Back to the main page

Archives Of Science Blog

Subscribe To Science Blog RSS Feed  RSS content feed What is RSS feed?

August 24, 2006, 9:11 PM CT

Pluto is not a planet

Pluto is not a planet Pluto
The "United Nations" of astronomers has announced a new definition of what a planet is, slightly revising the description preferred by an international panel including an MIT professor that was tasked with the challenge.

Members of the International Astronomical Union (IAU) voted on August 24 to define a planet as an object that is in orbit around the sun, is large enough for its own gravity to pull it into a nearly spherical shape, and has cleared the neighborhood around its orbit -- in other words, it has no other large bodies crossing its path.

The third condition was added to the draft definition of a planet submitted to the IAU about a week ago by MIT's Richard Binzel and his colleagues. Binzel, a professor of planetary science in the Department of Earth, Atmospheric and Planetary Sciences, took responsibility for presenting the final version of the resolution at the time of the final vote.

This means that while Pluto will still be considered a planet, it will technically be a dwarf planet because it is smaller than Mercury. It will be joined in that category by Ceres and 2003 UB313 (a temporary name for an object discovered only three years ago). More "dwarf planets" are expected to be announced by the IAU in the coming months and years.

As a result of the new definition, our solar system now contains eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, plus the three dwarf planets led by Pluto.........

Posted by: Edwin      Permalink         Source

August 23, 2006, 9:39 PM CT

New Water Filtration Technique

New Water Filtration Technique Microcystis (left), a type of blue-green algae
A water filtration technique that normally cleans up agricultural chemicals is also effective at removing a toxin secreted by algae found in lakes and rivers, an Ohio State University study has observed.

Engineers here determined that the technique greatly outperformed other methods by removing at least 95 percent of a toxin secreted by Microcystis, a blue-green algae.

Some water filtration plants around the country already use the technique, which couples activated carbon with membrane filters, said Hal Walker, associate professor of civil and environmental engineering and geodetic science at Ohio State.

Microcystis is native to freshwater lakes and rivers around the country, and secretes toxins that can cause liver damage in animals including humans. Worsening environmental pollution in Lake Erie during the last decade has caused algal blooms, the most recent of which began this August.

Some 13 million people rely on Lake Erie for their water supply, so Microcystis is a growing concern there, Walker said. But dangerous algal blooms have occurred across the country this summer, from Massachusetts to California.

And while a number of water filtration plants are beginning to use high-tech ultrafiltration membranes with very fine holes to filter water, Microcystin toxins are small enough to slip through. For example, the toxin used in this study was microcystin-lr, a tiny molecule made up of only seven amino acids.........

Posted by: John      Permalink         Source

August 23, 2006, 9:17 PM CT

Supercomputers To Study Atoms Linked To Black Holes

Supercomputers To Study Atoms Linked To Black Holes
Super-hot atoms in space hold the key to an astronomical mystery, and an Ohio State University astronomer is leading an effort to study those atoms here on Earth.

Anil Pradhan, professor of astronomy, and his team have used supercomputers to perform the most precise energy calculations ever made for these atoms and their properties. As a result, astronomers -- in particular, those hunting black holes -- will have a better idea of what they are looking at when they examine faraway space matter using X-ray telescopes.

The results appear in the recent issue of the Journal of Physics B: Atomic, Molecular and Optical Physics. And while the paper's subject matter is highly technical, it tells a story that weaves together atomic physics, Einstein's theory of relativity, cutting-edge astronomical observations, and some of the world's fastest supercomputers.

Astronomers have spied seas of super-hot atoms in plasma form, circling the centers of very bright galaxies, called active galactic nuclei. The plasma is believed to be a telltale sign of a black hole; the black hole itself is invisible, but any material spiraling into it should be very hot, and shine brightly with X-rays.

Before anyone can prove definitively whether active galaxies contain black holes, astronomers need to measure the energy levels of the excited atoms in the plasma very precisely, and match the measurements with what they know about atomic physics.........

Posted by: Edwin      Permalink         Source

August 23, 2006, 6:08 PM CT

Pearl The Robot

Pearl The Robot
Pearl, the Nursebot, is a personal robotic assistant that could help more elderly adults and people with disabilities live independently. Developed by scientists at Carnegie Mellon University and the University of Pittsburgh, the mobile robot could be used to prompt people with failing memories to take medicine or visit a doctor, to provide remote telepresence for professional careivers or to assist with tasks that would be difficult for people with limited mobility.

Credit: Ken Andreyo, Carnegie Mellon University.........

Posted by: John      Permalink         Source

August 23, 2006, 6:00 PM CT

Seeing the Invisible

Seeing the Invisible
By observing a rare head-on collision of galaxies at 10 million miles per hour, astronomers have made the first direct detection of "dark matter"--the mysterious, invisible stuff that comprises at least one-quarter of the universe.

Researchers have known for 70 years that there is much more mass in galaxies than can be seen. For example, spiral galaxies rotate at speeds that are only possible if the total mass of the galaxy is several times larger than the total of its component stars and dust. The "missing" mass is the dark matter. But dark matter neither emits nor reflects light, and only interacts with ordinary matter through gravity. Consequently, its presence has only been inferred, not observed directly. Moreover, it typically accompanies and envelops ordinary matter, often in the form of a "halo" around galaxies, and is not found by itself.

Marusa Bradac of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford, along with colleagues elsewhere, decided to hunt for dark matter by exploiting one of its few telltale visible effects: gravitational lensing. As Einstein predicted, mass curves space around it, and large masses curve it a lot. So light coming toward Earth from behind a large mass is bent by gravitationally curved space just as light in a telescope is bent by a curved lens. As a result, images of objects behind the mass are stretched. The amount of stretching is proportional to the quantity of mass warping space.........

Posted by: John      Permalink         Source

August 23, 2006, 5:46 PM CT

Handheld Computers Make Light Work

Handheld Computers Make Light Work
MIT students are helping bring science education out of the textbook and into the handheld.

Under the casually watchful eye of Eric Klopfer, director of the MIT Teacher Education Program, a roomful of students recruited under the Undergraduate Research Opportunities Program (UROP) is writing code for three different handheld (PDA) projects. All of them aim at making science, economics and other "dry" topics vividly interesting, interactive and fun, for students, teachers and citizens at large.

"We use cheap hardware with easily downloadable software that pairs with curricula and with related activities," said Klopfer, who is an associate professor in the Department of Urban Studies and Planning. All three projects use commercial, off-the-shelf handhelds, such as the Palm Pilot and Dell Axim, which are easy to use and more affordable for strapped school systems than laptop or desktop computers.

Ben Schmeckpeper, a 2005 MIT grad who is now working toward his master's in electrical engineering and computer science, is among the students working on the Augmented Reality project that utilizes GPS (global positioning system) capability. In addition to coding, his summer has included conducting three workshops for teachers -- two in Wisconsin and one at Harvard -- to introduce educators to the games the team has developed. The MIT group, in collaboration with colleagues at Harvard University and the University of Wisconsin, demoed two games, Hip-Hop Tycoon (an economics simulation game) and Sick at South Beach, aimed at seventh- and eighth-grade environmental science students, for a group of about 15 teachers in Milwaukee, which fortuitously is also Schmeckpeper's hometown.........

Posted by: John      Permalink         Source

August 22, 2006, 7:58 PM CT

carbon fiber to make tiny video displays

carbon fiber to make tiny video displays
Engineers who develop microelectromechanical systems (MEMS) like to make their tiny machines out of silicon because it is cheap, plentiful and can be worked on with the tools already developed for making microelectronic circuits. There is just one problem: Silicon breaks too easily.

For decades, scientists have been trying to make video displays using tiny mirrors mounted on silicon oscillators. But silicon won't oscillate fast enough and bend far enough.

"You need something incredibly stiff to oscillate at a resonant frequency of 60,000 times a second (the line-scanning rate of most video displays), but it also needs to bend a lot for adequate image size," explained Shahyaan Desai, a Cornell graduate student who has been working for more than three years to create a practical MEMS video display device.

So Desai and his Cornell colleagues have turned to carbon fiber, the same material used to reinforce auto and aircraft body parts, bicycle frames and fishing rods.

"Carbon fiber is twice as stiff as silicon but 10 times more flexible," said Desai.

He is first author of a paper with Michael Thompson, Cornell associate professor of materials science and engineering, and Anil Netravali, Cornell professor of fiber science, on using carbon fibers in MEMS, reported in the recent issue of the Journal of Micromechanics and Microengineering.........

Posted by: John      Permalink         Source

August 22, 2006, 6:59 PM CT

Close-up on Cuvier crater ridge

Close-up on Cuvier crater ridge
This high-resolution image, taken by the Advanced Moon Imaging Experiment (AMIE) on board ESA's SMART-1 spacecraft, shows the young crater 'Cuvier C' on the Moon.

Click for high resolution image

AMIE obtained this sequence on 18 March 2006 from a distance of 591 kilometres from the surface, with a ground resolution of 53 metres per pixel. The imaged area is centred at a latitude of 50.1º South and a longitude of 11.2º East, with a field of view of 27 km. The North is on the right of the image.

"This image shows the resolving power of the SMART-1 camera to measure the morphology of rims and craters in order to diagnose impact processes", says SMART-1 Project scientist Bernard Foing, "or to establish the statistics of small craters for lunar chronology studies".

Cuvier C, a crater about 10 kilometres across, is visible in the lower right part of the image. Cuvier C is located at the edge of the larger old crater Cuvier, a crater 77 kilometres in diameter. The upper left quadrant of the image contains the smooth floor of Cuvier, only one fourth of which is visible in this image.

Crater Cuvier was named after the creator of the comparative anatomy, Georges Cuvier, a 19th century French naturalist (1769 - 1832).........

Posted by: Edwin      Permalink         Source

August 22, 2006, 5:07 AM CT

New Methods for Screening Nanoparticles

New Methods for Screening Nanoparticles
Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have developed a screening method to examine how newly made nanoparticles - particles with dimensions on the order of billionths of a meter - interact with human cells following exposure for various times and doses. This has led to the visualization of how human cells interact with some specific types of carbon nanoparticles. The method is described in a review article on carbon nanoparticle toxicity in a special section of the August 23, 2006, issue of the Journal of Physics: Condensed Matter devoted to developments in nanoscience and nanotechnology, now available online.

Nanoparticles may have different physical, chemical, electrical, and optical properties than occur in bulk samples of the same material, in part due to the increased surface area to volume ratio at the nanoscale. A number of researchers think that understanding these nanoscale properties and finding ways to engineer new nanomaterials will have revolutionary impacts - from more efficient energy generation and data storage to improved methods for diagnosing and treating disease. Brookhaven Lab is currently building a Center for Functional Nanomaterials (CFN) with state-of-the-art facilities for the fabrication and study of nanomaterials, with an emphasis on atomic-level tailoring of nanomaterials and nanoparticles to achieve desired properties and functions.........

Posted by: John      Permalink         Source

August 22, 2006, 5:02 AM CT

First Direct Evidence For Dark Matter

First Direct Evidence For Dark Matter This composite image shows the galaxy cluster 1E0657-556, also known as the "bullet cluster",
Astronomers have discovered first direct proof that dark matter exists.

University of Arizona astronomers and their colleagues got side-on views of two merging galaxy clusters in observations made with state-of-the-art optical and X-ray telescopes.

"Nature gave us this fantastic opportunity to see hypothesized dark matter separated from ordinary matter in this merging system," said UA astronomer Douglas Clowe, leader of the study.

"Previous to this observation, all of our cosmological models were based on an assumption that we couldn't prove: that gravity behaves the same way on the cosmic scale as on Earth," Clowe said. "The clusters we've looked at in these images are a billion times larger than the largest scales at which we can measure gravity at present, which are on the scale of our solar system".

Douglas Clowe.

Clowe added, "What's amazing about this is that the process of galaxy clusters merging is thought to go on all of time. That's how galaxy clusters gain mass. But the fact that we caught this thing only 100 million years after it occurred -- so recently that it barely registers on the cosmic time scale -- is tremendous luck."

Astronomers have known since the 1930s that most of the universe must be made up of something other than normal matter, the stuff that makes stars, planets, all things and creatures. Given the way that galaxies move through space and scientists' understanding of gravity, astronomers theorize that the universe must contain about five times more dark matter than normal matter.........

Posted by: Edwin      Permalink         Source

Older Blog Entries   Older Blog Entries   1   2   3   4   5   6   7   8   9   10   11   12   13   14   15   16   17   18   19   20   21   22   23   24   25