Experiments Show Gravity Is Not an Emergent Phenomenon

One of the most exciting ideas in modern physics is that gravity is not a traditional force, like electromagnetic or nuclear forces. Instead, it is an emergent phenomenon that merely looks like a traditional force.

This approach has been championed by Erik Verlinde at the University of Amsterdam who put forward the idea in 2010. He suggested that gravity is merely a manifestation of entropy in the Universe, which always increases according to the second law of thermodynamics. This causes matter distribute itself in a way that maximises entropy. And the effect of this redistribution looks like a force which we call gravity.

Much of the excitement over Verlinde’s idea is that it provides a way to reconcile the contradictions between gravity, which works on a large scale, and quantum mechanics, which works on a tiny scale.

The key idea is that gravity is essentially a statistical effect. As long as each particle is influenced by a statistically large number of other particles, gravity emerges. That’s why it’s a large-scale phenomenon.

But today, Archil Kobakhidze at The University of Melbourne in Australia points to a serious problem with this approach. He naturally asks how gravity can influence quantum particles.

(via Technology Review)

Berkeley Scientists Discover an “Instant Cosmic Classic” Supernova

A supernova discovered yesterday five days ago is closer to Earth — approximately 21 million light-years away — than any other of its kind in a generation. Astronomers believe they caught the supernova within hours of its explosion, a rare feat made possible with a specialized survey telescope and state-of-the-art computational tools.

The finding of such a supernova so early and so close has energized the astronomical community as they are scrambling to observe it with as many telescopes as possible, including the Hubble Space Telescope.

Joshua Bloom, assistant professor of astronomy at the University of California, Berkeley, called it “the supernova of a generation.” Astronomers at Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley, who made the discovery predict that it will be a target for research for the next decade, making it one of the most-studied supernova in history.

The supernova, dubbed PTF 11kly, occurred in the Pinwheel Galaxy, located in the “Big Dipper,” otherwise known as the Ursa Major constellation. It was discovered by the Palomar Transient Factory (PTF) survey, which is designed to observe and uncover astronomical events as they happen.

“We caught this supernova very soon after explosion. PTF 11kly is getting brighter by the minute. It’s already 20 times brighter than it was yesterday,” said Peter Nugent, the senior scientist at Berkeley Lab who first spotted the supernova. Nugent is also an adjunct professor of astronomy at UC Berkeley. “Observing PTF 11kly unfold should be a wild ride. It is an instant cosmic classic.”

He credits supercomputers at the National Energy Research Scientific Computing Center (NERSC), a Department of Energy supercomputing center at Berkeley Lab, as well as high-speed networks with uncovering this rare event in the nick of time.

(via Berkeley Lab News Center)

Divers working for the Orda Cave Awareness Project have revealed images of the world’s longest underwater cave.

(via Orda Cave Awareness Project » gallery)

Interestingly, this link has a lot more great Hubble shots, and I recommend you go check it out.

scipsy:

NASA’s Great Observatories Examine the Galactic Center Region

(via apteryxrowi)

Neutrino Transformation Could Help Explain Mystery of Matter

Two research teams have found new evidence of transformations in elusive elementary particles called neutrinos. The findings may finally help explain why the universe didn’t vanish shortly after its birth.

“These results are just the beginning of the story for neutrinos,” said physicist Robert Plunkett of Fermilab in Chicago. “They could lead to clues … and tell us why there’s now far more matter than antimatter.”

Most neutrinos are emitted by the sun, and are so small and ghostly that billions pass through our bodies every second. Most go right through Earth without hitting anything. But some human-built devices — slabs of iron and plastic, big chambers of oil or water lined with photon detectors, or detector arrays plunged into seawater or Antarctic ice — can record the blip of light when a neutrino occasionally slams into an atom.

Using these detection events, physicists have identified three types of neutrino, called muon, tau and electron neutrinos. Further discoveries suggested that each type can transform into another, with muon-to-tau neutrino transformations being dominant, at least in particle-accelerator-powered experiments.

Researchers proposed a third and weaker change, that of muon-to-electron neutrinos, but until now lacked evidence for its existence.

(via Wired.com, h/t to eirizu)

Hubble Space Telescope discovers ‘dead galaxies’ forming stars

Scientists concluded as late as 2005 that elliptical galaxies were filled with evolved stars that were billions of years old. However, university astronomers have found out that these “dead galaxies” are still creating new stars.

In March 2005, scientists using NASA’s Spitzer Space Telescope were doing research on the formation of galaxies, black holes and general observations. In the research they concluded that galaxies are red because they are dead and that “no stars appeared to have formed for 1.5 billion years.”

More than six years later, scientists are surprised by their recent discovery.According to Universe Today, astronomers at the University of Michigan discovered that old galaxies are still forming new stars, which will now provide more information as to how galaxies are structured.

Astronomers Unveil Most Complete 3-D Map of Local Universe

Cambridge, MA - [On May 25th, 2011], astronomers unveiled the most complete 3-D map of the local universe (out to a distance of 380 million light-years) ever created. Taking more than 10 years to complete, the 2MASS Redshift Survey (2MRS) also is notable for extending closer to the Galactic plane than previous surveys - a region that’s generally obscured by dust.

Karen Masters (University of Portsmouth, UK) presented the new map today in a press conference at the 218th meeting of the American Astronomical Society.

“The 2MASS Redshift Survey is a wonderfully complete new look at the local universe - particularly near the Galactic plane,” Masters said. “We’re also honoring the legacy of the late John Huchra, an astronomer at the Harvard-Smithsonian Center for Astrophysics, who was a guiding force behind this and earlier galaxy redshift surveys.”

A galaxy’s light is redshifted, or stretched to longer wavelengths, by the expansion of the universe. The farther the galaxy, the greater its redshift, so redshift measurements yield galaxy distances - the vital third dimension in a 3-D map.

(via Research Blogging)

That’s amazing.

sunsurfer:

Transparent Butterfly, South America

photo by e3000

(via mariposima)

Part of Cai Guo-Qiang’s Odyssey, a permanent gunpowder drawing installation in the the Ting Tsung and Wei Fung Chao Arts of China Gallery, MFAH.

Longstanding Mystery of Sun’s Hot Outer Atmosphere Solved - US National Science Foundation (NSF)

One of the most enduring mysteries in solar physics is why the Sun’s outer atmosphere, or corona, is millions of degrees hotter than its surface.

Now scientists believe they have discovered a major source of hot gas that replenishes the corona: jets of plasma shooting up from just above the Sun’s surface.

The finding addresses a fundamental question in astrophysics: how energy is moved from the Sun’s interior to create its hot outer atmosphere.

“It’s always been quite a puzzle to figure out why the Sun’s atmosphere is hotter than its surface,” says Scott McIntosh, a solar physicist at the High Altitude Observatory of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., who was involved in the study.

“By identifying that these jets insert heated plasma into the Sun’s outer atmosphere, we can gain a much greater understanding of that region and possibly improve our knowledge of the Sun’s subtle influence on the Earth’s upper atmosphere.”

The research, results of which are published this week in the journal Science, was conducted by scientists from Lockheed Martin’s Solar and Astrophysics Laboratory (LMSAL), NCAR, and the University of Oslo. It was supported by NASA and the National Science Foundation (NSF), NCAR’s sponsor.

The Estimated Number of Stars in the Universe Just Tripled

“A study by Yale astronomer Pieter van Dokkum just took the estimated number of stars in the universe—100,000,000,000,000,000,000,000, or 100 sextillion—and tripled it. And you thought nothing good ever happens on Wednesdays.

Van Dokkum’s study in the journal Nature focuses on red dwarfs, a class of small, cool stars. They’re so small and cool, in fact, that up to now astronomers haven’t been able to spot them in galaxies outside our own. That’s a serious holdup when you’re trying to account for all the stars there are.”