Sunday, September 30, 2012

Evidence for a Stream on Mars

The first significant result from the Curiosity Rover in the deep Gale crater on Mars is the discovery of a set of rocks that look like they were shaped by a small river or stream of flowing water. 

Here is a picture with the Mars rocks on the left and rocks from an Earth stream bed on the right. Look how similar they are!

Scientists estimate that the stream of water on Mars that (long, long ago) produced these gravel formations was running at about 2 miles per hour. It was somewhere between ankle and hip deep.

That's great news. We landed in Gale Crater because pictures from orbit gave us hope that it had been full of water at one time. Now we have "ground-truth" for that idea. 

The gravel pieces on both pictures are too big to have been moved around by wind. It takes a fluid like water to knock these pieces together over the long time that water flowed. Within each rock, the largest gravel fragments are a couple of inches or so wide. (Scientists call this kind of rock a sedimentary conglomerate, and these are made by flowing water cementing rock fragments and smaller material together.) Both the kind of rock and the rounded shape of the fragments are strong arguments for a flowing stream of water on Mars. And our journey on Mars with Curiosity is just starting out!

For another image and the story from NASA, see: 

Tuesday, September 25, 2012

Remarkable New Mars Panorama

For your viewing pleasure, here is a dynamic 360-degree panorama of what you would see around you if you were with the Curiosity Rover on Mars, created from NASA images by Danish photographer Hans Nyberg. Note the tall mountain, Mt. Sharp, in the background.   Note that the picture above is only a static appetizer. You have to click on the link below to get to the really wonderful, processed panorama that you can move through.

Once you are there click on the box with the four arrows inside the picture to have it go full screen on your computer. The colors have been changed a bit to show you what the scene would look like in Earth sunlight, but the level of detail is quite spectacular.  Several people I have shown this to have commented that it really gives them the sense of what it might be like to stand on the surface of the red planet as a visitor.

Sunday, September 23, 2012

Searching for Intelligence Among the Stars & the Drake Equation

At the quarterly meeting of the Board of Trustees of the SETI Institute (to which I have the privilege to belong), I spent some time this week with Dr. Frank Drake, the astronomer who is the father of the science of the search for extra-terrestrial intelligence (SETI). Now over 80, Frank is still going strong and very much involved with the ongoing quest to find evidence that there are other intelligent species among the stars.  Today, 52 years after Frank made the first search for possible intelligent radio signals from other star systems, our technology for searching has become much more sophisticated, although funding for the searches is still sporadic.

The discovery of so many planets orbiting other stars is very encouraging to those who hope to find our counterparts out there.  The Kepler mission is showing that planets the size of Earth and planets in the habitable zones of their own stars are more common than most astronomers had dared to hope.

A few years ago, I had the pleasure of encouraging Frank (and his coauthor Dava Sobel) to update a historical summary of how he came up with the "Drake Equation." Not so much an equation as a way of making estimates, this formula (which you can see behind him in the photo) is now taught in many introductory astronomy classes. It helps us summarize our best knowledge of astronomy, biology and sociology to figure out how common our type of technological civilization might be in the Galaxy.

Thanks to the Astronomical Society of the Pacific (which published the column,) you can read the story of how he came up with the equation by going to:

Tuesday, September 4, 2012

An Interesting New Picture from Mars

Curiosity (the new Mars Rover) has been driving around a bit, testing all its instruments. Here is my favorite new image, showing some of the interesting geological (or should that be marsolog
ical?) features we encounter as we look toward Mount Sharp, the rover's target.

In this picture, taken by the camera on Curiosity's big mast, we are looking toward the base of Mt. Sharp. You can see the many layers in the rock that were probably the result of standing water in the great basin (crater) that Mt. Sharp is in the middle of. The little inset shows a dark rock that is about the same size as our rover. So the pyramid-shaped mound behind it is much bigger than our vehicle. Exploration in this region will take much skillful maneuvering when it starts.

Bear in mind that Mars today has no liquid water to speak of, so that the scenes we will see will remind us of the deserts of the Earth.  But we have excellent evidence that ancient Mars, which had a thick atmosphere, had liquid water galore -- rivers, lakes, maybe even oceans.