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Thorfinn Hrolfsson
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Thorfinn Hrolfsson

Space Exploration  - 
 
Limits and Signatures of Relativistic Spaceflight
Ulvi Yurtsever & and Steven Wilkinson
Raytheon Company, El Segundo, CA

While special relativity imposes an absolute speed limit at the speed of light, our Universe is not empty Minkowski spacetime. The constituents that fill the in terstellar/intergalactic vacuum, including the cosmic microwave background photons, impose a lower speed limit on any object travelling
at relativistic velocities. Scattering of cosmic microwave phtotons from an ultra-relativistic object may create radiation with a characteristic signature allowing the detection of such objects at large distances.
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Very interesting article. Thanks for posting the link!
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Stars form when gravity pulls together material within giant clouds of gas and dust. But gravity isn't the only force at work. Both turbulence and magnetic fields battle gravity, either by stirring things up or by channelling and restricting gas flows, respectively. New research focusing on magnetic fields shows that they influence star formation on a variety of scales, from hundreds of light-years down to a fraction of a light-year.

The new study, which the journal Nature is publishing online on March 30th, probed the Cat's Paw Nebula, also known as NGC 6334. This nebula contains about 200,000 suns' worth of material that is coalescing to form new stars, some with up to 30 to 40 times as much mass as our sun. It is located 5,500 light-years from Earth in the constellation Scorpius.

The team painstakingly measured the orientation of magnetic fields within the Cat's Paw. "We found that the magnetic field direction is quite well preserved from large to small scales, implying that self-gravity and cloud turbulence are not able to significantly alter the field direction," said lead author Hua-bai Li (The Chinese University of Hong Kong), who conducted the high-resolution observations while a post-doctoral fellow at the Harvard-Smithsonian Centre for Astrophysics (CfA).
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Luke Skywalker’s home in “Star Wars” is the desert planet Tatooine, with twin sunsets because it orbits two stars. So far, only uninhabitable gas-giant planets have been identified circling such binary stars, and many researchers believe rocky planets cannot form there. Now, mathematical simulations show that Earth like, solid planets such as Tatooine likely exist and may be widespread.

“Tatooine sunsets may be common after all,” concludes the study by astrophysicists Ben Bromley of the University of Utah and Scott Kenyon of the Smithsonian Astrophysical Observatory.

“Our main result is that outside a small region near a binary star, [either rocky or gas-giant] planet formation can proceed in much the same way as around a single star,” they write. “In our scenario, planets are as prevalent around binaries as around single stars.”
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Thorfinn Hrolfsson

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Feast your eyes on this beautiful Blue Dragon nudibranch! This beauty of a snail lacks a shell and spends its time floating on the ocean surface, eats poisonous jellyfish and stores their poison in sacs for their personal use. The potency of this poison is magnified thanks to this ability to store it! Wow!
Photo via http://www.nhm.ac.uk/nature-online/species-of-the-day/collections/our-collections/glaucus-atlanticus
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A supermassive black hole with a mass four million times that of the Sun lies at the heart of the Milky Way galaxy. It is orbited by a small group of bright stars and, in addition, an enigmatic dusty cloud, known as G2, has been tracked on its fall towards the black hole over the last few years.

Closest approach, known as peribothron, was predicted to be in May 2014.
The great tidal forces in this region of very strong gravity were expected to tear the cloud apart and disperse it along its orbit. Some of this material would feed the black hole and lead to sudden flaring and other evidence of the monster enjoying a rare meal. To study these unique events, the region at the galactic centre has been very carefully observed over the last few years by many teams using large telescopes around the world.

A team led by Andreas Eckart (University of Cologne, Germany) has observed the region using ESO’s Very Large Telescope (VLT) [1] over many years, including new observations during the critical period from February to September 2014, just before and after the peribothron event in May 2014. These new observations are consistent with earlier ones made using the Keck Telescope on Hawaii [2].
ESO, European Organisation for Astronomical Research in the Southern Hemisphere
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Nice Reading 
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The purple frog. Via Scientific Illustration for the Research Scientist | somersault18:24
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Thorfinn Hrolfsson

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An old Anglo-Saxon manuscript has the recipe to kill MRSA.



A 1,000-year-old treatment for eye infections could hold the key to killing antibiotic-resistant superbugs, scientists say.
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A team of scientists has a new explanation for the planet Mercury’s dark, barely reflective surface. In a paper published in Nature Geoscience, the researchers suggest that a steady dusting of carbon from passing comets has slowly painted Mercury black over billions of years.

Mercury’s dark surface has long been a mystery to scientists. On average, Mercury is much darker than its closest airless neighbour, our Moon. Airless bodies are known to be darkened by micrometeorite impacts and bombardment of solar wind, processes that create a thin coating of dark iron nano particles on the surface. But spectral data from Mercury suggests its surface contains very little nano-phase iron, certainly not enough to account for its dim appearance.
When heavenly bodies collide Impact material generated without the presence of carbon from complex organics, top left, is lighter than material generated with carbon, top right. Scanning electron microscope images, bottom row, show finer-scale structure and texture variations. Images: NASA/Ames ...
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Thorfinn Hrolfsson

Space Exploration  - 
 
Monica Pondrelli and colleagues investigated the Equatorial Layered Deposits (ELDs) of Arabia Terra in Firsoff crater area, Mars, to understand their formation and potential habitability. On the plateau, ELDs consist of rare mounds, flat-lying deposits, and cross-bedded dune fields. Pondrelli and colleagues interpret the mounds as smaller spring deposits, the flat-lying deposits as playa, and the cross-bedded dune fields as aeolian. They write that groundwater fluctuations appear to be the major factor controlling ELD deposition.
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Mima Mounds have been de-ciphered on Earth, and they are NOT related to water! Rather, they are formed by Gravitational "Jerk", which is a derivative of Acceleration, dA/dt. State Park near Little Rock, WA , exhibits these in Arcuate arrangements, and they form near Waterways- such as Puget Sound, where Glacial Oscillations create Reversals of ICE LOADING- regular Shifts of Weight!
Porogle.blogspot.com 
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Dark matter is a giant question mark looming over our knowledge of the Universe. There is more dark matter in the Universe than visible matter, but it is extremely elusive; it does not reflect, absorb or emit light, making it invisible. Because of this, it is only known to exist via its gravitational effects on the visible Universe (see e.g. heic1215a).

To learn more about this mysterious substance, researchers can study it in a way similar to experiments on visible matter — by watching what happens when it bumps into things [1]. For this reason, researchers look at vast collections of galaxies, called galaxy clusters, where collisions involving dark matter happen naturally and where it exists in vast enough quantities to see the effects of collisions [2].
Astronomers using observations from the NASA/ESA Hubble Space Telescope and NASA’s Chandra X-ray Observatory have studied how dark matter in clusters of galaxies behaves when the clusters collide. The results, published in the journal Science on 27 March 2015, show that dark matter interacts with itself even less than previously thought, and narrows down the options for what this mysterious substance might be.
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Dark matter, darker matter, darkest matter
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Thorfinn Hrolfsson

Space Exploration  - 
 
Researchers from Brown University have completed a new analysis of an ancient Martian lake system in Jezero Crater, near the planet’s equator. The study finds that the onslaught of water that filled the crater was one of at least two separate periods of water activity in the region surrounding Jezero.

“We can say that this one really well-exposed location makes a strong case for at least two periods of water-related activity in Mars’ history,” said Tim Goudge, a graduate student at Brown who led the work. “That tells us something really interesting about how early Mars operated.”
A huge Martian watershed A false-color topographic map (blue marks low elevations) shows the area around Jezero Crater. Flowing water would have gathered any biologic or organic material from a wide area and deposited it at the crater, making it a logical landing site for a future Mars rover ...
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One thing that's curious is that the biology of our entire system is still evolving. Our planets are just teenagers right now. We have many other planets in many stages of becoming to study too. Lots of data to be gathered and analyzed. 
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Tracking the rotation speed of solid planets, like the Earth and Mars, is a relatively simple task: Just measure the time it takes for a surface feature to roll into view again. But giant gas planets Jupiter and Saturn are more problematic for planetary scientists, as they both lack measurable solid surfaces and are covered by thick layers of clouds, foiling direct visual measurements by space probes. Saturn has presented an even greater challenge to scientists, as different parts of this sweltering ball of hydrogen and helium are known to rotate at different speeds, whereas its rotation axis and magnetic pole are aligned.
A new method devised by Tel Aviv University researcher Dr. Ravit Helled, published recently in Nature, proposes a new determination of Saturn's rotation period and offers insight into the internal structure of the planet, its weather patterns, and the way it formed. The method, by Dr. Helled of the Department of Geosciences at TAU's Raymond and Beverly Sackler Faculty of Exact Sciences and Drs. Eli Galanti and Yohai Kaspi of the Department of Earth and Planetary Sciences at the Weizmann Institute of Science, is based on Saturn's measured gravitational field and the unique fact that its east-west axis is shorter than its north-south axis.
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Why do you say "sweltering ball of hydrogen"? Isn't Saturn rather cold?
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