Showing posts with label earth. Show all posts
Showing posts with label earth. Show all posts

Monday, December 26, 2016

Earth's mantle cools more quickly than was previously thought

Oceanic crust newly formed thinner than the old one, according to research. This indicates that the shell thinning earth cooled more quickly than was previously supposed

Studies have shown that the thickness of the newly volcanic crust has thinned over the last 170 million years. At a symposium of the American Geophysical Union, the researchers noted that this newly formed crust cooled two times faster than was previously thought.

From Earth's deep mantle, scientists find a new way volcanoes form Phys.org

This process provides valuable information about how the tectonic plates moderates internal temperature of the planet, according to Harm Van Avendonk, co-author of the study and a geophysicist at the University of Texas at Austin.

The discovery is fascinating, although more information is missing because oceanic crust thickness measurement requires seisimice studies. It also may explain why such supercontinents Pangea broke.

The upwelling of material deep in Earth's mantle can produce Earth.com

The shell is made up of rock earth hot (500-900 ° C at the top), under high pressure. When this material rises to the earth's surface, the pressure drops and rock begins to melt. This material may ascend to the surface by ocean rifts and build new crust. When the jacket temperature is higher, thicker crust is formed.

Comparing now the crust of 170 million years ago it was noticed that the old one is thicker by 1.7 km. The chemical analysis shows the lava rocks in that the mat formed was cooled to 6-11 degrees per 100 million years in the past 2.5 billion years. But the average Jurassic (170 mil. Years), mantle cooled by an average of 15-20 degrees Celsius per 100 million years.

The Structure of the Earth Marcellus Community Science e-education.psu.edu


Researchers have hypothesized that the tectonic plates causes this cooling. By forming new crust and sinking tectonic plates, coat loses heat. It has been found that the mantle beneath the Pacific Ocean (area with little tectonic activity) was cooled to 13 degrees Celsius per 100 million years, and the sheath in the Atlantic was cooled to 37 ° C per 100 million years.

An important factor in temperature variation of the shell is the supercontinent. Atlantic and Indian Ocean have occurred due to breakage Pangaea. Before this process, the mantle underneath has been able to keep high temperature, due to the high thickness of continental crust. When breaking, ocean crust mantle beneath the newly cooled quickly, while lowering the temperature of the mantle beneath the Pacific Ocean remained constant.

Earth - The outer shell Britannica

Also, the accumulation of heat beneath the continental crust (as if Pangaea) in a long time, breaking them. Laurent Montesi, a scientist at the University of Maryland, says that "this may explain why a continent breaks after 100 million years."

Facts About Pangaea the Most Recent Supercontinent Geology In



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The above post is reprinted from materials provided by  Science News . Note: Materials may be edited for content and length.

Sunday, December 18, 2016

First detection of boron on the surface of Mars New finding provides more clues about water habitability

ChemCam target Catabola is a raised resistant calcium sulfate vein with the highest abundance of boron observed so far. The red outline shows the location of the ChemCam target remote micro images (inset). The remote micro images show the location of each individual ChemCam laser point (red crosshairs) and the B chemistry associated with each point (colored bars). The scale bar is 9.2 mm or about 0.36 inches. Credit: JPL-Caltech/MSSS/LANL/CNES-IRAP/William Rapin
Boron has been identified for the first time on the surface of Mars, indicating the potential for long-term habitable groundwater in the ancient past. This finding and others from NASA's Curiosity rover science team will be discussed in a press conference today in San Francisco during the American Geophysical Union conference.

"No prior mission to Mars has found boron," said Patrick Gasda, a postdoctoral researcher at Los Alamos National Laboratory. "If the boron that we found in calcium sulfate mineral veins on Mars is similar to what we see on Earth, it would indicate that the groundwater of ancient Mars that formed these veins would have been 0-60 degrees Celsius [32-140 degrees Fahrenheit] and neutral-to-alkaline pH." The temperature, pH, and dissolved mineral content of the groundwater could make it habitable. 

Mars with oceans - Imgur

The boron was identified by the rover's laser-shooting Chemistry and Camera (ChemCam) instrument, which was developed at Los Alamos National Laboratory in conjunction with the French space agency. Los Alamos' work on discovery-driven instruments like ChemCam stems from the Laboratory's experience building and operating more than 500 spacecraft instruments for national defense. Boron is famously associated with arid sites where much water has evaporated away -- think of the borax that mule teams once hauled from Death Valley. However, environmental implications of the boron found by Curiosity are still open to debate. Scientists are considering at least two possibilities for the source of boron that groundwater left in the veins: 

The Curiosity rover on Mars with a simulated Chem- Cam laser pulse ResearchGate 

It could be that the drying out of part of Gale lake resulted in a boron-containing deposit in an overlying layer, not yet reached by Curiosity. Some of the material from this layer could have later been carried by groundwater down into fractures in the rocks. Or perhaps changes in the chemistry of clay-bearing deposits and groundwater affected how boron was picked up and dropped off within the local sediments.The discovery of boron is only one of several recent findings related to the composition of Martian rocks. Curiosity is climbing a layered Martian mountain and finding rock-composition evidence of how ancient lakes and wet underground environments changed, billions of years ago, in ways that affected their favorability for microbial life.


As the rover has progressed uphill, compositions trend toward more clay and more boron. These and other variations can tell us about conditions under which sediments were initially deposited and about how later groundwater moving through the accumulated layers altered and transported ingredients.Groundwater and chemicals dissolved in it that appeared later on Mars left its effects most clearly in mineral veins that filled cracks in older layered rock. But it also affected the composition of that rock matrix surrounding the veins, and the fluid was in turn affected by the rock.

Map of shallow subsurface water distribution on Mars 

"There is so much variability in the composition at different elevations, we've hit a jackpot," said John Grotzinger, of Caltech, Pasadena, Calif. As the rover gets further uphill, researchers are impressed by the complexity of the lake environments when clay-bearing sediments were being deposited and also by the complexity of the groundwater interactions after the sediments were buried.

"A sedimentary basin such as this is a chemical reactor," Grotzinger said. "Elements get rearranged. New minerals form and old ones dissolve. Electrons get redistributed. On Earth, these reactions support life." Whether Martian life has ever existed is still unknown. No compelling evidence for it has been found. When Curiosity landed in Mars' Gale Crater in 2012 the mission's main goal was to determine whether the area ever offered an environment favorable for microbes.Four recent drilling sites, from "Oudam" this past June through "Sebina" in October, are spaced about 80 feet (about 25 meters) apart in elevation. This uphill pattern allows the science team to sample progressively younger layers that reveal


Mount Sharp's ancient environmental history. "Variations in these minerals and elements indicate a dynamic system," Grotzinger said. "They interact with groundwater as well as surface water. The water influences the chemistry of the clays, but the composition of the water also changes. We are seeing chemical complexity indicating a long, interactive history with the water. The more complicated the chemistry is, the better it is for habitability. The boron and clay underline the mobility of elements and electrons, and that is good for life.


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Monday, October 31, 2016

Another '' Habitable Planet Proxima B'' this exoplanet has important water reserves

Significant water reserves were discovered exoplanet Proxima b, Swiss scientists say. Proxima b could be the closest planet outside the Solar System, a telluric exoplanet, which is in the habitable zone of the star Proxima Centauri.

Proxima b has the same specific features Earth, it can be considered akin to Earth and has significant reserves of water, having dimensions substantially similar to Earth.


Habitable Proxima-b Planet Found Next Door to Milky Way  photo: youtube

All this comes in support of the theory of a life on distant Proxima b exoplanet, say researchers at the University of Berne Swiss. They conducted measurements and necessary research and assume exoplanet Proxima b is slightly larger than Earth, then it reached conclusions that about 90% of the mass of the exoplanet is hard rock specific mountain area and 10% is water, specific oceans. Proxima b is a duplicate of Earth.

According to researchers who study planetary science, small planets are among the best candidates for the role of "second Earth", where life can exist. As a result, studies on such objects will be continued and expanded, according to researchers, reports RIA Novosti news agency.



Recently scientists announced that the star next to the star Proxima Centauri was also invented the closest exoplanet to Earth, which closely resembles the Sun, which was noted potentiometers training cycle dark points.

Remember that Proxima b exoplanet was discovered by researchers this year using spectral analysis method. Spectral analysis is a method of physical research composition of substances by examining its spectrum of radiation.

According to the study published, these variations indicate the presence of a planet, performing a complete orbit around the star in 11.2 days Proxima Centauri. Proxima b exoplanet it is almost 7.5 million kilometers or 0.05 AU of the star (about 5% of the distance from Earth to the Sun).



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Monday, August 22, 2016

How life emerged on Earth? The old theory is removed

The argument is the fact that, until now, knew too little information on how life on Earth is driven.

For several decades, the main hypothesis on the origins of life was linked to the formation ,, primordial soup ", an event which would have occurred during the first bodies as a result of a chemical reaction triggered within an area with warm water. Recent research however, indicate that life on Earth would have appeared in the depths of the oceans, in the so-called hydrothermal vents ,, ".

A study published in the journal Nature Microbiology suggests that the oldest common ancestor of all living beings is fed with hydrogen as a gas in a high temperature environment, such as hydrothermal vents. On the other hand, the primordial soup hypothesis ,, "says that life would appear when an energy source came into contact with water from the Earth's surface, creating simple molecules first. They were subsequently grouped into structures DNA, which in time led to the formation of the first living organisms.

Recent studies made on genes that most likely were present and there were first living cells on Earth have shown that organisms first appeared on our planet in the deep-sea hydrothermal vents. From within these structures, the alkaline fluids penetrate into the ocean water, producing the natural gaps proton concentrations in a manner similar to the activating all living cells.

The research conducted recently suggests that in the early stages of development of living organisms, chemical reactions in the cells of these variations were driven proton. Then, the cells were able to reproduce these individual differences out of the area of ​​activity of hydrothermal vents, colonizing the oceans and, eventually, the entire planet.

Hydrothermal vents are the only known natural structures that could constitute places of occurrence of the first organic molecules. Aeastă hypothesis was accepted on ,, detriment of primordial soup "because until now knew very little about the principles that govern how life is driven.



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