Featured
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Feature |
Children's knowledge of the Earth
Children everywhere are fascinated by the sky, stars and Sun. Emerging evidence from cultures throughout the world suggests that even young children can acquire knowledge of the Earth and its place in the Universe.
- Michael Siegal
- , Gavin Nobes
- & Georgia Panagiotaki
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Editorial |
Apollo renaissance
Forty years ago, the Apollo missions brought unprecedented knowledge of the Moon. After a lengthy period of hibernation, the material recovered in the late 1960s and early 1970s is back in the limelight.
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News & Views |
A distinct source for lunar water?
The origin of water in the Earth–Moon system is an open question. Geochemical analysis of the rocks retrieved by the Apollo missions show that lunar and terrestrial water are isotopically distinct, suggesting acquisition after the Moon's formation.
- François Robert
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Letter |
Extreme oxygen isotope anomaly with a solar origin detected in meteoritic organics
The origins of the non-mass-dependent oxygen isotope anomaly in planetary materials remain controversial. An analysis of the carbon and oxygen isotopes of organic matter from a carbonaceous chondrite suggests that the signature was acquired in the envelope of the protosolar nebula, triggered by the photodissociation of carbon monoxide.
- Ko Hashizume
- , Naoto Takahata
- & Yuji Sano
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Letter |
Hydrogen isotope ratios in lunar rocks indicate delivery of cometary water to the Moon
Water has been found in many lunar rock samples, but its sources are unknown. Isotopic analyses of Apollo samples of lunar mare basalts and highlands rocks suggest that a significant volume of water was delivered to the Moon by comets shortly after its formation by giant impact.
- James P. Greenwood
- , Shoichi Itoh
- & Hisayoshi Yurimoto
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Letter |
Silica deposits in the Nili Patera caldera on the Syrtis Major volcanic complex on Mars
Extant or relict martian volcanic hydrothermal systems have been sought in the pursuit of evidence for habitable environments. Detection from orbit of hydrated silica deposits on the flanks of a volcanic cone in the martian Syrtis Major caldera complex suggests the possible preservation of a recent habitable microenvironment.
- J. R. Skok
- , J. F. Mustard
- & S. L. Murchie
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Letter |
Photolysis of sulphuric acid as the source of sulphur oxides in the mesosphere of Venus
The sulphur cycle plays fundamental roles in the chemistry and climate of Venus. Photochemical modelling suggests that the photolysis of sulphuric acid is a source of observed sulphur oxides in the Venusian mesosphere.
- Xi Zhang
- , Mao-Chang Liang
- & Yuk L. Yung
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News & Views |
Hidden martian carbonates
Evidence for the sedimentary carbonate rocks proposed to be prevalent on Mars has generally been lacking. Carbonate-bearing rocks found in the Leighton Crater may be associated with the formation of methane detected in the martian atmosphere.
- Timothy D. Glotch
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Research Highlights |
Our choice from the recent literature
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Letter |
Deep crustal carbonate rocks exposed by meteor impact on Mars
Mars may have once had a CO2-rich atmosphere, but carbonate rocks that could provide evidence for such conditions are sparse. Spectral analyses of rocks exposed from deep within an impact crater reveal that carbonate deposits may be extensive on Mars, but are buried under layers of younger volcanic rocks.
- Joseph R. Michalski
- & Paul B. Niles
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Research Highlights |
Our choice from the recent literature
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Letter |
The age of the Solar System redefined by the oldest Pb–Pb age of a meteoritic inclusion
The age of the Solar System is defined by the formation of the first solid grains in the solar nebula. Pb–Pb age dating of these solids, which were later trapped in a meteorite, indicates that the Solar System is 0.34–1.91 million years older than previously thought.
- Audrey Bouvier
- & Meenakshi Wadhwa
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News & Views |
Mantle of the Moon exposed?
The composition of the rocks brought back from the Moon by the Apollo astronauts still poses a conundrum. Spectroscopic measurements of the lunar surface may offer a resolution while providing a glimpse at the evolution of the lunar mantle.
- Paul Lucey
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Letter |
Possible mantle origin of olivine around lunar impact basins detected by SELENE
The composition, structure and evolution of the Moon’s mantle is poorly constrained. A global survey of the Moon’s surface, using the spectral profiler onboard the lunar explorer SELENE/Kaguya, identifies a number of exposures of olivine in concentric regions around lunar craters, with a possible mantle origin.
- Satoru Yamamoto
- , Ryosuke Nakamura
- & Junichi Haruyama
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News & Views |
Refilling the oceans of early Mars
The northern plains of Mars are thought to have harboured an ocean more than 3.6 billion years ago. Delta deposits and river-valley termini ring the proposed seabed and define an equipotential palaeoshoreline.
- Alberto G. Fairén
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Letter |
Ancient ocean on Mars supported by global distribution of deltas and valleys
The climate of early Mars could have supported a complex hydrological system. Analysis of ancient deltaic deposits and valley networks reveals the presence of a planet-wide equipotential surface in the northern lowlands, indicative of the existence of a vast ocean on Mars 3.5 billion years ago.
- Gaetano Di Achille
- & Brian M. Hynek
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Research Highlights |
Our choice from the recent literature
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Backstory |
Soil sampling in serenity
Vladimir Samarkin, Michael Madigan and colleagues travelled to Don Juan Pond in Antarctica, in an attempt to understand life on Mars. Instead, they discovered an unexpected link between the geosphere and atmosphere.
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Letter |
Origin of acidic surface waters and the evolution of atmospheric chemistry on early Mars
The sedimentary deposits at Meridiani Planum on Mars were formed in acidic surface waters. Geochemical calculations show that the oxidation of dissolved iron and the precipitation of oxidized iron minerals in the surface waters could be sufficient to generate the inferred acidity.
- Joel A. Hurowitz
- , Woodward W. Fischer
- & Ralph E. Milliken
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Editorial |
The people's camera
Taxpayer-funded scientific research carries with it the responsibility to communicate to the general public its relevance in an accessible, open and inspirational manner. The HiRISE project that steers a camera on Mars admirably achieves this aim.
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News & Views |
Tectonic overturn on Enceladus
The south pole of Saturn's icy moon Enceladus is anomalously warm, geologically youthful and cryovolcanically active. Episodic convective overturn explains how the moon's modest sources of internal heat can be channelled into intense geological activity.
- Paul Helfenstein
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Letter |
Origin of the Ganymede–Callisto dichotomy by impacts during the late heavy bombardment
Jupiter’s large moons Ganymede and Callisto are similar in size and composition, but different in surface and interior characteristics. Simulations with geophysical models of core formation indicate that the difference in impact energy received by the two satellites during the period of late heavy bombardment can explain the dichotomy.
- Amy C. Barr
- & Robin M. Canup
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Letter |
The role of episodic overturn in generating the surface geology and heat flow on Enceladus
Saturn’s satellite Enceladus shows higher heat loss than expected and a wide range of surface ages. Numerical simulations indicate that occasional catastrophic overturn events could be responsible for both observations by recycling portions of the icy lid to the interior, which would cause transiently enhanced heat loss.
- Craig O’Neill
- & Francis Nimmo
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