# Archive for category Special Topics

## Today's Postings

### The martian soil as a planetary gas pump

http://www.nature.com/nphys/journal/vaop/ncurrent/abs/nphys2821.html

Mars has an active surface, with omnipresent small dust particles and larger debris. With an ambient pressure below 10 mbar, which is less than 1% of the surface pressure on Earth, its CO2 atmosphere is rather tenuous. Aeolian processes on the surface such as drifting dunes, dust storms and dust devils are nevertheless still active1, 2, 3. The transport of volatiles below the surface, that is, through the porous soil, is unseen but needs to be known for balancing mass flows4, 5. Here, we describe a mechanism of forced convection within porous soils. At an average ambient gas pressure of 6 mbar, gas flow through the porous ground of Mars by thermal creep is possible and the soil acts as a (Knudsen) pump. Temperature gradients provided by local and temporal variations in solar insolation lead to systematic gas flows. Our measurements show that the flow rates can outnumber diffusion rates. Mars is the only body in the Solar System on which this can occur naturally. Our laboratory experiments reveal that the surface of Mars is efficient in cycling gas through layers at least centimetres above and below the soil with a turnover time of only seconds to minutes.

### Puzzling accretion onto a black hole in the ultraluminous X-ray source M 101 ULX-1

http://www.nature.com/nature/journal/v503/n7477/full/nature12762.html

There are two proposed explanations for ultraluminous X-ray sources1, 2 (ULXs) with luminosities in excess of 1039 erg s−1. They could be intermediate-mass black holes (more than 100–1,000 solar masses, ) radiating at sub-maximal (sub-Eddington) rates, as in Galactic black-hole X-ray binaries but with larger, cooler accretion disks3, 4, 5. Alternatively, they could be stellar-mass black holes radiating at Eddington or super-Eddington rates2, 6. On its discovery, M 101 ULX-14, 7 had a luminosity of 3 × 1039 erg s−1 and a supersoft thermal disk spectrum with an exceptionally low temperature—uncomplicated by photons energized by a corona of hot electrons—more consistent with the expected appearance of an accreting intermediate-mass black hole3, 4. Here we report optical spectroscopic monitoring of M 101 ULX-1. We confirm the previous suggestion8 that the system contains a Wolf-Rayet star, and reveal that the orbital period is 8.2 days. The black hole has a minimum mass of 5 , and more probably a mass of 20 −30 , but we argue that it is very unlikely to be an intermediate-mass black hole. Therefore, its exceptionally soft spectra at high Eddington ratios violate the expectations for accretion onto stellar-mass black holes9, 10, 11. Accretion must occur from captured stellar wind, which has hitherto been thought to be so inefficient that it could not power an ultraluminous source12, 13.

### What's So Special About Science (And How Much Should We Spend on It?)

#### What’s So Special About Science (And How Much Should We Spend on It?)

Scientific research probes the deepest mysteries of the universe and of living things, and it creates applications and technologies that benefit humanity and create wealth. This “Beauty and Benefits of Science” is the theme of this 2013 AAAS Annual Meeting.

The subject of my address is a different kind of mystery, although it is also related to this theme. It is the mystery of why society is willing to support an endeavor as abstract and altruistic as basic scientific research and an enterprise as large and practical as the research and development (R&D) enterprise as a whole. Put differently, it is the mystery that a unified scientific enterprise can be simultaneously the seed corn for economic advance and the confectionary corn syrup of pure, curiosity-driven scientific discovery.

### A Mixture of Ancient and Modern Understanding Concerning the Distance and Motion of the Moon

http://arxiv.org/abs/1311.2798

Ptolemy’s model of the Moon’s motion implied that its distance varies by nearly a factor of two, implying that its angular size should also vary by nearly a factor of two. We present an analysis of 100 naked eye observations of the Moon’s angular size obtained over 1145 days, showing regular variations of at least 3 arc minutes. Thus, ancient astronomers could have shown that a key implication of Ptolemy’s model was wrong. In modern times we attribute the variation of distance of the Moon to the combined effect of the ellipticity of the Moon’s orbit and the perturbing effect of the Sun on the Earth-Moon system. We show graphically how this affects the ecliptic longitudes and radial distance of the Moon. The longitude and distance “anomalies” are correlated with the Moon’s phase. This is illustrated without any complex equations or geometry.

### Majority is not Enough: Bitcoin Mining is Vulnerable

http://arxiv.org/abs/1311.0243

The Bitcoin cryptocurrency records its transactions in a public log called the blockchain. Its security rests critically on the distributed protocol that maintains the blockchain, run by participants called miners. Conventional wisdom asserts that the protocol is incentive compatible and secure against colluding minority groups, i.e., it incentivizes miners to follow the protocol as prescribed. We show that the Bitcoin protocol is not incentive- compatible. We present an attack with which colluding miners obtain a revenue larger than their fair share. This attack can have significant consequences for Bitcoin: Rational miners will prefer to join the selfish miners, and the colluding group will increase in size until it becomes a majority. At this point, the Bitcoin system ceases to be a decentralized currency.
Selfish mining is feasible for any group size of colluding miners. We propose a practical modification to the Bitcoin protocol that protects against selfish mining pools that command less than 1/4 of the resources. This threshold is lower than the wrongly assumed 1/2 bound, but better than the current reality where a group of any size can compromise the system.

# European agency selects mission themes, with X-ray telescope the biggest winner. http://www.nature.com/news/x-rays-top-space-agenda-1.14097

### Super-luminous supernovae on the rise

http://www.nature.com/nature/journal/v502/n7471/full/502310a.html

New observations suggest that certain extremely bright supernovae are not the nuclear explosions of very massive stars. Instead, they may be ordinary-mass events lit up by a potent central fountain of magnetic energy.

### Why does a beer bottle foam up after a sudden impact on its mouth?

http://arxiv.org/abs/1310.3747

A sudden vertical impact on the mouth of a beer bottle generates a compression wave that propagates through the glass towards the bottom. When this wave reaches the base of the bottle, it is transmitted to the liquid as an expansion wave that travels to free surface, where it bounces back as a compression wave. This train of expansion-compression waves drives the forced cavitation of existing air pockets, leading to their violent collapse. A cloud of very small daughter bubbles are generated upon these collapses, that expand much faster than their mothers due to their smaller size. These rapidly growing bubble clusters effectively act as buoyancy sources, what leads to the formation of bubble-laden plumes whose void fraction increases quickly by several orders of magnitude, eventually turning most of the liquid into foam.

### First results from the LUX dark matter experiment at the Sanford Underground Research Facility

Abstract:

The Large Underground Xenon (LUX) experiment, a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), was cooled and filled in February 2013. We report results of the first WIMP search dataset, taken during the period April to August 2013, presenting the analysis of 85.3 live-days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6 × 10^−46 cm^2 at a WIMP mass of 33 GeV/c^2. We find that the LUX data are in strong disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.

### Gauge-Gravity Duality and the Black Hole Interior

Donald Marolf*
Department of Physics, University of California, Santa Barbara, California 93106-9530, USA

Joseph Polchinski
Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106-4030, USA

Received 18 July 2013; published 21 October 2013

See accompanying Physics Viewpoint

We present a further argument that typical black holes with field theory duals have firewalls at the horizon. This argument makes no reference to entanglement between the black hole and any distant system, and so is not evaded by identifying degrees of freedom inside the black hole with those outside. We also address the Einstein-Rosen=Einstein-Podolsky-Rosen conjecture of Maldacena and Susskind, arguing that the correlations in generic highly entangled states cannot be geometrized as a smooth wormhole.

http://prl.aps.org/abstract/PRL/v111/i17/e171301

### Gamma-ray constraints on dark-matter annihilation to electroweak gauge and Higgs bosons

http://arxiv.org/abs/1310.6047

Gamma-ray constraints on dark-matter annihilation to electroweak gauge and Higgs bosons

Michael A. Fedderke, Edward W. Kolb, Tongyan Lin, Lian-Tao Wang

Dark-matter annihilation into electroweak gauge and Higgs bosons results in γ-ray emission. We use observational upper limits on the fluxes of both line and continuum γ-rays from the Milky Way Galactic Center and from Milky Way dwarf companion galaxies to set exclusion limits on allowed dark-matter masses. (Generally, Galactic Center γ-ray line search limits from the Fermi-LAT and the H.E.S.S. experiments are most restrictive.) Our limits apply under the following assumptions: a) the dark matter species is a cold thermal relic with present mass density equal to the measured dark-matter density of the universe; b) dark-matter annihilation to standard-model particles is described in the non-relativistic limit by a single effective operator O∝JDM⋅JSM, where JDM is a standard-model singlet current consisting of dark-matter fields (Dirac fermions or complex scalars), and JSM is a standard-model singlet current consisting of electroweak gauge and Higgs bosons; and c) the dark-matter mass is in the range 5 GeV to 20 TeV. We consider, in turn, the 34 possible operators with mass dimension 8 or lower with non-zero s-wave annihilation channels satisfying the above assumptions. Our limits are presented in a large number of figures, one for each of the 34 possible operators; these limits can be grouped into 13 classes determined by the field content and structure of the operators. We also identify three classes of operators (coupling to the Higgs and SU(2)L gauge bosons) that can supply a 130 GeV line with the desired strength to fit the putative line signal in Fermi data, while saturating the relic density and satisfying all other indirect constraints we consider.

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

Pair instability supernovae or weird coupling of a SN and a magnetar?

http://www.nature.com/nature/journal/v502/n7471/pdf/nature12569.pdf

### Journal group for the Anton Pannekoek

Let’s try if this works.

### Spoof paper reveals little or no scrutiny at many open-access journals

Who’s afraid of peer review?

by John Bohannon

Science,  4 October 2013,  Vol. 342 no. 6154 pp. 60-65  (DOI: 10.1126/science.342.6154.6)

… I created a scientific version of Mad Libs. The paper took this form: Molecule X from lichen species Y inhibits the growth of cancer cell Z. To substitute for those variables, I created a database of molecules, lichens, and cancer cell lines and wrote a computer program to generate hundreds of unique papers. …

A spoof paper concocted by Science reveals little or no scrutiny at many open-access journals.

(Bonus: accompanying infographic by Randall Munroe.)

### Black-Hole Bombs and Photon-Mass Bounds [arXiv gr-qc]

Black-Hole Bombs and Photon-Mass Bounds (Pani P., et al.)

Generic extensions of the standard model predict the existence of ultralight bosonic degrees of freedom. Several ongoing experiments are aimed at detecting these particles or constraining their mass range. Here we show that massive vector fields around rotating black holes can give rise to a strong superradiant instability which extracts angular momentum from the hole. The observation of supermassive spinning black holes imposes limits on this mechanism. We show that current supermassive black hole spin estimates provide the tightest upper limits on the mass of the photon (mv<4×10^{-20} eV according to our most conservative estimate), and that spin measurements for the largest known supermassive black holes could further lower this bound to mv<10^{-22} eV. Our analysis relies on a novel framework to study perturbations of rotating Kerr black holes in the slow-rotation regime, that we developed up to second order in rotation, and that can be extended to other spacetime metrics and other theories.

http://arxiv.org/abs/arXiv:1209.0465

### http://arxiv.org/pdf/1309.2225.pdf

The Muon Anomalous Magnetic Moment and the Pion Polarizability

### What is next for the Kepler mission?

White papers have been released by NASA into what type of mission Kepler can pursue with only two working reaction wheels. It would be interesting to discuss some of the more realistic and far-out-there options open to Kepler!

Full details are at: http://keplerscience.arc.nasa.gov/TwoWheelWhitePapers.shtml

A good summary of some of the ideas is provided at:

www.astrobites.org/2013/09/09/whats-next-for-kepler/

### Periastron Advance in Spinning Black Hole Binaries: Comparing Effective-One-Body and Numerical Relativity

http://arxiv.org/abs/1309.0544

We compute the periastron advance using the effective-one-body formalism for binary black holes moving on quasi-circular orbits and having spins collinear with the orbital angular momentum. We compare the predictions with the periastron advance recently computed in accurate numerical-relativity simulations and find remarkable agreement for a wide range of spins and mass ratios. These results do not use any numerical-relativity calibration of the effective-one-body model, and stem from two key ingredients in the effective-one-body Hamiltonian: (i) the mapping of the two-body dynamics of spinning particles onto the dynamics of an effective spinning particle in a (deformed) Kerr spacetime, fully symmetrized with respect to the two-body masses and spins, and (ii) the resummation, in the test-particle limit, of all post-Newtonian (PN) corrections linear in the spin of the particle. In fact, even when only the leading spin PN corrections are included in the effective-one-body spinning Hamiltonian but all the test-particle corrections linear in the spin of the particle are resummed we find very good agreement with the numerical results (within the numerical error for equal-mass binaries and discrepancies of at most 1% for larger mass ratios). Furthermore, we specialize to the extreme mass-ratio limit and derive, using the equations of motion in the gravitational skeleton approach, analytical expressions for the periastron advance, the meridional Lense-Thirring precession and spin precession frequency in the case of a spinning particle on a nearly circular equatorial orbit in Kerr spacetime, including also terms quadratic in the spin.

### Periastron Advance in Spinning Black Hole Binaries: Gravitational Self-Force from Numerical Relativity

http://arxiv.org/abs/1309.0541

We study the general relativistic periastron advance in spinning black hole binaries on quasi-circular orbits, with spins aligned or anti-aligned with the orbital angular momentum, using numerical-relativity simulations, the post-Newtonian approximation, and black hole perturbation theory. By imposing a symmetry by exchange of the bodies’ labels, we devise an improved version of the perturbative result, and use it as the leading term of a new type of expansion in powers of the symmetric mass ratio. This allows us to measure, for the first time, the gravitational self-force effect on the periastron advance of a non-spinning particle orbiting a Kerr black hole of mass M and spin S = -0.5 M^2, down to separations of order 9M. Comparing the predictions of our improved perturbative expansion with the exact results from numerical simulations of equal-mass and equal-spin binaries, we find a remarkable agreement over a wide range of spins and orbital separations.

### Paperscape Map

Paperscape is a tool to visualise the arXiv, an open, online repository for scientific research papers. The Paperscape map currently includes all (non-withdrawn) papers from the arXiv and is updated daily.

Each paper in the map is represented by a circle, with the area of the circle proportional to the number of citations that paper has. In laying out the map, an N-body algorithm is run to determine positions based on references between the papers. There are two “forces” involved in the N-body calculation: each paper is repelled from all other papers using an anti-gravity inverse-distance force, and each paper is attracted to all of its references using a spring modelled by Hooke’s law. We further demand that there is no overlap of the papers.

The map is rendered simply as a solid circle for each paper. The colour of the circle denotes the arXiv category of the paper, and the brightness indicates age. Brightness is sometime difficult to discern, and we are working on adding a heat-map overlay to indicate clearly the areas of the map which have the most recent activity.

As you zoom in on the map labels will start to appear on individual papers. These labels are (mostly) automatically extracted by analysing word frequency in the title and abstract of the paper, and are generally indicative of the subject matter of that paper. Zooming in closer also shows the author(s) of the paper. If a paper is deemed to be a review paper, or a set of lectures, this is noted.

References (and citation counting) are extracted by processing the TeX/LaTeX and PDF source obtained from the arXiv. This is done automatically each morning, and the map is finished updating about 3 or 4 hours after the arXiv’s new listing is announced. Some categories (noticeably hep-th and hep-ph) have better reference extraction than others and so the map for these areas has more variation in paper size and more structure. We are working on improving the reference extraction.

### Astrobetter Ethics and Diversity Poll

http://www.astrobetter.com/ethics-and-diversity-poll

C. Casey (IfA, U. Hawaii)  & K. Sheth (NRAO)

“The culture of academia can be rife with uncomfortable situations, some more clearcut than others.  We all began our research careers with expectations that both ourselves and our colleagues will behave ethically. Sometimes reality might be surprising.  Your judgement might be very different than your colleague’s down the hall due to cultural differences, the different subfields you work in, or different experiences in your careers.  Your own behavior might also evolve over the course of your career.”

“Below, we have collated 25 hypothetical scenarios that astronomers might face in their careers and we’re going to ask you to rank them on a continuous scale from 1 to 9 (1=bad, 9=good).  [...]  The results of this survey will be collated and shared in another post in two weeks’ time.  [...]  If you are struggling to figure out who to evaluate in each scenario that’s fine. We left several purposefully ambiguous and only ask that you evaluate your level of comfort with the situation. [...]  These are intended to lead to broader discussion within a group.”

### Rainbow Colo(u)r Map (Still) Consider Harmful

Following our discussion today about colour maps, this is an interesting paper that discusses way we should not (in some cases) use colour maps. It is a short paper published by IEEE computer society but its analysis is applicable to astronomy. Mike Wheatland and Stuart Gilchrist were the people that pointed out this paper to me earlier in the year.

http://www.jwave.vt.edu/~rkriz/Projects/create_color_table/color_07.pdf

### Determination of the intrinsic Luminosity Time Correlation in the X-ray Afterglows of GRBs

Gamma-ray bursts (GRBs), which have been observed up to redshifts z approx 9.5 can be good probes of the early universe and have the potential of testing cosmological models. The analysis by Dainotti of GRB Swift afterglow lightcurves with known redshifts and definite X-ray plateau shows an anti-correlation between the rest frame time when the plateau ends (the plateau end time) and the calculated luminosity at that time (or approximately an anti-correlation between plateau duration and luminosity). We present here an update of this correlation with a larger data sample of 101 GRBs with good lightcurves. Since some of this correlation could result from the redshift dependences of these intrinsic parameters, namely their cosmological evolution we use the Efron-Petrosian method to reveal the intrinsic nature of this correlation. We find that a substantial part of the correlation is intrinsic and describe how we recover it and how this can be used to constrain physical models of the plateau emission, whose origin is still unknown. The present result could help clarifing the debated issue about the nature of the plateau emission.

### weakling-magnetar-reveals-hidden-strength

Francine Berman, Vint Cerf

On 22 February, the U.S. Office of Science and Technology Policy (OSTP) released a memo calling for public access for publications and data resulting from federally sponsored research grants (1). The memo directed federal agencies with more than \$100 million R&D expenditures to “develop a plan to support increased public access to the results of research funded by the Federal Government.” Perhaps even more succinctly, a subsequent New York Times opinion page sported the headline “We Paid for the Research, So Let’s See It” (2). So who pays for data infrastructure?

### The Sound of a Fermi Gamma-ray Burst

http://blogs.nasa.gov/GLAST/2012/06/21/post_1340301006610/

Gamma rays from GRB 080916C collected by the Fermi Large Area Telescope and converted into music.

### Formation of sharp eccentric rings in debris disks with gas but without planets

Formation of sharp eccentric rings in debris disks with gas but without planets
Authors: W. Lyra & M. Kuchner
Nature, 499, 184–187 (11 July 2013), doi:10.1038/nature12281

‘Debris disks’ around young stars (analogues of the Kuiper Belt in our Solar System) show a variety of non-trivial structures attributed to planetary perturbations and used to constrain the properties of those planets. However, these analyses have largely ignored the fact that some debris disks are found to contain small quantities of gas, a component that all such disks should contain at some level. Several debris disks have been measured with a dust-to-gas ratio of about unity, at which the effect of hydrodynamics on the structure of the disk cannot be ignored. Here we report linear and nonlinear modelling that shows that dust–gas interactions can produce some of the key patterns attributed to planets. We find a robust clumping instability that organizes the dust into narrow, eccentric rings, similar to the Fomalhaut debris disk. The conclusion that such disks might contain planets is not necessarily required to explain these systems.

Subject terms: Exoplanets, Computational astrophysics

### THE HELIOTAIL REVEALED BY THE INTERSTELLAR BOUNDARY EXPLORER

Recent combined observations from the first three years of Interstellar Boundary Explorer (IBEX) data allow us to examine the heliosphere’s downwind region—the heliotail—for the first time. In contrast to a preliminary identification of a narrow “offset heliotail” structure, we find a broad slow solar wind plasma sheet crossing essentially the entire downwind side of the heliosphere at low to mid-latitudes, with fast wind tail regions to the north and south. The slow wind plasma sheet exhibits the steepest ENA spectra in the IBEX sky maps, appears as a two-lobed structure (lobes on the port and starboard sides), and is twisted in the sense of (but at a smaller angle than) the external magnetic field. The overall heliotail structure clearly demonstrates the intermediate nature of the heliosphere’s interstellar interaction, where both the external dynamic and magnetic pressures strongly affect the heliosphere.

http://iopscience.iop.org/0004-637X/771/2/77/pdf/0004-637X_771_2_77.pdf

### This is a story of how cosmic x-rays became music. A first step turned x-rays emitted by the binary system of EX Hydrae into sounds. A second step made these sounds into music.

http://www.cfa.harvard.edu/sed/projects/star_songs/index.html

### Japanese astronomers revealed the origin of the cosmic background light

Researchers from Kyoto University, using the Atacama Large Millimeter/ submillimeter Array (ALMA) revealed that approximately 80% of the unidentified millimeter wave light from the Universe is actually emitted from galaxies.

http://www.almaobservatory.org/en/press-room/press-releases/591

### Monday Colloquium Club - John Vaillancourt

Hi Srikar

I would suggest the following 2 papers (note both have astroph links):

“Observations of Polarized Dust Emission in the Far-infrared to Millimeter”
J. E. Vaillancourt, 2012, in ASP Conf. Ser. 449, Astronomical Polarimetry 2008, ed. P. Bastien, 169
(astro-ph/arXiV:0904.1979)

“Submillimeter Polarization of Galactic Clouds: A Comparison of 350μm and 850μm Data”
J. E. Vaillancourt & B. C. Matthews, 2012, ApJS, 201, 13
(astro-ph/arXiV:1204.1378)

Cheers, John

### Martian Fluvial Conglomerates at Gale Crater

R. M. E. Williams et al.

Science 31 May 2013: Vol. 340 no. 6136 pp. 1068-1072

Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters in diameter) and sand grains with textures typical of fluvial sedimentary conglomerates. Rounded pebbles in the conglomerates indicate substantial fluvial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent with minimal aqueous alteration of sediments. Sediment was mobilized in ancient water flows that likely exceeded the threshold conditions (depth 0.03 to 0.9 meter, average velocity 0.20 to 0.75 meter per second) required to transport the pebbles. Climate conditions at the time sediment was transported must have differed substantially from the cold, hyper-arid modern environment to permit aqueous flows across several kilometers.

### NASA's Fermi, Swift See 'Shockingly Bright' Burst (GRB 130427A)

http://www.nasa.gov/topics/universe/features/shocking-burst.html

See also Fermi-LAT GCN Circulars for further details regarding the GeV emission

http://gcn.gsfc.nasa.gov/gcn3/14471.gcn3

http://gcn.gsfc.nasa.gov/gcn3/14508.gcn3

### Dark Matter Search Results Using the Silicon Detectors of CDMS II

http://arxiv.org/abs/1304.4279

We report results of a search for Weakly Interacting Massive Particles (WIMPs) with the silicon (Si) detectors of the CDMS II experiment. A blind analysis of data from eight Si detectors, with a total raw exposure of 140.2 kg-days, revealed three WIMP-candidate events with a final surface-event background estimate of 0.41 (-0.08 +0.20)(stat.) (-0.24 +0.28) (syst.). Other known backgrounds from neutrons and 206Pb are limited to < 0.13 and < 0.08 events at the 90% confidence level, respectively. These data place a 90% upper confidence limit on the WIMP-nucleon cross section of 2.4E-41 cm^2 at a WIMP mass of 10 GeV/c^2. Simulations indicate a 5.4% probability that a statistical fluctuation of the known backgrounds would produce three or more events in the signal region. A profile likelihood ratio test that includes the measured recoil energies of the three events gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood was found for a WIMP mass of 8.6 GeV/c^2 and WIMP-nucleon cross section of 1.9E-41 cm^2.

### Proposed new NSF grant approval guidelines

U.S. Lawmaker Proposes New Criteria for Choosing NSF Grants

The new chairman of the House science committee has drafted a bill that, in effect, would replace peer review at the National Science Foundation (NSF) with a set of funding criteria chosen by Congress. For good measure, it would also set in motion a process to determine whether the same criteria should be adopted by every other federal science agency.

In effect, the proposed bill would force NSF to adopt three criteria in judging every grant. Specifically, the draft would require the NSF director to post on NSF’s website, prior to any award, a declaration that certifies the research is:

1) “…in the interests of the United States to advance the national health, prosperity, or welfare, and to secure the national defense by promoting the progress of science;

2) “… the finest quality, is groundbreaking, and answers questions or solves problems that are of utmost importance to society at large; and

3) “…not duplicative of other research projects being funded by the Foundation or other Federal science agencies.”

NSF’s current guidelines ask reviewers to consider the “intellectual merit” of a proposed research project as well as its “broader impacts” on the scientific community and society.

### Kepler-62: A Five-Planet System with Planets of 1.4 and 1.6 Earth Radii in the Habitable Zone

Borucki et al. published in Science Express

Also see Kaltenegger, Sasselov, & Rugheimer: http://voxcharta.org/2013/04/18/water-planets-in-the-habitable-zone-atmospheric-chemistry-observable-features-and-the-case-of-kepler-62e-and-62f/

### Life Before Earth

(Submitted on 28 Mar 2013)

An extrapolation of the genetic complexity of organisms to earlier times suggests that life began before the Earth was formed. Life may have started from systems with single heritable elements that are functionally equivalent to a nucleotide. The genetic complexity, roughly measured by the number of non-redundant functional nucleotides, is expected to have grown exponentially due to several positive feedback factors: gene cooperation, duplication of genes with their subsequent specialization, and emergence of novel functional niches associated with existing genes. Linear regression of genetic complexity on a log scale extrapolated back to just one base pair suggests the time of the origin of life 9.7 billion years ago. This cosmic time scale for the evolution of life has important consequences: life took ca. 5 billion years to reach the complexity of bacteria; the environments in which life originated and evolved to the prokaryote stage may have been quite different from those envisaged on Earth; there was no intelligent life in our universe prior to the origin of Earth, thus Earth could not have been deliberately seeded with life by intelligent aliens; Earth was seeded by panspermia; experimental replication of the origin of life from scratch may have to emulate many cumulative rare events; and the Drake equation for guesstimating the number of civilizations in the universe is likely wrong, as intelligent life has just begun appearing in our universe. Evolution of advanced organisms has accelerated via development of additional information-processing systems: epigenetic memory, primitive mind, multicellular brain, language, books, computers, and Internet. As a result the doubling time of complexity has reached ca. 20 years. Finally, we discuss the issue of the predicted technological singularity and give a biosemiotics perspective on the increase of complexity.

### Dark Matter Search Results Using the Silicon Detectors of CDMS II

We report results of a search for Weakly Interacting Massive Particles (WIMPs) with the silicon
(Si) detectors of the CDMS II experiment. A blind analysis of data from eight Si detectors, with
a total raw exposure of 140.2 kg-days, revealed three WIMP-candidate events with a ﬁnal surface-
event background estimate of 0.41+0.20 (stat.)+0.28 (syst.). Other known backgrounds from neutrons
−0.08       −0.24
and 206 Pb are limited to < 0.13 and < 0.08 events at the 90% conﬁdence level, respectively. These
data place a 90% upper conﬁdence limit on the WIMP-nucleon cross section of 2.4 × 10−41 cm2 at a
WIMP mass of 10 GeV/c2 . Simulations indicate a 5.4% probability that a statistical ﬂuctuation of
the known backgrounds would produce three or more events in the signal region. A proﬁle likelihood
ratio test that includes the measured recoil energies of the three events gives a 0.19% probability
for the known-background-only hypothesis when tested against the alternative WIMP+background
hypothesis. The highest likelihood was found for a WIMP mass of 8.6 GeV/c2 and WIMP-nucleon
cross section of 1.9×10−41 cm2 .

### Astropy v0.2: The First Release of the Community Built Astronomy Python Package

http://www.astrobetter.com/first-public-release-of-astropy/

The aim of the project is to co-ordinate the Python code development efforts in Astronomy so as to be able to present users with a coherent set of tools to perform their work.

On February 20th, we released the first public version, Astropy v0.2! This was the culmination of a year and a half of hard work, with contributions from over 30 developers. It was the biggest milestone of the project so far, and we are now looking forward to hearing from the community, fixing any issues, and adding new components and features.

The current release already contains the following functionality:

Astropy also includes a lot of infrastructure code that makes it very easy for users to develop their own Astronomy packages, using Astropy as a core dependency.

Astropy integrates PyFITS, PyWCS, asciitable, and vo.table as sub-packages. Each of these are being phased-out as standalone packages. We encourage users to migrate to using Astropy instead of these standalone packages as most development efforts are being concentrated on the integrated functionalities within Astropy: the project isn’t just about creating new code, but also avoiding duplicated efforts and ultimately reducing the number of packages that Astronomers have to search for and install.

### First Result from the Alpha Magnetic Spectrometer Experiment

http://prl.aps.org/abstract/PRL/v110/i14/e141102

A precision measurement by the Alpha Magnetic Spectrometer on the International Space Station of the positron fraction in primary cosmic rays in the energy range from 0.5 to 350 GeV based on 6.8×106 positron and electron events is presented. The very accurate data show that the positron fraction is steadily increasing from 10 to ∼250  GeV, but, from 20 to 250 GeV, the slope decreases by an order of magnitude. The positron fraction spectrum shows no fine structure, and the positron to electron ratio shows no observable anisotropy. Together, these features show the existence of new physical phenomena.

### Planck 2013 Results

Planck 2013 Results Papers are out today:

http://bit.ly/f1wPym

### Voyager 1 Exits Solar System

http://onlinelibrary.wiley.com/doi/10.1002/grl.50383/pdf

“Recent Voyager 1 data indicate that on August 25, 2012 at a distance of
121.7 AU from the Sun, sudden and unprecedented intensity changes were
observed in anomalous and galactic cosmic rays”

### Three Classes of Newtonian Three-Body Planar Periodic Orbits

http://arxiv.org/abs/1303.0181

(Submitted on 1 Mar 2013)

We present the results of a numerical search for periodic orbits of three equal masses moving in a plane under the influence of Newtonian gravity, with zero angular momentum. A topological method is used to classify periodic three-body orbits into families, which fall into four classes, with all three previously known families belonging to one class. The classes are defined by the orbits geometric and algebraic symmetries. In each class we present a few orbits initial conditions, 15 in all; 13 of these correspond to distinct orbits.

Related article from ScienceNOW:

http://news.sciencemag.org/sciencenow/2013/03/physicists-discover-a-whopping.html?ref=hp

### Measuring the Universe More Accurately Than Ever Before

After nearly a decade of careful observations an international team of astronomers has measured the distance to our neighbouring galaxy, the Large Magellanic Cloud, more accurately than ever before. This new measurement also improves our knowledge of the rate of expansion of the Universe — the Hubble Constant — and is a crucial step towards understanding the nature of the mysterious dark energy that is causing the expansion to accelerate. The team used telescopes at ESO’s La Silla Observatory in Chile as well as others around the globe. These results appear in the 7 March 2013 issue of the journal Nature:

http://www.eso.org/public/archives/releases/sciencepapers/eso1311/eso1311a.pdf

### The arrow of time and the nature of spacetime George F R Ellis

http://de.arxiv.org/abs/1302.7291

This paper extends the work of a previous paper [arXiv:1108.5261] on top-down causation and quantum physics, to consider the origin of the arrow of time. It proposes that a past condition’ cascades down from cosmological to micro scales, being realized in many microstructures and setting the arrow of time at the quantum level by top-down causation. This physics arrow of time then propagates up, through underlying emergence of higher level structures, to geology, astronomy, engineering, and biology. The appropriate space-time picture to view all this is an emergent block universe (EBU’), that recognizes the way the present is different from both the past and the future. This essential difference is the ultimate reason the arrow of time has to be the way it is.

### A rapidly spinning supermassive black hole at the centre of NGC 1365

http://www.nature.com/nature/journal/v494/n7438/full/nature11938.html

Broad X-ray emission lines from neutral and partially ionized iron observed in active galaxies have been interpreted as fluorescence produced by the reflection of hard X-rays off the inner edge of an accretion disk1, 2, 3, 4, 5, 6, 7. In this model, line broadening and distortion result from rapid rotation and relativistic effects near the black hole, the line shape being sensitive to its spin. Alternative models in which the distortions result from absorption by intervening structures provide an equally good description of the data8, 9, and there has been no general agreement on which is correct. Recent claims10 that the black hole11, 12 (2 × 106 solar masses) at the centre of the galaxy NGC 1365 is rotating at close to its maximum possible speed rest on the assumption of relativistic reflection. Here we report X-ray observations of NGC 1365 that reveal the relativistic disk features through broadened Fe-line emission and an associated Compton scattering excess of 10–30 kiloelectronvolts. Using temporal and spectral analyses, we disentangle continuum changes due to time-variable absorption from reflection, which we find arises from a region within 2.5 gravitational radii of the rapidly spinning black hole. Absorption-dominated models that do not include relativistic disk reflection can be ruled out both statistically and on physical grounds.

### A sub-Mercury-sized exoplanet

T. Barclay et al.

Since the discovery of the first exoplanets, it has been known that other planetary systems can look quite unlike our own. Until fairly recently, we have been able to probe only the upper range of the planet size distribution, and, since last year, to detect planets that are the size of Earth or somewhat smaller. Hitherto, no planets have been found that are smaller than those we see in the Solar System. Here we report a planet significantly smaller than Mercury. This tiny planet is the innermost of three that orbit the Sun-like host star, which we have designated Kepler-37. Owing to its extremely small size, similar to that of the Moon, and highly irradiated surface, the planet, Kepler-37b, is probably rocky with no atmosphere or water, similar to Mercury.

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11914.html

### The signature of proton acceleration in supernova remnants detected by Fermi

http://www.sciencemag.org/content/339/6121/807

Detection of the Characteristic Pion-Decay Signature in Supernova Remnants

Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) are the sources of galactic cosmic rays, unequivocal evidence for the acceleration of protons in these objects is still lacking. When accelerated protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma rays. This offers a compelling way to detect the acceleration sites of protons. The identification of pion-decay gamma rays has been difficult because high-energy electrons also produce gamma rays via bremsstrahlung and inverse Compton scattering. We detected the characteristic pion-decay feature in the gamma-ray spectra of two SNRs, IC 443 and W44, with the Fermi Large Area Telescope. This detection provides direct evidence that cosmic-ray protons are accelerated in SNRs.

### Energy release in the solar corona from spatially resolved magnetic braids

J. W. Cirtain1, L. Golub2, A. R. Winebarger1, B. De Pontieu3, K. Kobayashi4, R. L. Moore1, R. W. Walsh5, K. E. Korreck2, M. Weber2, P. McCauley2, A. Title3, S. Kuzin6 & C. E. DeForest7

It is now apparent that there are at least two heating mechanisms in the Sun’s outer atmosphere, or corona1–5. Wave heating may be the prevalent mechanism in quiet solar periods and may contribute to heating the corona to 1,500,000 K (refs 1–3). The active corona needs additional heating to reach 2,000,000–4,000,000 K; this heat has been theoretically proposed6–12 to come from the reconnection and unravelling of magnetic ‘braids’. Evidence favouring that pro- cess has been inferred13,14, but has not been generally accepted because observations are sparse and, in general, the braided mag- netic strands that are thought1–3,15–17 to have an angular width of about 0.2arc seconds have not been resolved10,18–20. Fine-scale braiding has been seen21,22 in the chromosphere but not, until now, in the corona. Here we report observations, at a resolution of 0.2 arc seconds, of magnetic braids in a coronal active region that are recon- necting, relaxing and dissipating sufficient energy to heat the struc- tures to about 4,000,000K. Although our 5-minute observations cannot unambiguously identify the field reconnection and sub- sequent relaxation as the dominant heating mechanism throughout active regions, the energy available

from the observed field relaxation in our example is ample for the observed heating.

doi:10.1038/nature11772

### Collective Motion of Moshers at Heavy Metal Concerts

http://arxiv.org/pdf/1302.1886v1.pdf

Human collective behavior can vary from calm to panicked depending on social context. Using videos publicly available online, we study the highly energized collective motion of attendees at heavy metal concerts. We find these extreme social gatherings generate similarly extreme behaviors: a disordered gas-like state called a mosh pit and an ordered vortex-like state called a circle pit. Both phenomena are reproduced in flocking simulations demonstrating that human collective behavior is consistent with the predictions of simplified models.

### Synchronous X-ray and Radio Mode Switches: A Rapid Global Transformation of the Pulsar Magnetosphere

Synchronous X-ray and Radio Mode Switches: A Rapid Global Transformation of the Pulsar Magnetosphere

W. Hermsen, J. W. T. Hessels, L. Kuiper, et al.

http://www.sciencemag.org/content/339/6118/436

Pulsars emit from low-frequency radio waves up to high-energy gamma-rays, generated anywhere from the stellar surface out to the edge of the magnetosphere. Detecting correlated mode changes across the electromagnetic spectrum is therefore key to understanding the physical relationship among the emission sites. Through simultaneous observations, we detected synchronous switching in the radio and x-ray emission properties of PSR B0943+10. When the pulsar is in a sustained radio-”bright” mode, the x-rays show only an unpulsed, nonthermal component. Conversely, when the pulsar is in a radio-”quiet” mode, the x-ray luminosity more than doubles and a 100% pulsed thermal component is observed along with the nonthermal component. This indicates rapid, global changes to the conditions in the magnetosphere, which challenge all proposed pulsar emission theories.

### A precise and accurate determination of the cosmic microwave background temperature at z=0.89

S. Muller1, A. Beelen2, J. H. Black1, S. J. Curran3,4, C. Horellou1, S. Aalto1, F. Combes5, M. Gu´elin6,7, and
C. Henkel8,9

ABSTRACT
Context. According to the Big Bang theory and as a consequence of adiabatic expansion of the Universe, the temperature
of the cosmic microwave background (CMB) increases linearly with redshift. This relation is, however, poorly explored,
and detection of any deviation would directly lead to (astro-)physics beyond the standard model.
Aims. We aim at measuring the temperature of the CMB with an accuracy of a few percent at z=0.89 toward the
molecular absorber in the galaxy lensing the quasar PKS 1830−211.
Methods. We adopt a Monte-Carlo Markov Chain approach, coupled with predictions from the non-LTE radiative
transfer code RADEX, to solve the excitation of a set of various molecular species directly from their spectra.
Results. We determine TCMB=5.08±0.10 K at 68% confidence level. Our measurement is consistent with the value
TCMB=5.14 K predicted by the standard cosmological model with adiabatic expansion of the Universe. This is the most
precise determination of TCMB at z>0 to date.

http://arxiv.org/pdf/1212.5456v1.pdf

### Giant magnetized outflows from the centre of the Milky Way

Authors:  Ettore Carretti, Roland M. Crocker, Lister Staveley-Smith, Marijke Haverkorn, Cormac Purcell, B. M. Gaensler, Gianni Bernardi, Michael J. Kesteven & Sergio Poppi

Nature 493, 66–69 (03 January 2013)  doi:10.1038/nature11734

http://www.nature.com/nature/journal/v493/n7430/full/nature11734.html

The nucleus of the Milky Way is known to harbour regions of intense star formation activity as well as a supermassive black hole1. Recent observations have revealed regions of γ-ray emission reaching far above and below the Galactic Centre (relative to the Galactic plane), the so-called ‘Fermi bubbles’2. It is uncertain whether these were generated by nuclear star formation or by quasar-like outbursts of the central black hole3, 4, 5, 6 and no information on the structures’ magnetic field has been reported. Here we report observations of two giant, linearly polarized radio lobes, containing three ridge-like substructures, emanating from the Galactic Centre. The lobes each extend about 60 degrees in the Galactic bulge, closely corresponding to the Fermi bubbles, and are permeated by strong magnetic fields of up to 15 microgauss. We conclude that the radio lobes originate in a biconical, star-formation-driven (rather than black-hole-driven) outflow from the Galaxy’s central 200 parsecs that transports a huge amount of magnetic energy, about 1055 ergs, into the Galactic halo. The ridges wind around this outflow and, we suggest, constitute a ‘phonographic’ record of nuclear star formation activity over at least ten million years.

### A vast, thin plane of corotating dwarf galaxies orbiting the Andromeda galaxy

Authors:  Rodrigo A. Ibata, Geraint F. Lewis, Anthony R. Conn, Michael J. Irwin, Alan W. McConnachie, Scott C. Chapman, Michelle L. Collins, Mark Fardal, Annette M. N. Ferguson, Neil G. Ibata, A. Dougal Mackey, Nicolas F. Martin, Julio Navarro, R. Michael Rich, David Valls-Gabaud & Lawrence M. Widrow

Nature 493, 62–65  (03 January 2013)    doi:10.1038/nature11717

http://www.nature.com/nature/journal/v493/n7430/full/nature11717.html

Dwarf satellite galaxies are thought to be the remnants of the population of primordial structures that coalesced to form giant galaxies like the Milky Way1. It has previously been suspected2 that dwarf galaxies may not be isotropically distributed around our Galaxy, because several are correlated with streams of H i emission, and may form coplanar groups3. These suspicions are supported by recent analyses4, 5, 6, 7. It has been claimed7 that the apparently planar distribution of satellites is not predicted within standard cosmology8, and cannot simply represent a memory of past coherent accretion. However, other studies dispute this conclusion9, 10, 11. Here we report the existence of a planar subgroup of satellites in the Andromeda galaxy (M 31), comprising about half of the population. The structure is at least 400 kiloparsecs in diameter, but also extremely thin, with a perpendicular scatter of less than 14.1 kiloparsecs. Radial velocity measurements12, 13, 14, 15 reveal that the satellites in this structure have the same sense of rotation about their host. This shows conclusively that substantial numbers of dwarf satellite galaxies share the same dynamical orbital properties and direction of angular momentum. Intriguingly, the plane we identify is approximately aligned with the pole of the Milky Way’s disk and with the vector between the Milky Way and Andromeda.

### At Voyager 1 Starting on about August 25, 2012 at a Distance of 121.7 AU From the Sun, a Sudden Disappearance of Anomalous Cosmic Rays and an Unusually Large Sudden Increase of Galactic Cosmic Ray H and He Nuclei and Electron Occurred

At the Voyager 1 spacecraft in the outer heliosphere, after a series of complex intensity changes starting at about May 8th, the intensities of both anomalous cosmic rays (ACR) and galactic cosmic rays (GCR) changed suddenly and decisively on August 25th (121.7 AU from the Sun). The ACR started the intensity decrease with an initial e-folding rate of intensity decrease of ~1 day. Within a matter of a few days, the intensity of 1.9-2.7 MeV protons and helium nuclei had decreased to less than 0.1 of their previous value and after a few weeks, corresponding to the outward movement of V1 by ~0.1 AU, these intensities had decreased by factors of at least 300-500 and are now lower than most estimates of the GCR spectrum for these lower energies and also at higher energies. The decrease was accompanied by large rigidity dependent anisotropies in addition to the extraordinary rapidity of the intensity changes. Also on August 25th the GCR protons, helium and heavier nuclei as well as electrons increased suddenly with the intensities of electrons reaching levels ~30-50% higher than observed just one day earlier. This increase for GCR occurred over ~1 day for the lowest rigidity electrons, and several days for the higher rigidity nuclei of rigidity ~0.5-1.0 GV. After reaching these higher levels the intensities of the GCR of all energies from 2 to 400 MeV have remained essentially constant with intensity levels and spectra that may represent the local GCR. These intensity changes will be presented in more detail in this, and future articles, as this story unfolds.

arxiv.org/abs/1212.0883

### How Einstein Discovered Dark Energy

(Submitted on 22 Nov 2012)

In 1917 Einstein published his Cosmological Considerations Concerning the General Theory of Relativity. In it was the first use of the cosmological constant. Shortly thereafter Schr\”odinger presented a note providing a solution to these same equations with the cosmological constant term transposed to the right hand side thus making it part of the stress-energy tensor. Einstein commented that if Schr\”odinger had something more than a mere mathematical convenience in mind he should describe its properties. Then Einstein detailed what some of these properties might be. In so doing, he gave the first description of Dark Energy. We present a translation of Schr\”odinger’s paper and Einstein’s response.

http://arxiv.org/abs/1211.6338

### What do we want graduate school to be?

Astrobites recently conducted a reader survey, gathering responses about the ’80-100 hours a week’ e-mail.  The survey received more than 400 responses from undergraduates, graduate students, faculty, and researchers around the world.  Given the large sample size, the responses are quite interesting.

### Binary Millisecond Pulsar Discovery via Gamma-Ray Pulsations

http://www.sciencemag.org/content/early/2012/10/24/science.1229054.full

Millisecond pulsars, old neutron stars spun-up by accreting matter from a companion star, can reach high rotation rates of hundreds of revolutions per second. Until now, all such “recycled” rotation-powered pulsars have been detected by their spin-modulated radio emission. In a computing-intensive blind search of gamma-ray data from the Fermi Large Area Telescope (with partial constraints from optical data), we detected a 2.5-millisecond pulsar, PSR J1311−3430. This unambiguously explains a formerly unidentified gamma-ray source that had been a decade-long enigma, confirming previous conjectures. The pulsar is in a circular orbit with an orbital period of only 93 minutes, the shortest of any spin-powered pulsar binary ever found.

### Is the solar system stable?

In this review Jacques Laskar reviews the question from Newton to Poincare to modern simulations using 154,000 polynomials and a million CPU hours. The inner solar system is known to exhibit chaotic behavior, which limits the amount of time we can run sims into the past or future. There is a 1% probability that Mercury’s eccentricity could grow such that it collides with Venus, or Mars with the Earth.

### Making the Moon from a Fast-Spinning Earth: A Giant Impact Followed by Resonant Despinning

Authors: Matija Ćuk and Sarah T. Stewart

From Science magazine, Wed Oct 17th, 2012

http://www.sciencemag.org/content/early/2012/10/16/science.1225542.abstract?sid=81686827-ac7f-4dce-8762-7eb154e27d0e

A common origin for the Moon and Earth is required by their identical isotopic composition. However, simulations of the current giant impact hypothesis for Moon formation find that most lunar material originated from the impactor, which should have had a different isotopic signature. Previous Moon-formation studies assumed that the angular momentum after the impact was similar to the present day; however, Earth-mass planets are expected to have higher spin rates at the end of accretion. Here, we show that typical last giant impacts onto a fast-spinning proto-Earth can produce a Moon-forming disk derived primarily from Earth’s mantle. Furthermore, we find that a faster-spinning early Earth-Moon system can lose angular momentum and reach the present state through an orbital resonance between the Sun and Moon.

### An Earth-mass planet orbiting alpha Centauri B

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11572.html

Xavier Dumusque,Francesco Pepe,Christophe Lovis,Damien Ségransan,Johannes Sahlmann,Willy Benz,François Bouchy,Michel Mayor,Didier Queloz,Nuno Santos& Stéphane Udry

Exoplanets down to the size of Earth have been found, but not in the habitable zone—that is, at a distance from the parent star at which water, if present, would be liquid. There are planets in the habitable zone of stars cooler than our Sun, but for reasons such as tidal locking and strong stellar activity, they are unlikely to harbour water–carbon life as we know it. The detection of a habitable Earth-mass planet orbiting a star similar to our Sun is extremely difficult, because such a signal is overwhelmed by stellar perturbations. Here we report the detection of an Earth-mass planet orbiting our neighbour star α Centauri B, a member of the closest stellar system to the Sun. The planet has an orbital period of 3.236 days and is about 0.04 astronomical units from the star (one astronomical unit is the Earth–Sun distance).

### Astrobetter: "Not what we want"

http://www.astrobetter.com/not-what-we-want/

Astrobetter links to a discussion of a letter that was purportedly sent out to the grad students of a astronomy department somewhere in the US.  I’m curious what people think about this and what it says about our community.

### Best Practices for Scientific Computing

http://arxiv.org/abs/1210.0530

(Submitted on 1 Oct 2012)

Scientists spend an increasing amount of time building and using software. However, most scientists are never taught how to do this efficiently. As a result, many are unaware of tools and practices that would allow them to write more reliable and maintainable code with less effort. We describe a set of best practices for scientific software development that have solid foundations in research and experience, and that improve scientists’ productivity and the reliability of their software.

### PNAS study on gender bias in science faculty

paper is at:   http://www.pnas.org/content/early/2012/09/14/1211286109
NYT article:   http://tinyurl.com/9pdwd27

### 2012 Ig Nobel Prize Winners

http://www.improbable.com/ig/winners/#ig2012

From the website: “The Ig Nobel Prizes honor achievements that first make people laugh, and then make them think. The prizes are intended to celebrate the unusual, honor the imaginative — and spur people’s interest in science, medicine, and technology.”

Click the link to see this years winners.

### The United States must rejoin the SKA

Astronomy: The United States must rejoin the SKA
Anthony J. Beasley and Ethan J. Schreier

Nature 489, 363 (20 September 2012) doi:10.1038/489363a
Published online 19 September 2012

The world’s most powerful astronomical instrument is currently being built in South Africa and Australia. A growing consortium of countries, soon to be marshalled by incoming director-general Phil Diamond, is laying the foundation for some unique science. When it comes online next decade, the Square Kilometre Array (SKA) will observe diffuse hydrogen ionized by the first stars and galaxies, use pulsars to explore general relativity, and detect the imprints of dark energy on the distribution of matter in the Universe.

There is one country notable by its absence in this endeavour: the United States. And its absence threatens to hinder the SKA’s pursuit of its scientific goals. After nearly 20 years of participation, US astronomers last year dropped out of the SKA collaboration as the result of disillusionment with the project’s planning process and budget pressure from the National Science Foundation (NSF). [...]

### Production of Near-Earth Asteroids on Retrograde Orbits

S. Greenstreet1, B. Gladman1, H. Ngo2, M. Granvik3, and S. Larson4
ApJ 749 L39 doi:10.1088/2041-8205/749/2/L39

http://iopscience.iop.org/2041-8205/749/2/L39

### The Encyclopedia of DNA Elements (ENCODE)

“2001 will always be remembered as the year of the human genome. The availability of its sequence transformed biology, and the exemplary way in which hundreds of researchers came together to form a public consortium paved the way for ‘big science’ in biology. It was an incredible achievement but it was always clear that knowing the ‘code’ was only the beginning. To understand how cells interpret the information locked within the genome much more needed to be learnt. This became the task of ENCODE, the Encyclopedia Of DNA Elements, the aim of which was to describe all functional elements encoded in the human genome. Nine years after launch, its main efforts culminate in the publication of 30 coordinated papers, 6 of which are in this issue of Nature.

Collectively, the papers describe 1,640 data sets generated across 147 different cell types. Among the many important results there is one that stands out above them all: more than 80% of the human genome’s components have now been assigned at least one biochemical function. [...]”

### On the reliability of stellar ages and age spreads inferred from pre-main-sequence evolutionary models

Review of presentation “On the reliability of stellar ages and age spreads inferred from pre-main-sequence evolutionary models” by Takashi Hosokawa. http://origins.mcmaster.ca/oi_planets/assets/img/Session5/2-hosokawa.pdf

http://iopscience.iop.org/0004-637X/738/2/140/

http://iopscience.iop.org/0004-637X/756/2/118/

### THE HERSCHEL AND IRAM CHESS SPECTRAL SURVEYS OF THE PROTOSTELLAR SHOCK L1157-B1: FOSSIL DEUTERATION (ApJL)

Kim will be leading the discussion on this ApJL article for this week’s Adler journal club:

http://iopscience.iop.org/2041-8205/757/1/L9;jsessionid=956F4D55B4694CF6F7A7F78E9F5667E4.c1

### A radio pulsar with an 8.5-second period that challenges emission models

Young, Manchester, and Johnston 1999, Nature, 400, 848

Radio pulsars are rotating neutron stars that emit beams of radiowaves from regions above their magnetic poles. Popular theories of the emission mechanism require continuous electron–positron pair production, with the potential responsible for accelerating the particles being inversely related to the spin period. Pair production will stop when the potential drops below a threshold, so the models predict that radio emission will cease when the period exceeds a value that depends on the magnetic field strength and configuration. Here we show that the pulsar J2144-3933, previously thought to have a period of 2.84 s, actually has a period of 8.51 s, which is by far the longest of any known radio pulsar. Moreover, under the usual model assumptions, based on the neutron-star equations of state, this slowly rotating pulsar should not be emitting a radio beam. Therefore either the model assumptions are wrong, or current theories of radio emission must be revised.

### Complementarity or/and/not firewalls

Black holes: Complementarity or firewalls? (Almheiri, Marolf, Polchinski, Sully):
Complementarity and firewalls (Susskind):

Complementarity, not firewalls (Harlow):

### NRO gives NASA two unused spy satellites

‘Repurposed’ Telescope May Explore Secrets of Dark Energy

The phone call came like a bolt out of the blue, so to speak, in January of 2011. On the other end of the line was someone from the National Reconnaissance Office, which operates the nation’s fleet of spy satellites. They had some spare unused “hardware” to get rid of. Was NASA interested?

And so it was that when John Grunsfeld, the physicist and former astronaut, walked into his office a year later to start his new job as NASA’s associate administrator for space science, he discovered that his potential armada was a bit bigger than he knew. Sitting in a clean room in upstate New York were a pair of space telescopes the same size as the famed Hubble Space Telescope, but which had been built to point down at the Earth instead of up at the heavens.