MessageToEagle.com -
A new study shows that current extimates of ice-giant planetary interiors overstate water's compressibility by as much as 30 percent.
The findings could dramatically change our understanding of the physical properties of such worlds.
In a challenge to current astrophysical models of the Universe, researchers at Sandia National Laboratories Z machine and the University
of Rostock in Germany have found that current estimates of ice-giant planetary interiors overstate water's compressibility by as much as 30 percent.
The work was reported in the paper "Probing the Interior of the Ice Giants" in the Feb. 27 Physical Review Letters.
"Our results question science's understanding of the internal structure of these planets," said Sandia lead author Marcus Knudson, "and
should require revisiting essentially all the modeling of ice giants within and outside our solar system."
An accurate estimate of water's shrinking volume under the huge gravitational pressures of large planets is essential to astrophysicists trying to model the
evolution of the Universe.
They need to assume how much space is taken up by water trapped under high density and pressure, deep inside a planet, to
calculate how much is needed of other elements to flesh out the planet's astronomical image.
This information is also useful for astrobiologists who are trying to understand how planets form and evolve in order to estimate the best locations
in which to search for habitable, extrasolar worlds.
Neptune is an ice giant. Credit: NASA
To come up with the composition of the so-called ice-giants Neptune and Uranus, as well as any of the ice-giant exoplanets being discovered in distant star systems,
astrophysicists begin with the orbit, age, radius and mass of each planet. Then, using equations that describe the behavior of elements as
the forming planet cooled, they calculate what light and heavy elements might have contributed to its evolution to end up with the current celestial object.
But if estimates of water volume are off-target, then so is everything else.
The measurements — 10 times more accurate than any previously reported — at Sandia's Z accelerator agree with results from a modern simulation effort
that uses the quantum mechanics of Schrödinger's wave equation — the fundamental equation of wave mechanics — to predict the behavior of water under
extreme pressure and density.
The model, developed through a University of Rostock and Sandia collaboration, is called "First Principles Modeling" because it contains no tuning
parameters.
"You're solving Schrödinger's equation from a quantum mechanical perspective with hydrogen and oxygen as input; there aren't any knobs for finagling
the result you want or expect," Knudson said.
The model's results are quite different from earlier chemical pictures of water's behavior under pressure, but agree quite well with the Z machine's
test results, said Knudson. These results were achieved by using Z's magnetic fields to shoot tiny plates 40 times faster than a rifle bullet into a
water-sample target a few millimeters away. The impact of each plate into the target created a huge shock wave that compressed the water to
roughly one-fourth its original volume, momentarily creating conditions similar to those in the interior of the ice giants.
Voyager 2 snapped this photo of ice giant Uranus in 1986. Credit: NASA
Sub-nanosecond observations captured the behavior of water under pressures and densities that occur somewhere between the surface and core of ice giants.
"We took advantage of recent, more precise methods to measure the speed of the shock wave moving through the water sample by measuring the
Doppler shift of laser light reflected from the moving shock front, to 0.1 percent accuracy," said Knudson.
The re-shocked state of water was also determined by observing its behavior as the shock wave reflected back into the water from a quartz
rear window (its characteristics also determined) in the target. These results provided a direct test of the First Principles model
along a thermodynamic path that mimics the path one would follow if one could bore deep into a planet's .
Multiple experiments were performed, providing a series of results at increasing pressures to create an accurate equation of state.
Such equations link changes in pressures with changes in temperatures and volumes.
Z can create more pressure — up to 20 megabars — than at Earth's core (roughly 3.5 megabars), and millions of times Earth's atmospheric
pressure. The Z projectiles, called flyer plates, achieve velocities from 12 to 27 kilometers a second, or up to 60,000 mph.
The pressure at the center of Neptune is roughly 8 megabars.
Water at Z's ice-giant pressures also was found to have reflectivity like that of a weak metal, raising the possibility that water's
charged molecular fragments might be capable of generating a magnetic field. This could help explain certain puzzling aspects
of the magnetic fields around Neptune and Uranus.
"Reducing uncertainty on the composition of planetary systems by precisely measuring the equation of state of water at extreme
conditions can only help us understand how these systems formed," Knudson said.
These experimental techniques also are used at Z to study materials of critical importance to the nuclear weapons program.
In addition to producing the largest amount of X-rays on Earth when firing, the huge pressures generated by Z make it useful
to astrophysicists seeking data similar to that produced by black holes and neutron stars.
MessageToEagle.com via Sandia National Laboratories
Hidden Misshapen Celestial "Wonder"
It is one of the brightest and strangest objects in the Milky Way - the corpse of a star that exploded around 1000 years ago.
Only a handful of such young supernova remnants are known.
The object named G350.1-0.3 is also incredibly small (only eight light years across) and young in astronomical terms.
Alien Species Living In The Inner Milky Way Could Be In Danger
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Mercury Surprises Scientists
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Living Earth Simulator - Supercomputer Predicting The Future
In Douglas Adams book the Hitchhikers Guide to the Galaxy we encounter a machine called Deep Thought. It is the most powerful computer ever built. Deep Thought is capable of answering questions
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Warp-Speed Planets Are Some Of The Fastest Objects In The Milky Way
Warped planets are some of the fastest objects in the Milky Way and they zoom through space near the speed of light.
Some years ago astronomers were astonished when they they found the first runaway star flying out of our Galaxy at a speed of 1.5 million miles per hour.
The discovery intrigued theorists, who wondered: If a star can get tossed outward at such an extreme velocity, could the same thing happen to planets?
Though the universe is filled with billions upon billions of stars, the discovery of a single variable star in 1923 altered the
course of modern astronomy. And, at least one famous astronomer of the time lamented that the discovery had shattered his world view.
Bright Star In The Constellation Lyra Is Cooler Than The Human Body
The coldest class of stars have temperatures as cool as the human body.
Astronomers hunted these dark orbs, termed Y dwarfs, for more than a decade without success.
When viewed with a visible-light telescope, they are nearly impossible to see.
Thermonuclear Burning In A Neutron Star Detected For The First Time!
It's a very important discovery!
For the first time, an international team of scientists have detected all phases of thermonuclear burning in a
neutron star, located close to the center of the galaxy in the globular cluster Terzan 5.
Astronomical Mystery - Tremendous Explosion And Appearance Of Odd Rings
Twenty five years ago, on 1987 February 23, the brightest supernova of modern times was observed in the Large Magellanic Cloud.
The collision occurred at speeds near 60 million kilometers per hour and shock-heats the ring material causing it to glow.
Over time, astronomers have watched and waited for the expanding debris from this tremendous stellar explosion to crash into previously expelled material...
Giant Jupiter - Our "Would-Be" Friend With Secrets From The Past
It knocked a giant planet into deep space, swallowed up a smaller rival before it could grow any bigger.
Careful observers saw dark spots rapidly changing places and almost a century ago, a luminous protuberance on the eastern edge of Jupiter,
on the equatorial side of the north equatorial belt was reported.
The "Cloaked" Star Was Difficult To Find
An object obscured by dust, and buried in a two-star system enshrouded by dense gas, is not easy to find.
A "cloaked" star was discovered after it ate a little of its neighbor. The meal must have given the star a bit of indigestion, because it
"burped" with a blast of high-energy radiation, which gave it away.
MessageToEagle.com -
A new study shows that current extimates of ice-giant planetary interiors overstate water's compressibility by as much as 30 percent.
The findings could dramatically change our understanding of the physical properties of such worlds.
It is one of the brightest and strangest objects in the Milky Way - the corpse of a star that exploded around 1000 years ago.
Only a handful of such young supernova remnants are known.
The object named G350.1-0.3 is also incredibly small (only eight light years across) and young in astronomical terms.
Few people doubt there is intelligent alien life in the Milky Way galaxy, but where can we expect to find it?
Astronomers think that while the inner sector of the MIlky Way Galaxy may be the most likely to support habitable worlds.
Unfortunately some of these places are also most dangerous to all life-forms.
It is still unknown how the supermassive black holes (SMBH) in galaxy centres accrete gas and grow.
Researchers from the University of Leicester (UK) and Monash University in Australia have investigated how some black holes got so big so fast that they are billions of times heavier than the sun.
On March 17, MESSENGER (MErcury Surface, Space Environment, GEochemistry, and Ranging) completed its one-year primary mission, orbiting Mercury, capturing nearly 100,000 images, and recording data
that reveals new information about the planet's core, topography, and the mysterious radar bright material in the permanently shadowed areas near the poles.
In Douglas Adams book the Hitchhikers Guide to the Galaxy we encounter a machine called Deep Thought. It is the most powerful computer ever built. Deep Thought is capable of answering questions
concerning life, the Universe, and simply everything. Now scientists are planning to create a similar machine. It is called the Living Earth Simulator (LES).
Warped planets are some of the fastest objects in the Milky Way and they zoom through space near the speed of light.
Some years ago astronomers were astonished when they they found the first runaway star flying out of our Galaxy at a speed of 1.5 million miles per hour.
The discovery intrigued theorists, who wondered: If a star can get tossed outward at such an extreme velocity, could the same thing happen to planets?
Though the universe is filled with billions upon billions of stars, the discovery of a single variable star in 1923 altered the
course of modern astronomy. And, at least one famous astronomer of the time lamented that the discovery had shattered his world view.
The coldest class of stars have temperatures as cool as the human body.
Astronomers hunted these dark orbs, termed Y dwarfs, for more than a decade without success.
When viewed with a visible-light telescope, they are nearly impossible to see.
It's a very important discovery!
For the first time, an international team of scientists have detected all phases of thermonuclear burning in a
neutron star, located close to the center of the galaxy in the globular cluster Terzan 5.
Twenty five years ago, on 1987 February 23, the brightest supernova of modern times was observed in the Large Magellanic Cloud.
It knocked a giant planet into deep space, swallowed up a smaller rival before it could grow any bigger.
An object obscured by dust, and buried in a two-star system enshrouded by dense gas, is not easy to find.