New York Times: Not long ago in this space, I spoke with Michio Kaku, the author of “Physics of the Impossible” and a professor of theoretical physics at the Graduate Center of the City University of New York, about science-fiction-inspired technological breakthroughs that might actually occur within our own lifetimes. This week, Kaku talks about three long dreamt-of technologies that he categorizes as class I, class II and class III impossibilities — in other words, things you’ll simply never see during your time on earth. (Unless, like me, you plan to live forever.)
Nature: The University of Toronto’s David Dunlap Observatory, which houses a 1.88-metre reflecting telescope in the town of Richmond Hill, Ontario, may see last light as soon as 30 June. The university is negotiating the sale of the observatory and 77 hectares of surrounding land, estimated to be worth Can$100 million (US$98 million).
New York Times: Back in 2002, astronomers from Wesleyan University concluded that a star brightening and waning in an unusual 48-day rhythm was dipping in and out of stuff swirling around the star in a so-called protoplanetary disk. At the time one astronomer called the system “a Rosetta stone,” for understanding how planets form.
Now, after six more years of observation with an international group of astronomers, led by William Herbst of Wesleyan, researchers say they know what the stuff in this disk is. In a paper published on Thursday in the journal Nature, they report that it is made of sand-size grains, roughly a millimeter in diameter, which must have grown from infinitesimal dust particles over the three million years that the star, known as KH 15D, has been in existence.
New Scientist: Long ago, antimatter all but vanished from existence, allowing matter to predominate and form the stars and planets of the universe. Exactly why this happened has been a mystery, but a particle accelerator in Japan may have found a new clue, and one that does not seem to fit the standard model of particle physics.
Nature: Alan Stern stepped down as head of science programmes at NASA on Tuesday.
NASA Administrator Mike Griffin has named Edward Weiler, currently director of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, as Stern’s interim replacement. Weiler held Stern’s post, of associate administrator for science, from 1998 to 2004.
Physics Update: A new study shows how a region of space could be rendered invisible to matter waves. In recent years the possibility of optical cloaking has become a hot topic (e.g., Science, 8 Sept 2006). Even cloaking with sound waves has been proposed. Now physicists in Xiang Zhang’s group at the University of California, Berkeley, are trying to extend the cloaking idea to atom waves (chilled atoms whose quantum wavelike properties are more important than their particle-like properties) moving through a medium.
The “medium” in question here is a concentric optical lattice, generated by standing electromagnetic waves with spatially controlled amplitudes and phases. Cloaking of an object bathed in light works by modulating the effective mass and potential of atom waves traversing the shell surrounding the object. The shell is analogous to the metamaterials (tailored materials often consisting of arrays of tiny rods and ring-shaped metal structures) used in the optical case.
One of the Berkeley researchers, Shuang Zhang says that the atom-wave equivalent of an index of refraction would be the modulation of the effective atomic mass inside the optical lattice. Zhang says that apart from cloaking, the creation of a metamaterial for atom waves might also help in focusing atom waves into tiny spot (super-lensing) or for steering particle beams at will. (Zhang et al., Physical Review Letters, 28 March 2008.
NPR: Along Florida’s “Space Coast,” people are worrying about what the end of the shuttle program will mean for workers and the region’s economy.
For many who live and work here, the looming end of the space shuttle brings back memories of the 1970s. Within just a few years of men landing on the Moon, the workforce at the Kennedy Space Center was cut from 25,000 employees to less than half that.
The ripple effects from those layoffs, Koller recalls, devastated Florida communities from Titusville to Melbourne.
The replacement for the space shuttle, Constellation, and the other future NASA programs at Cape Canaveral will require far fewer people than those needed for the space shuttle.
Lynda Weatherman, of the area’s economic development commission, says it’s important that Florida’s Space Coast diversify its aerospace industry and the role it plays in the nation’s space program.
“We don’t want to rely on launch. We can’t afford to rely on launch,” she says.
The Guardian: Gordon Brown is preparing for a battle with the European Union over biofuels after one of the government’s leading scientists warned they could exacerbate climate change rather than combat it.
In an outspoken attack on a policy which comes into force next week, Professor Bob Watson, the chief scientific adviser at the Department for Environment, Food and Rural Affairs, said it would be wrong to introduce compulsory quotas for the use of biofuels in petrol and diesel before their effects had been properly assessed.
“If one started to use biofuels … and in reality that policy led to an increase in greenhouse gases rather than a decrease, that would obviously be insane,” Watson said. “It would certainly be a perverse outcome.
New York Times: Mikki M. Osterloo of the University of Hawaii and colleagues have found evidence of chloride-bearing materials — in other words, salts — in the Martian southern highlands. The deposits are small and in some cases are fractured into polygonal shapes, suggesting that they consist of salts that precipitated out of saline water as it evaporated, which is how salt flats form in deserts on earth.
Physics Update: Light can be thought of as a series of waves or, in the dualistic view of reality prescribed by quantum science, as a collection of quanta, particle-like parcels of light energy referred to as photons. At any place along a light beam there may be many photons present or in special cases just one. Creating single photons is not easy to do. It is possible to make photons in pairs by sending laser light through special crystals. Even a pure-color laser beam will consist of many photons; but occasionally one of these photons will be “down converted,” that is, will turn into two photons each with half the energy of the original photon. When a pair has been created, the detection of one of these half-energy photons heralds the presence of its twin.
Furthermore, these photons are entangled, meaning that the properties of one photon are inextricably linked to those of its partner and detecting one can ruin the quantum state of the other. By minimizing these quantum correlations, the researchers obtained heralded photons with exceptionally high quality and short duration.
In the experiment the pairs of photons made had a central wavelength of about 830 nm, at the border between visible and near-infrared light. Each of these photons was (in units of time) about 65 femtoseconds (65 x 10-15 sec) long. In units of space, they were about 20 microns long. The shortest previously produced single photon was about 1picosecond (10-12 sec) long. Even shorter pulses of light—stretching only hundreds of attoseconds—have been made, but these pulses consist of many photons. One of the researchers, Peter Mosley of Oxford Universty, says that this new experiment represents the first time that textbook photons-identical, localized wavepackets containing a single quantum of energy-have been produced in a lab.