Institute of Astronomy

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Moon-dust cake mix shows moon may have had water from the start

Astronomy News - 29 November 2016 - 9:30am

Early moon geology recreated in the lab suggests water was there to begin with, not added later by comets

Corrigendum: Slowly fading super-luminous supernovae that are not pair-instability explosions

Astronomy News - 24 November 2016 - 9:29am

Corrigendum: Slowly fading super-luminous supernovae that are not pair-instability explosions

Nature 539, 7630 (2016). doi:10.1038/nature19850

Authors: M. Nicholl, S. J. Smartt, A. Jerkstrand, C. Inserra, M. McCrum, R. Kotak, M. Fraser, D. Wright, T.-W. Chen, K. Smith, D. R. Young, S. A. Sim, S. Valenti, D. A. Howell, F. Bresolin, R. P. Kudritzki, J. L. Tonry, M. E. Huber, A. Rest, A. Pastorello, L. Tomasella, E. Cappellaro, S. Benetti, S. Mattila, E. Kankare, T. Kangas, G. Leloudas, J. Sollerman, F. Taddia, E. Berger, R. Chornock, G. Narayan, C. W. Stubbs, R. J. Foley, R. Lunnan, A. Soderberg, N. Sanders, D. Milisavljevic, R. Margutti, R. P. Kirshner, N. Elias-Rosa, A. Morales-Garoffolo, S. Taubenberger, M. T. Botticella, S. Gezari, Y. Urata, S. Rodney, A. G. Riess, D. Scolnic, W. M. Wood-Vasey, W. S. Burgett, K. Chambers, H. A. Flewelling, E. A. Magnier, N. Kaiser, N. Metcalfe, J. Morgan, P. A. Price, W. Sweeney & C. Waters

Nature502, 346–349 (2013); doi:10.1038/nature12569In this Letter, we have identified an important error affecting Fig. 4 and Extended Data Fig. 6, as well as the values of some parameters derived from our model fits. We stress that

Magnetic reversals from planetary dynamo waves

Astronomy News - 24 November 2016 - 9:29am

Magnetic reversals from planetary dynamo waves

Nature 539, 7630 (2016). doi:10.1038/nature19842

Authors: Andrey Sheyko, Christopher C. Finlay & Andrew Jackson

A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth’s magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes place in Earth’s core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines by columnar convection. Here we present an example of another class of reversing-geodynamo model, which operates in a regime of comparatively low viscosity and high magnetic diffusivity. This class does not fit into the paradigm of reversal regimes that are dictated by the value of the local Rossby number (the ratio of advection to Coriolis force). Instead, stretching of the magnetic field by a strong shear in the east–west flow near the imaginary cylinder just touching the inner core and parallel to the axis of rotation is crucial to the reversal mechanism in our models, which involves a process akin to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.

History: Women who read the stars

Astronomy News - 24 November 2016 - 9:27am

History: Women who read the stars

Nature 539, 7630 (2016). doi:10.1038/539491a

Author: Sue Nelson

Sue Nelson delights in Dava Sobel's account of a rare band of human computers.

Astrophysics: Homing in on a fast radio burst

Astronomy News - 24 November 2016 - 9:26am

Astrophysics: Homing in on a fast radio burst

Nature 539, 7630 (2016). doi:10.1038/539470b

The origins of powerful, millisecond-long radio pulses from space called fast radio bursts (FRBs) remain a mystery. But researchers studying the brightest FRB seen so far have zeroed in on its location more accurately than ever before.Vikram Ravi at the California Institute of Technology

Hubble rounds up the first worlds we’ll check for alien life

Astronomy News - 24 November 2016 - 9:24am

The space telescope is set to spend hundreds of hours over the next year picking out the perfect planet for its successor, the James Webb Space Telescope, to probe in earnest

Honour for software writer on Apollo moon mission

Astronomy News - 24 November 2016 - 9:22am

Barack Obama awards medal to Margaret Hamilton to recognise role in sending humankind into space.

Schiaparelli: Esa gives update on Mars crash investigation

Astronomy News - 24 November 2016 - 9:22am

The European Space Agency's preliminary report into the Schiaparelli crash on Mars confirms the probe became confused about its altitude.

Two-year extensions confirmed for ESA's science missions

Astronomy News - 23 November 2016 - 9:26am
ESA's Science Programme Committee (SPC) has today confirmed two-year mission extensions for nine scientific missions in which the Agency is participating. This secures their operations until the end of 2018.

A dash of hydrogen and methane could have kept Mars warm

Astronomy News - 23 November 2016 - 9:25am

The Red Planet’s thin atmosphere of carbon dioxide can’t retain enough heat for water to flow on the planet, but new calculations suggest how it was once warmer

Is new talk of interstellar drive too good to be true?

Astronomy News - 21 November 2016 - 8:10am

Speculation about the EM drive, a proposed fuel-free, physics-busting starship engine, is back but is it still strictly for dreamers, wonders Geraint Lewis

Not so warped

Astronomy News - 21 November 2016 - 8:04am

From tractor beams to warp drive, sci-fi has inspired serious real-life research.

Icy surprises at Rosetta's comet

Astronomy News - 18 November 2016 - 8:51am

As Rosetta's comet approached its most active period last year, the spacecraft spotted carbon dioxide ice – never before seen on a comet – followed by the emergence of two unusually large patches of water ice.

Tidal evolution of the Moon from a high-obliquity, high-angular-momentum Earth

Astronomy News - 18 November 2016 - 8:49am

Tidal evolution of the Moon from a high-obliquity, high-angular-momentum Earth

Nature 539, 7629 (2016). doi:10.1038/nature19846

Authors: Matija Ćuk, Douglas P. Hamilton, Simon J. Lock & Sarah T. Stewart

In the giant-impact hypothesis for lunar origin, the Moon accreted from an equatorial circum-terrestrial disk; however, the current lunar orbital inclination of five degrees requires a subsequent dynamical process that is still unclear. In addition, the giant-impact theory has been challenged by the Moon’s unexpectedly Earth-like isotopic composition. Here we show that tidal dissipation due to lunar obliquity was an important effect during the Moon’s tidal evolution, and the lunar inclination in the past must have been very large, defying theoretical explanations. We present a tidal evolution model starting with the Moon in an equatorial orbit around an initially fast-spinning, high-obliquity Earth, which is a probable outcome of giant impacts. Using numerical modelling, we show that the solar perturbations on the Moon’s orbit naturally induce a large lunar inclination and remove angular momentum from the Earth–Moon system. Our tidal evolution model supports recent high-angular-momentum, giant-impact scenarios to explain the Moon’s isotopic composition and provides a new pathway to reach Earth’s climatically favourable low obliquity.

Pluto 'has slushy ocean' below surface

Astronomy News - 18 November 2016 - 8:45am

Pluto may harbour a slushy water ocean beneath its most prominent surface feature, known as the "heart".

'Roundest known space object' identified

Astronomy News - 18 November 2016 - 8:44am

Astronomers claim to have discovered the roundest object ever measured in nature.

Asteroid strike made 'instant Himalayas'

Astronomy News - 18 November 2016 - 8:44am
The asteroid impact that wiped out the dinosaurs moved rock huge distances as it dug out a crater in what is now the Gulf of Mexico, scientists say.

Mystery cosmic radio blasts come with side of gamma rays

Astronomy News - 18 November 2016 - 8:40am

Fast radio bursts have baffled astronomers for nearly 10 years. Now we’ve seen one accompanied by energetic gamma rays, meaning they’re more energetic than we thought

Spacecraft could taste Europa’s sea by sampling its atmosphere

Astronomy News - 15 November 2016 - 9:26am

The moon’s watery plumes may vent into space from its hidden ocean. Now we have a way to study these jets weeks after a blast and maybe spot signs of life

Beagle Mars probe probably didn’t crash, new analysis shows

Astronomy News - 14 November 2016 - 9:44am

New research shows that the lander deployed at least three - perhaps all four - of its solar panels after touching down on the planet