The site for humanity’s first-ever attempt to land a spacecraft on a comet has been chosen.
Philae, the tiny lander being carried by the Rosetta probe, will attempt on Nov. 12 to anchor itself to an area on the smaller of comet 67P/Churyumov-Gerasimenko. The location is known as Site J.
“Now that we know where we are definitely aiming for, we are an important step closer to carrying out this exciting – but high-risk – operation,” Fred Jansen, ESA’s Rosetta mission manager, said in a statement released Oct. 15.
Rosetta itself is now about 10 kilometers away from the comet. It will launch Philae, if all goes according to plan, when it is about 22.5 kilometers from the comet’s center.
Philae’s journey to the comet will take about seven hours. Communication confirming a successful landing on the comet can be expected to arrive at Earth during the early- to mid-morning hours in North America.
Rosetta’s mission team will confirm that the probe is on the correct trajectory and that Philae is ready to receive computer commands before the final authorization to send the tiny lander to comet 67P/Churyumov-Gerasimenko is transmitted.
Philae will not be idle during its movement from Rosetta to the comet. It will study the comet’s dust, gas, and plasma while moving slowly through the short distance in space.
Mission planners are not sure how much time Philae will have, once anchored on the comet, to study its nucleus and other features. The lander has a solar-powered battery, which will provide more or less energy depending on the degree to which the solar power receiver is covered by dust from the comet.
ESA said in a press release that Philae is not expected to be able to conduct scientific observations of the comet past March 2015.
Residents of the western states and New England may face a relatively mild winter this year, according to a new prediction by the National Oceanic & Atmospheric Administration.
The agency’s U.S. Winter Outlook, released today, indicates that the coastal and inter-mountain west will likely experience average winter temperatures that are above normal.
“The temperature outlook for November-December-January (NDJ) 2014-15 indicates elevated probabilities of above-normal mean temperatures for Alaska, the far west, along the northern tier of the continental U.S. eastward to include parts of the northeast and mid-Atlantic,” the document said. “Below-normal mean temperatures are most likely over areas from eastern New Mexico to the western Gulf coast states.”
Warmer does not mean drier, though. NOAA said that higher-than-average precipitation can be expected in southern California, the desert southwest, the southern Great Plains, across the deep south, and up the Atlantic coast to southern New England.
That may be good news for water-starved California, though the drought there is not likely to end.
“While we’re predicting at least a two-in-three chance that winter precipitation will be near or above normal throughout the state, with such widespread, extreme deficits, recovery will be slow,” Mike Halpert, acting director of NOAA’s Climate Prediction Center, said.
An El Nino event could well happen this winter, but if it does, it is expected to be a weak one. NOAA estimated on Oct. 9 that there is a 67 percent chance of an El Nino event in the coming months.
NASA has chosen three possible small objects in the region of space beyond Neptune that could serve as destinations for the New Horizons probe after it visits the dwarf planet Pluto.
The agency used the Hubble Space Telescope to select three Kuiper Belt objects, each only a tiny fraction the size of Pluto and ranging in size from 25-55 kilometers. All three KBOs are about one billion miles beyond Pluto.
New Horizons will visit the Pluto system next summer. After doing so, the spacecraft will continue to travel deeper into the farthest reaches of the solar system, where objects have remained frozen since the formation of the planets and dwarf planets billions of years ago.
New Horizons was launched on Jan. 19, 2006. By the time it reaches the three potential KBOs found by the Hubble Space Telescope, it will have traveled about four billion miles from the sun.
Global Carbon Project report: worldwide carbon dioxide emissions up 2.3% in 2013, 61 percent since 1990
A new report indicates that carbon dioxide emissions to the atmosphere continued to rise in 2013, reaching a record level of concentration.
Discharges of the most common greenhouse gas grew by 2.3 percent worldwide last year, with China and India exhibiting the largest year-over-year increase. The report concluded that planetary carbon dioxide emissions have now risen 61 percent since 1990, the base year for the Kyoto Protocol to the United Nations Framework Convention on Climate Change.
Given the trend, emissions will likely reach a record 40 billion metric tons this year.
“We are nowhere near the commitments necessary to stay below two degrees C[elsius] of climate change, a level that will be already challenging to manage for most countries around the world, even for rich nations,” Dr. Corinne Le Quéré, director of the Tyndall Center for Climate Change at the University of East Anglia in Great Britain, said. “Politicians meeting in New York need to think very carefully about their diminishing choices exposed by climate science.”
China and India, which have maintained a national commitment to reliance on coal as a primary source of electricity, saw carbon dioxide emission increases of 4.2 percent and 5.1 percent last year, while emissions of the heat-trapping gas rose by 2.9 percent in the United States after falling for several years.
Emissions in the European Union declined in 2013 by 1.8 percent.
The report, which was released by The Global Carbon Project, concludes that total future carbon dioxide emissions will need to be limited to 1,200 metric tons if an increase in average worldwide temperatures is to be limited to two degrees Celsius above the pre-industrial revolution era level, as recommended by the Intergovernmental Panel on Climate Change.
Charles Darwin gained his fame as the man who, along with Alfred Russel Wallace, hypothesized that Earth’s biodiversity is the result of evolution by natural selection. In the century and a half since Darwin’s pioneering publication of “The Origin of Species,” scientists have found that his ideas about how and why species change were essentially correct. Evolution by natural selection is as much a part of the fabric of science and just as important an explanation of how nature works as Copernicus’ contribution that Earth revolves around the sun and Newton’s insights on gravity.
Today is the 183rd anniversary of the date on which Darwin first saw the H.M.S. Beagle, the ship that took him on the journey that changed biology.
You can watch a wonderful short film about Darwin’s life and work here.
Paleontologists have discovered the first dinosaur known to have lived much of its life in the water.
The find of a variety of bones from an animal called Spinosaurus aegyptiacus vastly improves scientists’ understanding of the role played by the huge predatory dinosaur in the Cretaceous period ecosystem of modern-day North Africa.
“Today we are resurrecting a giant from deep time,” Dr. Nizar Ibrahim, a paleontologist at the University of Chicago and the lead author of a paper published in the Sept. 11, 2014 edition of Science Express, said. “The animal we are resurrecting is so bizarre, it is going to force dinosaur experts to re-think many things they thought they knew about dinosaurs.”
Spinosaurus aegyptiacus was first identified in 1915 by the German anatomist, geologist, and paleontologist Ernst Stromer von Reichenbach. He identified an animal unlike any other theropod dinosaur then known.
“The size of the bones suggested to Stromer that the animal rivaled Tyrannosaurus rex in size, but it clearly differed from the North American predator in many ways,” Ibrahim said. “The skull was more elongate and the tall spines formed a large sail on the back of Spinosaurus.”
Stromer stored the holotype in the Paläontologische Staassammlung in Munich, Germany. Unfortunately, an April 1944 bombing raid by Britain’s Royal Air Force destroyed Stromer’s fossils.
The German scientist’s drawings survived.
During the ensuing decades paleontologists used those drawings, along with a few fragmentary finds of additional Spinosaurus remains, to develop a rudimentary idea of the animal’s appearance. They conceived Spinosaurus as a land animal, the largest predatory dinosaur known.
The findings published Thursday cast no doubt on Spinosaurus’ size, but revealed a number of body features that are unique among dinosaurs and that indicate the animal likely searched for food in the rivers that were ubiquitous in the region now known as North Africa during the Mesozoic era. Those features include a nasal opening high on the skull, long teeth shaped like cones, and wide and flat feet that may have been webbed.
“Other more subtle, but equally startling, finds were made,” Dr. Paul C. Sereno, a vertebrate paleontologist at the University of Chicago and a principal author of the paper published online in Science Express, said. “The thigh bone was robust and shorter than the shin bone, a very unusual proportion for a large dinosaur. And all of the long bones were solid without a marrow cavity, something never before observed in a predatory dinosaur.”
The highly dense bones are similar to those found in modern-day penguins.
“This adaptation is useful to facilitate buoyancy control,” Dr. Simone Maganuco, a vertebrate paleontologist at Italy’s Museo di Storia Naturale di Milano and another co-author on the paper, said.
Spinosaurus’ skull also exhibited small pits at the end of its snout called foramina. The authors of the study used computer tomography to examine them and found that they served to regulate pressure.
The foramina closely resemble those found in modern-day crocodiles and that have been confirmed in at least one species of extinct marine reptile.
“The pressure receptors of crocs play a key role in capturing prey based on water movements, and permit to hunt even in darkness or in muddy water, without relying on sight,” Dr. Cristiano Dal Sasso, curator of vertebrate paleontology at the Museo di Storia Naturale di Milano and a co-author of the paper, said.
She explained that their presence in Spinosaurus’ skull is an indication that the dinosaur may have used its long snout to find prey, with no need to see it.
Sereno noted that the new Spinosaurus specimen also exhibited a tail with characteristics similar to those found in some modern fish.
“These facts strongly supported a semi-aquatic existence for Spinosaurus, the first water-adapted non-avian dinosaur on record,” Sereno said.
The spines on the animal’s back and the sail-like structure they formed were a means of communication.
“Even the big sail on the back of Spinosaurus may, in part, be an adaptation to a life often spent in water,” Ibrahim said. “It would have been a great display structure, and would remain visible even when the animal is partially submerged.”
Spinosaurus would not have been an agile creature, at least on land, and would have had most of its weight at its front.
“It’s quite short, but surprisingly, solid,” Dr. Thomas Holtz, a vertebrate paleontologist at the University of Maryland who was not a part of the research team, said. “These adaptations don’t make sense for a terrestrial strider but they are very reasonable for an animal that’s spending its time in the water and shuffling on land occasionally.”
“How it walked on land and swam are of much interest, its center of gravity far forward compared to other land-based predators,” Sereno said. “Foot-propelled paddling with webbed feet seems likely, to explain the anatomical findings at the rear of the beast. At the other end, its neck and trunk are particularly long, which give the skeletal model and mount its record-shattering 50-foot length. The bones at the base of the neck are also adapted for bending downward, perhaps for fishing while swimming.”
Nevertheless, Sereno explained, the animal would have been a formidable opponent of any land predator of its time, including the nearly T-rex-sized Carcharodontasaurus.
“Spinosaurus had a large head,” Sereno said. “It was nothing to sneer at. You would not want to encounter this animal.”
Despite its odd adaptations, Spinosaurus probably reproduced in a conventional way for its order: Like all other dinosaurs, it was almost certainly oviparous.
“As far as we know, no member of the dinosaur group was ever able to make that switch away from laying eggs,” Holtz explained. “It seems, until we have evidence to the contrary, that Spinosaurus probably did shuffle up onto land to lay its eggs there.”
Most of the fossils that serve as the basis for the new paper are of one individual, which also help scientists to understand the proportions of Spinosaurus aegyptiacus. The recently discovered remains were found in the Kem-Kem fossil beds of southeastern Morocco.
On Friday the National Geographic Society will premiere an exhibition in Washington, D.C. focused on Spinosaurus aegyptiacus.