Friday, December 28, 2012

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:

Sunday, December 23, 2012

A Fabulous New Saturn Image

This magnificent (but artificial color) image of the ringed planet Saturn was assembled and enhanced from 60 different pictures taken with the Cassini spacecraft. You are looking up at Saturn from a perspective below its rings, at a time when the Sun happened to be directly behind Saturn. Thus we are seeing the planets and the rings back-lit, something we can never see from Earth.

The image is constructed not merely with visible light pictures, but also with some in the infra-red (commonly called heat rays). So this is not what your eyes would see if you (like Cassini) were orbiting Saturn -- this is a view only our sophisticated instruments can make available. And the details have been enhanced to show you the complex structure of Saturn's rings (made up of billions of chunks of mostly water ice, all moving around the equator of Saturn in a traffic pattern so vast it puts the Los Angeles freeway system to shame.) 

From one side to the other, Saturn's giant ring system spans 170,000 miles across.   This means that if you were to take the ring system off Saturn and put it next to the Earth, it would almost fill the space between the Earth and the Moon.

Near the top of the picture, you see the round dark shadow that Saturn casts on its own rings. Below that shadow, the greenish glow is light reflected from the rings on to the cloudtops of Saturn.

The pictures that make up this fantastic mosaic were taken from a distance of about 500,000 miles from Saturn (quite close in astronomical terms.)  Just look at all the structure you can see in the ring system, which consists of many, many ringlets.

What a beautiful holiday ornament this planet makes!  Happy Holidays.

Friday, December 21, 2012

Happy Winter Solstice (Not Doomsday)

Let me wish all my readers a happy Dec. 21, the day of the winter solstice in the northern hemisphere. Despite the hue and cry of the doomsayers, the Sun rose today and our planet continues to orbit in the usual cosmic order of things. There is no greater or lesser chance of disaster today than any other day.

Today is special, however, for being the day that the Sun makes the lowest arc in our skies and thus gives us the shortest day of the year (as beautifully illustrated on the accompanying photo by Italian astro-photographer Danilo Privato.)

For thousands of years, civilizations throughout the northern half of our planet have planned special celebrations to cheer each other up around the time the day was shortest and the night was longest. They gathered with their tribe, lit a fire, danced and sang to implore their sun-god to return, made sacrifices (like burning a valued food animal), and perhaps gave a present of something they treasured to their loved ones.

Many of our modern traditions began with such winter solstice celebrations. I encourage you to reach out to relatives and friends today in the same way, perhaps sharing the beautiful solstice photo (a composite image made of 43 different exposures during a past solstice day from Santa Severa, Italy.)

Today, as on all other days of our annual journey around the Sun, we have far more to fear from our own actions than from the cosmos. It is a sad fact that the most likely form of local or global doomsday for planet Earth will come from humanity's own prejudices, superstitions, hatreds, and persistent refusal to face facts. In our lifetimes, our planet is probably going to suffer more from our pollution and carelessness than from the actions of the universe. Now that we seem to be surviving any "Doomsday 2012" coming from the skies, maybe we can resolve to do a little better as residents of planet Earth.

(Photograph used by permission. To check out the many astronomical photographs by Danilo Privato, please see his website: )

To learn more about why the Dec. 21, 2012 doomsday fears had no basis in science, you can check out the Calendar of the Sky website from the University of California, Berkeley Space Sciences Lab -- a site to which I had the pleasure of contributing.  You might start with the essay: 
and then browse through the menu at left.)

Wednesday, December 19, 2012

POSSIBLE Planet Around a Famous Nearby Star

Today came a news story that illustrates how hard progress is at the very frontiers of science. For both science and science fiction fans, the nearby star Tau Ceti (a sun-like star just 12 lightyears away) is legendary. In science, it was one of the two stars that Frank Drake searched for intelligent signals in his first SETI project back in 1960.  In science fiction, many authors and screenwriters have used Tau Ceti as the home base of alien species.

Naturally, astronomers have searched for planets orbiting this star and no "obvious" planets (such as a big Jupiter-like planet) have been found. A key way astronomers find planets too dim to see with a telescope is to watch the effect of the planet's gravity on the much brighter star. As planets orbit a star, the star will appear to wiggle back and forth slightly, which sophisticated instruments can detect.  (For the technically minded, we can take a spectrum -- spread out the light like a rainbow of colors -- and measure the motion of the star from the Doppler Effect.)

So an international team of astronomers has been analyzing 6000 previous observations of any possible "wiggle" of Tau Ceti from the pull of smaller planets to see if they can tease out any information when they combine the information gathered by three of the largest telescopes in the world, including the giant Keck Telescope in Hawaii. The complex analysis allows scientists to get down to smaller wiggles than have ever been observed before -- down to changes in the speed of the star of 2 miles per hour!

At this level, scientists are down to speeds that are "in the noise" -- smaller than the statistical variations in the observations and the movements of the star's own surface. As the experimenters themselves quickly say, this is new territory. Yet, when they do their best to model and explain the changes in the star's speed, their work is compatible with the possibility that there are five small planets orbiting Tau Ceti. One of these appears to be in the "habitable zone" where life like us may be comfortable.

The discoverers freely admit that it may take a decade to confirm that their tiny wiggles are real. But the possibility of planets around Tau Ceti -- coming so soon after the discovery of a planet around one of the stars in our nearest neighbor star system, Alpha Centauri -- brings new excitement to the idea that planets are going to be found around the majority of stars, even the ones nearby. More than 800 planets are now confirmed out there, and we have thousands of candidates in our catalogs. It's a wonderful universe!

Friday, November 30, 2012

Music Inspired by Astronomy

One of my hobbies is collecting examples of music that are seriously influenced by astronomy -- I've found astronomical ideas in both popular songs and classical music. A new catalog of such music (organized by topic) has just been published, and I thought some of you might enjoy seeing the collection of weird and wonderful pieces I have found over the years. (Only pieces available on commercial CD's are included.) The list can be found at:

Most of these pieces may not be your cup of tea, but if you are dying to know what six songs include scientifically valid information or ideas about black holes, this is the place you will find an answer.  (Note that this list doesn't including anything about astronauts or space travel, nor does it include any so-called new-age "space music.)   But perhaps you can discover a few pieces that you may enjoy reading about or hearing on your own music player.

Monday, November 19, 2012

A Super-Earth in a Zone Where Life May be Possible

An international team of astronomers recently announced the discovery of a planet that orbits a star in a zone where the conditions may be right for life -- and it's all just 44 lightyears 
away. The image here shows an artist's conception of this planet, which -- fair warning -- may not look anything like the Earth or this picture! It is the kind of planet we call a Super-Earth -- in this case it may be 7 times as massive as our planet or more. (No such planet exists in our solar system, so we don't know what it might be made of or would look like.  For example, we don't know if such Super-Earths are made mostly of rock like the Earth or mostly of gas and liquid, like Jupiter.)

Still, the newly discovered planet is one of six planets orbiting a quiet old star known only by its ugly catalog number HD40307. Of the six, the new planet is the only one at the right distance from the star that conditions on it (or perhaps one of its moons, if it has any) might be right for liquid water and life as we know it. The planet takes 198 Earth days to go around its star, and since the star is cooler than the Sun, that orbit turns out to be just right.

This is not the first Super-Earth that astronomers have uncovered in the habitable zone of its star, but it is the closest and the most interesting so far. Planet news just keeps rolling in, and we may someday look back at these decades following the discovery of the first planet outside the solar system (in 1995) as a golden age of planet discovery.  Recall from earlier posts that the Kepler mission (the big camera in space) is continuing to find a slew of planets and has thousands of candidate planets which scientists are checking out.  Stay tuned for more planet discoveries in the months and year ahead.

Wednesday, November 7, 2012

Lecture on "Finding the Next Earth" Now on the Web

With the restart of the Silicon Valley Astronomy Lectures, which I have the privilege of organizing, we are posting the talks on the Web as audio and video. The latest one, on the amazing pla
nets the Kepler mission is finding around other stars, by Kepler Mission Scientist Natalie Batalha, is now available free of charge to everyone.

Sunday, October 28, 2012

Giant Black Hole at the Center of Our Galaxy (and a Video)

A new observatory in space has caught the giant black hole at the center of our home galaxy in the process of having a snack. We know that the at the very heart of the Milky Way there lurks a black hole with as much material inside as 3 - 4 million Suns. When material falls into such a black hole, just before it enters, it gets very hot by friction and gives off (not light but) a glow of x-rays.

Once material falls into a black hole, then no light or x-rays can escape from it. But just before any such stuff goes to its doom, we do see a flare of x-rays from it. It is just this sort of flare that the NuSTAR satellite detected in July (just about a month after it was launched). It wasn't really a full meal for the black hole, merely an afternoon snack, but the temperature of the glowing gas cloud before it fell in was an astounding 180 million degrees Fahrenheit.

The so called "super-massive" black hole at the center of our Galaxy is a relatively small one, compared to some of the really massive black holes in the centers of other galaxies.  Some of these have billions (thousands of millions) of times the mass of our Sun contained within them.

If you are already a black hole fan, such observations will probably just confirm your view of how weird black holes are. But if you are not sure what black holes are, I might recommend a little video that the SETI Institute made of me during a family event there. It's a brief, friendly explanation of just what black holes are and why falling into one is a "once-in-a-lifetime experience." You can see it at:

Sunday, October 21, 2012

Extremely Deep View of the Universe

Last month, the Hubble Space Telescope released one of the most impressive astronomical images ever taken and I wanted to share it with you. Called the Hubble Extremely Deep Field, it shows a tiny, tiny portion of the sky in the constellation of Fornax -- a portion about the same size (angle) in our sky as one of the smaller dark splotches (maria) you can see on the Moon.

Between 2002 and 2012, a team of astronomers kept photographing this same bit of sky over and over again for 2 million seconds (almost 23 days) and the results, as you can see, are spectacular. Almost every bit of light you see on the accompanying picture is a galaxy (a collection of millions and, more likely, billions of stars). Some are so far away, light from them is estimated to take 13 billion YEARS to reach us!

This means that when you look at the faintest objects in this picture you are looking almost back to the beginning of time (the Big Bang is estimated to have taken place 13.7 billions years ago.) Some 5,500 galaxies are visible in the small frame of this image and they range in distance and time over billions of lightyears and years. In such images, which are like core samples in geology, astronomers can study the history of structure and matter in the universe.

The Hubble scientists have done this before, taking previous sets of deep images called the Hubble Deep Field and then the Hubble Ultra-deep Field.  But the current image (above) shows by far the deepest view (seeing the faintest galaxies and light from longest ago.)

Wednesday, October 17, 2012

Planet Found in Closest Star System to the Sun

Big News: Nearest Star System Has a Planet

European astronomers have announced a science-fiction dream come true. A planet is orbiting one of the stars in the nearest star system to the Earth -- Alpha Centauri. This system consists 
of two stars orbiting a common center in 80 years (and perhaps a third star, even further out.)

The smaller star of the main pair, called "Alpha B" is the one where a planet has been found. Astronomers use the "wiggle method," where they detect the pull of the planet by changes in the motion of the STAR. (The star is bright and can be seen, while the planet is small and dim and lost in the star's glare. So we had to find the planet by the pull of its gravity on its parent star.) It took FOUR years of careful measurement to tease out the tiny wiggle caused by the planet's pull!

The planet is small (roughly like the Earth) but much closer in than we are to the Sun. This new planet (for now called "Alpha Bb" -- we astronomers are NOT good at romantic names!) takes only 3 days to orbit its parent star. That means it is only a little more than 3 million miles away from the star (while the Earth is 93 million miles from the Sun.) The planet must be intensely hot and hardly a place to build a resort for space travelers.

Still, this is amazing and wonderful news for several reasons:

1. It's great to have a planet in the star system next door (and that system may yet reveal other planets too.) Alpha Centauri is about 4 lightyears away.

2. It's great that our instruments can make so precise and tiny a measurement at star distances (the change in the star's motion due to the planet's pull is only about 1 mile per hour) and this means other small planets may also be found using the wiggle method.

3. With over 842 planets now known for sure orbiting 664 other stars (and thousands more suspected), this discovery is one more piece of evidence that planets can exist not just among single stars like the Sun, but in systems of stars too.

Saturday, October 13, 2012

Cookie Monster on Mercury

In view of the sudden importance that Big Bird and Sesame Street have assumed in the national presidential campaign, you may be amused that just recently, astronomers examining images of the battered surface of the planet Mercury have released this image of a large crater and several smaller ones that resemble "Cookie Monster."

Cookie Monster joins a set of craters on Mercury that resembles Mickey Mouse:

and Miss Piggy on Venus:

among the cartoon characters that fool our eye on other worlds.

Such images remind us of the flap, years ago, about the so-called "Face on Mars," which, in an early crude image, sort-of, maybe reminded some people of a face.  Like the Cookie Monster on Mercury, it was a perfectly natural land form on Mars, which happened vaguely to resemble something familiar. 

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.

Tuesday, August 28, 2012

Star Corpses Help Us Prove Einstein Right

One of the most intriguing predictions of Einstein's theory of relativity is that, just like there are light waves and sound waves, there should also be GRAVITY WAVES. When the arrangements of massive objects in the universe changes (like two stars orbiting each other), Einstein's theory predicts that waves of gravity energy should be be given off.

But gravity waves are very, very weak and hard to detect. We have gravity wave telescopes operating, but so far they have not succeeded in catching some big gravity change that would give off enough waves to be measurable. So astronomers are turning the idea around. If we could find two massive stars in the universe that are in orbit, they should be giving off these subtle gravity waves and should be losing energy. That means the two stars will -- as their motion energy is lost -- spiral inward toward each other, something they would not normally do. The more compressed the star, the bigger the effect. Dead stars, that have fallen inward -- gotten "squozen" in death (as I like to say) are excellent subjects for testing this prediction.

Two astronomers in the mid-1970's, including one of my undergraduate advisors, Dr. Joseph Taylor, discovered two star corpses (collapsed stars) that showed exactly this kind of behavior. There were the two dead stars, called neutron stars, minding their own business in space, lost in each other's gravity embrace. Yet, they were very slowly approaching each other in orbit. And the energy they lost was exactly what Einstein predicted. Taylor and Russell Hulse won the 1993 Nobel Prize in physics for their painstaking observations of this pair. But their measurements were done with radio waves, since that was the only way to see these particular star corpses.  

(For those of you who know a little astronomy, the precise story is that most neutron stars are only observable as "pulsars" -- objects that give off regularly pulsing radio waves.  As the two pulsars orbit, they lose energy and their pulses change as they get closer to each other.)

Now, a larger team of astronomers has just announced finding a different pair of dead stars (called white dwarfs) that show the same spiraling behavior, but shining in visible light. The nameless pair of star corpses is about 3,000 lightyears away. As they orbit close around each other (taking only 13 minutes for an orbit!), we see one eclipse the other. Between April 2011 and today, the eclipses have come 6 seconds earlier, as the two dead stars lose energy and approach. This is, again, exactly what we would expect if Einstein is right, and the pair is losing energy via gravity waves.

(Just as a lightbulb loses energy as it shines away light, and you have to pay the electric company to replace it, so it seems orbiting stars slowly lose energy as gravity waves. The difference is that there is no source of new energy, and so the stars simply fall slowly toward each other.)

How nice that Einstein's ideas, now almost 100 years old, are being confirmed in some of the strangest astronomical environments we can find. He'd be proud.

Wednesday, August 22, 2012

"Doomsday 2012" and Cosmophobia

Photo: "Doomsday 2012" and Our Schools

As students return to school this fall, the media and web hype about Doomsday 2012 (the end of the world because a planet will hit us, something will align in the sky, the Earth's rotation or axis will change, or just because the ancient Maya said so) promises to reach a final, fevered pitch.  Those of us in science and science education are preparing to respond to concerns from people (especially young people) who are genuinely worried or confused. 

Two new resources are now available for educators, parents, 
youth group leaders, to address fears that world-wide disaster is coming on Dec. 21, 2012.  Perhaps you can let your favorite teacher, school counselor, scout leader and other adult working with kids know about these. 

I have put together (with lots of help) a guide to accessible written and audio-visual materials on this topic (most of them freely available on the Web).  You can find it in the on-line publication "Astronomy Education Review" at: 
(click on the "Download PDF" link under the author's name for
the easiest way to see the entire article).

And a video recording of a panel I had the privilege of leading on "Doomsday 2012 and Cosmophobia" at this summer's meeting of the Astronomical Society of the Pacific has now been posted by NASA's Lunar Science Institute at:

"Cosmophobia" is NASA astronomer David Morrison's name for the  unnecessary fear of celestial events and phenomena. When David and I were young, new discoveries in the sky were a source of awe and fascination.  Now, we are observing more and more people asking, as new things are discovered, "Should I be afraid?"  It's kind of sad, given that we live mostly in splendid cosmic isolation, and most things in the universe are really much too far away to hurt us.  

Please help spread the word that students will still have to take exams and we all still have to pay taxes in 2013.

As students return to school this fall, the media and web hype about Doomsday 2012 (the end of the world because a planet will hit us, something will align in the sky, the Earth's rotation or axis will change, or just because the ancient Maya said so) promises to reach a final, fevered pitch. Those of us in science and science education are preparing to respond to concerns from people (especially young people) who are genuinely worried or confused.

Two new resources are now available for educators, parents, youth group leaders, to address fears that world-wide disaster is coming on Dec. 21, 2012. Perhaps you can let your favorite teacher, school counselor, scout leader and other adult working with kids know about these.

I have put together (with lots of help) a guide to accessible written and audio-visual materials on this topic (most of them freely available on the Web). You can find it in the on-line publication "Astronomy Education Review" at:
(click on the "Download PDF" link under the author's name for the easiest way to see the entire article).

And a video recording of a panel I had the privilege of leading on "Doomsday 2012 and Cosmophobia" at this summer's meeting of the Astronomical Society of the Pacific has now been posted by NASA's Lunar Science Institute at:

"Cosmophobia" is NASA astronomer David Morrison's name for the unnecessary fear of celestial events and phenomena. When David and I were young, new discoveries in the sky were a source of awe and fascination. Now, we are observing more and more people asking, as new things are discovered, "Should I be afraid?" It's kind of sad, given that we live mostly in splendid cosmic isolation, and most things in the universe are really much too far away to hurt us.

Please help spread the word that students will still have to take exams and we all still have to pay taxes in 2013. ·  · 

Sunday, August 19, 2012

Mars Update

In this beautiful picture, you can see what the NASA publicity team is calling the "Promised Land" on Mars. The slope of Mount Sharp beckons in the distance in this color image taken by the Curiosity Rover's mast camera. The Mars light, by the way, has been adjusted on this image to show you what the scene would look like in Earth sunlight.   You can see that they have added a white bar on the mountain which is 2 km, or about 1.2 miles, wide.

The highest point on Mt. Sharp rises about 3 miles above its base. Note that in the picture, the lower parts of the mountain are darker than the rest. It is this dark region that we believe was covered with water long ago and is expected to show us the chemical and mineral traces of having been long submerged.

Also check out the image below for a bird's eye view (or more precisely, a spacecraft's eye view) of where Curiosity is now (green dot), where it is going first (Glenelg blue dot), and where it will approach Mt. Sharp (the blue dot in the center). Note that the elevation rises as you move toward the bottom right in this picture. 

Today, Curiosity fired its laser beam for the first time at a rock on Mars, with 30 pulses over 10 seconds. This vaporizes the rock, so that Curiosity can measure very precisely what it is made of. Scientists using the ChemCam instrument were delighted with the information coming into their little "mini-telescope" from the flash of the vaporized rock.  For more information, see: 

Wednesday, August 15, 2012

A Huge and Distant Cluster of Galaxies (and a Movie)

I want to introduce you to a short, but truly mind-boggling movie and then share a piece of news with you. 

All stars are organized into giant islands called galaxies. We live in one 
such island, called the Milky Way Galaxy, and our telescopes show many billions of other galaxies all around the sky. Like explorers on an unknown continent, we have recently been trying to map the way all these galaxies are distributed through space. Perhaps the most impressive such mapping project is called the Sloan Digital Sky Survey, and they just released a short film allowing you to fly through 400,000 galaxies whose positions in three-dimensional space have now been measured. Here is the movie: 

Note that each little object on your screen is a galaxy of billions of stars (stars like the Sun)! Also note that the galaxies are not evenly distributed. Just like stars, they tend to be "social" -- they collect into groups (or galaxy clusters). 

Just today, astronomers announced the discovery of one of the largest galaxy clusters ever seen, nicknamed the Phoenix Cluster. It contains enough material (in many many galaxies) to make more than 2 million billion Suns. And it is almost 6 billion light years away, which means the light we see tonight from this huge grouping of galaxies left on its way to us before the Sun and the Earth ever existed. Wow. 

What makes the Phoenix cluster of special interest to astronomers is that, at its center, the gas falling in from all over the cluster is leading to a huge rash of newly forming stars. 740 new stars form in the middle galaxy of the cluster EVERY SINGLE YEAR. Many such galaxy cluster have a core that is "red and dead" -- with little star formation going on in the central galaxy. But this cluster has a center that's "blue and new" -- with lots of new stars being born. 

You can just stop there if (like many people) your head now hurts from the movie and the huge numbers I am throwing around. Just let the feeling of the immensity of the cosmos overtake you. (It helps a lot when you can't stand the pettiness of presidential politics these days.) Or, for more on the Phoenix Cluster see:

Thursday, August 9, 2012

Color Mars Panorama and Meteor Shower Saturday Night

The first color panorama looking around the landing site has been taken by the cameras on the mast of the Curiosity rover.  In the picture, we are seeing a late afternoon scene, with the dramatic shadow of the rover, the reddish martian sand, and the grey splotches made where the rocket exhaust disturbed the ground.  The set of stitched-together images shows the scene 360 degrees around the rover; as if we were right there with Curiosity. I love it.  Even better images are going to be taken, but this first look around is what the scientists have been waiting for to get their bearings.
for the version with NASA's caption.

Coming back down to Earth, this Saturday night and Sunday morning are the peak of the Perseid (pronounced Purr--see--ud) meteor shower for 2012.  What that means in English is that, if you go outside and away from city lights after about 11 pm Saturday evening or early Sunday morning, you will see more shooting stars than usual.  If you are patient, allow your eyes to get adapted to the dark, and find a spot where you have a good view of the whole sky, you should be rewarded -- over time -- with a good number of chunks of cosmic material burning up in our planet's atmosphere.

The chunks in this "shooting star" shower are left over from an old comet called Swift-Tuttle, which has passed our way many times over the eons, and left a lot of dust in its wake.  When the Earth intersects that stream of dust and dirt, we get a shooting star each time a piece burns up by air friction.

I recommend viewing the shower with someone with who you enjoy spending time in the dark.

For more, see the nice article from Sky & Telescope magazine at:

Thursday, August 2, 2012

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:




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?

Wednesday, July 4, 2012

Saturn's Large Moon May Have Underground Ocean

Measurements from the Cassini spacecraft orbiting Saturn, made between 2006 and 2011, indicate that Saturn's largest moon may have a layer of liquid water under its icy surface. 

This intriguing moon, called Titan, is already notorious for having an atmosphere thicker than Earth's -- something no other known moon has. Under Titan's atmosphere, Cassini has shown us lakes and rivers made of methane (liquid swamp gas) and not water. The temperature in that cold region of the solar system is always low and Titan's frigid surface is at something like - 290 degrees Fahrenheit.

At such temperatures, water on the surface is frozen solid -- in fact, "rocks" on Titan (photographed by our little lander) are made of water ice. But the new measurements indicate that below its outer icy shell, Titan may contain an ocean of liquid water. 
 At such temperatures, water on the surface is frozen solid -- in fact, "rocks" on Titan (photographed by our little lander) are made of water ice. But the new measurements indicate that below its outer icy shell, Titan may contain an ocean of liquid water.

This is not the only moon in the solar system where astronomers suspect that liquid water may exist underground -- several of Jupiter's moons, especially the one called Europa -- also show indications of a sub-surface ocean. 

And, a much smaller moon of Saturn's, called Enceladus, has steamy geysers of salt water erupting from giant cracks. Water seems to be a common substance in the solar system (and the universe) and we are detecting it as vapor, as solid ice, and -- increasingly -- in liquid forms under the surface of other worlds.  

Saturday, May 26, 2012

From Dust to Dust: A Planet Too Close to Its Star

Astronomers have used the Kepler Observatory (a giant camera in space that is searching for evidence that planets orbit other stars) to make a remarkable discovery.  They found a planet taking only a little more than 15 hours to orbit its star.  Think about that figure!  Our own Earth takes 365 ¼ days -- what we call one year -- to orbit the Sun. Even heat-scorched Mercury takes 88 days to go around our star.  A planet whose “year” is only 15 hours must orbit extremely close to the star and must thus be exposed to searing heat.  

Indeed this planet is so close that the heat of its star appears to be evaporating its rocky surface and creating a cloud of dust, which we can see blocking the star light on each orbit. This planet is doomed to become nothing but dust in the next 200 million years or so, calculations show.  The temperatures at its surface are estimated to be 3300 degrees Fahrenheit.  

The star and planet are about 1500 light years away, so we are not likely to be visiting them any time soon.  But if you go, be sure you take a good asbestos space suit.  

Wednesday, May 9, 2012

Coming in June: SETIcon

Next month, the nonprofit SETI Institute (the organization devoted to the search for life in the universe) will be holding a big weekend public event in the San Francisco Bay Area which I will be part of. For those of you who will be (or could be) in the area, here is more information about some of the remarkable people who will be joining me:

SETIcon II: A Weekend Where Science and Imagination Meet
June 22 - 24, 2012
Hyatt Regency Hotel, Santa Clara, California

See: for more information

Guests will include:

* Frank Drake, the astronomer who undertook the first project to listen for extra-terrestrial radio messages and founded the SETI field
* Alan Stern, principal investigator for the New Horizons mission to Pluto and former associate administrator for science missions at NASA
* Robert J. Sawyer, award-winning science fiction writer -- who has written some of the best novels about alien contact
* Rosaly Lopes, planetary scientist at the Jet Propulsion Lab and one of the world's experts on volcanoes on other worlds
* Jill Tarter, the leader of the quest to find signals from alien civilizations -- on whom Jodie Foster's character in the film "Contact" is based

* Mae Jemison, Shuttle astronaut and the first African-American woman in space (who played Lieutenant Palmer on "Star Trek: Next Generation")
* Geoff Marcy, astronomer at the University of California, Berkeley, who is considered the foremost planet hunter in the world today
* Alex Filippenko, part of the team that received the 2011 Nobel Prize for discovering the "dark energy" that is speeding up the expansion of the entire universe
* Robert Picardo, television actor who has appeared in "Star Trek: Voyager," "Stargate," "China Beach," and other programs
* Debra Fischer, of Yale University, co-discoverer of the first system of planets around another star

* Seth Shostak, host of "Big Picture Science", Huffington Post columnist, and the public scientist at the SETI Institute
* Alex Hall, the senior director of the $30 million Google Lunar X-Prize
* Richard Rhodes, Pulitzer-prize winning author and historian of the atomic bomb
* Scott Hubbard, Stanford, NASA's first Mars Program Director and the former director of NASA's Ames Research Center
* David Morrison of NASA, who has been the point person in debunking the myth of Doomsday 2012

* plus members of the Kepler Mission science team, authors, artists, and many of the key scientists from the SETI Institute.

(Confession: I have the pleasure and privilege of being the Vice-chair of the Institute's Board of Trustees.  However, I am not being paid to be at the convention or for anything I do for the Institute, so I am not gaining financially in any way by sharing this information with you. I always like to be very clear about such things.)

Thursday, May 3, 2012

The Moon Over Lick Observatory
Photo by Rick Baldridge (Peninsula Astronomical Society)

"Super-moon" This Weekend (Sort of)

This weekend, two characteristics of the Moon will conspire to make it look a little brighter and a little bigger than usual. It might just give you an extra reason to take a night stroll with someone with whom you like to spend time in the dark. At about the same time, the Moon with be full and closest to the Earth in its slightly oval orbit. This means the full Moon Saturday night will be somewhat more spectacular than in a typical month. It has no bad effects on us, but it will be nice to look at. (The media are calling it a super-moon, which is a bit of an exaggeration, but it's worth glancing up at, if your evening is clear.)

Even the very responsible story from NASA is a bit strong, but it's probably the best reference to learn more:

If you worry that the full Moon is connected with "lunacy" and crazy behavior, and this close moon will only make things worse, fear not! Many experiments have now shown that there is NO connection between strange behavior, crimes, or births and the full moon. If you want to learn more, you can check out my resource guide to astronomical "pseudo-science" at:

Hope your Saturday night is a heavenly one!

Saturday, April 7, 2012

A Magnificent Cluster of Stars Captured

I wanted to share a remarkable new Hubble Space Telescope image with you. In the accompanying picture, you see a magnificent cluster of over 250,000 stars, a grouping whose catalog number is M9. (This designation comes from a list Charles Messier made long ago of fuzzy objects of interest in the sky.)  The colorful cluster is in the direction of the center of our Milky Way galaxy, some 25,000 light years away. (This means that, traveling at the speed of light, it would take you 25,000 years to travel there!) What's fascinating about this Hubble image -- taken with the Advanced Camera for Surveys -- is how clearly we can see individual stars in this crowded, distant group. (The cluster is so far away and so small that it takes up about as much of the sky as the head of pin, held at arms' length.)

The stars in this cluster are typically older than the Sun and contain fewer of the heavier elements that make life and technology on Earth possible. Such clusters, called globular clusters, are thought to be among the oldest objects in our Milky Way Galaxy.  We study the globular clusters like M9 to learn more about the archaeology of our home galaxy and how things were in our neighborhood long before the Sun and the Earth ever existed.