Super-massive Black Holes Grow Surprisingly Fast

This image depicts three hot blobs of matter orbiting a black hole. 

If placed in our Solar System, this black hole would appear like a dark abyss spread out nearly as wide as Mercury's orbit.

The three blobs (each as large as the Sun) would be as far out as Jupiter. 

They orbit the black hole in a lightning-quick 20,000 miles per second, over a tenth of the speed of light.

CREDIT: NASA/Dana Berry, SkyWorks Digital

Giant black holes are famous for their appetites, but these matter-munching monsters are even greedier than scientists once thought, a new study suggests.

The super-massive black holes that lurk at the center of most (if not all) galaxies are growing surprisingly quickly, the study found.

The result implies that these cosmic behemoths are sustained primarily by frequent small meals rather than rare and dramatic galactic mergers, as was previously believed.

Super-massive black holes are almost incomprehensibly huge, with some containing 10 billion or more times the mass of our own sun.

The research team used computer simulations to investigate how such black holes grow, especially in spiral galaxies like the Earth's Milky Way.

The astronomers found that, contrary to prevailing theory, central black holes can grow quite rapidly in quiet, merger-free spirals simply by sucking up galactic gas and other matter.

"These simulations show that it is no longer possible to argue that black holes in spiral galaxies do not grow efficiently," study lead author Victor Debattista, of the University of Central Lancashire in England, said in a statement.

"Our simulations will allow us to refine our understanding of how black holes grew in different types of galaxies."

Fungi Can Quickly Mutate to Produce an Infectious Ability

Fungi have significant potential for "horizontal" gene transfer, a new study has shown, similar to the mechanisms that allow bacteria to evolve so quickly, become resistant to antibiotics and cause other serious problems.

This discovery, to be published March 18 in the journal Nature, suggests that fungi have the capacity to rapidly change the make-up of their genomes and become infectious to plants and possibly animals, including humans.

They are not nearly as confined to the more gradual processes of conventional evolution as had been believed, scientists say. And this raises issues not only for crop agriculture but also human health, because fungi are much closer on the "evolutionary tree" to humans than bacteria, and consequently fungal diseases are much more difficult to treat.

The genetic mechanisms fungi use to do this are different than those often used by bacteria, but the end result can be fairly similar. The evolution of virulence in fungal strains that was once believed to be slow has now been shown to occur quickly, and may force a renewed perspective on how fungi can behave, change and transfer infectious abilities.

"Prior to this we've believed that fungi were generally confined to vertical gene transfer or conventional inheritance, a slower type of genetic change based on the interplay of DNA mutation, recombination and the effects of selection," said Michael Freitag, an assistant professor of biochemistry and biophysics at Oregon State University.

"But in this study we found fungi able to transfer an infectious capability to a different strain in a single generation," he said. "We've probably underestimated this phenomenon, and it indicates that fungal strains may become pathogenic faster than we used to think possible."

NASA study: California Lakes warming quicker than expected

New U.S. scientific findings suggest that climate change may be affecting aquatic environments faster and sooner than the atmosphere.

Researchers from NASA's Jet Propulsion Laboratory in Pasadena, Calif., came to conclusions after noticing that Lake Tahoe, Clear Lake and four other big lakes in Northern California and Nevada are heating up faster than the surrounding atmosphere, The Sacramento Bee reported Sunday.

The newspaper said the researchers tapped satellite sensor temperature data compiled over 18 years in what is believed to be the first time that long-range lake surface temperatures have been dissected. What the data reportedly showed is that the lakes' water temperature rose two times faster, on average, than the regional air temperatures.

"It was a big surprise to see that," Philipp Schneider, the study's lead author and a post-doctoral research scientist at the NASA lab, told the Bee. "If it turns out they're actually changing faster than the air temperature, then there's a whole new phenomenon going on here.

The lake ecosystems are going to be very much affected, especially because the trend we observed seems to be quite rapid."