The new research, based on images from the Galileo probe, suggests that water ‘lenses’ could lie as little as three kilometres below the bottom of the surface crust.
Lead scientist Dr Britney Schmidt, from the University of Texas, said: “One opinion in the scientific community has been, ‘If the ice shell is thick, that’s bad for biology – that it might mean the surface isn’t communicating with the underlying ocean’.
‘Now we see evidence that even though the ice shell is thick, it can mix vigorously. That could make Europa and its ocean more habitable.’
The research, published today in the journal Nature, involved computer simulations based on observations of Europa and Earth.
Dr Schmidt’s team focused on two circular bumpy regions on Europa’s surface – known as ‘chaos terrains’.
Their existence will only be confirmed by a new space mission designed to probe Europa’s ice shell.
Such a mission, likely to employ ground-penetrating radar, is now under consideration by American space agency Nasa.
Commenting on the study, Dr Robert Pappalardo, senior research scientist at Nasa’s planetary science section, said: “It’s the only convincing model that fits.’
The moment of inertia of a giant planet reveals important information about the planet’s internal density structure and this information is not identical to that contained in the gravitational moments. The forthcoming Juno mission to Jupiter might determine Jupiter’s normalized moment of inertia NMoI=C/MR^2 by measuring Jupiter’s pole precession and the Lense-Thirring acceleration of the spacecraft (C is the axial moment of inertia, and M and R are Jupiter’s mass and mean radius, respectively). We investigate the possible range of NMoI values for Jupiter based on its measured gravitational field using a simple core/envelope model of the planet assuming that J_2 and J_4 are perfectly known and are equal to their measured values. The model suggests that for fixed values of J_2 and J_4 a range of NMOI values between 0.2629 and 0.2645 can be found. The Radau-Darwin relation gives a NMoI value that is larger than the model values by less than 1%. A low NMoI of ~ 0.236, inferred from a dynamical model (Ward & Canup, 2006, ApJ, 640, L91) is inconsistent with this range, but the range is model dependent. Although we conclude that the NMoI is tightly constrained by the gravity coefficients, a measurement of Jupiter’s NMoI to a few tenths of percent by Juno could provide an important constraint on Jupiter’s internal structure. We carry out a simplified assessment of the error involved in Juno’s possible determination of Jupiter’s NMoI.