Sunday, November 29, 2015

SETI Institute Searches for Giant Alien Construction Sites (and Your Support)

The team searching for signals from intelligent civilizations among the stars at the SETI Institute recently turned its radio telescopes to a mysterious star whose light output varies in an unusual way.   Called by its catalog number KIC 8462852, the star is about 1500 lightyears away in the constellation of Cygnus the Swan. Observations with the Kepler space telescope had shown that the star’s brightness dipped at irregular intervals and with irregular amounts of darkening.

Such dips are how the Kepler telescope finds planets orbiting distant stars.  Astronomers photograph huge numbers of stars regularly, and search for regular dips in a star’s light when a planet gets in front of the star, reducing its brightness.  A planet circles its star regularly, and the dips in brightness come on a clockwork schedule.  If the planet takes 100 days to orbit its star, astronomers would see a dip in brightness every 100 days – just while the planet is in front of its star.  Here is a little animation to show you the idea:

But KIC 8462852’s dips in brightness are not regular at all and they vary in how much of the star’s light they block.  One such dip in brightness took away more than 20% of the star’s light, indicating that whatever was causing it must be much bigger than a planet.  What could be causing such unpredictable and large dips?  It could, for example, be a huge swarm of comets that orbit the star in different clumps.  It could be great clouds of dust from deep space which the star happens to be moving through.  But there is another possibility, which got some astronomers and all science fiction fans excited.

What if there is an advanced civilization around that star, far beyond our own in technology?  One thing such a civilization is likely to need is huge amounts of energy to carry out their projects.   An easy way to get that is to build huge “solar panels” orbiting their star.  Alternatively, perhaps they are building giant space habitats to house their excess population. 

Just like our cities are irregularly spaced and irregular in terms of internal construction, so these space construction projects could be different in size and spacing, causing the irregular dips we see as they move in front of their star.  While the explanation is most likely something natural in the universe, it’s fun to consider a cause that could be a signal for the existence of intelligent life.

The leading organization in the search for life beyond Earth is the SETI Institute (where I have the privilege of serving on the Board of Trustees.)   They have an instrument, called the Allen Telescope Array (ATA), with 42 coordinated radio telescopes in Northern California, specifically designed to find intelligent radio or microwave signals from the stars.

For more than two weeks, the Institute team, led by Dr. Seth Shostak, trained the ATA on KIC 8462852, to see if any pattern of signals might be leaking from such an advanced civilization.  At a distance of 1500 lightyears (where each lightyear is 6,000 billion miles), the alien transmissions would have to be awfully strong to be detectable from Earth.  Still, a civilization able to build huge space structures might have powerful beacons to communicate with its own outposts, and we might be able to eavesdrop on one of their messages pointed our way.

So far, in the channels the Institute team searched, no intelligent signal was detectable.  They also searched for a much broader beam of microwaves, which advanced aliens might use to push giant ships through space.  No such beam was found either.

But what exciting ideas such observations bring to our minds!  The possibility of detecting some kind of intelligent species that is out there in the Galaxy has intrigued humanity for centuries.  Today, for the first time, we actually have the technology to do experiments in this area.  I’d love to see us find evidence that we have “cousins” among the stars.  This is why I have served on the SETI Board for many years now.

The Institute also does other wonderful research, in many areas of astronomy and planetary science.  (One of our scientists, Mark Showalter, found two of the small moons of Pluto, for example.)  There is also great work going on in education and public outreach, including the syndicated “Big Picture Science” radio show that Seth Shostak co-hosts.

December 1 is “Giving Tuesday” – a day designed for all of us to pause after the shopping frenzy that follows Thanksgiving, and consider giving to non-profit organizations whose work we believe in.  Perhaps you’d like to join me in supporting the SETI Institute.  For ways you can help, see their website at:

(NOTE: The photo shows a few of the radio telescopes that make up the Allen Telescope Array.)
And KIC stands for Kepler Input Catalog.

Sunday, November 22, 2015

Hot Discovery: Venus-like Planet around Red Dwarf Star

A newly discovered planet is as hot as your oven at full strength and takes less than two days to orbit its star.

As the number of confirmed planets orbiting other stars nears 2000 (when just twenty years ago, that number was zero), we are finding many planets that are not like any we know in our own solar system. The new planet orbits a red dwarf, a star 200 times fainter than our Sun, called GJ1132. (GJ stands for Gliese-Jahreiss, the name of two German astronomers who produced a remarkable catalog of the stars closest to our Sun.)

Astronomers used telescopes around the world to pin down the characteristics of the new planet, which is just 39 light years away, very close by cosmic standards. It turns out to be a rocky planet, a little bigger and more massive than Earth.

But it is so close to its star it takes only 1.6 days to go around. (In other words, a year on that planet would be just 1.6 Earth days. That means an Earth 10-year old would be about 2280 years old on that planet!)

At so close a distance (only a million and a half miles away from its star), the planet experiences temperatures on the order of 450 degrees Fahrenheit. So it reminds us more of superhot Venus in our solar system than our own Earth. Interestingly, other planets known to be rocky that we have discovered orbiting other stars are even hotter. (Hot, close planets are easier to find, so they are over-represented among our early discoveries.)

Still, if for some reason, you need a turkey cooked really fast this week, perhaps a quick trip to GJ 1132b (as the planet is boringly designated) would be in order. Or just give thanks that you live in a cooler planet which takes its time orbiting the Sun.

[P.S. The image is just an artist's impression. We can't photograph such small close in planets -- they are lost in the glare of their star.]

Monday, November 9, 2015

Pluto Has a Crazy Tumbling Moon (Great Video)

Pluto has five moons around it and one of them, it was reported today, spins 89 times for each orbit it makes around Pluto. Hydra, the outermost of Pluto's four tiny moons, takes 38 Earth days to go once around the dwarf planet. During that time, it rotates 89 times.

For a hypnotic video of the motion of all the moons, see:…/defau…/files/dps-slides-showalter1.mp4

(Note that on the video, the moons are not to scale. In real life, the outer 4 moons are much much smaller than Pluto and the giant inner moon Charon, which is about half of Pluto's size. But the motion you see on the video is real.)

Hydra is the purple object on the video. The moon colored yellow, called Nix, spins almost fourteen times during one of its orbits. (The colors mean nothing on the video; they just help our eyes tell the moons apart.)

Astronomer Mark Showalter of the SETI Institute, who discovered two of the moons, is part of a team that suspects that the tumbling of the moons is caused by the extra pull that the giant moon Charon adds to the pull of Pluto in this system.

Another interesting fact about the motions in the Pluto system is that Pluto's day is equal to Charon's month.  In other words, Pluto rotates at the same rate as its giant moon orbits it.  That means Pluto and Charon are synchronized -- one side of Pluto always has Charon above it as it turns, and the other side of Pluto never sees Charon.  

By the way, it also appears from the New Horizons data coming back to Earth that Hydra and Kerberos (the green colored moon) are each made of two smaller chunks of ice that "merged" into one close system early in Pluto's history. Perhaps all four of the small moons are the result of such mergers. So here are two chunks of cosmic material living together intimately for billions of years. Perhaps the Tea Party fundamentalists and Supreme Court Justice Scalia might not approve of such a "marriage" between icy chunks, but I think it's pretty cool.

Sunday, November 1, 2015

We Fly Through the Geysers Coming from Saturn's Moon

Last week, the Cassini spacecraft flew through the water geysers spurting from Saturn's mysterious little moon, Enceladus. NASA's steered the spacecraft to within 30 miles of the moon's surface and through the salt-water vapor that's coming up through the cracks of the moon's icy surface. How great that we can still maneuver the Cassini probe to do this after 11 years of orbiting Saturn!

Planetary scientists believe that there is likely to be an ocean of liquid water under Enceladus' crust. (The name, by the way is pronounced "En - salad - us," not as hard as it first looks.) You can see some of the deep cracks through which the water emerges in the foreground on our top image. Below is a drawing of how scientists imagine the moon's structure could be arranged inside.

We will know more about what the plumes are made of when the data are analyzed in coming weeks. Even from further away, previous flyby's have already identified some of the most basic chemicals that are the earliest building blocks of life in the plumes.

How a small frigid moon way out where Saturn orbits -- a moon only 300 miles or so across -- can have an underground ocean and geysers is still a puzzle, but it shows us that we should not take even the smaller moons in the outer solar system for granted.

As always, you can see the pictures in more detail if you click on them.  For more information on the Cassini mission, see: