Science & TechnologyS


Star

Sun Is Not A Perfect Sphere, NASA Spacecraft Finds


Science Daily
Mon, 06 Oct 2008 14:41 UTC
Scientists using NASA's RHESSI spacecraft have measured the roundness of the sun with unprecedented precision. They find that it is not a perfect sphere. During years of high solar activity the sun develops a thin "cantaloupe skin" that significantly increases its apparent oblateness: the sun's equatorial radius becomes slightly larger than its polar radius.
© Gary Palmer"Cantaloupe ridges" on the sun. The glowing white magnetic network is what gives the sun its extra oblateness during times of high solar activity. Amateur astronomer Gary Palmer took the picture in July 2005 using a violet calcium-K filter.

Their results appear the Oct. 2nd edition of Science Express.

"The sun is the biggest and therefore smoothest object in the solar system, perfect at the 0.001% level because of its extremely strong gravity," says study co-author Hugh Hudson of UC Berkeley. "Measuring its exact shape is no easy task."

The team accomplished the task by analyzing data from the Reuven Ramaty High-Energy Solar Spectroscopic Imager, RHESSI for short, an x-ray/gamma-ray space telescope launched in 2002 on a mission to study solar flares. Although RHESSI was never intended to measure the roundness of the sun, it has turned out ideal for the purpose. RHESSI observes the solar disk through a narrow slit and spins at 15 rpm. The spacecraft's rapid rotation and high data sampling rate (necessary to catch fast solar flares) make it possible for investigators to trace the shape of the sun with systematic errors much less than any previous study. Their technique is particularly sensitive to small differences in polar vs. equatorial radius or "oblateness."
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Sun

Sun Warms and Cools the Earth

Dr Zbigniew Jaworowski
Center for Political Research
Sat, 20 Sep 2008 12:53 UTC
In an op-ed in a Polish weekly I commented recently on a remarkable decrease of global temperature in 2008, and over the past decade. Not surprisingly the op-ed evoked a strong reaction from Polish co-workers of IPCC, denying the existence of cooling. Surprising, however, was that the criticism dwelled upon a "global climatic conspiracy", and "colossal international plot". I did not use these words nor even hinted at such an idea. The idea was probably apparent from the data and facts I presented, showing weaknesses of the man-made global warming hypothesis. Without irrational political or ideological factors, it is really difficult to understand why so many people believe in human causation of the Modern Warm Period, which was never plausibly proved by scientific evidence. Some of these factors I will discuss here.
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Bomb

Flashback Friend or Foe? Crows Never Forget a Face, It Seems

Michelle Nijhuis
New York Times
Mon, 25 Aug 2008 04:19 UTC
Image
© Keith Brust; Jeff WallsI KNOW YOU - John M. Marzluff, a wildlife biologist tested crows’ ability to distinguish between faces.
Crows and their relatives - among them ravens, magpies and jays - are renowned for their intelligence and for their ability to flourish in human-dominated landscapes. That ability may have to do with cross-species social skills. In the Seattle area, where rapid suburban growth has attracted a thriving crow population, researchers have found that the birds can recognize individual human faces.

The researchers used a simple hat and masks to test the animals' abilities.

Comment: Interesting that the power structures of society have nearly destroyed an analogous ability within the human population to recognize pychopathic predators and share that knowledge, particularly in women.

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Cow Skull

Big fossil found in hurricane Ike-ravaged home's front yard


Associated Press
Fri, 03 Oct 2008 21:42 UTC
A homeowner whose beachfront property in Texas was destroyed during Hurricane Ike has found a football-size fossil tooth in the debris.

Dorothy Sisk asked her colleague, Lamar University paleontologist Jim Westgate, to accompany her to her Bolivar Peninsula home after Ike hit. Together they found something unusual in the remains of Sisk's front yard: a six-pound fossil tooth.
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Telescope

Dark matter makes galaxy's stars live long and prosper

Rachel Courtland
New Scientist
Sun, 05 Oct 2008 16:08 UTC
Stars at the centre of the Milky Way could gobble up enough dark matter to extend their lifetimes by a billion or more years, a new study suggests. If such stars are found, they could help reveal what the mysterious dark matter is actually made of.
Sun-like stars on tight orbits around the centre of the Milky Way
© E L Wright/UCLA/COBE/DIRBE/NASASun-like stars on tight orbits around the centre of the Milky Way may gobble up enough dark matter to appear redder and brighter than they would otherwise.

Although it constitutes roughly 90% of the Milky Way's mass, dark matter is thought to be too diffuse in most parts of the galaxy to have a large effect on stars. But close to the colossal black hole at the galactic centre, the material might be sufficiently dense that stars can capture it at high rates.

To investigate dark matter's effect on such stars, Pat Scott of Stockholm University in Sweden and colleagues modelled the evolution of stars as they gravitationally accumulated weakly interacting massive particles, or WIMPs - a popular group of dark matter candidates.
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Telescope

What happened to the Kuiper Belt's smallest objects?

Maggie McKee
New Scientist
Sun, 05 Oct 2008 15:31 UTC
The hunt continues for the outer solar system's tiniest residents. A two-year search to find small objects there has turned up nothing, bolstering theories that 'all hell broke loose' in the solar system just a few hundred million years after it formed.

Astronomers have found more than 1000 objects in the Kuiper Belt, a ring of icy bodies beyond Neptune. There are fewer large Kuiper Belt Objects than smaller ones, but the exact size distribution is unknown because only a handful of KBOs smaller than 70 kilometres across have been found - they simply reflect too little sunlight to be observed.
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Meteor

Meteorites From Inner Solar System Match Up To Earth's Platinum Standard


Science Daily
Sat, 04 Oct 2008 03:52 UTC
Some of the world's rarest and most precious metals, including platinum and iridium, could owe their presence in the Earth's crust to iron and stony-iron meteorites, fragments of a large number of asteroids that underwent significant geological processing in the early Solar System.
asteroid impact with early Earth
© ESAArtist's impression of asteroid impact with early Earth that led to lunar formation.

Dr Gerhard Schmidt from the University of Mainz, Germany, has calculated that about 160 metallic asteroids of about 20 kilometres in diameter would be sufficient to provide the concentrations of these metals, known as Highly Siderophile Elements (HSE), found in the Earth's crust. Dr Schmidt will be presenting his findings at the European Planetary Science Congress in Münster on Monday 22nd September.

Dr Schmidt said, "A key issue for understanding the origin of planets is the knowledge of the abundances of HSE in the crust and mantle of the Earth, Mars and the Moon. We have found remarkably uniform abundance distributions of HSE in our samples of the Earth's upper crust. A comparison of these HSE values with meteorites strongly suggests that they have a cosmochemical source."
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Star

Spotless Sun: Blankest Year of the Space Age


NASA Press Release
Tue, 30 Sep 2008 14:40 UTC
Astronomers who count sunspots have announced that 2008 is now the "blankest year" of the Space Age.
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Sherlock

Old violins reveal their secrets

Philip Ball
Nature News
Sat, 04 Oct 2008 03:14 UTC
Why do the violins made by Stradivari and Guarneri del Gesù sound so good? Countless theories have been proposed for the secret of these eighteenth-century Italian instrument-makers, but attempts to identify a unique acoustic signature have proved fruitless. Now a study has finally identified a measurable sound quality that distinguishes these old violins from cheap, factory-made instruments.

After spending ten years painstakingly measuring the acoustics of violins rated from "bad" to "excellent" by professional musicians, George Bissinger of East Carolina University in Greenville, North Carolina, says that the 'excellent' old Italian violins in his sample show a significantly stronger acoustic response in the lower octaves than do the 'bad' violins, whereas those rated merely 'good' have intermediate values1. The high-quality tone is caused by a single mode of vibration of air inside the body, which radiates sound strongly through the violin's f-holes.
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Binoculars

Jupiter, looking sharp

Phil Plait
Discover Magazine
Thu, 02 Oct 2008 18:09 UTC
This weird-looking image
Jupiter MAD
© Discover MagazineJupiter, looking sharp and hot
is the sharpest picture of Jupiter ever taken from the ground. Taken with a device called - are you ready for this? - the Multi-Conjugate Adaptive Optics Demonstrator (or MAD, in an acronymic stretch), it has a resolution better than Hubble's!

The Earth's atmosphere roils and waves, distorting ground-based views of the sky. That's one of the reasons we launch telescopes into space, to get above all that mess. But if you can observe a point-like object such as a star at the same time you observe your target object, it's possible to compensate for the distortion by taking extremely rapid fire snapshots and measuring the way the star image changes. You then apply a correction to the image, and presto! It's cleaner. However, you can only do this for the area near the star. Distortions change across a telescope's field of view, making this technique somewhat limited.
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