Tag: field (page 6 of 43)

What astronomers learned when Messenger space probe crashed into Mercury



Excerpt from statecolumn.com


On April 30, NASA concluded an historic voyage known as the Mercury Surface, Space Environment, Geochemistry and Ranging mission. The mission came to an end when the spacecraft carrying analytical instruments, Messenger, crashed into the planet’s surface after consuming all of its fuel.
The mission was far from a waste, however, as NASA rarely expects to see the majority of the spacecraft they launch ever again. According to Discovery, The probe sent back a spectacular photo of the surface of Mercury, using the craft’s Narrow Angle Camera in tandem with the Mercury Dual Imaging System. The photo shows a mile-wide view of the nearby planet’s surface in 2.1 meters per pixel resolution.
Right after the probe delivered the photo to NASA’s Deep Space Network, which is a collection of global radio antennae that tracks data on the agency’s robotic missions around the solar system, the signal was lost in what scientists assume was the craft’s final contact with the closest planet to the sun.
The four-year mission came to an end when the craft could no longer maintain its orbit around the solar system’s innermost planet due to lack of fuel. Mercury is just 36 miles from the sun, compared to Earth, which is 93 million miles away from the center of the solar system. Mercury is a peculiar world, with both frigid and extremely hot temperatures. Messenger also revealed that Mercury has a magnetic field similar to that of Earth’s, created by the motion of metallic fluids within the planet’s core.
The main challenge the Messenger mission faced was getting the space probe into orbit around Mercury. Due to the planet’s proximity to the sun, it was extremely difficult for flight engineers to avoid its gravitational pull. In addition to the challenge of catching Mercury’s comparatively weak gravitational force, high temperatures also made things tricky. Messenger was equipped with a sunshield designed to protect the spaceship cool on the side that faced the sun. NASA engineers also attempted to chart a long, elliptical orbit around Mercury, giving Messenger time to cool off as it rounded the backside of the planet.
Messenger made over 4,000 orbits around Mercury between 2011 and 2015, many more than the originally planned one-year mission would allow.
With the close-up shots of Mercury’s surface provided by Messenger, NASA scientists were able to detect trace signals of magnetic activity in Mercury’s crust. Using clues from the number of impact craters on the surface, scientists figured that Mercury’s magnetized regions could be as old as 3.7 billion years. Astronomers count the craters on a planet in order to estimate its age – the logic being that younger surfaces should have fewer impact sites than older surfaces.
The data sent back by Messenger has caused astronomers to reconsider their understanding of Mercury’s magnetic history. They now date the beginning of magnetism on Mercury to about 700 million years after the planet was formed. They cannot say for sure, however, if the magnetic field has been consistently active over this timeframe.
According to Messenger guest investigator Catherine Johnson, geophysicist at the University of British Columbia in Vancouver, that it was possible the magnetic field has been active under constant conditions, though she suspects it might also oscillate over time, like Earth’s. Information for the time period between 4 billion years ago and present day is sparse, though Johnson added that additional research is in the pipeline.
Johnson was pleased, however, with the insight offered into Mercury’s formation provided by these new magnetic clues. Magnetism on a planetary scale typically indicates a liquid metal interior. Since Mercury is so tiny, scientists originally believed that its center would be solid, due to the rate of cooling. The presence of liquid in the planet’s center suggests other materials’ presence, which would lower the freezing point. This suggests that a totally solid core would be unlikely.
Mercury’s magnetic field offers valuable insight into the formation of the planet, the solar system, and even the universe. Magnetism on Mercury indicates that it has a liquid iron core, according to Messenger lead scientist Sean Solomon of Columbia University.

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Take a spaceship journey to a galaxy cluster five billion light-years away


Annotated image of the field around CLASS B1608+656

Most of the galaxies visible in this Hubble image are members of a huge cluster called CLASS B1608+656, which lies about five billion light-years away. But the field also contains other objects that are both significantly closer and far more distant — including two gravitational lenses dubbed Fred and Ginger.

These contain enough mass to visibly distort the light from objects behind them. Fred, also known more prosaically as [FMK2006] ACS J160919+6532, lies near the lens galaxies in CLASS B1608+656, while Ginger ([FMK2006] ACS J160910+6532) is markedly closer to us. Despite their different distances from us, both can be seen near to CLASS B1608+656 in the central region of this Hubble image, and are labelled.
Credit:ASA, ESA


Click to zoom

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Astronomers Measure Distance to Farthest Galaxy Yet



The farthest confirmed galaxy observed to date was identified in this Hubble image of a field of galaxies.  The inset image of the galaxy has been colored blue as suggestive of its young stars. Credit NASA/European Space Agency/Yale/University of California, Santa Cruz


Excerpt from nytimes.com

Leapfrogging backward in time to when the universe was apparently feeling its oats, a group of astronomers reported Tuesday that they had measured a bona fide distance to one of the farthest and thus earliest galaxies known.

The galaxy, more than a few billion light-years on the other side of the northern constellation Boötes, is one of the most massive and brightest in the early universe and goes by the name of EGS-zs8-1. 
It flowered into stardom only 670 million years after the Big Bang.
The light from that galaxy has taken 13 billion years to reach telescopes on Earth. By now, however, since the universe has continued to expand during that time, the galaxy is about 30 billion light-years away, according to standard cosmological calculations.
The new measurements allow astronomers to see the galaxy in its infancy. Despite its relative youth, however, it is already about one-sixth as massive as the Milky Way, which is 10 billion years old. And it is getting bigger, making stars 80 times faster than the Milky Way is making them today. The discovery was reported in The Astrophysical Journal by Pascal Oesch of Yale University and his colleagues.

By the rules of the expanding universe, the farther away a galaxy is, the faster it is retreating from us, measured by the “redshift” of its light being broadened to longer wavelengths, the way an ambulance siren seems to lower its pitch as it goes by.

In the past few years, as astronomers have raced one another into the past with instruments like the Hubble Space Telescope, galaxies have been found that appear even more distant. Those measurements, however, were estimates based on the colors of the objects — so-called photometric redshifts.

The new galaxy stuck out in a survey of distant galaxies by the Hubble and Spitzer space telescopes known as Candels, for Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. Its redshift was precisely measured with a powerful spectrograph known as Mosfire — Multi-Object Spectrometer for Infrared Exploration — on Keck 1, one of a pair of 10-meter-diameter telescopes on Mauna Kea in Hawaii. That makes it the highest redshift confirmed in this way, said Garth Illingworth, of the University of California, Santa Cruz, one of the astronomers in the study.

How galaxies were able to form and grow so rapidly after the lights came on in the universe is a mystery that will be addressed by a coming generation of instruments like the James Webb Space Telescope and the Thirty Meter Telescope, a goliath planned for Mauna Kea, already home to a dozen telescopes.

Recently, however, construction of the Thirty Meter Telescope, a $1.4 billion project, has been halted by protests by Hawaii residents who feel their mountain has been abused. An echo of that controversy appears in the new paper, in which Dr. Oesch and his colleagues write: “The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.”

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6 Natural Solutions To Decontaminate Soil

Marco Torres, Prevent DiseaseWith a progressively educated population becoming more aware of the inherent dangers of the conventional food supply, urban farming has become hugely popular. However, more people are also becoming aware of contaminated soil and how heavy metals pose potential risks to their food crops. As backyard gardening continues to explode in popularity, we must ask how contaminated is our soil?Many municipalities in many countries are embracing urban agri [...]

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IBM advances bring quantum computing closer to reality



ibm research jerry chow
 
Research scientist Jerry Chow performs a quantum computing experiment at IBM's Thomas J. Watson Research Center in Yorktown Heights, N.Y. Jon Simon/IBM


Excerpt from computerworld.com
By Sharon Gaudin

IBM scientists say they have made two critical advances in an industrywide effort to build a practical quantum computer, shaving years off the time expected to have a working system.

"This is critical," said Jay Gambetta, IBM's manager of theory of quantum computing. "The field has got a lot more competitive. You could say the [quantum computing] race is just starting to begin… This is a small step on the journey but it's an important one."

Gambetta told Computerworld that IBM's scientists have created a square quantum bit circuit design, which could be scaled to much larger dimensions. This new two-dimensional design also helped the researchers figure out a way to detect and measure errors.
Quantum computing is a fragile process and can be easily thrown off by vibrations, light and temperature variations. Computer scientists doubt they'll ever get the error rate down to that in a classical computer.


Because of the complexity and sensitivity of quantum computing, scientists need to be able to detect errors, figure out where and why they're happening and prevent them from recurring.

IBM says its advancement takes the first step in that process.
"It tells us what errors are happening," Gambetta said. "As you make the square [circuit design] bigger, you'll get more information so you can see where the error was and you can correct for it. We're showing now that we have the ability to detect, and we're working toward the next step, which would allow you to see where and why the problem is happening so you can stop it from happening."

Quantum computing is widely thought to be the next great step in the field of computing, potentially surpassing classical supercomputers in large-scale, complex calculations. 

Quantum computing would be used to cull big data, searching for patterns. It's hoped that these computers will take on questions that would lead to finding cures for cancer or discovering distant planets – jobs that might take today's supercomputers hundreds of years to calculate.

IBM's announcement is significant in the worlds of both computing and physics, where quantum theory first found a foothold.

Quantum computing, still a rather mysterious technology, combines both computing and quantum mechanics, which is one of the most complex, and baffling, areas of physics. This branch of physics evolved out of an effort to explain things that traditional physics is unable to.

With quantum mechanics, something can be in two states at the same time. It can be simultaneously positive and negative, which isn't possible in the world as we commonly know it. 

For instance, each bit, also known as a qubit, in a quantum machine can be a one and a zero at the same time. When a qubit is built, it can't be predicted whether it will be a one or a zero. A qubit has the possibility of being positive in one calculation and negative in another. Each qubit changes based on its interaction with other qubits.

Because of all of these possibilities, quantum computers don't work like classical computers, which are linear in their calculations. A classical computer performs one step and then another. A quantum machine can calculate all of the possibilities at one time, dramatically speeding up the calculation.

However, that speed will be irrelevant if users can't be sure that the calculations are accurate.

That's where IBM's advances come into play.

"This is absolutely key," said Jim Tully, an analyst with Gartner. "You do the computation but then you need to read the results and know they're accurate. If you can't do that, it's kind of meaningless. Without being able to detect errors, they have no way of knowing if the calculations have any validity."

If scientists can first detect and then correct these errors, it's a major step in the right direction to building a working quantum computing system capable of doing enormous calculations. 

"Quantum computing is a hard concept for most to understand, but it holds great promise," said Dan Olds, an analyst with The Gabriel Consulting Group. "If we can tame it, it can compute certain problems orders of magnitude more quickly than existing computers. The more organizations that are working on unlocking the potential of quantum computing, the better. It means that we'll see something real that much sooner."
However, there's still debate over whether a quantum computer already exists.

A year ago, D-Wave Systems Inc. announced that it had built a quantum system, and that NASA, Google and Lockheed Martin had been testing them.

Many in the computer and physics communities doubt that D-Wave has built a real quantum computer. Vern Brownell, CEO of the company, avows that they have.

"I think that quantum computing shows promise, but it's going to be quite a while before we see systems for sale," said Olds.
IBM's Gambetta declined to speculate on whether D-Wave has built a quantum computing but said the industry is still years away from building a viable quantum system.

"Quantum computing could be potentially transformative, enabling us to solve problems that are impossible or impractical to solve today," said Arvind Krishna, senior vice president and director of IBM Research, in a statement.

IBM's research was published in Wednesday's issue of the journal Nature Communications.

quantum computing infographics ibm

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This revolutionary discovery could help scientists see black holes for the first time


supermassive black hole
Artist's concept of the black hole.



Excerpt from finance.yahoo.com
Of all the bizarre quirks of nature, supermassive black holes are some of the most mysterious because they're completely invisible.
But that could soon change.
Black holes are deep wells in the fabric of space-time that eternally trap anything that dares too close, and supermassive black holes have the deepest wells of all. These hollows are generated by extremely dense objects thousands to billions of times more massive than our sun.
Not even light can escape black holes, which means they're invisible to any of the instruments astrophysicists currently use. Although they don't emit light, black holes will, under the right conditions, emit large amounts of gravitational waves — ripples in spacetime that propagate through the universe like ripples across a pond's surface.
And although no one has ever detected a gravitational wave, there are a handful of instruments around the world waiting to catch one.

Game-changing gravitational waves



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black hole
This illustration shows two spiral galaxies - each with supermassive black holes at their center - as they are about to collide. 

Albert Einstein first predicted the existence of gravitational waves in 1916. According to his theory of general relativity, black holes will emit these waves when they accelerate to high speeds, which happens when two black holes encounter one another in the universe.  

As two galaxies collide, for example, the supermassive black holes at their centers will also collide. But first, they enter into a deadly cosmic dance where the smaller black hole spirals into the larger black hole, moving increasingly faster as it inches toward it's inevitable doom. As it accelerates, it emits gravitational waves.
Astrophysicists are out to observe these waves generated by two merging black holes with instruments like the Laser Interferometer Gravitational-Wave Observatory.
"The detection of gravitational waves would be a game changer for astronomers in the field," Clifford Will, a distinguished profess of physics at the University of Florida who studied under famed astrophysicist Kip Thorne told Business Insider. "We would be able to test aspects of general relativity that have not been tested."
Because these waves have never been detected, astrophysicists are still trying to figure out how to find them. To do this, they build computer simulations to predict what kinds of gravitational waves a black hole merger will produce. 

Learn by listening

In the simulation below, made by Steve Drasco at California Polytechnic State University (also known as Cal Poly), a black hole gets consumed by a supermassive black hole about 30,000 times as heavy.
You'll want to turn up the volume.
What you're seeing and hearing are two different things.
The black lines you're seeing are the orbits of the tiny black hole traced out as it falls into the supermassive black hole. What you're hearing are gravitational waves.
"The motion makes gravitational waves, and you are hearing the waves," Drasco wrote in a blog post describing his work.
Of course, there is no real sound in space, so if you somehow managed to encounter this rare cataclysmic event, you would not likely hear anything. However, what Drasco has done will help astrophysicists track down these illusive waves.

Just a little fine tuning 

Gravitational waves are similar to radio waves in that both have specific frequencies. On the radio, for example, the number corresponding to the station you're listening to represents the frequency at which that station transmits.


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gwaves
3D visualization of gravitational waves produced by 2 orbiting black holes. Right now, astrophysicists only have an idea of what frequencies two merging black holes transmit because they’re rare and hard to find. In fact, the first ever detection of an event of this kind was only announced this month. 

Therefore, astrophysicists are basically toying with their instruments like you sometimes toy with your radio to find the right station, except they don’t know what station will give them the signal they’re looking for.
What Drasco has done in his simulation is estimate the frequency at which an event like this would produce and then see how that frequency changes, so astrophysicists have a better idea of how to fine tune their instruments to search for these waves.
Detecting gravitational waves would revolutionize the field of astronomy because it would give observers an entirely new way to see the universe. Armed with this new tool, they will be able to test general relativity in ways never before made possible.

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Study says the universe may be a hologram






Holograms are two-dimensional pictures that appear to the human eye as three-dimensional objects. Some scientists believe that our universe may behave similarly, existing as a sort of all-encompassing hologram.
As explained by Nature World News, “a mathematical description of the Universe actually requires one fewer dimension than it seems” according to the “holographic principle,” which would indicate that what appears to be a 3-D universe may actually “just be the image of 2-D processes on a huge cosmic horizon.”
Prior to this study, scientists looked into this holographic principle by applying their calculations to a universe presenting Anti de Sitter space. Anti de Sitter is the term used to describe space as having a hyperbolic shape, much like a saddle. This hyperbolic space shape behaves, mathematically, as special relativity would predict.
Special relativity is a theory put forth by Albert Einstein to describe the relationship between space and time, and is especially useful when studying very small particles moving at extreme speeds over cosmic distances. The concept of Anti de Sitter space assumes that spacetime itself is hyperbolic in its natural state, in the absence of matter or energy.
A team at the Vienne University of Technology looked at the holographic principle not in the usual Anti de Sitter space framework, but instead applied the principle to flat spacetime, as represents our physical universe.“Our Universe, in contrast, is quite flat – and on astronomic distances, it has positive curvature,” team member Daniel Grumiller said in a statement.
The team created several gravitational theories that apply to flat space to see if calculations regarding quantum gravity would indicate a holographic description as has occurred in former calculations with theories applied to Anti de Sitter space.
“If quantum gravity in a flat space allows for a holographic description by a standard quantum theory, then there must be physical quantities, which can be calculated in both theories – and the results must agree,” Grumiller said.
The team found that the amount of quantum entanglement required for gravitational theory models expressed the same value in flat quantum gravity as in a low dimensional field theory, showing that the theory of a holographic universe can be successfully applied to the reality of the relatively flat field of spacetime evident in our universe.
“This calculation affirms our assumption that the holographic principle can also be realized in flat spaces. It is evidence for the validity of this correspondence in our universe” team member Max Riegler said.
The results were published in the journal Physical Review Letters.


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Explosive Culprit? Russian Fireball’s Origins Found


A photograph of the Annama meteorite fireball over Russia's Kola Peninsula.



Excerpt from space.com

A crackling fireball that exploded over Russia last year appears to share an orbit with a huge asteroid discovered in October 2014, a new study reports.

The Kola fireball was spotted on April 19, 2014, as it lit up the night sky above the Kola Peninsula near the Finnish-Russian border. Its orbit is "disturbingly similar" to the asteroid 2014 UR116, slated to pass by the moon in 2017, the study authors said.
Camera observations by the Finnish Fireball Network, which monitors the sky for meteors and fireballs, and video from eyewitnesses helped scientists recreate the meteoroid's trajectory and hunt down meteorite fragments on the ground. 


Josep Maria Trigo-Rodríguez, a researcher at the Institute of Space Sciences in Barcelona, Spain, led the international team of scientists who analyzed the meteorite's orbit. They calculated the fireball's size and path through Earth's atmosphere by examining its flight and the meteorite's final impact site. A computer model based on these figures was used to estimate the space rock's orbital path. 

The 1,100-pound (500 kilogram) meteorite is an ordinary H5 chondrite, a type of stony meteorite responsible for 31 percent of Earth's impacts. The fragments are called the "Annama meteorite" because the meteorite fell near the Annama River in Russia.

Annama meteorite

The precise detective works suggests the fireball escaped from the innermost region of the asteroid belt, the study researchers reported. The rock has an elliptical orbit that is typical of the Apollo family of near-Earth orbiting asteroids, and it likely came from the same broad source region as the Lost City, Peekskill and Buzzard Coulee meteorites, the researchers said.

The researchers compared the Annama meteorite's orbit with known near-Earth asteroids (there are more than 1,500). Of 12 potential matches, by far the closest match was with the asteroid 2014 UR116, they said.

The findings were published April 7 in the journal Monthly Notices of the Royal Astronomical Society.

The new report does not suggest that asteroid 2014 UR116 flung the Annama meteorite directly at Earth. However, the two bodies could be related. Scientists think that streams of asteroid fragments — such as the remnants of interstellar collisions — can sail on nearly identical orbits. Tidal forces may stretch out these rocky debris patches over time. Asteroids may also fragment from the stress of passing near the planets, the researchers noted.

"The tidal effect on an asteroid, which rapidly rotates under the gravitational field of a planet, can fragment these objects or release large rocks from its surface, which could then become dangerous projectiles at a local scale, such as the one that fell in Chelyabinsk, Russia," Trigo-Rodríguez said in a statement.

Asteroid 2014 UR116, discovered by Russian scientists on Oct. 27, 2014, measures 1,312 feet (400 meters) across, but does not pose an impact danger to Earth, according to NASA.

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