Type Ia supernovae stem from the explosion of white dwarfs coupled with twin stars

Type Ia supernovae stem from the explosion of white dwarfs coupled with twin stars: A new model postulating the fusion of two white dwarfs is now challenging the predominant one, consisting of a white dwarf and a normal star. The new scenario does not imply the existence of a maximum mass limit and will not, therefore, necessarily produce explosions of similar luminosity...

"If these results were to gain general acceptance, the cosmological consequences would be weighty, because the use of type Ia supernovae to measure distances would come into question," the researcher concludes.

New Material, Darker Than Black, Could Help Space Cameras See Better | Popular Science

New Material, Darker Than Black, Could Help Space Cameras See Better | Popular Science: Scientists make Vantablack by depositing carbon nanotubes close together on a thin sheet of aluminum. The tiny spaces between the tubes trap light, preventing it from reflecting off the material. A number of research groups have made super-absorbing black materials with similar microstructures. One advantage of Vantablack is that it doesn't require as high of temperatures to make as other carbon nanotube materials, according to Surrey NanoSystems. That means engineers can deposit Vantablack coatings on a wider range of materials.

How to Build an Evryscope | MIT Technology Review

How to Build an Evryscope | MIT Technology Review: Their new gigapixel-scale telescope will be capable of photographing the entire sky simultaneously and continuously at relatively low cost...

It consists of 23 small telescopes mounted on a hemispherical dome that can rotate to track the sky. Each small telescope has a 7 cm aperture and a field of view of a few hundred square degrees. Each one focuses light onto 29 megapixel chip.

The dome is designed so that the fields of view of each of the small telescopes overlap to cover around 10,000 square degrees of sky simultaneously and to produce 0.7 gigapixel images. The dome rotates on equatorial mount so that the Evryscope can record exposures of up to 3 hours before ratcheting back and tracking the next sky area.

The Major Blunders That Held Back Progress in Modern Astronomy� — The Physics arXiv Blog — Medium

The Major Blunders That Held Back Progress in Modern Astronomy� — The Physics arXiv Blog — Medium: “A very common flaw of astronomers is to believe that they know the truth even when data is scarce,” says Loeb...

In 1952, the Russian-American astronomer Otto Struve suggested that close-in planets may exist and would be easy to spot but his paper was ignored because of exactly the same prejudices.

Square Kilometre Array will see sky bubbling with exploding stars

Square Kilometre Array will see sky bubbling with exploding stars: The catch is that a gamma-ray burst is not an explosion that we can see from all directions but is comprised of a very narrow, energetic jet, so we need to be looking down the barrel of the jet at the right time...

The radio afterglow should be visible from any direction though and for long periods of time, even if we missed the burst.

How To Build A Quantum Telescope — Medium

How To Build A Quantum Telescope — Medium: Her idea is to use the astrophysical photons to stimulate the production of an entangled pair, inside a telescope. The first of this pair then hits the detector, generating an image. But the other can be used to increase the information known about the first, thereby increasing the resolution and beating the diffraction limit.

Physicists Demonstrate First Laser Made From a Cloud of Gas | MIT Technology Review

Physicists Demonstrate First Laser Made From a Cloud of Gas | MIT Technology Review:  In recent years, physicists have found an answer in the form of random lasers. These consist of some kind of disordered medium, such as semiconductor powder. The light that stimulates emission is not confined by mirrors but by the disordered state of the powder–the light simply bounces around inside it at random...




These guys have built their laser out of a small cloud of rubidium atoms confined in a magneto-optical trap. They excite the atoms and then zap them with a laser tuned close to the expected emission frequency of rubidium. This bounces around at random inside the cloud triggering the stimulated emission of light.

‘Point of no return’ found | Harvard Gazette

‘Point of no return’ found | Harvard Gazette: According to Einstein’s theory of general relativity, a black hole’s mass and spin determine how close material can orbit before becoming unstable and falling in toward the event horizon. The team was able to measure this innermost stable orbit and found that it’s only 5.5 times the size of the black hole’s event horizon. This size suggests that the accretion disk is spinning in the same direction as the black hole.

Mystery of dark matter may be near to being deciphered

Mystery of dark matter may be near to being deciphered: "We have observed a very unique emission of radio radiation from the centre of our galaxy, the Milky Way. By using different methods to separate the signal for very broad range of   wavelengths, we have been able to determine the spectrum of the radiation. The radiation originates from synchrotron emission, i.e. electrons and positrons circulating at high energies around the lines of the Magnetic Field in the centre of the galaxy, and there are quite strong indications that it could come from dark matter..."

"The radiation cannot be explained by the structural mechanisms in the galaxy and it cannot be radiation from supernova explosions. We believe that this could be proof of dark matter. Otherwise, we have discovered absolutely new (and unknown for physics) mechanism of acceleration of particles in the Galactic centre..."

Flaring black holes may solve cosmic ray puzzle - New Scientist - New Scientist

Flaring black holes may solve cosmic ray puzzle: Then they found a clue: gamma-ray burst GRB110328A, which happened in March 2011. Its afterglow persisted for over a week, instead of a few hours like normal ones. The culprit was most likely a star falling into a galaxy's central black hole. This would make a weak black hole flare up, producing a burst of gamma rays that in turn spits out cosmic rays, suggests Farrar...

Futurity.org – ‘Near perfect’ amp may grab space signals

Futurity.org – ‘Near perfect’ amp may grab space signals: One type of highly sensitive amplifier is a parametric amplifier, which boosts a weak input signal by using a strong signal called the pump signal...
The problem with many parametric amplifiers and sensitive devices like it, however, is that they can only amplify a narrow frequency range and often have a poor dynamic range.
But the Caltech and JPL researchers say their new amplifier, which is a type of parametric amplifier, combines only the best features of other amplifiers. It operates over a frequency range more than ten times wider than other comparably sensitive amplifiers, can amplify strong signals without distortion, and introduces nearly the lowest amount of unavoidable noise...

One of the key features of the new parametric amplifier is that it incorporates superconductors... titanium nitride (TiN) and niobium titanium nitride (NbTiN), which have just the right properties to allow the pump signal to amplify the weak signal.

Dark matter makes a comeback

Dark matter makes a comeback: The researchers point out the stars within the local neighborhood move slower than the average velocity assumed by the ESO team, in a behavior called asymmetric drift. This lag varies with a cluster’s position within the galaxy, but, according to Bovy and Tremaine, “this variation cannot be measured for the sample [used by Moni Biden's team] as the data do not span a large enough range.”
When the IAS researchers took Moni Biden’s observations but replaced the ESO team’s “invalid” assumptions on star movement within and above the galactic plane with their own “data-driven” ones, the dark matter reappeared.

Astrophile: The case of the disappearing pulsar - New Scientist - New Scientist

Astrophile: The case of the disappearing pulsar: The star was a spectacular find: unlike every other pulsar ever observed, this one was in a close binary orbit with another pulsar. Together, the pair provided a precise laboratory to test Einstein's theory of general relativity, and a means of detailing how pulsars behave.
But in March 2008, Pulsar B went dark...
No one snuffed out Pulsar B – it just rotated out of view...

"We can see the light from one pulsar being bent as it travels through the gravitational well of the other pulsar," she says. "It's really neat. We have proof that one of these objects is distorting spacetime."
The eclipsing pulsars also provided a test of "spin precession", the idea that the pulsars' axes should wobble around like a top as they spin.

Short Sharp Science: Spinning space telescope's view of a pulsar

Short Sharp Science: Spinning space telescope's view of a pulsar: It can't be so easy to keep the Fermi Gamma-ray Space Telescope trained on one spot in the sky as it maps the universe. Fermi orbits the Earth every 95 minutes while rocking between the north and the south on alternate orbits, On top of this, the satellite also completes one rotation every 54 days to keep its solar panels facing the sun.

This image traces Fermi's view via its Large Area Telescope of the gamma rays emitted by the Vela pulsar from August 2008 to August 2010. The Vela pulsar is a neutron star, itself spinning at a dizzying 11 times per second and the brightest and most persistent source of gamma rays in the sky, giving an anchoring point for Fermi's own spin.

Nearby dark-matter-free zone poses cosmic conundrum

Nearby dark-matter-free zone poses cosmic conundrum: ...until now most velocity measurements considered only stars zipping around the Milky Way radially, like an ant sitting on a vinyl record. By contrast, Moni Bidin's team looked outward from the plane of the galaxy, perpendicular to the galactic disc. Using historical survey data and new observations from telescopes at the La Silla Observatory and the Las Campanas Observatory, both in Chile, the researchers mapped the motions of more than 400 stars up to 13,000 light-years from the sun.

They used those measurements to calculate the mass of matter in a volume four times larger than had been considered before at this level of precision. Under the standard dark matter theory, there should be at least as much dark matter as visible matter in this region. "Contrary to our expectations, there is none," Moni Bidin says. "The result matches the visible mass strongly."

Photon sieves make super-cheap space telescopes

Photon sieves make super-cheap space telescopes: Traditional telescopes use lenses or mirrors to focus light by refraction or reflection, but the photon sieve uses diffraction instead. The sieve is an ultra-thin plastic disc perforated by millions of microscopic holes, each of which bends light at different angles to create a focal point.

Less light reaches the focal point compared with traditional lenses or mirrors, making it hard to image dim objects, and the device can only take black-and-white pictures. But the sieve is cheap, lightweight and easy to manufacture at large sizes. It can also be tightly folded and unfurled without being damaged.

BBC News - Survey gets a grip on dark energy

BBC News - Survey gets a grip on dark energy: "What we've done is measure the 3D positions for just over 250,000 galaxies, covering the largest volume of the Universe ever surveyed. That gives us an amazing map that we can then analyse to try to understand how and why the Universe's expansion is accelerating..."


One concerns so-called baryon acoustic oscillations. These are pressure-driven waves that passed through the very early Universe and which were imprinted on the distribution of matter once conditions had cooled below a certain point.

Today, these "wiggles" show themselves as a preferred scale in the separation of galaxies and can be used as a kind of standard ruler to measure the geometry of the cosmos...

The other technique being used by BOSS involves "redshift space distortions". These describe the component in the velocity of galaxies that stems from the growth of structure in the Universe. The team can see if neighbouring galaxies are clustering in the way that would be expected from the action of gravity.

Finding the star in this supernova could unlock the secrets of the universe

Finding the star in this supernova could unlock the secrets of the universe: At the center of this supernova remnant should be the companion star to the star that blew up. Identifying this star is important for understanding just how Type Ia supernova detonate, which in turn could lead to a better understanding of why the brightness of such explosions are so predictable, which in turn is key to calibrating the entire nature of our universe. The trouble is that even a careful inspection of the center of SNR 0509-67.5 has not found any star at all.

Astronomy Without A Telescope – Could Dark Matter Not Matter?

Astronomy Without A Telescope – Could Dark Matter Not Matter?  ...Carati has come along with a seemingly implausible idea that the rotational curves of spiral galaxies could be explained by the gravitational influence of faraway matter, without needing to appeal to dark matter at all.


Conceptually the idea makes little sense. Positioning gravitationally significant mass outside of the orbit of stars might draw them out into wider orbits, but it’s difficult to see why this would add to their orbital velocity. Drawing an object into a wider orbit should result in it taking longer to orbit the galaxy since it will have more circumference to cover. What we generally see in spiral galaxies is that the outer stars orbit the galaxy within much the same time period as more inward stars.

But although the proposed mechanism seems a little implausible, what is remarkable about Carati’s claim is that the math apparently deliver galactic rotation curves that closely fit the observed values of at least four known galaxies. Indeed, the math delivers an extraordinarily close fit.

Perfect black coating can render a 3D object flat, raises intriguing dark veil possibility in astronomy

Perfect black coating can render a 3D object flat, raises intriguing dark veil possibility in astronomy: To demonstrate this concept, the researchers made a raised, microscopic tank shape on a piece of silicon. They then grew the carbon nanotube carpet on top of the entire silicon chip. In photos taken through an optical microscope, they show that the tank is imperceptible. As a control, they did this again, carving out a rectangle that was not coated with carbon nanotubes. The rectangle is visible on this chip, but the tank remains hidden.