Science News: The black holes at the center of most galaxies usually make up only one-tenth of a percent of the galaxy’s mass. But a black hole of roughly 17 billion solar masses accounts for 14% of galaxy NGC 1277‘s mass. That finding led Erin Bonning of Quest University Canada in Squamish, British Columbia, and Gregory Shields of the University of Texas at Austin to examine the galaxy and its neighbors in the Perseus cluster. Their study revealed that a giant galaxy in Perseus, NGC 1275, is more likely to be able to support a black hole the size of NGC 1277′s. Bonning and Shields created computer simulations that they say show that NGC 1275 could have formed from the collision of two smaller galaxies, resulting in the ejection of one of the two black holes, which then was grabbed by NGC 1277. If that is the case, then it would be the first evidence of a nomadic supermassive black hole. However, because the theory requires the occurrence of several rare events, even Shields says that he isn’t wholly convinced. Bonning and Shields hope to continue performing computer simulations to better determine the likelihood of their proposal.
Daily Archives: February 25, 2013
Ancient subcontinent may lie beneath Indian Ocean
BBC: More than 750 million years ago, most or all of Earth’s land consisted of a single supercontinent now called Rodinia. As Rodinia gradually fragmented to form the separate continents that exist today, some bits may have broken off and sunk over time. From studying grains of sand on Mauritius, researchers found that while the sand grains dated back to a volcanic eruption 9 million years ago, there were also zircons that dated back as far as 600 million years ago. Trond Torsvik from the University of Oslo in Norway and colleagues explain in a paper published in Nature Geoscience that they believe the zircons were dragged up to the surface of Mauritius from one of those fragments of ancient continent during a volcanic eruption. Torsvik says further research in the form of seismic imaging or drilling is needed to find any still-existing early continental fragments.
Sensor-equipped seals help with study of Antarctic water flow
Nature: To better study Antarctic bottom water (AABW)—cold, salty water that forms near the shores of Antarctica—researchers recruited elephant seals that they outfitted with sensors. “The seals went to an area of the coastline that no ship was ever going to get to, particularly in the middle of winter,” said Guy Williams of the Antarctic Climate and Ecosystem Cooperative Research Centre in Hobart, Australia, and a coauthor of the study published yesterday in Nature Geoscience. Three sources of AABW had previously been identified. Thanks to the seals, a fourth was found: in the Cape Darnley polynya. A polynya is an area of open water surrounded by sea ice; winds and ocean currents keep the water from freezing, and it has a high saline content due to the expulsion of salt by sea-ice formation. Because the water is denser than typical ocean water, it sinks and then starts flowing north, creating deep-ocean currents of cold water. According to the researchers, the formation of AABW is a key process in global ocean circulation and can have important effects on Earth’s climate.
White House issues new public-access policy for federally funded research
Science: On 22 February, the White House Office of Science and Technology Policy (OSTP) released a directive to all federal agencies that spend more than $100 million on scientific research. The new policy requires the results of all federally funded research be made freely available online within 12 months of the papers’ original publications. The requirement closely resembles the National Institutes of Health’s 2008 decision that all agency research be posted in PubMed Central within 12 months of initial publication. However, the OSTP’s policy does not specify where the agencies will publish the papers or how they will be indexed. Each agency has six months to draft a plan that will determine those details. For the last several years, there has been extensive debate, including a petition to the White House, about whether to make results of research freely available to the public. The new policy can be seen as a compromise solution between the position of publishers who make money from the journals where the papers are originally published and the open-access advocates who desire immediate and free access to results.