Search Publications
The lakes of Titan
Lorenz, R. D.; Stiles, B.; Kelleher, K. +35 more
The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive…
Extremely fast acceleration of cosmic rays in a supernova remnant
Maeda, Yoshitomo; Takahashi, Tadayuki; Uchiyama, Yasunobu +2 more
Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) …
Dark matter maps reveal cosmic scaffolding
Refregier, Alexandre; Ellis, Richard; Mobasher, Bahram +17 more
Ordinary baryonic particles (such as protons and neutrons) account for only one-sixth of the total matter in the Universe. The remainder is a mysterious `dark matter' component, which does not interact via electromagnetism and thus neither emits nor reflects light. As dark matter cannot be seen directly using traditional observations, very little …
A black hole in a globular cluster
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +1 more
Globular star clusters contain thousands to millions of old stars packed within a region only tens of light years across. Their high stellar densities make it very probable that their member stars will interact or collide. There has accordingly been considerable debate about whether black holes should exist in these star clusters. Some theoretical…
Shear heating as the origin of the plumes and heat flux on Enceladus
Spencer, J. R.; Nimmo, F.; Pappalardo, R. T. +1 more
Enceladus, a small icy satellite of Saturn, has active plumes jetting from localized fractures (`tiger stripes') within an area of high heat flux near the south pole. The plume characteristics and local high heat flux have been ascribed either to the presence of liquid water within a few tens of metres of the surface, or the decomposition of clath…
Early geochemical environment of Mars as determined from thermodynamics of phyllosilicates
Bibring, Jean-Pierre; Poulet, Francois; Chevrier, Vincent
Images of geomorphological features that seem to have been produced by the action of liquid water have been considered evidence for wet surface conditions on early Mars. Moreover, the recent identification of large deposits of phyllosilicates, associated with the ancient Noachian terrains suggests long-timescale weathering of the primary basaltic …
Eruptions arising from tidally controlled periodic openings of rifts on Enceladus
Helfenstein, P.; Bills, B. G.; Hurford, T. A. +2 more
In 2005, plumes were detected near the south polar region of Enceladus, a small icy satellite of Saturn. Observations of the south pole revealed large rifts in the crust, informally called `tiger stripes', which exhibit higher temperatures than the surrounding terrain and are probably sources of the observed eruptions. Models of the ultimate inter…
The loss of ions from Venus through the plasma wake
Coates, A. J.; Kallio, E.; Fedorov, A. +47 more
Venus, unlike Earth, is an extremely dry planet although both began with similar masses, distances from the Sun, and presumably water inventories. The high deuterium-to-hydrogen ratio in the venusian atmosphere relative to Earth's also indicates that the atmosphere has undergone significantly different evolution over the age of the Solar System. P…
An unusually brilliant transient in the galaxy M85
Cenko, S. B.; Sanders, D. B.; Gal-Yam, A. +11 more
Historically, variable and transient sources have both surprised astronomers and provided new views of the heavens. Here we report the discovery of an optical transient in the outskirts of the lenticular galaxy Messier 85 in the Virgo cluster. With a peak absolute R magnitude of -12, this event is distinctly brighter than novae, but fainter than t…
Association of the jets of Enceladus with the warmest regions on its south-polar fractures
Porco, Carolyn C.; Spitale, Joseph N.
Jets of material have been seen emanating from the south-polar terrain of Saturn's satellite Enceladus. Observations have shown that this region is anomalously warm, with the hottest measured temperatures coinciding with the four `tiger stripe' fractures, named Alexandria, Cairo, Baghdad and Damascus, that straddle the region. Here we use Cassini …