Science & Technology
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Telescope

Why is the universe's brightest blast still blazing?



Hubble image
©NASA/ESA/N Tanvir/U of Leicester/A Fruchter/STScI
The afterglow of the most powerful explosion ever recorded is shown in this Hubble Space Telescope image. A few galaxies are also visible, but not the host galaxy for the explosion

The most powerful explosion ever observed may have been even more powerful than first thought. Nearly three weeks after the bright 'gamma-ray burst' occurred, it is still outshining its host galaxy, dumbfounding astronomers with its amazing longevity.
Magnify

What Happened at Meteor Crater?

Scientists have discovered why there isn't much impact-melted rock at Meteor Crater in northern Arizona.The iron meteorite that blasted out Meteor Crater almost 50,000 years ago was traveling much slower than has been assumed, University of Arizona Regents' Professor H. Jay Melosh and Gareth Collins of the Imperial College London report in the cover article of Nature.

"Meteor Crater was the first terrestrial crater identified as a meteorite impact scar, and it's probably the most studied impact crater on Earth," Melosh said. "We were astonished to discover something entirely unexpected about how it formed."

Meteor crater
©Jim Hurley
Meteor Crater, Arizona

Previous research supposed that the meteorite hit the surface at a velocity between about 34,000 mph and 44,000 mph (15 km/sec and 20 km/sec).
Info

Underwater Microscope Helps Prevent Shellfish Poisoning Along Gulf Coast of Texas

Through the use of an automated, underwater cell analyzer developed at the Woods Hole Oceanographic Institution (WHOI), researchers and coastal managers were recently able to detect a bloom of harmful marine algae in the Gulf of Mexico and prevent human consumption of tainted shellfish.
Arrow Down

Geologists Discover New Way of Estimating Size and Frequency of Meteorite Impacts

Scientists have developed a new way of determining the size and frequency of meteorites that have collided with Earth.

Their work shows that the size of the meteorite that likely plummeted to Earth at the time of the Cretaceous-Tertiary (K-T) boundary 65 million years ago was four to six kilometers in diameter. The meteorite was the trigger, scientists believe, for the mass extinction of dinosaurs and other life forms.

François Paquay, a geologist at the University of Hawaii at Manoa (UHM), used variations (isotopes) of the rare element osmium in sediments at the ocean bottom to estimate the size of these meteorites. The results are published in this week's issue of the journal Science.
Eye 1

Powerful new satellite to debut over Pacific

The United States is set to start operating a powerful new military communications satellite over the Pacific next week, the first of a planned six-satellite network that will boost data flows 10-fold, the Air Force Space Command said Thursday.

On its own, the maiden Boeing Co-built Wideband Global Satellite will provide more capacity for video, data and voice than the entire group of 10 or so satellites it is designed to replace, the command said.

"We expect to start cutting over operational communications networks from the existing constellation to the new satellite next week," said Air Force Col. James Wolf, chief of the command's military satellite communications division.

Australia joined the WGS program last year, providing funds that expanded it to include the sixth satellite, which had been an option under a contract awarded to Boeing in January 2001.
Rocket

How Rocket Engines Can Be Destroyed By Mysterious Sound Waves



rocket sound waves
©Georgia Institute of Technology
An image of destructive acoustic waves building inside a small, simulated rocket combustor.

There's a strange wave phenomenon that's plagued rocket scientists for years, a lurking threat with the power to destroy an engine at almost any time. For decades, scientists have had a limited understanding of how or why it happens because they could not replicate or investigate the problem under controlled laboratory conditions.
Arrow Down

"Dino Killer" Asteroid Was Half the Size Predicted?

The meteorite that wiped out the dinosaurs might have been less than half the size of what previous models predicted.

That's the finding of a new technique being developed to estimate the size of ancient impactors that left little or no remaining physical evidence of themselves after they collided with Earth.

Scientists working on the technique used chemical signatures in seawater and ocean sediments to study the dino-killing impact that occurred at the end of the Cretaceous period, about 65 million years ago.
Evil Rays

How strong is a hurricane? Just listen

Knowing how powerful a hurricane is, before it hits land, can help to save lives or to avoid the enormous costs of an unnecessary evacuation. Some MIT researchers think there may be a better, cheaper way of getting that crucial information.

So far, there's only one surefire way of measuring the strength of a hurricane: Sending airplanes to fly right through the most intense winds and into the eye of the storm, carrying out wind-speed measurements as they go.

That's an expensive approach--the specialized planes used for hurricane monitoring cost about $100 million each, and a single flight costs about $50,000. Monitoring one approaching hurricane can easily require a dozen such flights, and so only storms that are approaching U.S. shores get such monitoring, even though the strongest storms occur in the Pacific basin (where they are known as tropical cyclones).
Butterfly

Picture This: Explaining Science Through Drawings

If a picture is worth a thousand words, creating one can have as much value to the illustrator as to the intended audience. This is the case with "Picturing to Learn," a project in which college students create pencil drawings to explain scientific concepts to a typical high school student. The National Science Foundation (NSF), Division of Undergraduate Education, provides support for this effort.

What sets this project apart is its emphasis on inviting students to draw in order to explain scientific concepts to others. The act of creating pencil drawings calls into play a different kind of thought process that forces students to break down larger concepts into their constitutive pieces.

This helps clarify the underlying science--from Brownian motion (the movement of particles suspended in a liquid or gas and the impact of raising the temperature of the liquid), to chemical bonding, to the quantum behavior of a particle in a box. In the same assignment, students are asked to evaluate their own drawings, which helps them identify and appreciate critical components.

Image
©Kara Culligan and Eunji Chung, Harvard University; Lina Garcia, Massachusetts Institute of Technology
The act of creating pencil drawings calls into play a different kind of thought process that forces students to break down larger concepts into their constitutive pieces. This helps clarify the underlying science--from chemical bonding, to the quantum behavior of a particle in a box, to Brownian motion (the movement of particles suspended in a liquid or gas and the impact of raising the temperature of the liquid). In the same assignment, students are asked to evaluate their own drawings which helps them identify and appreciate critical components.
Telescope

NASA Spacecraft Images Mars Moon In Color And In 3D

A new stereo view of Phobos, the larger and inner of Mars' two tiny moons, has been captured by a NASA spacecraft orbiting Mars.

The High Resolution Imaging Science Experiment (HiRISE) on NASA's Mars Reconnaissance Orbiter took two images of Phobos 10 minutes apart on March 23. Scientists combined the images for a stereo view.

"Phobos is of great interest because it may be rich in water ice and carbon-rich materials," said Alfred McEwen, HiRISE principal investigator at the Lunar and Planetary Laboratory at the University of Arizona, Tucson.

Phobos
©NASA/JPL-Caltech/University of Arizona
The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took two images of the larger of Mars' two moons, Phobos, within 10 minutes of each other on March 23, 2008.
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