NASA | IPCC Projections of Temperature and Precipitation in the 21st Century


New data visualizations from the NASA Center for Climate Simulation and NASA’s Scientific Visualization Studio show how climate models — those used in the new report from the United Nations’ Intergovernmental Panel on Climate Change (IPCC) — estimate how temperature and precipitation patterns could change throughout the 21st century.
For the IPCC’s Physical Science Basis and Summary for Policymakers reports, scientists referenced an international climate modeling effort to study how the Earth might respond to four different scenarios of how much carbon dioxide and other greenhouse gases would be emitted into the atmosphere throughout the 21st century.

The Summary for Policymakers, the first official piece of the group’s Fifth Assessment Report, was released Fri., Sept. 27.

That modeling effort, called the Coupled Model Intercomparison Project Phase 5 (CMIP5), includes dozens of climate models from institutions around the world, including from NASA’s Goddard Institute for Space Studies.

To produce visualizations that show temperature and precipitation changes similar to those included in the IPCC report, the NASA Center for Climate Simulation calculated mean model results for each of the four emissions scenarios. The final products are visual representations how much temperature and precipitation patterns would change through 2100 compared to the historical average from the end of the 20th century. The changes shown compare the model projections to the average temperature and precipitation benchmarks observed from 1971-2000. This baseline is different from the IPCC report, which uses a 1986-2005 baseline. Because the reference period from 1986-2005 was slightly warmer than 1971-2000, the visualizations are slightly different than those in the report, even though the same model data is used.

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NASA’s Mars Rover Team Has More Sad News About Mars


The rover Curiosity found much less methane gas on the Martian surface than expected, further closing the door on hopes for microbes on Mars.

The Sun’s Heat Wave


Extracted news site Sky and Telescope

Coronal hole

Growing evidence suggests that magnetic waves are the reason our star’s corona is so hot.

A close-up, false-color look at the Sun shows the large, dark polar coronal hole astronomers studied in order to determine what heats our star’s corona. White lines show the position of the Hinode spacecraft’s spectrometer slits, used to observe gas motions in the corona.
Courtesy Michael Hahn

Last week, while many of us were suffering from sweltering temperatures, solar physicists meeting in Bozeman, Montana, were discussing their own heat problem: the enduring mystery of why the Sun’s corona is roughly 100 times hotter than the layers below it.

A new analysis by Michael Hahn and Daniel Savin (Columbia University) suggests that astronomers might have the culprit in hand. This culprit, the so-called Alfvénic waves, has been a suspect for more than seven decades. The oscillations move along solar magnetic field lines like the vibrations in a plucked guitar string, and it’s thought that somehow they transfer their energy to the Sun’s hot, ionized gas. In 2011 the waves were detected permeating the upper solar atmosphere.

Last year two teams (one including Hahn and Savin) reported observations suggesting the waves were indeed dumping their energy into the corona. Both teams agreed that this energy might not only heat the corona but power the fast solar wind, the charged particles that stream out from coronal holes at 800 kilometers per second. But the researchers didn’t know how much energy the waves were depositing.

Hahn and Savin reanalyzed a subset of their previous observations from the Hinode spacecraft to try to answer this question. The astronomers couldn’t observe the waves directly; instead, they looked at how wide various spectral lines were for ionized elements (primarily iron) in the corona. This width depends on two things: how hot the gas is, and how much the Alfvénic waves slosh the gas along the line of sight (which in turn depends on the waves’ energy).

Unfortunately, astronomers can’t directly solve for both the temperature and the wave sloshing without making some assumptions. The Columbia duo made two: one, the ions’ temperature doesn’t change at different heights; two, the waves haven’t yet lost their energy when they reach the corona’s base. These assumptions are based on observations and should be reasonable, Hahn says.

wave energy lost in coronal hole

This graph shows the amount of energy lost by magnetic waves in the lower regions of the solar corona. Between 1.1 and 1.5 solar radii from the Sun’s center, the waves appear to lose enough energy to heat the plasma in the coronal hole and power the fast solar wind.
Michael Hahn

Using these assumptions, Hahn and Savin managed to separate the temperature and wave contributions. That in turn allowed them to calculate how much energy the waves lost as they moved higher into the corona. The team found that, by the time the waves had traveled through the lowest quarter or so of the solar atmosphere, they had lost roughly 600 watts per square meter — just what’s needed to heat both the gas in the coronal hole and power the fast solar wind coming from it during the solar minimum, when the observations were taken.

“These results are very important, but unfortunately this is not the ‘end’ to the long story of the coronal heating problem,” says Alessandro Bemporad (Turin Astronomical Observatory, Italy), who coauthored the other 2012 study exploring Alfvénic waves’ energy loss. The assumptions and corrections made for instrumental effects are reasonable, but it’s hard to determine whether such corrections are in fact correct, he explains. Plus, no one knows exactly what kind of wave astronomers are detecting (hence my use of –ic in the waves’ name) or why the waves would lose energy. “Many, many questions are still open.”

The result also only applies to coronal holes, so it’s unclear whether the magnetic waves would be able to heat other regions of the corona, which are generally hotter. Hahn says they hope to look at that issue next.

They’re also exploring the lingering question of how the waves lose their energy. Among the possibilities are friction from the ionized gas as the waves move the plasma around and reflection, in which changes in the plasma’s properties (such as density or magnetic field) could cause some waves to reflect back and interact with outgoing waves, creating turbulence that ultimately encourages the waves to lose energy faster than usual.

NASA | IBEX Provides First View of the Solar System’s Tail


NASA’s Interstellar Boundary Explorer, or IBEX, recently mapped the boundaries of the solar system’s tail, called the heliotail. By combining observations from the first three years of IBEX imagery, scientists have mapped out a tail that shows a combination of fast and slow moving particles. The entire structure twisted, because it experiences the pushing and pulling of magnetic fields outside the solar system

NASA Mars Curiosity Rover Report


A NASA Mars Curiosity rover team member gives an update on developments and status of the planetary exploration mission. The Mars Science Laboratory spacecraft delivered Curiosity to its target area on Mars at 1:31:45 a.m. EDT on Aug. 6, 2012 which includes the 13.8 minutes needed for confirmation of the touchdown to be radioed to Earth at the speed of light. The rover will conduct a nearly two-year prime mission to investigate whether the Gale Crater region of Mars ever offered conditions favorable for microbial life.

Curiosity carries 10 science instruments with a total mass 15 times as large as the science payloads on NASA’s Mars rovers Spirit and Opportunity. Some of the tools, such as a laser-firing instrument for checking rocks’ elemental composition from a distance, are the first of their kind on Mars. Curiosity will use a drill and scoop, which are located at the end of its robotic arm, to gather soil and powdered samples of rock interiors, then sieve and parcel out these samples into the rover’s analytical laboratory instruments.

Sunny super-Earth?


Noticie extracted from site Thecnology.org

Posted on June 14, 2013

Image of Super-Earth “GJ3470b”. The size of the planet (front) and primary star (back) is draw with actual ratio.

Image of Super-Earth “GJ3470b”. The size of the planet (front) and primary star (back) is draw with actual ratio.

Researchers from NAOJ and the University of Tokyo have observed the atmosphere of super-Earth “GJ3470b” in Cancer for the first time in the world using two telescopes at OAO (Okayama Astrophysical Observatory, NAOJ). This super-Earth is an exoplanet, having only about 14 times the mass of our home planet, and it is the second lightest one among already-surveyed exoplanets. The observational data revealed that this planet is highly likely to NOT be covered by thick clouds.

The researchers expect that future detection of the specific composition of the planet’s atmosphere based on highly accurate observations with larger aperture telescopes, such as the Subaru Telescope. This planet orbits around its primary star very closely at a rapid rate. We don’t yet understand the formation process of such planets. If future detailed observations of the atmosphere detect any substance that becomes ice at low temperatures, it probably means that this planet was originally formed at a distance (a few astronomical units) from the primary star, where ice could exist, and moved toward the primary star thereafter. In contrast, if such a substance cannot be found in the atmosphere, this planet was quite likely formed at its present location (near the primary star) from its early stage. Thus, it is expected that the detailed observations of the atmosphere of GJ3470b can begin to reveal the mysteries behind the formation of super-Earths.

Details of results

It is very difficult to measure the radii of exoplenets, so in many cases we have information only about masses. However, if an exoplanet has a particular orbit of “Planetary Transit (Primary Transit)” where it passes in front of the primary star (parent star), we can estimate the radius of the planet. During the transit, the observed brightness of the star slightly drops depending on the size of the planet. So, we can estimate the radius of the planet by measuring the fading rate of light very precisely.

Read more at: Phys.org

Researchers claim reexamination of rock samples confirms meteoritic origin of Tunguska cosmic body


Noticies extracted from site Thecnology. org

SEM images of the Tunguska diamond-lonsdaleite-graphite intergrowths with natural rounded surface. Credit: Planetary and Space Science, http://dx.doi.org/10.1016/j.pss.2013.05.003

SEM images of the Tunguska diamond-lonsdaleite-graphite intergrowths with natural rounded surface. Credit: Planetary and Space Science, http://dx.doi.org/10.1016/j.pss.2013.05.003

A team of researchers with members from the U.S., Germany and Ukraine is claiming in a paper they’ve had published in the journal Planetary and Space Science, that they have found evidence to prove the Tunguska event was caused by a meteor that exploded in the atmosphere above the Russian plain.

The Tunguska event was, of course, an explosion that occurred in a remote part of Siberia in 1908. Most scientists agree that it was caused by either a meteor or comet strike, and as such, was the largest to ever strike our planet in recorded history. The blast flattened thousands of acres of forestland and led to numerous research efforts to determine its cause. Due to the immense power of the blast however, no physical evidence of the source of the blast has ever been found. Now, however, the researchers in this new effort claim they have found proof that some rocks found by a Ukrainian scientist back in 1978 are remnants of the meteor that caused the massive explosion.

The rock samples were found in a bog by Mykola Kovalyukh near the epicenter of the explosion—he claimed at the time that his samples offered proof that the explosion was caused by a meteor. Critics dismissed his claims however, because the rock samples contained too little iridium.

Picking up where Kovalyukh left off, the new team working in the Ukraine used more modern tools to reexamine the stone samples. They claim that transmission electron microscopy has revealed finely veined iron-based minerals that include schreibersite, troilite and taenite, an iron–nickel alloy. They say the patterns and amounts of the materials in the rock samples are very similar to other known meteorite samples and thus, it is a near certainty that the samples found in the bog came from a meteor as well.