Mercury’s Origins Traced To Rare Meteorite

Around 4.6 billion years ago, the universe was a chaos of collapsing gas and spinning debris. Small particles of gas and dust clumped together into larger and more massive meteoroids that in turn smashed together to form planets. Scientists believe that shortly after their formation, these planets — and particularly Mercury — were fiery spheres of molten material, which cooled over millions of years.

mercury

Now, geologists at MIT have traced part of Mercury’s cooling history and found that between 4.2 and 3.7 billion years ago, soon after the planet formed, its interior temperatures plummeted by 240 degrees Celsius, or 464 degrees Fahrenheit.

They also determined, based on this rapid cooling rate and the composition of lava deposits on Mercury’s surface, that the planet likely has the composition of an enstatite chondrite — a type of meteorite that is extremely rare here on Earth.

Timothy Grove, the Cecil and Ida Green Professor of Geology in MIT’s Department of Earth, Atmospheric, and Planetary Sciences, says new information on Mercury’s past is of interest for tracing Earth’s early formation.

“Here we are today, with 4.5 billion years of planetary evolution, and because the Earth has such a dynamic interior, because of the water we’ve preserved on the planet, [volcanism] just wipes out its past,” Grove says. “On planets like Mercury, early volcanism is much more dramatic, and [once] they cooled down there were no later volcanic processes to wipe out the early history. This is the first place where we actually have an estimate of how fast the interior cooled during an early part of a planet’s history.”

Grove and his colleagues, including researchers from the University of Hanover, in Germany; the University of Liége, in Belgium; and the University of Bayreuth, in Germany, have published their results in Earth and Planetary Science Letters.

Compositions in craters

For their analysis, the team utilized data collected by NASA’s MESSENGER spacecraft. The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) probe orbited Mercury between 2011 and 2015, collecting measurements of the planet’s chemical composition with each flyby. During its mission, MESSENGER produced images that revealed kilometer-thick lava deposits covering the entire planet’s surface.

An X-ray spectrometer onboard the spacecraft measured the X-ray radiation from the planet’s surface, produced by solar flares on the sun, to determine the chemical composition of more than 5,800 lava deposits on Mercury’s surface.

Grove’s co-author, Olivier Namur of the University of Hanover, recalculated the surface compositions of all 5,800 locations, and correlated each composition with the type of terrain in which it was found, from heavily cratered regions to those that were less impacted. The density of a region’s craters can tell something about that region’s age: The more craters there are, the older the surface is, and vice versa. The researchers were able to correlate Mercury’s lava composition with age and found that older deposits, around 4.2 billion years old, contained elements that were very different from younger deposits that were estimated to be 3.7 billion years old.

“It’s true of all planets that different age terrains have different chemical compositions because things are changing inside the planet,” Grove says. “Why are they so different? That’s what we’re trying to figure out.”

A rare rock, 10 standard deviations away

To answer that question, Grove attempted to retrace a lava deposit’s path, from the time it melted inside the planet to the time it ultimately erupted onto Mercury’s surface.

To do this, he started by recreating Mercury’s lava deposits in the lab. From MESSENGER’s 5,800 compositional data points, Grove selected two extremes: one representing the older lava deposits and one from the younger deposits. He and his team converted the lava deposits’ element ratios into the chemical building blocks that make up rock, then followed this recipe to create synthetic rocks representing each lava deposit.

The team melted the synthetic rocks in a furnace to simulate the point in time when the deposits were lava, and not yet solidified as rock. Then, the researchers dialed the temperature and pressure of the furnace up and down to effectively turn back the clock, simulating the lava’s eruption from deep within the planet to the surface, in reverse.

Throughout these experiments, the team looked for tiny crystals forming in each molten sample, representing the point at which the sample turns from lava to rock. This represents the stage at which the planet’s solid rocky core begins to melt, creating a molten material that sloshes around in Mercury’s mantle before erupting onto the surface.

The team found a surprising disparity in the two samples: The older rock melted deeper in the planet, at 360 kilometers, and at higher temperatures of 1,650 C, while the younger rock melted at shallower depths, at 160 kilometers, and 1,410 C. The experiments indicate that the planet’s interior cooled dramatically, over 240 degrees Celsius between 4.2 and 3.7 billion years ago — a geologically short span of 500 million years.

“Mercury has had a huge variation in temperature over a fairly short period of time, that records a really amazing melting process,” Grove says.

The researchers determined the chemical compositions of the tiny crystals that formed in each sample, in order to identify the original material that may have made up Mercury’s interior before it melted and erupted onto the surface. They found the closest match to be an enstatite chondrite, an extremely rare form of meteorite that is thought to make up only about 2 percent of the meteorites that fall to Earth.

“We now know something like an enstatite chondrite was the starting material for Mercury, which is surprising, because they are about 10 standard deviations away from all other chondrites,” Grove says.

Grove cautions that the group’s results are not set in stone and that Mercury may have been an accumulation of other types of starting materials. To know this would require an actual sample from the planet’s surface.

“The next thing that would really help us move our understanding of Mercury way forward is to actually have a meteorite from Mercury that we could study,” Grove says. “That would be lovely.”

Opal Discovered In Antarctic Meteorite

Planetary scientists have discovered pieces of opal in a meteorite found in Antarctica, a result that demonstrates that meteorites delivered water ice to asteroids early in the history of the solar system. Led by Professor Hilary Downes of Birkbeck College London, the team announce their results at the National Astronomy Meeting in Nottingham on Monday 27 June.

meteorite

Opal, familiar on Earth as a precious stone used in jewellery, is made up of silica (the major component of sand) with up to 30% water in its structure, and has not yet been identified on the surface of any asteroid. Before the new work, opal had only once been found in a meteorite, as a handful of tiny crystals in a meteorite from Mars.

Downes and her team studied the meteorite, named EET 83309, an object made up of thousands and broken pieces of rock and minerals, meaning that it originally came from the broken up surface, or regolith, of an asteroid. Results from other teams show that while the meteorite was still part of the asteroid, it was exposed to radiation from the Sun, the so-called solar wind, and from other cosmic sources. Asteroids lack the protection of an atmosphere, so radiation hits their surfaces all the time.

EET 83309 has fragments of many other kinds of meteorite embedded in it, showing that there were many impacts on the surface of the parent asteroid, bringing pieces of rock from elsewhere in the solar system. Downes believes one of these impacts brought water ice to the surface of the asteroid, allowing the opal to form.

She comments: “The pieces of opal we have found are either broken fragments or they are replacing other minerals. Our evidence shows that the opal formed before the meteorite was blasted off from the surface of the parent asteroid and sent into space, eventually to land on Earth in Antarctica.”

“This is more evidence that meteorites and asteroids can carry large amounts of water ice. Although we rightly worry about the consequences of the impact of large asteroid, billions of years ago they may have brought the water to the Earth and helped it become the world teeming with life that we live in today.”

The team used different techniques to analyse the opal and check its composition. They see convincing evidence that it is extra-terrestrial in origin, and did not form while the meteorite was sitting in the Antarctic ice. For example, using the NanoSims instrument at the Open University, they can see that although the opal has interacted to some extent with water in the Antarctic, the isotopes (different forms of the same element) match the other minerals in the original meteorite.

Super-Slow Circulation Allowed World’s Oceans To Store Huge Amounts Of Carbon During Last Ice Age

The way the ocean transported heat, nutrients and carbon dioxide at the peak of the last ice age, about 20,000 years ago, is significantly different than what has previously been suggested, according to two new studies. The findings suggest that the colder ocean circulated at a very slow rate, which enabled it to store much more carbon for much longer than the modern ocean.

earth

Using the information contained within the shells of tiny animals known as foraminifera, the researchers, led by the University of Cambridge, looked at the characteristics of the seawater in the Atlantic Ocean during the last ice age, including its ability to store carbon. Since atmospheric CO2 levels during the period were about a third lower than those of the pre-industrial atmosphere, the researchers were attempting to find if the extra carbon not present in the atmosphere was stored in the deep ocean instead.

They found that the deep ocean circulated at a much slower rate at the peak of the last ice age than had previously been suggested, which is one of the reasons why it was able to store much more carbon for much longer periods. That carbon was accumulated as organisms from the surface ocean died and sank into the deep ocean where their bodies dissolved, releasing carbon that was in effect ‘trapped’ there for thousands of years. Their results are reported in two separate papers in Nature Communications.

The ability to reconstruct past climate change is an important part of understanding why the climate of today behaves the way it does. It also helps to predict how the planet might respond to changes made by humans, such as the continuing emission of large quantities of CO2 into the atmosphere.

The world’s oceans work like a giant conveyor belt, transporting heat, nutrients and gases around the globe. In today’s oceans, warmer waters travel northwards along currents such as the Gulf Stream from the equatorial regions towards the pole, becoming saltier, colder and denser as they go, causing them to sink to the bottom. These deep waters flow into the ocean basins, eventually ending up in the Southern Ocean or the North Pacific Ocean. A complete loop can take as long as 1000 years.

“During the period we’re looking at, large amounts of carbon were likely transported from the surface ocean to the deep ocean by organisms as they died, sunk and dissolved,” said Emma Freeman, the lead author of one of the papers. “This process released the carbon the organisms contained into the deep ocean waters, where it was trapped for thousands of years, due to the very slow circulation.”

Freeman and her co-authors used radiocarbon dating, a technique that is more commonly used by archaeologists, in order to determine how old the water was in different parts of the ocean. Using the radiocarbon information from tiny shells of foraminifera, they found that carbon was stored in the slowly-circulating deep ocean.

In a separate study led by Jake Howe, also from Cambridge’s Department of Earth Sciences, researchers studied the neodymium isotopes contained in the foraminifera shells, a method which works like a dye tracer, and came to a similar conclusion about the amount of carbon the ocean was able to store.

“We found that during the peak of the last ice age, the deep Atlantic Ocean was filled not just with southern-sourced waters as previously thought, but with northern-sourced waters as well,” said Howe.

What was previously interpreted to be a layer of southern-sourced water in the deep Atlantic during the last ice age was in fact shown to be a mixture of slowly circulating northern- and southern-sourced waters with a large amount of carbon stored in it.

“Our research looks at a time when the world was much colder than it is now, but it’s still important for understanding the effects of changing ocean circulation,” said Freeman. “We need to understand the dynamics of the ocean in order to know how it can be affected by a changing climate.”

The research was funded in part by the Natural Environment Research Council (NERC), the Royal Society and the Isaac Newton Trust.

Fastest-Spinning Brown-Dwarf Star Is Detected By Its Bursts Of Radio Waves

Astronomers have detected what may be the most-rapidly-rotating, ultra-cool, brown-dwarf star ever seen. The super-fast rotation period was measured by using the 305-meter Arecibo radio telescope — the same telescope that was used to discover the first planets ever found outside our solar system.

dwarf planet

“Our new detection of an ultra-cool dwarf emphasizes Arecibo’s amazing sensitivity, which enables measurements of the magnetic fields of very-low-mass stars, brown dwarfs, and potentially planets. Because planetary magnetic fields protect life from the harmful effects of stellar activity, it is clear that future programs of this kind using the Arecibo telescope will be crucial to our understanding of the habitability of planets around other stars,” said Alex Wolszczan, a co-discoverer with Matthew Route of radio emission from this new brown-dwarf star.

The discovery is detailed in a recent issue of The Astrophysical Journal Letters (Volume 821, L21), coauthored by Wolszczan, Evan Pugh University Professor of Astronomy and Astrophysics at Penn State University; and Route, a Senior Scientific Applications Analyst at Purdue University and a Penn State Ph.D. graduate. The repeated radio flares that they found being emitted by the brown dwarf allowed them to measure the extremely fast rotation of this exotic object. Their record-breaking detection demonstrates that even the coolest brown dwarfs, and possibly young giant planets, can be discovered and studied using radio observations.

“Our discovery of the super-fast rotation of J1122+25 poses new challenges for the theoretical models of the rotational evolution of these objects and the internal dynamos that power their magnetic fields,” Route said. J1122+25 is the short version of the scientific name of this new brown dwarf, WISEPC J112254.73+255021.5. “The radio flaring and rapid rotation of J1122+25 can reveal a lot about the origin and evolution of the magnetic fields of brown dwarfs, and how this knowledge can be applied to young giant planets,” Route said.

The data collected so far from this brown dwarf show that it could be rotating every 17, 34, or 51 minutes — an ambiguity that requires the collection of more data to identify which of the three measurements is this star’s rotational period. But, the scientists report, even the longest of these rotation periods would mean this brown dwarf rotates much faster than any measured so far.

The brown dwarf was first discovered by the Wide-field Infrared Survey Explorer (WISE) in 2011. Route and Wolszczan subsequently observed J1122+25 at five epochs spread over an eight-month period as part of an ongoing search for brown dwarfs with sudden outbursts of energy at radio wavelengths — called flaring ratio emission. “J1122+25 is about 55 light years away and is only one of six coolest brown dwarfs for which radio flares have been detected,” Route said.

Brown dwarfs like J1122+25 are sometimes called “failed stars” because they did not accumulate enough material when they formed in order to fuse hydrogen into helium, the process that enables stars to shine. The lack of continuous energy production from fusion makes brown dwarfs much colder and dimmer than most stars and gives them much different chemistry. For some of them, internal structure in connection with rapid rotation can generate strong magnetic fields and the dramatic radio flares that have been detected by the Arecibo telescope.

Many astronomers treat brown dwarfs as the “missing link” between stars and planets. Brown dwarfs share many physical traits with gas-giant planets like Jupiter. Studies of ultra-cool brown dwarfs like J1122+25 can be used to infer the properties of giant planets, which are much harder than stars to study in detail. J1122+25 is about one-sixth the temperature of the Sun, and emits light primarily in infrared wavelengths

Meteor Activity Outlook for June 25-July 1, 2016

by Robert Lunsford – American Meteor Society

The June Bootids (JBO) are usually a very weak shower that occasionally produces outbursts. Nothing out of the ordinary is expected this year but with the moon out of the way so viewing for unusual activity is warranted. These meteors are best seen from June 23-25, with maximum activity occurring on the 23rd. At maximum the radiant is located at 14:56 (224) +48. This position lies in northwestern Bootes, 15 degrees east of the second magnitude star known as Alkaid (Eta Ursae Majoris). This radiant is best placed in the evening sky just as the sky becomes dark. Observers in the northern hemisphere have a distinct advantage over those located south of the equator as the radiant lies much higher in the evening sky. No matter your location, little activity is expected from this source. With an entry velocity of 13 km/sec., the average June Bootid meteor would be of very slow velocity.

skywatch

During this period the moon reaches its last quarter phase on Monday June 27th. At this time the moon will lie 90 degrees west of the sun and will rise between midnight and 0100 local daylight saving time for most sites located in mid-northern latitudes. The half-illuminated moon will interfere with meteor observing, but to a much lesser degree than when near its full phase. Toward the end of the period the waning crescent moon will rise during the late morning hours allowing  most of the night to be free of lunar glare. The estimated total hourly meteor rates for evening observers this week is near 2 for observers located in the northern hemisphere and 3 for observers located in tropical southern locations (25S). For morning observers the estimated total hourly rates should be near 4 as seen from mid-northern latitudes (45N) and 6 as seen from tropical southern locations (25S).

Morning rates are reduced during this period due to interfering moonlight. The actual rate  s 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 estimates 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 June 25/26. 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 center. Vi  ewing 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 far 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 f Ophiuchids (FOP) were discovered by Sirko Molau and Juergen Rendtel using video data from the IMO network of cameras. These meteors are only active on 3 nights centered on June 30th. Maximum actually occurs on June 29th when the radiant is located at 17:40 (265) +08. This area of the sky is located in central Ophiuchus, 3 degrees north of the 3rd magnitude star known as Celbalrai (beta Ophiuchi). The radiant is best placed near midnight LDT when it lies on the meridian and is highest in the sky. Rates of less than 1 per hour are expected, even at maximum. With an entry velocity of 17 km/sec., the average f Ophiuchid meteor would be of very slow velocity.

The center of the large Anthelion (ANT) radiant is currently located at 19:08 (287) -22. This position lies in central Sagittarius, just south of the the twin stars known as pi and omicron Sagittarii.  Due to the large size of this radiant, Anthelion activity may also appear from the nearby constellations of Scutum, Serpens Caput, southern Aquila, and western Capricornus as well as Sagittarius. This radiant is best placed near 0100 local daylight saving (LDST), when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be near 2 as seen from mid-northern latitudes and 3 as seen from tropical southern latitudes. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

The Sigma Capricornids (SA) were discovered by Zdenek Sekanina and are active for a month lasting from June 19 through July 24. Maximum occurs on June 27th when the radiant is located at 20:24 (306) -07. This area of the sky is actually located in southeastern Aquila, five degrees north of the naked eye double star Algiedi (Alpha Capricornii). The radiant is best placed near 0300 LDT when it lies on the meridian and is highest in the sky. Rates at this time should be near one per hour no matter your location. With an entry velocity of 42 km/sec., the average Sigma Capricornid meteor would be of medium velocity. This velocity is significantly faster than the stronger Alpha Capricornids, which appear from the same general area of the sky during the second half of July.

The Pi Piscids (PPS) were discovered by Dr. Peter Brown in his meteoroid stream survey using the Canadian Meteor Orbit Radar. This shower was later verified by Dr. Peter Jenniskens and David Holman using data from the CAMS network in northern California. These meteors are active from June 11 through July 25 with maximum activity occurring on July 1st. The current position of the radiant is 00:44 (011) +23. This position actually lies in southeastern Andromeda, 2 degrees west of the 4th magnitude star known as eta Andromedae. Rates are currently expected to be less than 1 per hour no matter your location. Rates will increase to near 2 per hour at maximum. With an entry velocity of 68 km/sec., the average Pi Piscid meteor would be of swift speed.

The c-Andromedids (CAN) was discovered by Sirko Molau and Juergen Rendtel using video data from the IMO network. Activity from this source is seen from June 26 though July 20 with maximum activity occurring on July 12. The radiant currently lies at 00:54 (013) +41, which places it in northern Andromeda, close to the faint star known as nu Andromedae. This position is also just 1 degree east of the naked eye Andromeda Galaxy. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Observers in the northern hemisphere are better situated to view this activity as the radiant rises much higher in the sky before dawn as seen from northern latitudes. Current rates would be less than 1 per hour no matter your location. With an entry velocity of 60 km/sec., the average meteor from this source would be of swift velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 6 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 9 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates during this period are reduced due to moonlight.

The June Bootids (JBO) are usually a very weak shower that occasionally produces outbursts. Nothing out of the ordinary is expected this year but with the moon out of the way so viewing for unusual activity is warranted. These meteors are best seen from June 23-25, with maximum activity occurring on the 23rd. At maximum the radiant is located at 14:56 (224) +48. This position lies in northwestern Bootes, 15 degrees east of the second magnitude star known as Alkaid (Eta Ursae Majoris). This radiant is best placed in the evening sky just as the sky becomes dark. Observers in the northern hemisphere have a distinct advantage over those located south of the equator as the radiant lies much higher in the evening sky. No matter your location, little activity is expected from this source. With an entry velocity of 13 km/sec., the average June Bootid meteor would be of very slow velocity.

During this period the moon reaches its last quarter phase on Monday June 27th. At this time the moon will lie 90 degrees west of the sun and will rise between midnight and 0100 local daylight saving time for most sites located in mid-northern latitudes. The half-illuminated moon will interfere with meteor observing, but to a much lesser degree than when near its full phase. Toward the end of the period the waning crescent moon will rise during the late morning hours allowing  most of the night to be free of lunar glare. The estimated total hourly meteor rates for evening observers this week is near 2 for observers located in the northern hemisphere and 3 for observers located in tropical southern locations (25S). For morning observers the estimated total hourly rates should be near 4 as seen from mid-northern latitudes (45N) and 6 as seen from tropical southern locations (25S).

Morning rates are reduced duri this period due to interfering moonlight. The actual rate  s 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 estimates 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 June 25/26. 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 center. Vi  ewing 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 far 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 f Ophiuchids (FOP) were discovered by Sirko Molau and Juergen Rendtel using video data from the IMO network of cameras. These meteors are only active on 3 nights centered on June 30th. Maximum actually occurs on June 29th when the radiant is located at 17:40 (265) +08. This area of the sky is located in central Ophiuchus, 3 degrees north of the 3rd magnitude star known as Celbalrai (beta Ophiuchi). The radiant is best placed near midnight LDT when it lies on the meridian and is highest in the sky. Rates of less than 1 per hour are expected, even at maximum. With an entry velocity of 17 km/sec., the average f Ophiuchid meteor would be of very slow velocity.

The center of the large Anthelion (ANT) radiant is currently located at 19:08 (287) -22. This position lies in central Sagittarius, just south of the the twin stars known as pi and omicron Sagittarii.  Due to the large size of this radiant, Anthelion activity may also appear from the nearby constellations of Scutum, Serpens Caput, southern Aquila, and western Capricornus as well as Sagittarius. This radiant is best placed near 0100 local daylight saving (LDST), when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be near 2 as seen from mid-northern latitudes and 3 as seen from tropical southern latitudes. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

The Sigma Capricornids (SCA) were discovered by Zdenek Sekanina and are active for a month lasting from June 19 through July 24. Maximum occurs on June 27th when the radiant is located at 20:24 (306) -07. This area of the sky is actually located in southeastern Aquila, five degrees north of the naked eye double star Algiedi (Alpha Capricornii). The radiant is best placed near 0300 LDT when it lies on the meridian and is highest in the sky. Rates at this time should be near one per hour no matter your location. With an entry velocity of 42 km/sec., the average Sigma Capricornid meteor would be of medium velocity. This velocity is significantly faster than the stronger Alpha Capricornids, which appear from the same general area of the sky during the second half of July.

The Pi Piscids (PPS) were discovered by Dr. Peter Brown in his meteoroid stream survey using the Canadian Meteor Orbit Radar. This shower was later verified by Dr. Peter Jenniskens and David Holman using data from the CAMS network in northern California. These meteors are active from June 11 through July 25 with maximum activity occurring on July 1st. The current position of the radiant is 00:44 (011) +23. This position actually lies in southeastern Andromeda, 2 degrees west of the 4th magnitude star known as eta Andromedae. Rates are currently expected to be less than 1 per hour no matter your location. Rates will increase to near 2 per hour at maximum. With an entry velocity of 68 km/sec., the average Pi Piscid meteor would be of swift speed.

The c-Andromedids (CAN) was discovered by Sirko Molau and Juergen Rendtel using video data from the IMO network. Activity from this source is seen from June 26 though July 20 with maximum activity occurring on July 12. The radiant currently lies at 00:54 (013) +41, which places it in northern Andromeda, close to the faint star known as nu Andromedae. This position is also just 1 degree east of the naked eye Andromeda Galaxy. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Observers in the northern hemisphere are better situated to view this activity as the radiant rises much higher in the sky before dawn as seen from northern latitudes. Current rates would be less than 1 per hour no matter your location. With an entry velocity of 60 km/sec., the average meteor from this source would be of swift velocity.

As seen from the mid-norther hemisphere (45N) one would expect to see approximately 6 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 9 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates during this period are reduced due to moonlight.

BREAKING NEWS: New Study Reinforces Cyclical Magnetic Pole Reversals

It is important to understand there are scientifically identified varying forms of cyclical events, sometimes referred to as time-variable control parameters. As it is with the nature of scientific formulas and equations, it can be a bit complicated. Therefore, I will explain in a way that is reflective of schematics.

magnetic-field-earth

Specially related to Geophysics and Paleomagnetism, periods of magnetic reversals are basically defined in three forms of cycles. The reason for such variables, is unlike the study of solar cycles goes back only a few hundred years, the research related to Earth’s magnetic reversals covers billions of years. And to this researcher, it highlights Earth’s relationship to our galaxy Milky Way and beyond which I believe already shows cycles going back hundreds of thousands years, and at the rate of new research coming in, I believe new data will identify cyclical events related to our solar system going back to near the Big Bang.

http://www.dreamstime.com/stock-photo-earth-core-structure-to-scale-isolated-illustrated-geological-layers-according-black-elements-d-image-furnished-image38470080

One measurement of a magnetic reversal (MR) is defined as ‘below random’. The reason for this variable is the period between supercrons and clustering. This is because of the variance in convection between the Earth’s core and mantle. In simple terms, it is yet specifically identified as to the external cause of heating and cooling cycles of Earth’s core. Again, to this writer, it is a sure sign the convection process goes far beyond or Sun’s influence. Remember, the Sun’s magnetic field reversal has only a 22 year oscillation; which actually suggests it plays a small part related to Earth’s magnetic reversal. However, this does not mean the solar flux does not cause harmful effects to Earth and humans. During times of high solar activity, solar flares and cmes can pierce through the magnetic field. And during times of low solar activity, the lack of solar plasma allows the more harmful and damaging Galactic Cosmic Rays to enter our atmosphere which brings with it a blast of radiation.

liquid-core

A second measurement of a MR cycle is defined as ‘nearly periodic’. Again, this has to do with periods of Earth’s development such as the Paleozoic, Mesozoic, and Cenozoic eras. As the Earth’s inner core developed, of course this would have a developing influence on the convection process.

A third measurement of a MR cycle is defined as ‘time-dependent periodic’. This is to say, from the time of Earth’s fully developed inner core, there is a time-dependent cycle of magnetic fluctuation of a pre, during, and post reversal. The reason for the term “time-dependent” is directly related to the ebb and flow of mantle plumes. In other words, it is directly related to the heating and cooling of Earth’s core through the process of convection.

multipile magnetic fields ancient earth

Why is this important? Because it can be fully identified and measured. In other words, there will be signs and symptoms during the process. In fact, we are already seeing them. First the magnetic north pole will drift. It will continue and speed up over time and may go as far south as 40th degree parallel. Then in its final stages it will bounce back and forth between north and south, then finally and perhaps in a single day, flip completely.

More coming soon…………

 

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X-ray Echoes Of A Shredded Star Provide Close-up Of ‘Killer’ Black Hole

Some 3.9 billion years ago in the heart of a distant galaxy, the intense tidal pull of a monster black hole shredded a star that passed too close. When X-rays produced in this event first reached Earth on March 28, 2011, they were detected by NASA’s Swift satellite, which notified astronomers around the world. Within days, scientists concluded that the outburst, now known as Swift J1644+57, represented both the tidal disruption of a star and the sudden flare-up of a previously inactive black hole.

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Now astronomers using archival observations from Swift, the European Space Agency’s (ESA) XMM-Newton observatory and the Japan-led Suzaku satellite have identified the reflections of X-ray flares erupting during the event. Led by Erin Kara, a postdoctoral researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland, College Park (UMCP), the team has used these light echoes, or reverberations, to map the flow of gas near a newly awakened black hole for the first time.

“While we don’t yet understand what causes X-ray flares near the black hole, we know that when one occurs we can detect its echo a couple of minutes later, once the light has reached and illuminated parts of the flow,” Kara explained. “This technique, called X-ray reverberation mapping, has been previously used to explore stable disks around black holes, but this is the first time we’ve applied it to a newly formed disk produced by a tidal disruption.”

Stellar debris falling toward a black hole collects into a rotating structure called an accretion disk. There the gas is compressed and heated to millions of degrees before it eventually spills over the black hole’s event horizon, the point beyond which nothing can escape and astronomers cannot observe. The Swift J1644+57 accretion disk was thicker, more turbulent and more chaotic than stable disks, which have had time to settle down into an orderly routine. The researchers present the findings in a paper published online in the journal Nature on Wed., June 22.

One surprise from the study is that high-energy X-rays arise from the inner part of the disk. Astronomers had thought most of this emission originated from a narrow jet of particles accelerated to near the speed of light. In blazars, the most luminous galaxy class powered by supermassive black holes, jets produce most of the highest-energy emission.

“We do see a jet from Swift J1644, but the X-rays are coming from a compact region near the black hole at the base of a steep funnel of inflowing gas we’re looking down into,” said co-author Lixin Dai, a postdoctoral researcher at UMCP. “The gas producing the echoes is itself flowing outward along the surface of the funnel at speeds up to half the speed of light.”

X-rays originating near the black hole excite iron ions in the whirling gas, causing them to fluoresce with a distinctive high-energy glow called iron K-line emission. As an X-ray flare brightens and fades, the gas follows in turn after a brief delay depending on its distance from the source.

“Direct light from the flare has different properties than its echo, and we can detect reverberations by monitoring how the brightness changes across different X-ray energies,” said co-author Jon Miller, a professor of astronomy at the University of Michigan in Ann Arbor.

Swift J1644+57 is one of only three tidal disruptions that have produced high-energy X-rays, and to date it remains the only event caught at the peak of this emission. These star shredding episodes briefly activate black holes astronomers wouldn’t otherwise know about. For every black hole now actively accreting gas and producing light, astronomers think nine others are dormant and dark. These quiescent black holes were active when the universe was younger, and they played an important role in how galaxies evolved. Tidal disruptions therefore offer a glimpse of the silent majority of supersized black holes.

“If we only look at active black holes, we might be getting a strongly biased sample,” said team member Chris Reynolds, a professor of astronomy at UMCP. “It could be that these black holes all fit within some narrow range of spins and masses. So it’s important to study the entire population to make sure we’re not biased.”

The researchers estimate the mass of the Swift J1644+57 black hole at about a million times that of the sun but did not measure its spin. With future improvements in understanding and modeling accretion flows, the team thinks it may be possible to do so.