Posts tagged solar system

Science and Space Posters by Ron Guyatt

Part of a series for spacevidcast.com to help inspire and spread the Good Word of Science! Prints available at etsy.

Artist: Tumblr / Website / Facebook

via ianbrooks

(via project-argus)

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Potential Future Landing Site in Holden Crater

Potential Future Landing Site in Holden Crater

(Source: beautifulmars, via darylelockhart)

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WHAT IF other planetary bodies orbited our world at the same distance as the moon?

(via distant-traveller)

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I look up — many people feel small because they’re small and the Universe is big — but I feel big, because my atoms came from those stars. There’s a level of connectivity.

That’s really what you want in life, you want to feel connected, you want to feel relevant, you want to feel like a participant in the goings on of activities and events around you.

That’s precisely what we are, just by being alive…


- Dr. Neil DeGrasse Tyson [ x ]

(Source: kavaeric, via songsofstarlight)

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Lord of the Rings, Saturn

(via expose-the-light)

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scinerds:

New Mars Photo Christens Deep-Space Antenna


  Europe’s newest deep-space tracking station has received its first interplanetary message: a photo of a half-lit Mars as seen by an orbiting spacecraft.

scinerds:

New Mars Photo Christens Deep-Space Antenna

Europe’s newest deep-space tracking station has received its first interplanetary message: a photo of a half-lit Mars as seen by an orbiting spacecraft.

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 Water found on Mercury

Permanently Shadowed Polar Craters  Shown in red are areas of Mercurys north polar region that are in shadow in all images acquired by MESSENGER to date. Image coverage, and mapping of shadows, is incomplete near the pole. The polar deposits imaged by Earth-based radar are in yellow (from Image 2.1), and the background image is the mosaic of MESSENGER images from Image 2.2. This comparison indicates that all of the polar deposits imaged by Earth-based radar are located in areas of persistent shadow as documented by MESSENGER images. Updated from N. L. Chabot et al., Journal of Geophysical Research, 117, doi: 10.1029/2012JE004172 (2012). New observations by the MESSENGER spacecraft provide compelling support for the long-held hypothesis that Mercury harbors abundant water ice and other frozen volatile materials in its permanently shadowed polar craters.

Three independent lines of evidence support this conclusion: the first measurements of excess hydrogen at Mercury’s north pole with MESSENGER’s Neutron Spectrometer, the first measurements of the reflectance of Mercury’s polar deposits at near-infrared wavelengths with the Mercury Laser Altimeter (MLA), and the first detailed models of the surface and near-surface temperatures of Mercury’s north polar regions that utilize the actual topography of Mercury’s surface measured by the MLA. These findings are presented in three papers published online today in Science Express.

Given its proximity to the Sun, Mercury would seem to be an unlikely place to find ice. But the tilt of Mercury’s rotational axis is almost zero — less than one degree — so there are pockets at the planet’s poles that never see sunlight. Scientists suggested decades ago that there might be water ice and other frozen volatiles trapped at Mercury’s poles.

The idea received a boost in 1991, when the Arecibo radio telescope in Puerto Rico detected unusually radar-bright patches at Mercury’s poles, spots that reflected radio waves in the way one would expect if there were water ice. Many of these patches corresponded to the location of large impact craters mapped by the Mariner 10 spacecraft in the 1970s. But because Mariner saw less than 50 percent of the planet, planetary scientists lacked a complete diagram of the poles to compare with the images.

MESSENGER’s arrival at Mercury last year changed that. Images from the spacecraft’s Mercury Dual Imaging System taken in 2011 and earlier this year confirmed that radar-bright features at Mercury’s north and south poles are within shadowed regions on Mercury’s surface, findings that are consistent with the water-ice hypothesis.

Now the newest data from MESSENGER strongly indicate that water ice is the major constituent of Mercury’s north polar deposits, that ice is exposed at the surface in the coldest of those deposits, but that the ice is buried beneath an unusually dark material across most of the deposits, areas where temperatures are a bit too warm for ice to be stable at the surface itself.

MESSENGER uses neutron spectroscopy to measure average hydrogen concentrations within Mercury’s radar-bright regions. Water-ice concentrations are derived from the hydrogen measurements. “The neutron data indicate that Mercury’s radar-bright polar deposits contain, on average, a hydrogen-rich layer more than tens of centimeters thick beneath a surficial layer 10 to 20 centimeters thick that is less rich in hydrogen,” writes David Lawrence, a MESSENGER Participating Scientist based at The Johns Hopkins University Applied Physics Laboratory and the lead author of one of the papers. “The buried layer has a hydrogen content consistent with nearly pure water ice.”

Data from MESSENGER’s Mercury Laser Altimeter (MLA) — which has fired more than 10 million laser pulses at Mercury to make detailed maps of the planet’s topography — corroborate the radar results and Neutron Spectrometer measurements of Mercury’s polar region, writes Gregory Neumann of the NASA Goddard Space Flight Center. In a second paper, Neumann and his colleagues report that the first MLA measurements of the shadowed north polar regions reveal irregular dark and bright deposits at near-infrared wavelength near Mercury’s north pole.

“These reflectance anomalies are concentrated on poleward-facing slopes and are spatially collocated with areas of high radar backscatter postulated to be the result of near-surface water ice,” Neumann writes. “Correlation of observed reflectance with modeled temperatures indicates that the optically bright regions are consistent with surface water ice.”


The MLA also recorded dark patches with diminished reflectance, consistent with the theory that the ice in those areas is covered by a thermally insulating layer. Neumann suggests that impacts of comets or volatile-rich asteroids could have provided both the dark and bright deposits, a finding corroborated in a third paper led by David Paige of the University of California, Los Angeles.

Paige and his colleagues provided the first detailed models of the surface and near-surface temperatures of Mercury’s north polar regions that utilize the actual topography of Mercury’s surface measured by the MLA. The measurements “show that the spatial distribution of regions of high radar backscatter is well matched by the predicted distribution of thermally stable water ice,” he writes.

According to Paige, the dark material is likely a mix of complex organic compounds delivered to Mercury by the impacts of comets and volatile-rich asteroids, the same objects that likely delivered water to the innermost planet.The organic material may have been darkened further by exposure to the harsh radiation at Mercury’s surface, even in permanently shadowed areas.

This dark insulating material is a new wrinkle to the story, says Sean Solomon of the Columbia University’s Lamont-Doherty Earth Observatory, principal investigator of the MESSENGER mission. “For more than 20 years the jury has been deliberating on whether the planet closest to the Sun hosts abundant water ice in its permanently shadowed polar regions. MESSENGER has now supplied a unanimous affirmative verdict.”

“But the new observations have also raised new questions,” adds Solomon. “Do the dark materials in the polar deposits consist mostly of organic compounds? What kind of chemical reactions has that material experienced? Are there any regions on or within Mercury that might have both liquid water and organic compounds? Only with the continued exploration of Mercury can we hope to make progress on these new questions.”

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This is a false-color composite image of Valles Marineris, Planet Mars’ very own Grand Canyon, captured by the High Resolution Stereo Camera (HRSC) aboard ESA’s Mars Express spacecraft. Stretching across the Martian highlands for 2,485 miles (4,000 kilometers) in length, 124 miles wide and up to 6.8 miles deep, Valles Marineris is considered one of the largest known canyon systems in the solar system.

This is a false-color composite image of Valles Marineris, Planet Mars’ very own Grand Canyon, captured by the High Resolution Stereo Camera (HRSC) aboard ESA’s Mars Express spacecraft. Stretching across the Martian highlands for 2,485 miles (4,000 kilometers) in length, 124 miles wide and up to 6.8 miles deep, Valles Marineris is considered one of the largest known canyon systems in the solar system.

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1. The Orion Nebula is arguably the finest of all nebulae within the Milky Way visible from the Northern Hemisphere. With a gaseous repository of 10,000 suns, and illuminated by a cluster of hot young stars, the clouds of Messier 42 — as it is also known — glow with fantastic colors and shapes, giving us a bird’s eye view of one of the greatest star forming nurseries in our part of the Milky Way. Messier 42 is a complex of glowing gas, mostly hydrogen but also helium, carbon, nitrogen, and oxygen in decreasing amounts, located 1,500 light-years away. At its very heart, we find the Trapezium, a group of four very hot stars that illuminate the nebula. They are the brightest of an extended cluster of several thousand young stars many of which lie unseen within the opaque gas and dust. Amazingly, whilst the Orion Nebula is easy to identify with the unaided eye, there is apparently no written record of its existence before the 17th century. This image is based on data acquired with the 1.5 m Danish telescope at the ESO La Silla Observatory in Chile, through three filters (B: 60 s, V: 30 s, R: 21 s). East is at the upper right corner and North is at the lower right. Credit: ESO/IDA/Danish 1.5 m/R.Gendler, J.-E. Ovaldsen, and A. Hornstrup.

2. This photo was taken on the plain of Castelluccio by Maurizio Pignotti. Shooting data: 12 shots with Canon 5d old - sigma 12/24 - ISO 800 to 470 Second Heaven - 30 seconds static subject - Star Tracker DIY - tripod - remote control. Double exposure. Credit: Maurizio Pignotti.

3. A prominence is a large, bright feature extending outward from the Sun’s surface, often in a loop shape. Prominences are anchored to the Sun’s surface in the photosphere, and extend outwards into the Sun’s corona. While the corona consists of extremely hot ionized gases, known as plasma, which do not emit much visible light, prominences contain much cooler plasma, similar in composition to that of the chromosphere. A prominence forms over timescales of about a day, and stable prominences may persist in the corona for several months. Credit: Alan Friedman

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