R2-D2 to Curiosity: Good Fiction to Great Science (by NASAKennedy)Source: youtube.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
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.
First Mars Express gravity results plot volcanic history
Five years of Mars Express gravity mapping data are providing unique insights into what lies beneath the Red Planet’s largest volcanoes. The results show that the lava grew denser over time and that the thickness of the planet’s rigid outer layers varies across the Tharsis region.
The measurements were made while Mars Express was at altitudes of between 275–330 km above the Tharsis volcanic ‘bulge’, which includes Olympus Mons and the three smaller Tharsis Montes that are evenly spaced in a row. The region is thought to have been volcanically active until 100-250 million years ago, relatively recent on a geological timescale.
The new data reveal how the lava density changed during the construction of the three Tharsis Montes volcanoes. They started with a lighter andesitic lava that can form in the presence of water, and were then overlaid with heavier basaltic lava that makes up the visible surface of the martian crust.
The data also describe the thickness of the lithosphere – the outermost shell of the planet, including the upper portion of the mantle – and find surprising lateral variations between Olympus Mons and the Tharsis Montes, with the three smaller volcanoes having a much higher density underground ‘root’ than Olympus Mons.
Animation: The large mass of the volcanoes caused tiny ‘wobbles’ in the trajectory of Mars Express as it flew overhead; these were measured from Earth via radio tracking and translated into measurements of density variations below the surface.
Flowing Barchan Sand Dunes on Mars
When does Mars act like a liquid? Although liquids freeze and evaporate quickly into the thin atmosphere of Mars, persistent winds may make large sand dunes appear to flow and even drip like a liquid.
Visible on the above image right are two flat top mesas in southern Mars when the season was changing from Spring to Summer. A light dome topped hill is also visible on the far left of the image. As winds blow from right to left, flowing sand on and around the hills leaves picturesque streaks.
The dark arc-shaped droplets of fine sand are called barchans, and are the interplanetary cousins of similar Earth-based sand forms. Barchans can move intact a downwind and can even appear to pass through each other. When seasons change, winds on Mars can kick up dust and are monitored to see if they escalate into another of Mars’ famous planet-scale sand storms.