The pill is a sledgehammer approach to contraception…. A second-generation of [drugs] is being designed to do the job without upsetting a woman’s normal cycle of ovulation and menstruation…. A contraceptive administered to the man can be given only for a short time without actually affecting the development of sperm … and, therefore, is not being considered for actual clinical use. —Science News, April 15, 1967
Update Contraceptives have come a long way since 1967. Women can choose low-dose pills, hormonal rings, implants and intrauterine devices — effective methods that can be less disruptive to normal menstrual cycles. Men have far fewer options, but that may eventually change. A long-acting gel injected into 16 adult male rhesus monkeys’ reproductive tracts completely prevented pregnancy in their partners over one to two breeding periods. The gel works like a vasectomy but is less invasive and can be reversed more easily, researchers report February 7 in Basic and Clinical Andrology.
A misfit gang of superconducting materials may be losing their outsider status.
Certain copper-based compounds superconduct, or transmit electricity without resistance, at unusually high temperatures. It was thought that the standard theory of superconductivity, known as Bardeen-Cooper-Schrieffer theory, couldn’t explain these oddballs. But new evidence suggests that the standard theory applies despite the materials’ quirks, researchers report in the Dec. 8 Physical Review Letters.
All known superconductors must be chilled to work. Most must be cooled to temperatures that hover above absolute zero (–273.15° Celsius). But some copper-based superconductors work at temperatures above the boiling point of liquid nitrogen (around –196° C). Finding a superconductor that functions at even higher temperatures — above room temperature — could provide massive energy savings and new technologies (SN: 12/26/15, p. 25). So scientists are intent upon understanding the physics behind known high-temperature superconductors. When placed in a magnetic field, many superconductors display swirling vortices of electric current — a hallmark of the standard superconductivity theory. But for the copper-based superconductors, known as cuprates, scientists couldn’t find whirls that matched the theory’s predictions, suggesting that a different theory was needed to explain how the materials superconduct. “This was one of the remaining mysteries,” says physicist Christoph Renner of the University of Geneva. Now, Renner and colleagues have found vortices that agree with the theory in a high-temperature copper-based superconductor, studying a compound of yttrium, barium, copper and oxygen.
Vortices in superconductors can be probed with a scanning tunneling microscope. As the microscope tip moves over a vortex, the instrument records a change in the electrical current. Renner and colleagues realized that, in their copper compound, there were two contributions to the current that the probe was measuring, one from superconducting electrons and one from nonsuperconducting ones. The nonsuperconducting contribution was present across the entire surface of the material and masked the signature of the vortices.
Subtracting the nonsuperconducting portion revealed the vortices, which behaved in agreement with the standard superconductivity theory. “That, I think, is quite astonishing; it’s quite a feat,” says Mikael Fogelström of Chalmers University of Technology in Gothenburg, Sweden, who was not involved with the research. The result lifts some of the fog surrounding cuprates, which have so far resisted theoretical explanation. But plenty of questions still surround the materials, Fogelström says. “It leaves many things still open, but it sort of gives a new picture.”
Proxima Centauri has a temper. Earth’s nearest planet-hosting neighbor released a gigantic flare in March 2017, a new analysis of observations of the star shows. And that’s bad news for the potential for life on the star’s planet, Proxima b.
The star got 1,000 times brighter over 10 seconds before dimming again. That can best be explained by an enormous stellar flare, astronomer Meredith MacGregor of the Carnegie Institution for Science in Washington, D.C., and colleagues report February 26 in Astrophysical Journal Letters. Because Proxima b is so much closer to its star than Earth is to the sun, the flare would have blasted Proxima b with 4,000 times more radiation than Earth typically gets from the sun’s flares. “If there are flares like this at all frequently, then [the exoplanet] is likely not in the best shape,” MacGregor says.
Proxima b was one of the most sought-after sites for finding life outside the solar system. Just four light-years away, it has a mass about the same as Earth’s and probably has temperatures suitable for liquid water (SN: 12/24/16, p. 20). But its star is an M dwarf, a class of small dim stars notoriously prone to flares that could rip away their planets’ atmospheres (SN: 6/24/17, p. 18). MacGregor and her colleagues reanalyzed data from a recent study led by astronomer Guillem Anglada of the Institute of Astrophysics of Andalusia in Granada, Spain. Anglada and his colleagues had observed Proxima Centauri with the Atacama Large Millimeter Array telescopes in Chile. The team saw extra light that it interpreted as a ring of dust analogous to the solar system’s Kuiper Belt, scattering the light in all directions, the team reported November 15 in Astrophysical Journal Letters. But Anglada and his colleagues had averaged the amount of light over 10 hours of observations. That smeared out any short-term changes in the star’s brightness — such as a bright flare.
When MacGregor’s team reanalyzed the data, they found that all the excess light came from the same two-minute period on March 24. A massive flare explains all the extra light, she says — none of it was masquerading as a glittering dust ring.
Anglada says he and his colleagues are aware of the March 24 flare and are currently revising their original claim. But he says the flare can’t account for all the extra light, so the dust ring theory might still survive.
Physicist Stephen Hawking, a black hole whisperer who divined secrets of the universe’s most inscrutable objects, died March 14 at age 76. In addition to his scientific research, Hawking, a professor at the University of Cambridge, was known for his popular science books, including the best-selling A Brief History of Time, which captivated readers with lucid explanations of the universe’s birth and the physical laws that rule the cosmos.
In one of his best-known discoveries, Hawking determined that black holes are not truly black. Instead, they emit a faint haze of particles, known as Hawking radiation (SN: 5/31/14, p. 16). This discovery, which arose at the interface of gravity and quantum mechanics, had remarkable consequences. It suggested that black holes are not eternal, but eventually evaporate. That led to a conundrum known as the black hole information paradox (SN: 10/3/15, p. 10): When a black hole disappears, what happens to the information that fell into it? Physicists are still puzzling over that question.
In the face of physical disabilities due to amyotrophic lateral sclerosis, which profoundly limited his mobility and ability to communicate, Hawking became one of science’s most well-known figures, and survived far beyond the timeline initially expected given his condition.
Science News has covered Hawking’s work extensively over the past decades, including his four laws of black hole mechanics, his work on miniature black holes and, most recently, Hawking’s search for a solution to the black hole paradox.