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Thorfinn Hrolfsson
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Thorfinn Hrolfsson

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Turtle love! Via Paul Bertner

Photo from Sani lodge, Bordering Yasuni NP, Ecuador.
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Thorfinn Hrolfsson

Space Exploration  - 
 
by Carnegie Institution for Science.
When a star is young, it is often still surrounded by a primordial rotating disk of gas and dust from which planets can form. Astronomers like to find such disks because they might be able to catch the star partway through the planet-formation process, but it’s highly unusual to find such disks around brown dwarfs or stars with very low masses. New work from a team led by Anne Boucher of Université de Montréal, and including Carnegie’s Jonathan Gagné and Jacqueline Faherty, has discovered four new low-mass objects surrounded by disks. The results will be published by The Astrophysical Journal.

Three of the four objects discovered by these researchers are quite small, somewhere between only 13 and 18 times the mass of Jupiter. The fourth has about 120 times Jupiter’s mass. (For comparison the Sun is just over 1,000 times more massive than Jupiter.)

“Finding disks in low-mass systems is really interesting to us, because objects that exist at the lower limit of what defines a star and that still have disks that indicate planet formation can tell us a lot about both stellar and planetary evolution,” said first author Boucher, who works at her university’s Institute for Research on Exoplanets (iREx).

Journal Reference:
Anne Boucher, David Lafrenière, Jonathan Gagné, Lison Malo, Jacqueline K. Faherty, René Doyon, Christine H. Chen. BANYAN. VIII. New Low-Mass Stars and Brown Dwarfs with Candidate Circumstellar Disks. The Astrophysical Journal, 2016
https://arxiv.org/pdf/1608.08259v1.pdf
When a star is young, it is often still surrounded by a primordial rotating disk of gas and dust from which planets can form. Astronomers like to find such disks because they might be able to catch the star partway through the planet-formation process, but it’s highly unusual to find such disks around brown dwarfs or stars with very low masses. New work has discovered four new low-mass objects surrounded by disks. Because they exist at the lower ...
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Thats cool man
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Thorfinn Hrolfsson

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Many great photos in this weeks collection, with #10 getting the artistic star.

Warning ABC is reusing URLs
Here is a selection of photos sent in by ABC Open audience members from around Australia.
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by European Southern Observatory - ESO.
International teams of astronomers have used the Atacama Large Millimetre/submillimetre Array (ALMA) to explore the distant corner of the Universe first revealed in the iconic images of the Hubble Ultra Deep Field (HUDF). These new ALMA observations are significantly deeper and sharper than previous surveys at millimetre wavelengths. They clearly show how the rate of star formation in young galaxies is closely related to their total mass in stars. They also trace the previously unknown abundance of star-forming gas at different points in time, providing new insights into the “Golden Age” of galaxy formation approximately 10 billion years ago.
The new ALMA results will be published in a series of papers appearing in the Astrophysical Journal and Monthly Notices of the Royal Astronomical Society. These results are also among those being presented this week at the Half a Decade of ALMA conference in Palm Springs, California, USA.
In 2004 the Hubble Ultra Deep Field images — pioneering deep-field observations with the NASA/ESA Hubble Space Telescope — were published. These spectacular pictures probed more deeply than ever before and revealed a menagerie of galaxies stretching back to less than a billion years after the Big Bang. The area was observed several times by Hubble and many other telescopes, resulting in the deepest view of the Universe to date.

Astronomers using ALMA have now surveyed this seemingly unremarkable, but heavily studied, window into the distant Universe for the first time both deeply and sharply in the millimetre range of wavelengths. This allows them to see the faint glow from gas clouds and also the emission from warm dust in galaxies in the early Universe.

ALMA has observed the HUDF for a total of around 50 hours up to now. This is the largest amount of ALMA observing time spent on one area of the sky so far.

This research was presented in papers titled:
“A deep ALMA image of the Hubble Ultra Deep Field”, by J. Dunlop et al., to appear in the Monthly Notices of the Royal Astronomical Society.
http://www.eso.org/public/archives/releases/sciencepapers/eso1633/eso1633a.pdf

“The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Search for the [CII] Line and Dust Emission in 6 < z < 8 Galaxies”, by M. Aravena et al., to appear in the Astrophysical Journal.
http://www.eso.org/public/archives/releases/sciencepapers/eso1633/eso1633b.pdf

“The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Molecular Gas Reservoirs in High-Redshift Galaxies”, by R. Decarli et al., to appear in the Astrophysical Journal.
http://www.eso.org/public/archives/releases/sciencepapers/eso1633/eso1633c.pdf

“The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: CO Luminosity Functions and the Evolution of the Cosmic Density of Molecular Gas”, by R. Decarli et al., to appear in the Astrophysical Journal.
http://www.eso.org/public/archives/releases/sciencepapers/eso1633/eso1633d.pdf

“The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Continuum Number Counts, Resolved 1.2-mm Extragalactic Background, and Properties of the Faintest Dusty Star Forming Galaxies”, by M. Aravena et al., to appear in the Astrophysical Journal.
http://www.eso.org/public/archives/releases/sciencepapers/eso1633/eso1633e.pdf

“The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Survey Description”, by F. Walter et al., to appear in the Astrophysical Journal.
http://www.eso.org/public/archives/releases/sciencepapers/eso1633/eso1633f.pdf

“The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: the Infrared excess of UV-selected z= 2-10 Galaxies as a Function of UV-continuum Slope and Stellar Mass”, by R. Bouwens et al., to appear in the Astrophysical Journal.
http://www.eso.org/public/archives/releases/sciencepapers/eso1633/eso1633g.pdf

“The ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Implication for spectral line intensity mapping at millimeter wavelengths and CMB spectral distortions”, by C. L. Carilli et al. to appear in the Astrophysical Journal.
http://www.eso.org/public/archives/releases/sciencepapers/eso1633/eso1633h.pdf
International teams of astronomers have used the Atacama Large Millimeter/submillimeter Array (ALMA) to explore the distant corner of the Universe first revealed in the iconic images of the Hubble Ultra Deep Field (HUDF). These new ALMA observations are significantly deeper and sharper than previous surveys at millimetre wavelengths. They clearly show how the rate of star formation in young galaxies is closely related to their total mass in stars...
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by LMU.
When the maps appeared at the end of March, experts were electrified. The images revealed an orange-red disk pitted with circular gaps that looked like the grooves in an old-fashioned long-playing record. But this was no throwback to the psychedelic Sixties. It was a detailed portrait of a so-called protoplanetary disk, made up of gas and dust grains, associated with a young star – the kind of structure out of which planets could be expected to form. Not only that, the maps showed that the disk around the star known as TW Hydrae exhibits several clearly defined gaps.  Astronomers speculated that these gaps might indicate the presence of protoplanets, which had pushed away the material along their orbital paths. And to make the story even more seductive, one prominent gap is located at approximately the same distance from TW Hydrae as Earth is from the Sun – raising the possibility that this putative exoplanet could be an Earth-like one.

Now an international team led by Professor Barbara Ercolano at LMU’s Astronomical Observatory has compared the new observations with theoretical models of planet formation. The study indicates that the prominent gap in the TW Hydrae system is unlikely to be due to the action of an actively accreting protoplanet. Instead, the team attributes the feature to a process known as photoevaporation. Photoevaporation occurs when the intense radiation emitted by the parent star heats the gas, allowing it to fly away from the disk. But although hopes of a new exo-Earth orbiting in the inner gap of TW Hydrae may themselves have evaporated, the system nevertheless provides the opportunity to observe the dissipation of a circumstellar disk in unprecedented detail. The new findings appear in the journal Monthly Notices of the Royal Astronomical Society (MNRAS).

Journal Reference:
Barbara Ercolano, Giovanni P. Rosotti, Giovanni Picogna, Leonardo Testi. A photo-evaporative gap in the closest planet forming disc. Monthly Notices of the Royal Astronomical Society: Letters, 2016; slw188
http://dx.doi.org/10.1093/mnrasl/slw188
Planet formation. The death of a planet nursery? München, 09/16/2016. The dusty disk surrounding the star TW Hydrae exhibits circular features that may signal the formation of protoplanets. LMU astrophysicist Barbara Ercolano argues, however, that the innermost actually points to the impending ...
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by Case Western Reserve University (via newswise).
In the late 1970s, astronomers Vera Rubin and Albert Bosma independently found that spiral galaxies rotate at a nearly constant speed: the velocity of stars and gas inside a galaxy does not decrease with radius, as one would expect from Newton's laws and the distribution of visible matter, but remains approximately constant. Such 'flat rotation curves' are generally attributed to invisible, dark matter surrounding galaxies and providing additional gravitational attraction.

Now a team led by Case Western Reserve University researchers has found a significant new relationship in spiral and irregular galaxies: the acceleration observed in rotation curves tightly correlates with the gravitational acceleration expected from the visible mass only.

“If you measure the distribution of star light, you know the rotation curve, and vice versa,” said Stacy McGaugh, chair of the Department of Astronomy at Case Western Reserve and lead author of the research.

The finding is consistent among 153 spiral and irregular galaxies, ranging from giant to dwarf, those with massive central bulges or none at all. It is also consistent among those galaxies comprised of mostly stars or mostly gas.

Journal Reference:
Stacy McGaugh, Federico Lelli, Jim Schombert. The Radial Acceleration Relation in Rotationally Supported Galaxies. Physical Review Letters, 2016
https://arxiv.org/pdf/1609.05917v1.pdf
Researchers have found a significant new relationship in spiral and irregular galaxies: the acceleration observed in rotation curves tightly correlates with the gravitational acceleration expected from the visible mass only. The discovery may alter the understanding of dark matter and the internal dynamics of galaxies.
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by NASA.
In the last century, humans realized that space is filled with types of light we can’t see – from infra-red signals released by hot stars and galaxies, to the cosmic microwave background that comes from every corner of the universe. Some of this invisible light that fills space takes the form of X-rays, the source of which has been hotly contended over the past few decades.

It wasn’t until the flight of the DXL sounding rocket, short for Diffuse X-ray emission from the Local galaxy, that scientists had concrete answers about the X-rays’ sources. In a new study, published Sept. 23, 2016, in the Astrophysical Journal, DXL’s data confirms some of our ideas about where these X-rays come from, in turn strengthening our understanding of our solar neighbourhoods early history. But it also reveals a new mystery – an entire group of X-rays that don’t come from any known source.

The two known sources of X-ray emission are the solar wind, the sea of solar material that fills the solar system, and the Local Hot Bubble, a theorized area of hot interstellar material that surrounds our solar system.
“We show that the X-ray contribution from the solar wind charge exchange is about forty percent in the galactic plane, and even less elsewhere,” said Massimiliano Galeazzi, an astrophysicist at the University of Miami and an author on the study. “So the rest of the X-rays must come from the Local Hot Bubble, proving that it exists.”

However, DXL also measured some high-energy X-rays that couldn’t possibly come from the solar wind or the Local Hot Bubble.  “At higher energies, these sources contribute less than a quarter of the X-ray emission,” said Youaraj Uprety, lead author on the study and an astrophysicist at University of Miami at the time the research was conducted. “So there’s an unknown source of X-rays in this energy range.”

In the decades since we first discovered the X-ray emission that permeates space, three main theories have been bandied about to explain its origins. First, and quickly ruled out, was the idea that these X-rays are a kind of background noise, coming from the distant reaches of the universe. Our galaxy has lots of neutral gas that would absorb X-rays coming from distant sources – meaning that these X-rays must originate somewhere near our solar system.

Journal Reference:
Y. Uprety, M. Chiao, M. R. Collier, T. Cravens, M. Galeazzi, D. Koutroumpa, K. D. Kuntz, R. Lallement, S. T. Lepri, W. Liu, D. McCammon, K. Morgan, F. S. Porter, K. Prasai, S. L. Snowden, N. E. Thomas, E. Ursino, B. M. Walsh. SOLAR WIND CHARGE EXCHANGE CONTRIBUTION TO THEROSATALL SKY SURVEY MAPS. The Astrophysical Journal, 2016; 829 (2): 83
http://dx.doi.org/10.3847/0004-637X/829/2/83
The sources of X-rays observed in space have been contended for decades. The DXL sounding rocket provided insight into the source of some -- but this small mission also found an entire group of X-rays that don’t come from any known source.
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thank you.

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Thorfinn Hrolfsson

Space Exploration  - 
 
by Brown University.
Ever since NASA’s New Horizons spacecraft flew by Pluto last year, evidence has been mounting that the dwarf planet may have a liquid ocean beneath its icy shell. Now, by modelling the impact dynamics that created a massive crater on Pluto’s surface, a team of researchers has made a new estimate of how thick that liquid layer might be.

The study, led by Brown University geologist Brandon Johnson and published in Geophysical Research Letters, finds a high likelihood that there’s more than 100 kilometres of liquid water beneath Pluto’s surface. The research also offers a clue about the composition of that ocean, suggesting that it likely has a salt content similar to that of the Dead Sea.
“Thermal models of Pluto’s interior and tectonic evidence found on the surface suggest that an ocean may exist, but it’s not easy to infer its size or anything else about it,” said Johnson, who is an assistant professor in Brown’s Department of Earth, Environmental and Planetary Sciences. “We’ve been able to put some constraints on its thickness and get some clues about composition.”

The research focused on Sputnik Planum, a basin 900 kilometres across that makes up the western lobe the famous heart-shaped feature revealed during the New Horizons flyby. The basin appears to have been created by an impact, likely by an object 200 kilometres across or larger.

Journal Reference:
Brandon C. Johnson, Timothy J. Bowling, Alexander J. Trowbridge, Andrew M. Freed. Formation of the Sputnik Planum basin and the thickness of Pluto's subsurface ocean.. Geophysical Research Letters, 2016
http://dx.doi.org/10.1002/2016GL070694
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+David Hamilton
 the observations are available, so write a rebuttal
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Thorfinn Hrolfsson

Space Exploration  - 
 
by Taylor & Francis
Plants will play a critical role in the survival of human beings on long-duration space missions, such as a mission to Mars.  However, as a paper published in Botany Letters shows, many challenges need to be addressed if astronauts are to successfully grow enough food on board spacecraft and on other planets.

Lucie Poulet and colleagues from the University of Clermont-Ferrand, Auvergne outline in their review that while healthy plants can be grown in space, the long-term effects of the space environment on plant growth and reproduction are not yet well known.

Since the 1960s, experiments conducted in space stations and research rockets have shown that plants can grow normally in microgravity provided factors such as confinement, lack of ventilation and elevated radiation levels are taken into account.  

However, microgravity can reduce cell growth, alter gene expression and change the pattern of root growth – all aspects which critically affect plant cultivation in space.

Seeds produced in orbit also seem to have different composition and developmental stages from seeds grown on Earth.  As well as affecting the performance and nutritional content of space seeds, this could damage the flavour of plants produced in space, which might become a problem for crews reliant on plant-based diets during long space missions.

While there appears to be no major obstacle to plant growth in space, large-scale tests for food production in reduced gravity are still lacking, and a number of viable technologies for space agriculture need to be developed.
These include efficient watering and nutrient-delivery systems, precise atmospheric controls for temperature, humidity and air composition, and low-energy lighting which could include sun collection systems that take advantage of sunlight on the surface of planets and moons.

Selecting the right crops to grow in space is also essential.  Given the limited amount of room available on board a spacecraft, plants with reduced size but high yields need to be developed: for example, dwarf varieties of wheat, cherry tomato, rice, pepper, soybean and pea have been successfully grown in orbit and in simulated planetary habitats.

Lucie Poulet said: “Challenges remain in terms of nutrient delivery, lighting and ventilation, but also in the choice of plant species and traits to favour.  Additionally, significant effort must be made on mechanistic modelling of plant growth to reach a more thorough understanding of the intricate physical, biochemical and morphological phenomena involved if we are to accurately control and predict plant growth and development in a space environment.”

Journal Reference:
L. Poulet, J.-P. Fontaine, C.-G. Dussap. Plant’s response to space environment: a comprehensive review including mechanistic modelling for future space gardeners. Botany Letters, 2016; 163 (3): 337
http://www.tandfonline.com/doi/pdf/10.1080/23818107.2016.1194228?needAccess=true
Plants will play a critical role in the survival of human beings on long-duration space missions, such as a mission to Mars. However, as a paper published in Botany Letters shows, many challenges need to be addressed if astronauts are to successfully grow enough food on board spacecraft and on ...
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Thorfinn Hrolfsson

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The Ig® Nobel Prize
For achievements that first make people LAUGH
then make them THINK
The 2016 Ig Nobel Prizes were awarded on Thursday night, September 22, 2016 at the 26th First Annual Ig Nobel Prize Ceremony, at Harvard's Sanders Theatre. The ceremony was webcast live. REPRODUCTION PRIZE [EGYPT] — The late Ahmed Shafik, for studying the effects of wearing polyester, cotton, ...
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Lol. Volkswagen getting the Chemistry prize.
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by University College London.
The new study, published today in Physical Review Letters, studied the cosmic microwave background (CMB) which is the remnant radiation from the Big Bang. It shows the universe expands the same way in all directions, supporting the assumptions made in cosmologists’ standard model of the universe.

First author, Daniela Saadeh (UCL Physics & Astronomy), said: “The finding is the best evidence yet that the universe is the same in all directions. Our current understanding of the universe is built on the assumption that it doesn’t prefer one direction over another, but there are actually a huge number of ways that Einstein’s theory of relativity would allow for space to be imbalanced. Universes that spin and stretch are entirely possible, so it’s important that we’ve shown ours is fair to all its directions.”

The team from UCL and Imperial College London used measurements of the CMB taken between 2009 and 2013 by the European Space Agency's Planck satellite. The spacecraft recently released information about the polarisation of CMB across the whole sky for the first time, providing a complementary view of the early universe that the team was able to exploit.

Journal Reference:
Daniela Saadeh, Stephen M. Feeney, Andrew Pontzen, Hiranya V. Peiris, Jason D. McEwen. How Isotropic is the Universe? Physical Review Letters, 2016; 117 (13)
http://dx.doi.org/10.1103/PhysRevLett.117.131302
UCL News RSS Feed: The latest news from UCL.
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what would be the reason for the expansion of the space in which nothing is ... that there is nothing that should gravitational influence on its surroundings?Though I agree with the premise that spreads in all directions as well.
The result may not be so clear-cut
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by University of Colorado Boulder.
Self-assembling carbon microstructures created in a lab by University of Colorado Boulder researchers could provide new clues – and new cautions – in efforts to identify microbial life preserved in the fossil record, both on Earth and elsewhere in the solar system.

The geological search for ancient life frequently zeroes in on fossilized organic structures or biominerals that can serve as “biosignatures,” that survive in the rock record over extremely long time scales. Mineral elements such as  sulphur are often formed through biological activity. Microbes can also produce a variety of tell tale extracellular structures that resemble sheaths and stalks.

However, according to new findings published today in the journal Nature Communications, carbon-sulphur microstructures that would be recognized today by some experts as biomaterials are capable of self-assembling under certain conditions, even without direct biological activity. These “false” biosignatures could potentially be misinterpreted as signs of biological activity due to their strong resemblance to microbial structures.

“Surprisingly, we found that we could create all sorts of biogenic-like materials that have the right shape, structure and chemistry to match natural materials we assume are produced biologically,” said Associate Professor Alexis Templeton of CU Boulder’s Department of Geological Sciences and senior author of the new study.

Journal Reference:
Julie Cosmidis, Alexis S. Templeton. Self-assembly of biomorphic carbon/sulfur microstructures in sulfidic environments. Nature Communications, 2016; 7: 12812
http://dx.doi.org/10.1038/ncomms12812
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Cuidado con los falso positivos. Ellos son particularmente peligrosos cuando no se dispone de un sample, o muestra, grande suficiente como para que los métodos estadístcos puedan detectar tales falsos positivos. Good call por parte de los geólogos de Boulder, CO. 
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