03/04/2010
04:22 PM
Shields Up: Magnetized Rocks Push Back Origin of Earth’s Magnetic Field
Earth’s robust magnetic field protects the planet and its inhabitants from the full brunt of the solar wind, a torrent of charged particles that on less shielded planets such as Venus and Mars has over the ages stripped away water reserves and degraded their upper atmospheres. Unraveling the timeline for the emergence of that magnetic field and the mechanism that generates it–a dynamo of convective fluid in Earth’s outer core–can help constrain the early history of the planet, including the interplay of geologic, atmospheric and astronomical processes that rendered the world habitable. [More]
03/04/2010
03:30 PM
A Theory Set in Stone: An Asteroid Killed the Dinosaurs, After All
Although any T. Rex –enthralled kid will tell you that a gigantic asteroid wiped the dinosaurs off the planet, scientists have always regarded this impact theory as a hypothesis subject to revision based on further evidence gathered from around the globe. Other possible causes, such as volcanism and smaller, multiple asteroid strikes, never actually went away, and over the years researchers raised important points that did not fully jibe with a history-changing celestial impact near the Yucatan peninsula one awful day some 65.5 million years ago. [More]
03/04/2010
09:45 AM
Impact Factor: Can a Scientific Retraction Change Public Opinion?
When science revises its stance, the field itself follows established protocol to adapt, but public opinion can be slow to catch up. Rather than wiping the slate clean, last month’s retraction of a key paper proposing a link between childhood vaccines and autism seem only to have widened the societal divide on the issue. And the rising rate of retractions–roughly ninefold between 1990 and 2008–suggest that there could be more cases in which public opinion carries on long after science has reversed course. [More]
03/03/2010
09:55 AM
More evidence piles up that the moon harbors lots of ice
Chandrayaan 1, the first moon mission launched by the Indian Space Research Organization, did not last long– in August 2009, controllers lost contact with the probe 10 months into its two-year mission . But the data Chandrayaan gathered while orbiting the moon continues to inform lunar science, especially in the realm of identifying potential stores of water on the moon. [More]
03/02/2010
04:30 PM
How the earthquake in Chile could change Earth’s axis
The magnitude 8.8 earthquake that jolted Chile on Saturday was felt as far away as São Paulo. But NASA scientists are proposing that its repercussions are truly global in a geophysical sense: it likely shifted Earth’s axis by about eight centimeters. [More]
03/01/2010
01:30 PM
Mars’s Environment Shown to Be Hostile, but Not Untenable for Earthly Microbes
Microbes similar to those on Earth would have a tough time surviving the harsh environment of Mars, but it is not inconceivable that they could persist there given a little protection, according to a new study. The finding supports similar, previous work and lends credence to the theory that if microbial life ever arose on Mars, it could exist below the planet’s surface to this day. [More]
02/27/2010
06:45 AM
Algae, Art and Attitudes: A Roundtable about the AAAS Conference
Scientific American staffers Mark Fischetti and Robin Lloyd talk with podcast host Steve Mirsky [ left ] about sessions they attended–including those about algae for energy, dissecting the astronomy in art, and attitudes about climate change–at the recent meeting of the American Association for the Advancement of Science. [More]
02/25/2010
01:30 PM
Wild Ride: Comet Sample May Help Constrain the Early Evolution of the Solar System
The comets that come streaking through Earth’s neighborhood are visitors from frigid, distant regions in the outer solar system. The icy, dusty bodies formed there billions of years ago, far from the heat and radiation of the sun, so it was long thought that they comprised unsullied scraps left over from the solar system’s formation. But a new analysis of a particle from Comet Wild 2 indicates that the mote formed close to the sun and then migrated outward to be captured by the comet millions of years after the solar system began taking shape. Along with similar investigations of other samples , the new finding reinforces the theory that comets originating in the Kuiper belt, the distant field of icy debris where Pluto orbits and beyond, contain fragments that formed somewhat later than the solar system’s primordial grains, and much closer to the sun. [More]
02/22/2010
12:17 PM
Space shuttle Endeavour glides to Earth, several tons lighter
The STS-130 mission came to an uneventful close Sunday night in Florida when space shuttle Endeavour landed safely at Kennedy Space Center. The orbiter touched down at 10:20 P.M. after a two-week trip to the International Space Station (ISS). [More]
02/22/2010
06:00 AM
The Moon That Would Be a Planet (preview)
If we had not known the images were coming back from Titan, we might have guessed they were new pictures of Mars or Earth. Some people in the control room saw the California coast, some saw the French Riviera, and one person even said that Saturn’s biggest moon looked like his backyard in Tucson. For three weeks, the Huygens probe had coasted, dormant, after detaching from the Cassini spacecraft and being sent on its way to Titan. Those of us watching anxiously felt a deep personal connection with the probe. Not only had we worked on the mission for a large part of our careers, but we had developed its systems and instrumentation by putting our minds in its place, to think through how it would function on an alien and largely unknown world. We imagined Titan might be like the comparably large moons of the outer solar system, such as Jupiter’s cratered Callisto or grooved Ganymede.
And so on the morning of January 14, 2005, at the European Space Operations Center in Darmstadt, Germany, the pictures caused jubilation and puzzlement in equal measure. None of us expected the landscape to look so Earth-like. As Huygens parachuted down, its aerial pictures showed branching river channels cut by rain-fed streams. It landed on the damp, pebble-covered site of a recent flash flood. What was alien about Titan was its eerie familiarity.
[More]
02/19/2010
12:25 PM
Kepler Spacecraft May Be Able to Spot Elusive Oort Cloud Objects
The Kepler spacecraft’s mission is a straightforward one: keep a vigilant watch on a large patch of stars to see if they dim, even just slightly, on a regular basis. The idea is that a planet passing in front of its host star will reveal itself to Kepler by blotting out a fraction of the star’s light. This transit method has already borne fruit: NASA’s Kepler spotted five planets in the first few weeks after its 2009 launch, and dozens more have been detected over the past decade from the ground and from other spacecraft. But Kepler’s strength lies in its unique sensitivity to Earth-like planets–small, terrestrial worlds in temperate orbits that allow liquid water to persist. [More]
02/17/2010
10:03 PM
Murchison Meteorite’s Chemical Bonanza
The famous Murchison meteorite smashed into the Australian ground in 1969. Researchers then discovered that the space rock contained many organic chemicals, including amino acids–the building blocks of proteins. But a new study says that by focusing on the organic molecules by which life on earth might have been jumpstarted, those scientists missed possibly millions of other cosmic compounds.
Using high-resolution structural spectroscopy, a European research team [led by Philippe Schmitt-Kopplin of the Institute for Ecological Chemistry in Munich, Germany] has probed the errant rock further and found more than 14,000 basic combinations of molecules. They estimate that those compounds indicate that millions of different chemicals are present in the meteorite. And that suggests an extraterrestrial diversity of molecules far greater than the chemical makeup of Earth. The report is in the Proceedings of the National Academy of Sciences .
[More]
02/17/2010
02:30 PM
Science, Stimulated: 7 Stimulus-Funded Research Projects [Slide Show]
Can you put a price on science? The American Recovery and Reinvestment Act (ARRA), signed into law on February 17, 2009–a year ago today–sent some $31 billion to scientific pursuits. [More]
02/17/2010
01:25 PM
Blast Off: Unsettled Mechanism of Supernova Detonation Gets a New Twist
When stellar cataclysms known as type Ia supernovae flare up far across the universe, their brightness and consistency allow astronomers to use them as so-called standard candles to measure cosmological distances. Just over a decade ago, two teams used the supernovae to show that the universe is accelerating in its expansion due to the influence of dark energy, a shocking discovery that thrust type Ia supernovae into the astrophysical limelight. But how exactly did these cosmic mileposts come to be? [More]
02/17/2010
01:00 PM
Is the Recovery Act Stimulating Science and the Economy?
So far, $9.3 million for researchers building robotic bees, $1.3 million to hunt for viruses that infect single-celled organisms, and $845,000 to study past climate change in Russia has been doled out. The National Science Foundation (NSF) has been able to fund thousands of new research projects with money from the American Recovery and Reinvestment Act of 2009 (ARRA), aka the economic stimulus package , which was passed a year ago today. [More]
02/15/2010
02:30 PM
Meteorite That Fell in 1969 Still Revealing Secrets of the Early Solar System
Fragments of a chemically primitive meteorite that landed near Murchison, Australia, in 1969 have long been known to harbor a variety of interesting compounds, including dozens of amino acids. But as analytic techniques become more sophisticated, the Murchison meteorite continues to reveal even more diversity and complexity in the early solar system, and new work by a team of European researchers is no exception. [More]
02/15/2010
11:18 AM
Space shuttle astronauts install two large space station components
Astronauts on the STS-130 mission have installed the two major pieces of European-built hardware they delivered to the International Space Station on space shuttle Endeavour, edging the station ever closer to its long-awaited completion. The shuttle lifted off February 8 from Kennedy Space Center in Florida. [More]
02/15/2010
06:00 AM
Dark Side of Black Holes: Dark Matter Could Explain the Early Universe’s Giant Black Holes
Black holes one billion times the sun’s mass or more lie at the heart of many galaxies, driving their spin and development. Common today, some 14 billion years after the big bang, such supermassive black holes were rare in the early universe–or at least they were supposed to be. Evidence of supermassive black holes existing when the universe was less than one billion years old has stumped scientists, because current theories of stellar evolution suggest that such giants should take much longer to grow. Now it seems this enigma could be solved by a mystery substance–dark matter.
The puzzle of early supermassive holes took shape in 2003, when the Sloan Digital Sky Survey detected roughly half a dozen of them. According to conventional thinking, the first regular stars were born when the universe was about 200 million years old, but given the state of the universe at the time, they could have formed black holes at most only about 100 times the sun’s mass. It would simply take too long to merge and make the billion-year-old, billion-solar-mass monsters seen by the Sloan survey.
[More]
02/12/2010
07:00 AM
100 Years Ago: The Flooding of Paris
FEBRUARY 1960 METEOR DUST – “The recent extension of geophysical investigations into nearby space has given emphasis to the fact that life on earth is shielded by the earth’s atmosphere. Death from ‘meteoritic stroke’ might be a not-uncommon coroner’s verdict if the protective canopy of the atmosphere were not spread above our heads. During the past 13 years I have been engaged in efforts to secure direct measurement of the meteoritic fallout. My samples of meteoritic dust and cosmic spherules have come from the tops of high mountains remote from industrial civilization, and from the bottom of the ocean. The data now show that meteoritic material comes down to earth in much larger quantity (about five million tons per year) than earlier estimates. Moreover, it appears that the rate of fall has varied during the past 10 or 15 million years. –Hans Pettersson”
[More]
02/11/2010
10:37 AM
NASA’s Solar Dynamics Observatory launches successfully
A NASA satellite that promises to deliver an unprecedented volume of data about the workings of the sun launched successfully atop an Atlas 5 rocket Thursday. The Solar Dynamics Observatory , or SDO, lifted off from Cape Canaveral Air Force Station in Florida at 10:23 A.M. (Eastern Standard Time) after a one-day delay due to high winds at the launch site. The satellite separated from the upper rocket stage and deployed its solar arrays about two hours later. [More]