"The Martian" and Other News of the Solar System

If you've seen, read, or heard about "The Martian" film or novel, you may know that it's a story by an engineer about survival on Mars. If you'd like some background on how author Andy Weir tried to make the story realistic, using known science, check out his talk at NASA's Ames Research Center at: https://www.youtube.com/watch?v=KBtXuBuZPpQ

The image accompanying this post is a selfie of a real "martian" -- the Curiosity Rover on Mars, which took the pictures from which this great Mars image was assembled in August. If you click on the picture, you get a bigger version.

For a listing of other Mars science fiction stories with reasonable astronomy, you can download my one-page resource guide at: https://www.researchgate.net/publication/282505754_Mars_Science_Fiction_with_Reasonable_Science

A fantastic new image and movie of Pluto's giant moon Charon (with its mysterious red polar cap) can now be seen at: http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20151001 

For those of you who are in the Northern California area, or have friends there, there are two exciting events coming up this week:

1) Dr. Carolyn Porco, the head of the imaging team for the Cassini mission at Saturn, is giving a free public lecture (with fabulous pictures) at Foothill College Wednesday night: http://www.foothill.edu/news/newsfmt.php?sr=2&rec_id=3852

2) The Astronomical Society of the Pacific and Chabot Space Science Center are sponsoring an all-day Family Astronomy Festival in Oakland Saturday Oct. 10. See: https://www.astrosociety.org/education/asp-annual-meeting/

The Lake that Built a Mountain on Mars

NASA’s instrument-laden Curiosity Rover is now at the foot of Mt. Sharp, its ultimate target on Mars. New results from the rover have confirmed and filled in our ideas about what the 3-mile high mountain is doing in the middle of 96-mile wide Gale Crater. And, most important, the new observations give us even more confidence in the notion that ancient Mars was very different from Mars today – it may well have had a much thicker atmosphere, flowing rivers, and occasionally full lakes of water.

Mt. Sharp is an interesting mountain, in that it seems to be built up out of layer after layer of sediment. This material might have been carried to the center of the crater by either water or winds, scientists thought. The new results indicate that both water and wind may have had a role in building Mt. Sharp over the millennia.

We already knew that one or more dry river channels end at Gale Crater, making it likely that long ago, water probably flowed into the crater. Over long periods of time, the crater lake may have formed and evaporated again and again. Rivers flowing over the red sands of Mars would have carried quite a bit of sediment into the crater and would have deposited this material in its center. As the central mountain began to accumulate, the next river flood would lap up against it. The resulting waves could carry material higher than the river’s original level, thus building up the mountain further.

When the lake was dry, the big wind storms, that other instruments have shown us are a regular feature of Mars weather, could have added wind blown sand to the top of the mountain. So Mt. Sharp could have grown during both wet and dry periods.

Curiosity is only at the bottom of the mountain right now, but it has the ability to climb up to higher layers over the coming months. Scientists are very interested in what the layers higher up might reveal to us about how Mt. Sharp grew and how the climate on ancient Mars changed as time passed.

Our top picture, taken on Mars on Nov. 2, shows some of the layers building up at the bottom of Mt. Sharp in a formation scientists have nicknamed "Whale Rock." For a version of this picture that shows scale, see: http://photojournal.jpl.nasa.gov/figures/PIA19081_fig1.jpg 

The picture below is an earlier "selfie" that the Curiosity rover took showing its instruments and cameras at work. Click on either photo and you'll see a larger version, full of amazing detail -- straight from the surface of Mars!

An Eclipse of the Sun from Mars

Our Moon is not the only astronomical body that can eclipse the Sun. In August of last year, the cameras aboard the Curiosity rover on Mars caught one of the little moons of Mars, Phobos, making an eclipse.

In the photo, you can see Phobos go across the face of the Sun. Note that the moon's shape is that of a potato (not a sphere).

Phobos is really a small moon (we believe it's an asteroid that Mars captured long ago) -- it is only about 16 miles wide in its longest dimension. The reason it covers so much of the Sun in the picture is that it orbits very close to Mars. It's only 3700 miles above the surface of the red planet.  (Compare that to the 240,000-mile distance of our own Moon!)

If you stood on the surface of Mars, Phobos would be a dim light in the night sky, rising in the west and setting in the east, and taking about 4 hours to go from horizon to horizon. (In other words, Phobos orbits Mars faster than Mars spins or rotates!)

The three black and white images of Phobos crossing the Sun were taken on Aug. 21, 2013 three seconds apart. Not a bad feat of photography by the team running the rover on its mission in Gale crater!


If you want to see Phobos better, below is a remarkable close-up photo of the little moon, taken with the Mars Reconnaissance Orbiter spacecraft, and photo processed to make the color differences more intense:

I was reminded of eclipses because I've just come back from an astronomy meeting where we discussed another August eclipse. In August 2017, our Moon will eclipse the Sun completely. The total eclipse will be visible in only one country -- the United States -- and in a band only 150 miles or so wide. Everyone else in North America will see a "partial eclipse" -- a nice bite taken out of the Sun. We estimate that 500 million people will be able to see the partial eclipse. This could become one of the most dramatic opportunities and challenges for astronomy education in our time. But we'll talk more about that in future blog posts, as the time gets closer.

Curiosity Mars Rover Takes a Self-Portrait

At the beginning of November, the Curiosity rover on Mars used a camera on its big arm to take this wonderful panoramic picture of itself and its surroundings. Dozens of individual pictures were stitched together carefully to make this self-portrait. 

You can see four little trenches in the front where the arm scooped up some martian dirt for analysis.

Curiously, the way the images are taken and assembled, the arm is NOT visible in the picture. (You could imagine something similar if you held a camera out way in front of you and then took pictures from all sides. You could crop and assemble those pictures in a way so that your arm is always out of sight on the final image.)

In the background, on the upper right, you can see Mount Sharp, the mountain in the center of Gale Crater, which is the rover's ultimate destination. (See my blog post of August 19, 2012 for more on this mountain and its location.)

So far, all the instruments on board Curiosity are working fine, and the mission -- one of the most exciting astronomy events of the past year -- is continuing to send back good information from our red neighbor planet. As expected, we are already seeing clear evidence that there was lots of flowing water on Mars in the distant past.

P.S. If you are interested, you can see an animation of how this complex picture was taken and put together at:
http://www.nasa.gov/multimedia/videogallery/index.html?media_id=156880341

Seven Minutes of Terror: Curiosity Rover to Land on Mars

If all goes well, and keep all your fingers crossed that it does, the most complex laboratory ever sent to another world will land on Mars next Sunday night. The Curiosity Mars Rover is slated for Ma

rs touchdown Sunday, August 5, at 10:31 PM Pacific time, in a never-before-tried rocket-powered sky-crane landing. To see, what's involved and why NASA's Mars scientists all have their nails bitten down to the fingertips, check out the video about the "Seven Minutes of Terror" after the craft reaches the top of Mars; thin atmosphere:

http://www.youtube.com/watch?v=Ki_Af_o9Q9s

 

 

 

Here is a great image from the Jet Propulsion Laboratory, which builds and manages so many of our robot probes to the planets. This show the three generations of Mars rovers, the little Sojourner at the front left, S

pirit/Opportunity to the left of the two technicians, and then big Curiosity (the one that we hope to land on Sunday) on the right. NASA says if Spirit and Opportunity were golf carts, then Curiosity is a car. It has 10 science instruments, weighs almost one ton, and requires too much power to use solar cells (as the previous generations of rovers did). It has a generator powered by radioactive plutonium dioxide on board. 

Among its tools is a microscope that can see things as small as the width of a human hair! And the microscope tool carries a small light so it can do night work. Its laser can vaporize rocks up to 23 feet away, and "smell" what they are made of from the vapor. Since (at the time of the landing) messages from Earth will take 14 minutes to get to Mars, the rover has artificial intelligence software for making any immediate decisions that are required. The question is, is Curiosity smarter than your little brother?