Scintilla

Neutron stars are some of the densest objects in existence, only beaten out by black holes. Neutron stars are something of a paradox. They are inherently simple, their formation being governed by a rather straightforward competition between quantum mechanics and gravity. This clean system and its resulting dynamics make them a model object for both quantum mechanics and astrophysics courses, where students can be expected to come up with analytical models of neutron stars as part of a three-hour, six-question exam.

On the other hand, there is a lot of subtle variation in the details that provide a rich vein of discovery for observational and theoretical physics. Combine that with modern observatories that collect data faster than we can analyze it, and astrophysicists with an interest in neutron stars are sitting on a lifetime's worth of interesting results. In this week's Nature, researchers present the first ever observational evidence of the atmosphere of a very young neutron star, which implies that, even for neutron stars, youth is smooth skinned and old age is crusty.

Proceedings of the National Academy of Sciences, November 3
Two studies in PNAS focused on the wildlife and landscape of East Africa. In the first, researchers looked back in history to Kenya’s infamous man-eating lions, which reportedly devoured 135 railroad laborers in 1898. The two lions were eventually shot, killed, stuffed, and shipped to Chicago’s Field Museum for display–which allowed researchers to analyze samples of the lions’ bones and fur. By comparing the isotopes present in the man-eating lions to those found in other lions, humans, wildebeest, and buffalo, the researchers could precisely determine the lions’ diet. The results brought the body count down considerably: The scientists estimate that one of the lions ate 24 people, while the other gobbled up 11. The second study looked ahead, and predicted that Mount Kilimanjaro, the highest peak in Africa, could lose its distinctive ice cap by 2022 due to global warming.

Journal of the American Medical Association, November 4
A new study of hospitalizations in California due to swine flu has highlighted a neglected risk factor: obesity. In the study group of patients whose weight was known, researchers found that 25 percent of the people were morbidly obese, although less than 5 percent of the U.S. population falls into that category. Researchers also found that 58 percent of these hospitalized patients were obese–in the population as a whole, about 34 percent of people are obese. The increased risks come partially from health problems associated with obesity, like heart disease, lung ailments, and diabetes. But physiological factors may also be to blame: The lungs of obese patients are squeezed by the abdomen pressing upward on the diaphragm.

Nature, November 5
A new astronomy study has solved a mystery that began brewing in 1680, when Britain’s first Astronomer Royal spotted a supernova in the constellation Cassiopeia. Supernova typically collapse into a super-dense object like a black hole or a neutron star, but for decades astronomers have looked for such an object at the center of the supernova remnant, to no avail. Now, a new examination suggests that there is indeed a baby neutron star there, but it escaped detection because it’s swaddled in an unusual atmosphere of carbon gas. Further studies of the 330-year-old star will give researchers insight into how such stars mature. Another study brings us from the macro to the micro, with an investigation into the evolution of bacteria. Researchers forced bacteria to evolve in constantly changing conditions, so that natural selection couldn’t produce microbes that were ideally suited to a single environment. Instead, researchers proved that the bacteria hedged their bets by evolving into a strain that could form several different shapes from the same genetic material. The will to survive: It’s an amazing thing.

Science, November 6
The biggest study from Science reveals a very promising treatment for the fatal, inherited brain disease that was made famous by the movie Lorenzo’s Oil. Adrenoleukodystrophy (ALD) is caused by a faulty gene that leads to the destruction of nerve fibers’ insulating sheaths; without that insulation, electrical signals can’t be transmitted. The progressive disease is usually diagnosed in young boys, who typically die before adulthood. In the new experimental treatment, researchers used a deactivated HIV virus to ferry a working gene into the stem cells found in the patients’ bone marrows. Since the virus integrates itself permanently into the DNA of the cells it enters, researchers hope the patients will keep the working genes for the rest of their lives. More than two years after the treatment, the patients show no sign of further deterioration, and are able to live relatively normal lives. While the boys will continue to be monitored for side effects, the study brings fresh hope not just to ALD sufferers, but also to those who believe that gene therapy holds tremendous medical promise, despite earlier setbacks.

Current Biology, November 3
When Charles Darwin and the crew of the HMS Beagle arrived at the remote Falkland Islands, 300 miles from the tip of Argentina, they wondered how the islands came to be populated with the strange Falkland wolves. The small wolves were the only mammals present on the islands, and one theory of their origin posited that they were descended from dogs brought over by Native Americans. Now a new genetic study of four museum specimens (sadly, the wolves have since gone extinct) has proven that theory wrong. The study showed that the wolves shared a common ancestor at least 70,000 years ago, which suggests that the wolves arrived on the islands long before the first humans made it to the new world.

A supernova that was observed in 1680 by Britain’s first Astronomer Royal, John Flamsteed, has been revealed to have produced a strange little neutron star that will give astronomers insight into how such stars are born and mature. The remains of the supernova, known as Cassiopeia A, have been something of a mystery to astronomers. Supernovae usually leave behind an extremely dense object such as a black hole or neutron star. But for decades no such object was seen at the centre of Cassiopeia A [Nature News]. Now new observations suggest that the 330-year-old neutron star escaped detection because of its odd atmosphere.

Instead of resembling more mature neutron stars, which are surrounded by hydrogen, this baby star is blanketed in carbon gas – a discovery that could provide important new insights into the evolution of neutron stars [Physics World]. The new study, published in Nature, suggests that the star is still extremely hot in the aftermath of the supernova–about 2 billion degrees Fahrenheit. This overheated condition caused a nuclear fusion reaction on the star’s surface that converts all the hydrogen and helium into carbon gas, researchers say. As time goes on, and as the star cools, the researchers think the surface fusion reaction will stop and the star will develop a more traditional hydrogen atmosphere.

Related Content:
80beats: Detoured Light From Tycho’s Supernova Finally Makes it to Earth
80beats: Mysterious Stellar Blast in the 1840s Was a “Supernova Imposter”
DISCOVER: Sliced: Inside a Supernova
DISCOVER: One Spectacular Stellar Death

Image: NASA / CXC / Southampton / W. Ho / M. Weiss