Water Hidden in the Moon May Have Proto-Earth Origin

Water found in ancient Moon rocks might have actually originated from the proto-Earth and even survived the Moon-forming event. Latest research into the amount of water within lunar rocks returned during the Apollo missions is being presented by Jessica Barnes at the European Planetary Science Congress in London on Monday 9th September.

The Moon, including its interior, is believed to be much wetter than was envisaged during the Apollo era. The study by Barnes and colleagues at The Open University, UK, investigated the amount of water present in the mineral apatite, a calcium phosphate mineral found in samples of the ancient lunar crust.

“These are some of the oldest rocks we have from the Moon and are much older than the oldest rocks found on Earth. The antiquity of these rocks make them the most appropriate samples for trying to understand the water content of the Moon soon after it formed about 4.5 billion years ago and for unraveling where in the Solar System that water came from,” Barnes explains.

Barnes and her colleagues have found that the ancient lunar rocks contain appreciable amounts of water locked into the crystal structure of apatite. They also measured the hydrogen isotopic signature of the water in these lunar rocks to identify the potential source(s) for the water.

“The water locked into the mineral apatite in the Moon rocks studied has an isotopic signature very similar to that of the Earth and some carbonaceous chondrite meteorites,” says Barnes. “The remarkable consistency between the hydrogen composition of lunar samples and water-reservoirs of the Earth strongly suggests that there is a common origin for water in the Earth-Moon system.”

Source : Science Daily

N.H.Khider

'World's largest volcano discovered beneath Pacific

 

 

 

Scientists say that they have discovered the single largest volcano in the world, a dead colossus deep beneath the Pacific waves.

A team writing in the journal Nature Geoscience says the 310,000 sq km (119,000 sq mi) Tamu Massif is comparable in size to Mars' vast Olympus Mons volcano - the largest in the Solar System.

The structure topples the previous largest on Earth, Mauna Loa in Hawaii.

The massif lies some 2km below the sea.

It is located on an underwater plateau known as the Shatsky Rise, about 1,600km east of Japan.

It was formed about 145 million years ago when massive lava flows erupted from the centre of the volcano to form a broad, shield-like feature.

The researchers doubted the submerged volcano's peak ever rose above sea level during its lifetime and say it is unlikely to erupt again.

"The bottom line is that we think that Tamu Massif was built in a short (geologically speaking) time of one to several million years and it has been extinct since," co-author William Sager, from the University of Houston, US, told the AFP news agency.

"One interesting angle is that there were lots of oceanic plateaus (that) erupted during the Cretaceous Period (145-65 million years ago) but we don't see them since. Scientists would like to know why."

Prof Sager began studying the structure two decades ago, but it had been unclear whether the massif was one single volcano or many - a kind that exists in dozens of locations around the planet.

While Olympus Mons on Mars has relatively shallow roots, the Tamu Massif extends some 30 km (18 miles) into the Earth's crust.

And other volcanic behemoths could be lurking among the dozen or so large oceanic plateaux around the world, he thought.

"We don't have the data to see inside them and know their structure, but it would not surprise me to find out that there are more like Tamu out there," said Dr Sager.

"Indeed, the biggest oceanic plateau is Ontong Java plateau, near the equator in the Pacific, east of the Solomon Islands. It is much bigger than Tamu - it's the size of France."

The name Tamu comes from Texas A&M University, where Prof Sager previously taught before moving to the University of Houston

Source : BBC

N.H.Khider

 

 

 

Blue Light Observations Indicate Water-Rich Atmosphere of Super-Earth

A Japanese research team of astronomers and planetary scientists has used Subaru Telescope's two optical cameras, Suprime-Cam and the Faint Object Camera and Spectrograph (FOCAS), with a blue transmission filter to observe planetary transits of super-Earth GJ 1214 b (Gilese 1214 b). The team investigated whether this planet has an atmosphere rich in water or hydrogen. The Subaru observations show that the sky of this planet does not show a strong Rayleigh scattering feature, which a cloudless hydrogen-dominated atmosphere would predict. When combined with the findings of previous observations in other colors, this new observational result implies that GJ 1214 b is likely to have a water-rich atmosphere.

Super-Earths are emerging as a new type of exoplanet (i.e., a planet orbiting a star outside of our Solar System) with a mass and radius larger than Earth's but less than those of ice giants in our Solar System, such as Uranus or Neptune. Whether super-Earths are more like a "large Earth" or a "small Uranus" is unknown, since scientists have yet to determine their detailed properties. The current Japanese research team of astronomers and planetary scientists focused their efforts on investigating the atmospheric features of one super-Earth, GJ 1214 b, which is located 40 light years from Earth in the constellation Ophiuchus, northwest of the center of our Milky Way galaxy. This planet is one of the well-known super-Earths discovered by Charbonneau et. al. (2009) in the MEarth Project, which focuses on finding habitable planets around nearby small stars. The current team's research examined features of light scattering of GJ 1214 b's transit around its star.

Current theory posits that a planet develops in a disk of dense gas surrounding a newly formed star (i.e., a protoplanetary disk). The element hydrogen is a major component of a protoplanetary disk, and water ice is abundant in an outer region beyond a so-called "snow line." Findings about where super-Earths have formed and how they have migrated to their current orbits point to the prediction that hydrogen or water vapor is a major atmospheric component of a super-Earth. If scientists can determine the major atmospheric component of a super-Earth, they can then infer the planet's birthplace and formation history.

Planetary transits enable scientists to investigate changes in the wavelength in the brightness of the star (i.e., transit depth), which indicate the planet's atmospheric composition. Strong Rayleigh scattering in the optical wavelength is powerful evidence for a hydrogen-dominated atmosphere. Rayleigh scattering occurs when light particles scatter in a medium without a change in wavelength. Such scattering strongly depends on wavelength and enhances short wavelengths; it causes greater transit depth in the blue rather than in the red wavelength.

The current team used the two optical cameras Suprime-Cam and FOCAS on the Subaru Telescope fitted with a blue transmission filter to search for the Rayleigh scattering feature of GJ 1214 b's atmosphere. This planetary system's very faint host star in blue light poses a challenge for researchers seeking to determine whether or not the planet's atmosphere has strong Rayleigh scattering. The large, powerful light-collecting 8.2 m mirror of the Subaru Telescope allowed the team to achieve the highest-ever sensitivity in the bluest region.

The team's observations showed that GJ 1214 b's atmosphere does not display strong Rayleigh scattering. This finding implies that the planet has a water-rich or a hydrogen-dominated atmosphere with extensive clouds.

Although the team did not completely discount the possibility of a hydrogen-dominated atmosphere, the new observational result combined with findings from previous research in other colors suggests that GJ 1214 b is likely to have a water-rich atmosphere. The team plans to conduct follow-up observations in the near future to reinforce their conclusion.

Although there are only a small number of super-Earths that scientists can observe in the sky now, this situation will dramatically change when the Transiting Exoplanet Survey Satellite (TESS) begins its whole sky survey of small transiting exoplanets in our solar neighborhood. When new targets become available, scientists can study the atmospheres of many super-Earths with the Subaru Telescope and next generation, large telescopes such as the Thirty Meter Telescope (TMT). Such observations will allow scientists to learn even more about the nature of various super-Earths.

Source:Science Daily

R.Sawas

Researchers a Step Closer to Finding Cosmic Ray Origins

The origin of cosmic rays in the universe has confounded scientists for decades. But a study by researchers using data from the IceCube Neutrino Observatory at the South Pole reveals new information that may help unravel the longstanding mystery of exactly how and where these "rays" (they are actually high-energy particles) are produced.

Cosmic rays can damage electronics on Earth, as well as human DNA, putting astronauts in space especially at risk.

The research, which draws on data collected by IceTop, the IceCube Observatory's surface array of detectors, is published online in Physical Review D, a leading journal in elementary particle physics.

University of Delaware physicist Bakhtiyar Ruzybayev is the study's corresponding author. UD scientists were the lead group for the construction of IceTop with support from the National Science Foundation and coordination by the project office at the University of Wisconsin, Madison.

The more scientists learn about the energy spectrum and chemical composition of cosmic rays, the closer humanity will come to uncovering where these energetic particles originate.

Cosmic rays are known to reach energies above 100 billion giga-electron volts (1011 GeV). The data reported in this latest paper cover the energy range from 1.6 times 106 GeV to 109 GeV.

Researchers are particularly interested in identifying cosmic rays in this interval because the transition from cosmic rays produced in the Milky Way Galaxy to "extragalactic" cosmic rays, produced outside our galaxy, is expected to occur in this energy range.

Exploding stars called supernovae are among the sources of cosmic rays here in the Milky Way, while distant objects such as collapsing massive stars and active galactic nuclei far from the Milky Way are believed to produce the highest energy particles in nature.

As Ruzybayev points out, the cosmic-ray energy spectrum does not follow a simple power law between the "knee" around 4 PeV (peta-electron volts) and the "ankle" around 4 EeV (exa-electron volts), as previously thought, but exhibits features like hardening around 20 PeV and steepening around 130 PeV.

"The spectrum steepens at the 'knee,' which is generally interpreted as the beginning of the end of the galactic population. Below the knee, cosmic rays are galactic in origin, while above that energy, particles from more distant regions in our universe become more and more likely," Ruzybayev explained. "These measurements provide new constraints that must be satisfied by any models that try to explain the acceleration and propagation of cosmic rays."

 

IceTop consists of 81 stations in its final configuration, covering an area of one square kilometer on the South Pole surface above the detectors of IceCube, which are buried over a mile deep in the ice. The analysis presented in this article was performed using data taken from June 2010 to May 2011, when the array consisted of only 73 stations.

The IceCube collaboration includes nearly 250 people from 39 research institutions in 11 countries, including the University of Delaware.

Source:Science Daily

R.Sawas

New Camera Captures Images Moving Faster Than Sound

Researchers have designed a new digital streak camera that captures high-resolution images of projectiles travelling up to 3,350 m/s - 10 times the speed of sound.

The system was designed to replace the outdated film-based streak cameras , researchers said. 

Film-based streak photography records the motion of an object as it passes in front of lens, while the film moves behind a vertical slit aperture during the exposure. The result is a long, continuous composite image of the object. However, the transition from film to digital has changed the photography industry, and the specialized film required for streak photography is no longer being manufactured.

Source: India Times

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