Sun Important Factor of Earth Climate

There has been much discussion as to whether variations in the strength of the Sun have played a role in triggering climate change in the past, but more and more research results clearly indicate that solar activity — i.e. the amount of radiation coming from the Sun — has an impact on how the climate varies over time.

Sun-Earth Connection

Sun-Earth Connection

In a new study published in the scientific journalGeology, researchers from institutions including Aarhus University in Denmark show that, during the last 4,000 years, there appears to have been a close correlation between solar activity and the sea surface temperature in summer in the North Atlantic. This correlation is not seen in the preceding period.

Since the end of the Last Ice Age about 12,000 years ago, the Earth has generally experienced a warm climate. However, the climate has not been stable during this period, when temperatures have varied for long periods. We have generally had a slightly cooler climate during the last 4,000 years, and the ocean currents in the North Atlantic have been weaker.

“We know that the Sun is very important for our climate, but the impact is not clear. Climate change appears to be either strengthened or weakened by solar activity. The extent of the Sun’s influence over time is thus not constant, but we can now conclude that the climate system is more receptive to the impact of the Sun during cold periods — at least in the North Atlantic region,” says Professor Marit-Solveig Seidenkrantz, Aarhus University, who is one of the Danish researchers in the international team behind the study.

A piece of the climate puzzle

In their study, the researchers looked at the sea surface temperatures in summer in the northern part of the North Atlantic during the last 9,300 years. Direct measurements of the temperature are only found for the last 140 years, when they were taken from ships.

However, by examining studies of marine algae — diatoms — found in sediments deposited on the North Atlantic sea bed, it is possible to use the species distribution of these organisms to reconstruct fluctuations in sea surface temperatures much further back in time.

The detailed study makes it possible to draw comparisons with records of fluctuations of solar energy bursts in the same period, and the results show a clear correlation between climate change in the North Atlantic and variations in solar activity during the last 4,000 years, both on a large time scale over periods of hundreds of years and right down to fluctuations over periods of 10-20 years.

The new knowledge is a small but important piece of the overall picture as regards our understanding of how the entire climate system works, according to Professor Seidenkrantz.

“Our climate is enormously complex. By gathering knowledge piece by piece about the way the individual elements work together and influence each other to either strengthen an effect or mitigate or compensate for an impact, we can gradually get an overall picture of the mechanisms. This is also important for understanding how human-induced climate change can affect and be affected in this interaction,” she says.

 

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Meteor Activity Outlook for February 28-March 6, 2015

March is the slowest month for meteor activity. No major annual showers are active and only a few very weak minor showers produce activity this month. The sporadic rates are also near their annual minimum so there is not much to look forward to this month except for the evening fireballs that seem to peak this time of year from the northern hemisphere.

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This could be due to the fact the Antapex radiant lies highest above the horizon this time of year during the evening hours. From the southern hemisphere, activity from the Centaurid complex begins to wane with only the weak activity visible from Norma and perhaps others areas nearby. At least southern sporadic rates are still strong to make the late summer viewing a bit more pleasurable.

During this period the moon will reach its full phase on Thursday March 5th. At this time the moon is located opposite the sun and remains above the horizon all night long. This weekend the waxing gibbous moon will set during the early morning hours allowing a few hours of dark sky viewing before the start of dawn.

The estimated total hourly meteor rates for evening observers this week is near 2 for observers situated at mid-northern latitudes and 4 for observers viewing from the southern tropics (latitude 25 S.). For morning observers the estimated total hourly rates should be near 7 for observers situated at mid-northern latitudes and 14 for observers viewing from the southern tropics. Evening rates are reduced during this period due to lunar interference. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Note that the hourly rates listed below are estima  tes as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brightest meteors will be visible from such locations.

The radiant (the area of the sky where meteors appear to shoot from) positions and rates listed below are exact for Saturday night/Sunday morning February 28/March 1. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available at science stores and planetariums) will provide maps with grid lines of the celestial coordinates so that you may find out exactly where these positions are located in the sky. A planisphere or computer planetarium program is also useful in showing the sky at any time of night on any date of the year.

Activity from each radiant is best seen when it is positioned highest in the sky, either due north or south along the meridian, depending on your latitude. It must be remembered that meteor activity is rarely seen at the radiant position. Rather they shoot outwards from the radiant so it is best to center your field of view so that the radiant lies at the edge and not the c  enter. Viewing there will allow you to easily trace the path of each meteor back to the radiant (if it is a shower member) or in another direction if it is a sporadic. Meteor activity is not seen from radiants that are located below the horizon. The positions below are listed in a west to east manner in order of right ascension (celestial longitude). The positions listed first are located further west therefore are accessible earlier in the night while those listed further down the list rise later in the night.

These sources of meteoric activity are expected to be active this week.

The center of the large Anthelion (ANT) radiant is currently located at 11:04 (166) +04. This position lies on the Leo/Virgo border, 4 degrees west of the 4th magnitude Zavijava (Beta Virginis). Due to the large size of this radiant, Anthelion activity may also appear from Sextans, Crater, western Virgo as well as eastern Leo. This radiant is best placed near 0100 local standard time (LST), when it lies on the meridian and is located highest in the sky. Rates at this time should be near 2 per hour no matter your location. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 5 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 1 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 12 per hour as seen from rural observing sites and 3 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates are reduced during this period due to moonlight.

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Prosthetic Hand Controlled by Mind

Three Austrian men have become the first in the world to undergo a new technique called “bionic reconstruction,” enabling them to use a robotic prosthetic hand controlled by their mind, according to new research published in The Lancet. All three men suffered for many years with brachial plexus injuries and poor hand function as a result of motor vehicle and climbing accidents.

prostetic hand controlled by thoughts_m

The new technique was developed by Professor Oskar Aszmann, Director of the Christian Doppler Laboratory for Restoration of Extremity Function at the Medical University of Vienna, together with engineers from the Department of Neurorehabilitation Engineering of the University Medical Center Goettingen. It combines selective nerve and muscle transfers, elective amputation, and replacement with an advanced robotic prosthesis (using sensors that respond to electrical impulses in the muscles). Following comprehensive rehabilitation, the technique restored a high level of function, in all three recipients, aiding in activities of daily living.

“In effect, brachial plexus avulsion injuries represent an inner amputation, irreversibly separating the hand from neural control. Existing surgical techniques for such injuries are crude and ineffective and result in poor hand function,” explains Professor Aszmann. “The scientific advance here was that we were able to create and extract new neural signals via nerve transfers amplified by muscle transplantation. These signals were then decoded and translated into solid mechatronic hand function.”

Before amputation, all three patients spent an average of 9 months undergoing cognitive training, firstly to activate the muscles, and then to use the electrical signals to control a virtual hand. Once they had mastered the virtual environment, they practiced using a hybrid hand — a prosthetic hand attached to a splint-like device fixed to their non-functioning hand.

Three months after amputation, robotic prostheses gave all three recipients substantially better functional movement in their hands, improved quality of life, and less pain. For the first time since their accidents all three men were able to accomplish various everyday tasks such as picking up a ball, pouring water from a jug, using a key, cutting food with a knife, or using two hands to undo buttons.

Brachial plexus injuries occur when the nerves of the brachial plexus — the network of nerves that originate in the neck region and branch off to form the nerves that control movement and sensation in the upper limbs, including the shoulder, arm, forearm, and hand — are damaged. Brachial plexus injuries often occur as a result of trauma from high speed collisions, especially in motorcycle accidents, and in collision sports such as rugby and American Football.

According to Professor Aszmann, “So far, bionic reconstruction has only been done in our centre in Vienna. However, there are no technical or surgical limitations that would prevent this procedure from being done in centres with similar expertise and resources.”

Writing in a linked Comment, Professor Simon Kay who carried out the UK’s first hand transplant, and Daniel Wilks from Leeds Teaching Hospitals NHS Trust, Leeds, UK say, “The present findings — and others — are encouraging, because this approach provides additional neural inputs into prosthetic systems that otherwise would not exist. However, the final verdict will depend on long-term outcomes, which should include assessment of in what circumstances and for what proportion of their day patients wear and use their prostheses. Compliance declines with time for all prostheses, and motorized prostheses are heavy, need power, and are often noisy, as well as demanding skilled repair when damaged.”

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New Discovery Measures Strength of Ultra-fast Black Hole Winds

A new first time discovery has allowed astronomers to measure the strength of ultra-fast black hole winds and show that they are mighty enough to affect the fate of their host galaxies.

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By looking at the speed of ambient gas spewing out from a well-known quasar, astronomers are gaining insight into how black holes and their host galaxies might have evolved at the same time.

Using the Nuclear Spectroscopic Telescope Array (NuSTAR) , researchers were able to use the X-ray spectra of an extremely luminous black hole (quasar PDS 456) to detect a nearly spherical stream of highly ionized gas streaming out of it.

The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy.

“We know that black holes in the centers of galaxies can feed on matter, and this process can produce winds. This is thought to regulate the growth of the galaxies,” said Fiona Harrison of the California Institute of Technology, the principal investigator of NuSTAR and a co-author on a new paper about the results appearing in the Feb. 19 issue of the journal Science. “Knowing the speed, shape and size of the winds, we can figure out how powerful they are.”

Supermassive black holes blast matter into their host galaxies, including X-ray-emitting winds traveling at up to one-third the speed of light. In the new study, astronomers determined that PDS 456, an extremely luminous active black hole, or quasar, has winds that carry more energy every second than what is emitted by more than 1 trillion suns.

That’s enough of a punch to affect the entire galaxy and its ability to make stars.

“By looking at this huge spherical outflow, we can now see a mechanism to explain the correlation between black hole and galaxy formation,” said Bill Craig of Lawrence Livermore National Laboratory and the Space Science Laboratory at University of California, Berkeley.

NuSTAR and the European Space Agency’s XMM-Newton simultaneously observed PDS 456, located more than 2 billion light-years away, on five separate occasions in 2013 and 2014. The space telescopes complement each other by seeing different parts of the X-ray light spectrum: XMM-Newton sees low-energy X-rays and NuSTAR sees high-energy X-rays. Their goal was to look for iron, which is blown from the black hole winds along with other matter.

The researchers looked for scattered light signatures from iron atoms originating from the sides of the supermassive black hole.

The NuSTAR’s higher-energy X-ray data, when combined with observations from XMM-Newton, provided the key information, proving that the winds emanate not in a beam but in a nearly spherical fashion.

With the shape and extent of the winds determined, the researchers could then determine the power of the wind and the degree to which they can quench the formation of new stars.

The new report demonstrates that a supermassive black hole and the galaxy that nurtures it are connected by high-speed winds. As the black holes bulk up in size, their winds push vast amounts of matter outward through the galaxy, which ultimately stops new stars from forming.

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Comet Survives Close Encounter with Sun

An unusual comet skimmed past the Sun on Feb 18-21, 2015, as captured by the European Space Agency (ESA) and NASA’s Solar and Heliospheric Observatory, or SOHO.

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Most comets seen by SOHO belong to the Kreutz family — all of which broke off from a single giant comet many centuries ago.

Known as sungrazers, these comets usually evaporate in the intense sunlight. This comet made it to within 2.2 million miles of the Sun’s surface — but survived the trip intact.

“There’s a half-decent chance that ground observers might be able to detect it in the coming weeks,” said Karl Battams, a solar scientist at the Naval Research Lab in Washington, D.C. “But it’s also possible that events during its trip around the sun will cause it to die fairly fast.”

Since launching in 1995, SOHO has become the number one comet finder of all time — this was comet discovery number 2,875. However, SOHO sees non-group comets like this only a few times a year.

Toward the end of the video, as the comet begins to develop a tail, the Sun releases an eruption of solar material, called a coronal mass ejection, or CME, to add something more to the scene.

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Origin of Sun’s Magnetic Field May Have Been Discovered

The magnetic field that covers the Sun and determines its behavior such as the eleven year cycle and its related sunspots and solar storms; also has another side to it – a magnetic web that covers the entire surface of the Sun at rest and whose net magnetic flow is greater than that of the active areas. A study led by the Institute of Astrophysics of Andalusia (IAA-CSIC) has revealed where the flow that feeds this web comes from.

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The outline of the solar magnetic web coincides with the boundaries of the so-called supergranules, structures linked to the existence of hot gas rising to the surface (similar to the bubbles made by boiling water) some twenty thousand kilometers in diameter.

“We have discovered that inside these supergranules, in what is known as intranetwork, small magnetic elements appear which travel toward the outer boundaries and interact with the web”, says Milan Gosic, IAA researcher in charge of the study.

The monitoring of these little known elements was a considerable advance in and of itself, but the calculation of their contribution to the solar magnetic web has come as a major surprise: these small elements can generate and transfer, in the span of barely fourteen hours, the entire magnetic flow detected on the web.

“Bearing in mind that only about 40% of this flow ends up on the web, we find that the intranetwork can replenish the flow of the web in twenty four hours”, says Luis Bellot (IAA-CSIC), a member of the research team.

Paradigm Change

The dominant model until now postulated that the magnetic fields of the web resulted from the decay of active zones such as spots, on the one hand, and from structures known as ephemeral regions, which provide a lot of flow but are not very common, on the other.

In that sense, the study by Gosic et al. has triggered a paradigm change because it has shown that ephemeral regions are too scarce to have significant impact. “In the course of forty hours we detected only two ephemeral regions, so their contribution to the web cannot be more than 10% of the total flow. By contrast, the small elements in the intranetwork are continuous and clearly dominant. “, says Gosic (IAA-CSIC).

The finding was made in the course of extraordinarily long temporal sequences of observation – about forty hours – using the high resolution Japanese HINODE satellite – a record for this type of instruments – which made it possible to monitor the evolution of supergranular cells throughout their life.

“It is believed that the magnetic elements of the intranetwork and their interactions with the web might be responsible for the warming up of the outer layers of the Sun’s atmosphere, one of the most pressing unsolved problems of Solar Physics”, says Luis Bellot (IAA-CSIC).

The study of the magnetic elements using the Hinode data will permit a more efficient scientific use of the data of the European Space Agency’s Solar Orbiter mission, for which IAA-CSIC is building the IMAX instrument.

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JUST IN: Sun’s Magnetic Field Has Greater Effect on Solar System Than Previously Known

New research suggests that the Sun’s magnetic field controls the large-scale shape of the heliosphere “much more than had been previously thought,” says Merav Opher, associate professor of astronomy and director of the Center for Space Physics at Boston University (BU).

heliosphere 2015_m

In the new model, the magnetic field squeezes the solar wind along the Sun’s North and South axes, producing two jets that are then dragged downstream by the flow of the interstellar medium through which the heliosphere moves.

The model indicates that the heliospheric tail doesn’t extend to large distances but is split into two by the two jets, and that the format of the jets is similar to that of astrophysical jets observed in many other stars and around black holes.

“Most researchers don’t believe in the importance of the solar magnetic field, because the magnetic pressure on the solar wind’s particles is far lower than the thermal pressure of the particles,” says Opher, lead author on a paper appearing today in Astrophysical Journal Letters.

However, the model shows that tension of the magnetic field controls what happens to the solar wind in the tail.

Picture a tube of toothpaste with rubber bands wrapped around it, suggests co-author James Drake, professor of physics and director of the Joint Space-Science Institute at the University of Maryland. In this case, the toothpaste is the jet’s plasma, and the rubber bands are the rings of the solar magnetic field. “Magnetic fields have tension just like rubber bands, and these rings squeeze in,” he says. “So imagine you wrap your toothpaste tube very tightly with a lot of rubber bands, and they will squeeze the toothpaste out the end of your tube.”

“Jets are really important in astrophysics,” Drake adds. “And from what we can tell, the mechanism that’s driving these heliospheric jets is basically the same as it is in, for example, the Crab Nebula. Yet this is really close by. If we’re right about all of this, it gives us a local test bed for exploring some very important physics.”

“It’s also exciting that these jets are very turbulent, and will be very good particle accelerators,” says Opher. The jets might, for example, play a role in the acceleration of so-called anomalous cosmic rays “We don’t know where these particles are accelerated; it’s a bit of a puzzle,” she says.

Solving such puzzles will be important for space travel. The heliosphere acts as “a cocoon to protect us, by filtering galactic cosmic rays,” she says. “Understanding the physical phenomena that govern the shape of the heliosphere will help us understand the filter.”

The new view of the heliosphere was discovered by accident as the team studied surprising data from the Voyager 1 spacecraft and tried to understand how the galaxy’s magnetic field interacts with the heliosphere.

One of two identical twin spacecraft launched in 1977, Voyager 1 in 2012 became the first man-made object to exit the heliosphere and plunge into interstellar space, according to the National Aeronautics and Space Administration (NASA).

As the spacecraft approached and then crossed this boundary, “Voyager had very bizarre observations,” remarks Opher. It did not register the anticipated major change in the direction of magnetic field as it made the crossing.

Struggling to explain these unexpected results, the team initially focused on the nose of the heliosphere rather than its tail. “The Voyagers had a flashlight in the kitchen, and nobody was looking in the attic,” she remarks. “We noticed, while studying the draping of the galaxy’s magnetic field around the nose, that the heliosphere was much shorter than we anticipated.”

When she ran a much larger numerical simulation that continued to follow the flow of the solar wind, she unveiled the unforeseen two-tailed shape

More data on the heliosphere’s boundaries will become available sometime in the next few years when Voyager 2, like its twin, crosses into interstellar space.

In the meantime, additional evidence about the shape of the heliosphere is available from two spacecraft that measure so-called neutral energetic atoms (ENAs), particles that are created by interactions between the solar wind and neutral atoms from the interstellar medium, and whose presence gives an indication of the heliosphere’s border.

Opher says that results from the Interstellar Boundary Explorer (IBEX) project can be interpreted to offer support for the two-lobed tail model, although she notes that IBEX scientists offer a different interpretation. Data from the Cassini spacecraft’s ENA measurements also may suggest an almost “tailless” heliosphere, she adds.

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