(via scinerds)Source: space.kinja.com
Beautiful patterns on Mars
This fantastic image by NASA’s High Resolution Imaging Science Experiment (HiRISE) camera shows some of the remarkable patterns which criss-cross Mars’ surface. The Nili Patera dune field has some of the most beautiful patterns seen. Based on the imagery gathered by HiRISE shows that local wind speeds could reach ‘hurricane force’.
(Image credit: NASA/HiRISE)
(via throughascientificlens)Source: fyeahuniverse
Contemplating the Sun
Image Credit & Copyright: Steven Gilbert
Explanation: Have you contemplated your home star recently? Pictured above, a Sun partially eclipsed on the top left by the Moon is also seen eclipsed by earthlings contemplating the eclipse below. The above menagerie of silhouettes was taken from the Glenn Canyon National Recreational Area near Page, Arizona, USA, where park rangers and astronomers expounded on the unusual event to interested gatherers. Also faintly visible on the Sun’s disk, just to the lower right of the dark Moon’s disk, is a group of sunspots. Although exciting, some consider this event a warm-up act for next week’s chance to comtemplate the Sun — a much more rare partial eclipse by the planet Venus.
(via moonpedia)Source: apod.nasa.gov
Edge-on View of Near-Earth Asteroids
New results from NASA’s NEOWISE survey find that more potentially hazardous asteroids (PHAs), are closely aligned with the plane of our solar system than previous models suggested. PHAs are defined as being large enough to survive passage through Earth’s atmosphere and cause damage on a regional, or greater, scale.
This diagram shows an edge-on view of our solar system. The dots represent a snapshot of the population of NEAs and PHAs that scientists think are likely to exist based on the NEOWISE survey. Positions of a simulated population of PHAs on a typical day are shown in bright orange, and the simulated NEAs are blue. Earth’s orbit is green.
The diagram shows that the orbits of the PHAs tend to be more closely aligned with the plane of our solar system, or less tilted above and below the plane, than the NEAs. This characteristic of PHAs was known before the NEOWISE survey. Now, NEOWISE has found the PHAs to be about twice as likely to have these “lower-inclination” orbits than previously thought.
The latest NEOWISE results provide the best count yet of the total PHA population, finding about 4,700 plus or minus 1,500, with diameters larger than 100 meters. These numbers are in loose agreement with prior, rougher predictions. The NEOWISE team estimates that about 20 to 30 percent of the PHAs thought to exist have actually been discovered to date.
The Hustle and Bustle of our Solar System
This diagram illustrates the differences between orbits of a typical near-Earth asteroid (blue) and a potentially hazardous asteroid, or PHA (orange). Our yellow sun sits at the center of the crowd, while the orbits of the planets Mercury, Venus and Mars are shown in grey.
Earth’s orbit stands out in green between Venus and Mars. As the diagram indicates, the PHAs tend to have more Earth-like orbits than the rest of the NEAs. The asteroid orbits are simulations of what a typical object’s path around the sun might look like.
The dots in the background are based on data from NASA’s NEOWISE, the asteroid-hunting portion of the WISE space telescope, which scanned the whole sky twice in infrared light before entering hibernation mode in 2011. The blue and orange dots represent a simulation of the population of near-Earth asteroids and the PHAs, respectively, which are larger than 100 meters.
NEOWISE has provided the best overall look at the PHA population yet, refining estimates of their numbers, sizes, types of orbits and potential hazards. The NEOWISE team estimates that about 20 to 30 percent of the PHAs thought to exist have actually been discovered to date.
The Fermi Gamma-ray Space Telescope orbits Earth with a complicated motion. This map shows the position of a particular pulsar (the Vela pulsar) inside the field of view of the telescope as it orbits around the Earth rocking north/south; rolls to keep its solar panels facing the Sun; and processes around its axis once every 54 days. It is a compound of these three motions that gives rise to this image.
A Dangerous Sunrise on Gliese 876d
On planet Gliese 876d, sunrises might be dangerous. Although nobody really knows what conditions are like on this close-in planet orbiting variable red dwarf star Gliese 876, the above artistic illustration gives one impression.
With an orbit well inside Mercury and a mass several times that of Earth, Gliese 876d might rotate so slowly that dramatic differences exist between night and day. Gliese 876d is imagined above showing significant volcanism, possibly caused by gravitational tides flexing and internally heating the planet, and possibly more volatile during the day.
The rising red dwarf star shows expected stellar magnetic activity which includes dramatic and violent prominences. In the sky above, a hypothetical moon has its thin atmosphere blown away by the red dwarf’s stellar wind. Gliese 876d excites the imagination partly because it is one of the few extrasolar planets known to be in or near to the habitable zone of its parent star.