Mystery Of Voyager Spacecraft

With a new 3D-model for energy simulation scientists from Bochum and Huntsville, USA, are studying the ‘physical mystery’ of the Voyager spacecraft. Over 30 years ago the spacecraft detected particles in solar wind which were ‘hotter’ than they should have been according to the existing theory expounded by the mathematician Andrey Kolmogorov in 1941

The Bochum plasma physicists Prof. Padma Kant Shukla and Dr. Dastgeer Shaikh from the University of Alabama are thereby the first to verify by means of computer simulation that the non-linear characteristics of turbulences in the plasma carried by the solar wind differs from the familiar model for dynamic fluids. The scientists have published their results in ‘Physical Review Letters.’

Recognized for over 60 years: The 5/3 law

According to Kolmogorov’s theory there is a relationship between the size of eddies and the amount of energy released or dissipated by hot solar particles. The smaller an eddy gets the more it interacts with its surroundings, so the greater the energy loss.  For example this can be observed in the turbulent wake caused by a bridge piling in a flowing river. The energy of the tumbling wake dissipates only at the edges, where the smallest eddies interact with the smooth flowing water. The Kolmogorov law set the exponents for the relationship between eddy size and energy at 5/3: In a dynamic fluid, the amount of energy released should increase by a factor of  x5/3 when the size of the eddy is reduced by a factor of x.

7/3 law: Efficiency increases by 40 percent

Observations made by the Voyager, other spacecraft and satellites show that the energy flow in plasma tends to follow a 7/3 law rather than the so-called 5/3 law proposed by Kolmogorov. The dynamic spectrum of the wave lengths in plasma is therefore significantly greater than in other hydrodynamic systems. The efficiency of energy transfer between hot particles carried in the solar wind and cooler particles increases by 40 percent. The computer model developed by Shukla and Shaikh explains the sudden increase by the interaction between magnetic fields and the outward flowing currents of hot atoms, ions and electrons. The magnetic field is responsible for energy cascades. Influenced and ‘constrained’ by magnetic fields, the small eddies serve to “damp” the energy in them.

Explanation  for gigantic quantities of cosmic energy

“This is the same kind of thing that happens in a microwave oven,” Shaikh said. “If there is nothing there, the microwaves go out without releasing their energy. But the microwaves are absorbed by the food, causing them to release the energy and heat the food.” “This development of the two scientists helps us to understand how the particles in the solar wind contain enormous quantities of energy. Prof. Shukla continued “It might also explain where the fastest and most powerful cosmic rays get their boost.” Scientists have struggled for decades to find plausible natural processes that could explain how some cosmic rays (atoms stripped of their electrons) are accelerated to almost the speed of light.

The source of the meteorites

They were ejected from their asteroidal “parent body” after a collision, were injected into a new orbit, and they finally felt onto the Earth. Meteorites are a major tool for knowing the history of the solar system because their composition is a record of past geologic processes that occurred while they were still incorporated in the parent asteroid.

One fundamental difficulty is that we do not know exactly where the majority of meteorite specimens come from within the asteroidal main belt. For many years, astronomers failed to discover the parent body of the most common meteorites, the ordinary chondrites that represent 75% of all the collected meteorites.

To find the source asteroid of a meteorite, astronomers must compare the spectra of the meteorite specimen to those of asteroids. This is a difficult task because meteorites and their parent bodies underwent different processes after the meteorite was ejected. In particular, asteroidal surfaces are known to be altered by a process called “space weathering”, which is probably caused by micrometeorite  and solar wind action that progressively transforms the spectra of asteroidal surfaces. Hence, the spectral properties of asteroids become different from those of their associated meteorites, making the identification of asteroidal parent body more difficult.

Collisions are the main process to affect asteroids. As a consequence of a strong impact, an asteroid can be broken up, its fragments following the same orbit as the primary asteroid. These fragments constitute what astronomers call “asteroid families”. Until recently, most of the known asteroid families have been very old (they were formed 100 million to billions of years ago). Indeed, younger families are more difficult to detect because asteroids are closer to each other [2]. In 2006, four new, extremely young asteroid families were identified, with an age ranging from 50000 to 600000 years. These fragments should be less affected than older families by space weathering after the initial breakup. Mothé-Diniz and Nesvorný then observed these asteroids, using the GEMINI telescopes (one located in Hawaii, the other in Chile), and obtained visible spectra. They compared the asteroids spectra to the one of an ordinary chondrite (the Fayetteville meteorite [3]) and found good agreement.

Astronomer (SMU) a Hollywood Star

Saint Mary’s University observatory technician David Lane now has a star on the astronomy geek’s version of the Hollywood Walk of Fame.

He’s in good company too, with rock and roll’s Frank Zappa just one of the famous names to make the list. Several Canadian cities and universities have also been honoured, including Saint Mary’s in Halifax, where Mr. Lane works as a systems administrator in the astronomy and physics department.

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Asteroid Impacts On Earth

 A century ago this week, an event in far-off Siberia rang a cosmic wake-up call for Earth. That explosive event over remote Tunguska is generally viewed by scientists as a large space rock that pierced through the atmosphere of Siberia, then detonated to flatten some 2,000 square kilometers of trees.
Cialis buy cheap size-medium wp-image-5″ title=”Asteriod impact Earth” src=”http://nccao.org/wp-content/uploads/2008/07/080701194344-large-238×300.jpg” alt=”" width=”238″ height=”300″ />One hundred years later, there is certainty in the stars – the thought that an asteroid loitering out there in space has Earth’s name on it. But today, a matching of technology and space governance could negate such events from happening in the future.

“The Tunguska event just 100 years ago reminds us that the threat of an asteroid strike is real,” said Ray Williamson, Executive Director of the Secure World Foundation (SWF). “If that object had struck in New York City or London, it would have killed hundreds of thousands and created untold fear in human hearts. Yet, as near Earth object strikes go, it was relatively small,” he pointed out.

“We need to be much better prepared than we are today to deal with this important, if uncommon, threat by creating the international institutions and governance methods to find objects likely to strike Earth and devise the means to divert them from Earth’s path,” Williamson explained.

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Volcanic Activity on Mercury

In 1975, the Mariner 10 spacecraft returned intriguing images that showed smooth plains covering large swaths of Mercury’s surface. But scientists could not determine whether the plains had been created by volcanic activity or by material ejected from below the surface when objects had collided into it. Thus, they could not reach a consensus over Mercury’s geologic past.

Now, a research team led by Brown University planetary geologist James Head has determined that volcanism played a central role in forming Mercury’s surface. In a paper that appears in the July 4 issue of Science, part of a special section describing the MESSENGER spacecraft’s first flyby of Mercury, the researchers have found evidence of past volcanic  activity, suggesting that the planet underwent an intense bout of changes to its landscape about 3 to 4 billion years ago – and that the source for much of that reshaping was within.

“What this shows is that Mercury was not dead on arrival,” says Head, the paper’s lead author. “It had a pulse for a while. Now, we want to know when it had that pulse and what caused it to slow down and eventually stop.”

A major clue to Mercury’s geologic past came from the scientists’ finding of volcanic vents along the margins of the Caloris basin, one of the solar system’s largest and youngest impact basins. The group zeroed in on a kidney-shaped depression that was surrounded by a bright ring, lending a halo-like impression to the landscape. The scientists determined that the depression was a volcanic vent, and the bright ring around it was pyroclastic, remnants of lava that had been spewed outward, much like a volcanic fountain on Earth.

Another larger ring surrounding the vent and halo ring showed that another type of volcanism, called effusion, in which molten rock from within the planet oozes outward and covers the surface, had occurred. Together these deposits create a surface feature shaped like a volcanic shield – a clear sign to scientists that volcanic activity helped form the surrounding plains.

Black Holes NASA’s Chandra X-Ray Observatory

Not even light can escape a black hole’s grip, but gas falling into a black hole can heat up and become an intense source of X-rays, at temperatures up to 1,000 times hotter than the sun. Astronomers use the Chandra X-Ray Observatory — a NASA satellite — to map these X-ray sources and study their properties

They are deep and dense, and not even light can escape their grip. We’re talking about black holes, but they may not be as dark as you think.

“If you have binoculars, you might be able to make out a smudge, which would be the nearest galaxies,” says Jon Miller, an assistant professor of astronomy at the University of Michigan in Ann Arbor.

But what you won’t see — even with a telescope — black holes! In fact, Miller doesn’t even use one to study black holes. He uses his computer.

“I think it’s really for the best that NASA doesn’t let people like me drive billion-dollar satellites. So instead, we get data distributed through the computer networks,” Miller tells DBIS.

These data reveal just how complex black holes are. As gravity pulls matter into the hole, it is heated 1,000-times hotter than the sun and forms mega-heated gases. As the hole’s magnetic Propecia buy cheap field pulls these gases into its center, it creates a light show.

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