Standard-Candle Supernovae are Still Standard, but Why? � Berkeley Lab News Center

Standard-Candle Supernovae are Still Standard, but Why? � Berkeley Lab News Center: ... a new analysis of normal Type Ia supernovae... shows that in fact they have a range of masses. Most are near or slightly below the Chandrasekhar mass, and about one percent somehow manage to exceed it...

A supernova eruption thoroughly trashes its white dwarf progenitor, so the most practical way to tell how much stuff was in the progenitor is by spectrographically “weighing” the leftover debris, the ejected mass...

The SNfactory team compared masses and other factors with light curves: the shape of the graph, whether narrow or wide, that maps how swiftly a supernova achieves its brightest point, how bright it is, and how hastily or languorously it fades away. The typical method of “standardizing” Type Ia supernovae is to compare their light curves and spectra....

“The conventional wisdom holds that the light curve width is determined primarily or exclusively by the nickel-56 mass,” Scalzo says, “whereas our results show that there must also be a deep connection with the ejected mass, or between the ejected mass and the amount of nickel-56 created in a particular supernova.”

Cosmologist claims Universe may not be expanding : Nature News & Comment

Cosmologist claims Universe may not be expanding : Nature News: But, as Wetterich points out, the characteristic light emitted by atoms is also governed by the masses of the atoms' elementary particles, and in particular of their electrons. If an atom were to grow in mass, the photons it emits would become more energetic. Because higher energies correspond to higher frequencies, the emission and absorption frequencies would move towards the blue part of the spectrum. Conversely, if the particles were to become lighter, the frequencies would become redshifted.

Because the speed of light is finite, when we look at distant galaxies we are looking backwards in time — seeing them as they would have been when they emitted the light that we observe. If all masses were once lower, and had been constantly increasing, the colours of old galaxies would look redshifted in comparison to current frequencies, and the amount of redshift would be proportionate to their distances from Earth. Thus, the redshift would make galaxies seem to be receding even if they were not.

Giant fractals are out – the universe is a big smoothie - New Scientist - New Scientist

Giant fractals are out - the universe is a big smoothie: They tested for clusters by placing any given galaxy in the centre of an imaginary sphere and counted the number of galaxies within it. If clustering exists, there should be more galaxies within a sphere than if the 220,000 galaxies were distributed randomly throughout the huge cube.

With relatively small spheres – up to about 330 million light years wide – they did find galactic clusters. But in larger spheres the number of galaxies met expectations for randomness.

How can we measure the size of the universe?

How can we measure the size of the universe?: "By now you should be getting a pretty good idea how the most distant galaxies can be further away than 13.8 billion light years. For the first part of the trip, the light that is just now reaching us was traveling through a much more compact universe than we have now. As time went on and space expanded, the distance between the photon and where it started increased at 'faster than light.' Again, this doesn't mean that light was traveling faster than light. Anyone watching the beam go by would measure it at 3x108 m/s, the ordinary cosmic speed limit.

Even so, there's a maximum distance that light could have traveled since time began. This is known as the horizon, and based on our best cosmological measurements, it's about 48 billion light years. The light that we see from the Cosmic Microwave Background Radiation is reaching us from a point very near to the horizon."

New look at relativity: Electrons can't exceed the speed of light -- thanks to light itself, says biologist

New look at relativity: Electrons can't exceed the speed of light -- thanks to light itself, says biologist: "Any space with a temperature above absolute zero consists of photons. As a result of the Doppler effect, the moving electron experiences the photons crashing into the front of it as being blue-shifted, and the photons colliding with the back of it as being red-shifted. Since blue-shifted photons exert more momentum than red-shifted photons, the photons themselves exert a counterforce on the moving electron, just as the cytoplasm in a cell exerts a viscous force on the moving organelles. The viscous force that arises from the Doppler-shifted photons prevents electrons from exceeding the speed of light, according to Randy Wayne, associate professor of plant biology."

Early Bloomer: Faraway Galaxy Pushes Cosmic View Closer to the Dawn of the Universe: Scientific American

Early Bloomer: Faraway Galaxy Pushes Cosmic View Closer to the Dawn of the Universe: Scientific American: At the redshift inferred for UDFy-38135539, the hydrogen line happens to fall in a quiet part of the infrared spectrum, but the signal-to-noise ratio leaves some open questions. "It's right on the edge of what you'd believe, to be frank," Dunlop says, noting that confirmation would be much easier with a space-borne infrared spectrograph such as that planned for NASA's James Webb Space Telescope (JWST). But that technology will not be available until JWST launches in 2014, at the earliest. "So you're faced with trying to follow these things up from the largest telescopes on the ground," Dunlop says.