We don’t get to hear a lot about Ganymede these days, what with everyone paying so much attention to Titan and Enceladus and Europa and several other moons out there. Which is too bad because 1. Ganymede is plenty fascinating in its own right; and 2. it’s the LARGEST MOON IN THE SOLAR SYSTEM (and we shouldn’t forget it!) That’s why I was so happy to see this news come out today: geologists have created the first map of Ganymede that focuses exclusively on its complex geology, as observed close-up by the Voyager and Galileo spacecraft during their respective flybys. The resulting global map — which reminds me of some of the ornate illustrations that Giovanni Schiaparelli made of Mars in the 1880s — is a colorful layout of the many different terrains found across icy Ganymede, providing evidence of its complex history and a guide to future exploration missions.
Image credit: USGS Astrogeology Science Ctr/Wheaton/ASU/NASA/JPL-Caltech
Prometheus is at it again! On Feb. 5, Cassini acquired a series of images with its narrow-angle camera of Saturn’s reflective and ropy F ring, around the inside of which travels the shepherd moon Prometheus. As it orbits Saturn it regularly arcs outwards toward the inner edge of the F ring and tumbles back inwards again, a scalloping orbit by a potato-shaped moon that yanks at the fine icy particles of the ring with its gravitational tug. However faint they might be, these tidal forces are enough to pull the wispy ring particles into long strands, gaps, and clumps that follow Prometheus’ passage before eventually settling back down again.
If you count at least slightly over two years old as “brand new” then yes, this one is certainly that!
Seen above in an image taken by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter on Nov. 19, 2013, a 100-foot-wide (30-meter) crater is surrounded by bright rays of ejected material and blown-clear surface. Since HiRISE calibrates color to surface textures, the less-dusty cleared surface at the crater site appears blue. (See a true-color calibrated scan here.)
By narrowing down when this particular spot was last seen to be crater-free, scientists have determined that the impact event that caused this occurred between July 2010 and May 2012.
Ejected material from this cratering event was thrown outward over 9 miles (15 km). It’s estimated that impacts producing craters at least 12.8 feet (3.9 meters) in diameter occur on Mars at a rate of over 200 per year.
What are asteroids made of? While composed of metals, rocks, ices, and also many elements that are difficult to find and retrieve here on Earth — hence the growing interest in asteroid-mining missions — these drifting denizens of the Solar System have many different possible ways of forming. Some may be dense hunks of rock and metal, created during violent collisions and breakups of once-larger bodies, while others may be little more than loose clusters of gravel held together by gravity. Knowing how to determine the makeup of an asteroid is important to astronomers, not only to know its history but also to be better able to predict its behavior as it moves through space, interacting with other bodies — other asteroids, future exploration craft, radiation from the Sun, and potentially (although we hope not!) our own planet Earth.
Now, using the European Southern Observatory’s New Technology Telescope (NTT) researchers have probed the internal structure of the 535-meter-long near-Earth asteroid Itokawa, and found out that different parts have greatly varying densities, possibly an indication of how it — and others like it — formed.
“Come with me and I will tell you the story of how I became who I am.”
With those words, spoken through a custom-built computer and software controlled by the faintest movements of his cheek and eye muscles, 72-year-old physicist Stephen Hawking takes us on a journey through his own life. In this, his first autobiographical film, we see the the precocious child of free-thinking, Oxford-educated parents become an indolent wunderkind at Cambridge University and then, after both true love and a degenerative neurological disease take hold of him, the world-famous theoretical physicist and best-selling author that he is today.
Released by PBS, “Hawking” is the story of one of the world’s most well-known scientists, a man who has become as famous for his discoveries about the nature of the universe as he has for his illness, which has left him wheelchair-bound for most of his 72 years. But despite the loss of use of his body — or perhaps because of it — Hawking’s mind has remained free to roam the cosmos, investigating its deepest secrets through an incredible power of will, imagination, and mathematics.
But “Hawking” isn’t about endless numbers and brain-numbing equations. It’s about the man himself, and how he became who he is today and overcame the challenges that life placed along his way. It’s a fascinating tale of a brilliant man who, through his own resolve as well as the devotion of those he brought close to him, opened a window onto the universe for the entire world.
Find out how you can win a copy of Hawking on DVD below:
On this day in 1966, the Soviet Luna 9 spacecraft made the first successful soft landing on the Moon and, 7 hours later, transmitted its first images of the lunar surface back to Earth. The image above is the Luna 9 lander’s first view.
It was the very first time we had ever seen images taken from the surface of another world.
It’s a journey spanning 85 years and billions of miles: humanity’s first-ever encounter with the dwarf planet system of Pluto and Charon, located in the frozen far reaches of our Solar System where our entire planet is a barely-visible pale blue dot — just a “mote of dust suspended in a sunbeam.” Launched in 2006, the New Horizons spacecraft will pass by Pluto in July 2015 and send back images and data in unprecedented detail, 85 years after its discovery. With the flyby just about a year and a half away, the excitement in the space community is rapidly building even now.
The video above is a “teaser” for the event from the Applied Physics Laboratory at Johns Hopkins University — check it out. (Warning: may contain scenes of intense scientific discovery!) Also, watch a longer documentary below on the history of Pluto and the New Horizons mission:
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