BREAKING NEWS: Supernova Showered Earth with Radioactive Debris

An international team of scientists has found evidence of a series of massive supernova explosions near our solar system, which showered the Earth with radioactive debris. The scientists found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic and Indian Oceans.

supernova mingus

Some theories suggest cosmic rays from the supernova could have increased cloud cover. The scientists believe the supernova in this case were less than 300 light years away; close enough to be visible during the day and comparable to the brightness of the Moon.

The supernova explosions create many heavy elements and radioactive isotopes which are strewn into the cosmic neighborhood. Although Earth would have been exposed to an increased cosmic ray bombardment, the radiation would have been too weak to cause direct biological damage or trigger mass extinctions.

supernova3

Any iron-60 dating from the Earth’s formation more than four billion years ago has long since disappeared. The iron-60 atoms reached Earth in minuscule quantities and so the team needed extremely sensitive techniques to identify the interstellar iron atoms.

The team from Australia, the University of Vienna in Austria, Hebrew University in Israel, Shimizu Corporation and University of Tokyo, Nihon University and University of Tsukuba in Japan, Senckenberg Collections of Natural History Dresden and Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in Germany, also found evidence of iron-60 from an older supernova around eight million years ago, coinciding with global faunal changes in the late Miocene.

supernova_nedir

The iron-60 was concentrated in a period between 3.2 and 1.7 million years ago, which is relatively recent in astronomical terms, said research leader Dr Anton Wallner from The Australian National University (ANU).

“We were very surprised that there was debris clearly spread across 1.5 million years,” said Dr Wallner, a nuclear physicist in the ANU Research School of Physics and Engineering. “It suggests there were a series of supernova, one after another. “It’s an interesting coincidence that they correspond with when the Earth cooled and moved from the Pliocene into the Pleistocene period.”

stellar-wind

The dating showed the fallout had only occurred in two time periods, 3.2 to 1.7 million years ago and eight million years ago. Current results from TU Munich are in line with these findings.

A possible source of the supernova is an ageing star cluster, which has since moved away from Earth, independent work led by TU Berlin has proposed in a parallel publication. The cluster has no large stars left, suggesting they have already exploded as supernova, throwing out waves of debris.

Planet 9 Takes Shape: Newfound Planet In Our Outer Solar System Simulated

Astrophysicists at the University of Bern have modelled the evolution of the putative planet in the outer solar system. They estimate that the object has a present-day radius equal to 3.7 Earth radii and a temperature of minus 226 degrees Celsius.

planet

How big and how bright is Planet 9 if it really exists? What is its temperature and which telescope could find it? These were the questions that Christoph Mordasini, professor at the University of Bern, and his PhD student Esther Linder wanted to answer when they heard about the possible additional planet in the solar system suggested by Konstantin Batygin and Mike Brown of the California Institute of Technology in Pasadena.

The Swiss scientists are experts in modelling the evolution of planets. They usually study the formation of young exoplanets in disks around other stars light years away and the possible direct imaging of these objects with future instruments such as the James Webb Space Telescope.

Therefore, Esther Linder says: “For me candidate Planet 9 is a close object, although it is about 700 times further away as the distance between the Earth and the Sun.” The astrophysicists assume that Planet 9 is a smaller version of Uranus and Neptune — a small ice giant with an envelope of hydrogen and helium. With their planet evolution model they calculated how parameters like the planetary radius or the brightness evolved over time since the solar system has formed 4.6 billion of years ago.

Heated from the inside

In their paper accepted by the journal Astronomy & Astrophysics the scientists conclude that a planet with the projected mass equal to 10 Earth masses has a present-day radius of 3.7 Earth radii. Its temperature is minus 226 degrees Celsius or 47 Kelvin. “This means that the planet’s emission is dominated by the cooling of its core, otherwise the temperature would only be 10 Kelvin,” explains Esther Linder: “Its intrinsic power is about 1000 times bigger than its absorbed power.” Therefore, the reflected sunlight contributes only a minor part to the total radiation that could be detected. This also means that the planet is much brighter in the infrared than in the visual. “With our study candidate Planet 9 is now more than a simple point mass, it takes shape having physical properties,” says Christoph Mordasini.

The researchers also checked if their results explain why planet 9 hasn’t been detected by telescopes so far. They calculated the brightness of smaller and bigger planets on various orbits. They conclude that the sky surveys performed in the past had only a small chance to detect an object with a mass of 20 Earth masses or less, especially if it is near the farthest point of its orbit around the Sun. But NASA’s Wide-field Infrared Survey Explorer may have spotted a planet with a mass equal to 50 Earth masses or more. “This puts an interesting upper mass limit for the planet,” Esther Linder explains. According to the scientists, future telescopes like the Large Synoptic Survey Telescope under construction near Cerro Tololo in Chile or dedicated surveys should be able to find or rule out candidate Planet 9. “That is an exciting perspective,” says Christoph Mordasini.

The study was financed by the research project of the Swiss National Science Foundation PlanetsInTime and the National Center for Competence in Research (NCCR) PlanetS.

Bullet Indicates Lawrence of Arabia Accurate Recall

A bullet fired by Lawrence of Arabia during one of his most famous acts of guerrilla warfare has been discovered in the Arabian Desert by a team of archaeologists, led by the University of Bristol, confirming the accuracy of Lawrence’s own account of the attack in his war memoir Seven Pillars of Wisdom.

lawrence of arabia2

The spent bullet was found at the site of the 1917 Hallat Ammar train ambush – immortalized in a scene in David Lean’s Oscar-winning biopic Lawrence of Arabia – during fieldwork by Bristol’s Professor Nicholas Saunders and Dr Neil Faulkner, and colleagues, as part of the Great Arab Revolt Project (GARP).

The project has excavated dozens of sites across the Arabian Desert associated with the 1916-1918 revolt by Arab forces against the Ottoman Turks, then allied to Germany.  T.E. Lawrence – later known as Lawrence of Arabia – served as a liaison officer with the rebel forces, an experience he described in Seven Pillars of Wisdom.

lawrence-bullet

Professor Nicholas Saunders said: “The bullet we found came from a Colt automatic pistol, the type of gun known to be carried by Lawrence and almost certainly not used by any of the ambush’s other participants.”

While several of Lawrence’s biographers have accused him of embellishing his stories, nothing the archaeologists found at any of the sites they excavated supports this view.

Lawrence and the Bedouin

Dr Neil Faulkner said: “Lawrence has something of a reputation as a teller of tall tales, but this bullet – and the other archaeological evidence we unearthed during ten years of fieldwork – indicates how reliable his account of the Arab Revolt in Seven Pillars of Wisdom is.”

In an unlikely coincidence, just two months ago, another Hallat Ammar connection appeared when a Hejaz Railway engine nameplate came to light after being ‘lost’ for almost 80 years.  Lawrence had given it to the family of his friend, Vyvyan Richards, for safekeeping in 1933 but never retrieved it before his death in 1935.  The inscription is in Ottoman Turkish written in Arabic script and translates as ‘iron road’, that is ‘Hejaz Railway’.

The family tradition records that it was ‘souvenired’ by Lawrence from one of the trains he attacked.  Many of these raids were on bridges and tracks rather than on locomotives, and, when they were, there was little time to safely hang around and take souvenirs.

The best documented example of such an opportunity is the ambush at Hallat Ammar, where the Turkish train had two locomotives not one, and there was ample time to lever off a nameplate.  The ambush was so spectacularly successful that it probably meant more to Lawrence than his other railway attacks, and so could have merited this souvenir.

“It is extraordinary,” Professor Saunders added, “that after 100 years new discoveries like this are still being made, casting new light on a guerrilla war which helped reshape the Middle East after 1918 – the consequences of which we are still living with today.”

BREAKING NEWS: New Study Finds Mantle Plumes, Not Global Warming, Cause of Ice Melt

To understand Greenland’s ice of today – researchers have to go far back into Earth’s history. The island’s lithosphere has hot depths which originate in its distant geological past and cause Greenland’s ice to rapidly flow and melt from below.

greenland-iceland-mantle-plume3

An anomaly zone crosses Greenland from west to east where present-day accelerated ‘mantle plumes’ are shown to be the cause of ice sheets melting in Greenland and Iceland along the Mid-Atlantic-Ridge. With this anomaly, an international team of geoscientists led by Irina Rogozhina and Alexey Petrunin from the GFZ German Research Center for Geosciences could explain observations from radar and ice core drilling data that indicate a widespread melting beneath the ice sheet and increased sliding at the base of the ice that drives the rapid ice flow over a distance of 750 kilometers from the summit area of the Greenland ice sheet to the North Atlantic Ocean.

Iceland - Greenland Mid-Atlantic Ridge3

The North Atlantic Ocean is an area of active plate tectonics. Between 80 and 35 million years ago tectonic processes moved Greenland over an area of abnormally hot mantle material that still today is responsible for the volcanic activity of Iceland. The mantle material heated and thinned Greenland at depth producing a strong geothermal anomaly that spans a quarter of the land area of Greenland.

greenland-iceland-mid-atlantic-ridge

This ancient and long-lived source of heat has created a region where subglacial meltwater is abundant, lubricating the base of the ice and making it flow rapidly. The study indicates that about a half of the ice in north-central Greenland is resting on a thawed bed and that the meltwater is routed to the ocean through a dense hydrological network beneath the ice.

iceland mantle plume

The team of geoscientists has now, for the first time, been able to prove strong coupling between processes deep in the Earth’s interior with the flow dynamics and subglacial hydrology of large ice sheets: “The geothermal anomaly which resulted from the Icelandic mantle-plume tens of millions of years ago is an important motor for today’s hydrology under the ice sheet and for the high flow-rate of the ice” explains Irina Rogozhina. “This, in turn, broadly influences the dynamic behavior of ice masses and must be included in studies of the future response to climate change.”

______________

_science of cycles banner2

We are always in need of additional funds. Please consider
sponsoring our service.

If the banner does not open – Click Here

 

New Study Shows How Black Holes and Galaxies Formed

Until recently, many researchers thought supermassive black holes were seeded by the collapse of some of the first stars. But modeling work by several groups has suggested that this process would only lead to small black holes.

how galaxies and black holes formed.jpg

Kentaro Nagamine at Osaka University’s Department of Earth and Space Science, Isaac Shlosman at the University of Kentucky and co-workers simulated a different situation, in which supermassive black holes are seeded by clouds of gas falling into potential wells created by dark matter – the invisible matter that astronomers believe makes up 85% of the mass of the Universe.

Simulating the dynamics of huge gas clouds is extremely complex, so the team had to use some numerical tricks called ‘sink particles’ to simplify the problem.

“Although we have access to extremely powerful supercomputers at Osaka University’s Cybermedia Center and the National Astronomical Observatory of Japan, we can’t simulate every single gas particle,” explains Nagamine. “Instead, we model small spatial scales using sink particles, which grow as the surrounding gas evolves. This allows us to simulate much longer timescales than was previously possible.”

The researchers found that most seed particles in their simulations did not grow very much, except for one central seed, which grew rapidly to more than 2 million Sun-masses in just 2 million years, representing a feasible path toward a supermassive black hole. Moreover, as the gas spun and collapsed around the central seed it formed two misaligned accretion discs, which have never been observed before.

In other recent work, Nagamine and co-workers described the growth of massive galaxies that formed around the same time as supermassive black holes. “We like to push the frontier of how far back in time we can see,” says Nagamine. The researchers hope their simulations will be validated by real data when NASA’s James Webb Space Telescope, due to be launched in 2018, observes distant sources where direct gas collapse is happening.

Chemistry of Star and Planet Formation

In the last two decades, humanity has discovered thousands of extrasolar planetary systems. Recent studies of star- and planet-formation have shown that chemistry plays a pivotal role in both shaping these systems and delivering water and organic species to the surfaces of nascent terrestrial planets. Professor Geoffrey A. Blake in Chemical Engineering at the California Institute of Technology talked to Duke faculty and students over late-afternoon pizza in the Physics building on the role of chemistry in star and planet formation and finding other Earth-like planets.

chemistry of stars

In the late 18th century, French scholar Pierre-Simon Laplace analyzed what our solar system could tell us about the formation & evolution of planetary systems. Since then, scientists have used the combination our knowledge for small bodies – asteroids – and large bodies – planets – to figure out how solar systems and planets are formed.

In 2015, Professor Blake and other researchers investigated more into ingredients in planets necessary for the development of life.
Using the Earth and our solar system as the basis for their data, they explored the relative disposition of carbon and nitrogen in each stage of star and planet formation to learn more about core formation and atmospheric escape. Analyzing the carbon-silicon atomic ratio in planets and comets, Professor Blake discovered that rocky bodies in the solar system are generally carbon-poor. Since carbon is essential for our survival, however, Blake needed to determine the range of carbon content that terrestrial planets can have and still have active biosystem.

With the Kepler mission, scientists have detected a variety of planetary objects in the universe. How many of these star-planet systems – based on measured distributions – have ‘solar system’ like outcomes? A “solar system” like planetary system has at least one Earth-like planet at approximately 1 astronomical unit (AU) from the star – where more ideal conditions for life can develop – and at least one ice giant like Jupiter at 3-5 AU in order to keep away comets from the Earth-like planet. In our galaxy alone, there are around 10 billion stars and at least 10 million planets. For those stars similar to our sun, there exist over 4 million planetary systems similar to our solar system, with the closest Earth-like planet at 20 light years away. With the rapid improvement of scientific knowledge and technology, Professor Blake estimates that we would be able to collect evidence within next 5-6 years of planets within 40-50 light years to determine if they have a habitable atmosphere.

How does an Earth and a Jupiter form at their ideal distances from a star? Let’s take a closer look at how stars and planets are created – via the astrochemical cycle. Essentially, dense clouds of gas and dust become so opaque and cold that they collapse into a disk. The disk, rotating around a to-be star, begins to transport mass in toward the center and angular momentum outward. Then, approximately 1% of the star mass is left over from the process, which is enough to form planets. This is also why planets around stars are ubiquitous.

How are the planets formed? The dust grains unused by the star collide and grow, forming larger particles at specific distances from the star – called snowlines – where water vapor turns into ice and solidifies. These “dust bunnies” grow into planetesimals (~10-50 km diameter), such as asteroids and comets. If the force of gravity is large enough, the planetesimals increase further in size to form oligarchs (~0.1-10 times the mass of the Earth), that then become the large planets of the solar system.

In our solar system, a process called dynamic reorganization occurred that restructured the order of our planets, putting Uranus before Neptune. This means that if other solar systems did not undergo such dynamic reorganization at an early point in formation of solar system, then other Earths may have lower organic and water content than our Earth. In that case, what constraints do we need to apply to determine if a water/organic delivery mechanism exists for exo-Earths? Although we do not currently have the scientific knowledge to answer this, with ALMA and the next generation of optical/IR telescopes, we will be able image the birth of solar systems directly and better understand how our universe came to be.

To the chemistry students at Duke, Professor Blake relayed an important message: learn chemistry fundamentals very carefully while in college. Over the next 40-50 years, your interests will change gears many times. Strong fundamentals, however, will serve you well, since you are now equipped to learn in many different areas and careers.

BREAKING NEWS: New Study Suggests Moon Has Great Influence on Earth’s Magnetic Field

The Earth’s magnetic field permanently protects us from the charged particles and radiation produced by our Sun. This shield is created by the geodynamo process, the rapid motion of huge quantities of liquid iron alloy in the Earth’s outer core. To maintain this magnetic field until the present day, the classical model required the Earth’s core to have cooled by around 3,000° C over the past 4.3 billion years.

moon's geodynamo

Now, a team of researchers from French National Center for Scientific Research (CNRS) and Université Blaise Pascal1 suggests that, on the contrary, its temperature has fallen by only 300° C. The action of the moon, overlooked until now, is thought to have compensated for this difference and kept the geodynamo active. Their work is published in the March 30 2016 journal Earth and Planetary Science Letters.

moon's magnetic field2

The classical model of the formation of Earth’s magnetic field has raised a major paradox. For the geodynamo to work, the Earth would have had to be totally molten four billion years ago, and its core would have had to slowly cool from around 6800° C at that time to 3800° C today. However, recent modeling of the early evolution of the internal temperature of the planet, together with geochemical studies of the composition of the oldest carbonatites and basalts, do not support such cooling. With such high temperatures being ruled out, the researchers propose another source of energy in their study.

The gravitational effects associated with the presence of the Moon and Sun on Earth induces cyclic deformation of the mantle and oscillations of the axis of rotation. This mechanical forcing applied to the entire planet induces strong currents in the outer core made of an iron alloy of very low viscosity. These currents are sufficient to generate the Earth’s magnetic field.

It is likely that the liquid metallic cores of many early asteroids generated dynamo magnetic fields.
It is likely that the liquid metallic cores of many early asteroids generated dynamo magnetic fields.

The Earth has a slightly flattened shape and rotates about an inclined axis that wobbles around the poles. Its mantle deforms elastically due to tidal effects caused by the moon. The researchers show that this effect could continuously stimulate the motion of the liquid iron alloy making up the outer core, and in return generate Earth’s magnetic field. The Earth continuously receives 3700 billion watts of power through the transfer of the gravitational and rotational energy of the Earth-moon-Sun system, and over 1,000 billion watts is thought to be available to bring about this type of motion in the outer core. This energy is enough to generate the Earth’s magnetic field, which together with the moon, resolves the major paradox in the classical theory. The effect of gravitational forces on a planet’s magnetic field has already been well documented for two of Jupiter’s moons, Io and Europa, and for a number of exoplanets.

moon's core

As neither the rotation of the Earth around its axis, or orientation of the axis, or the orbit of the moon are perfectly regular – their combined influence on Earth’s inner and outer core, becomes unstable causing fluctuations in the geodynamo. This phenomenon helps explain what would be the catalyst for the ebb and flow of mantle plumes.

Historically, this could lead to melting peaks in the deep mantle and possible major volcanic events on the surface of the Earth. This new model underlines that the influence of the moon on the Earth therefore goes well beyond the simple case of the tides.