Sunday, January 31, 2016

An "All-American" Eclipse of the Sun Next Year


On August 21, 2017, there will be a gorgeous total eclipse of the Sun visible from the U.S. (and only the US!) The path of what is being called the “All American” total eclipse is only about 60 miles wide and goes from a beach in Oregon to a beach in South Carolina, crossing the country diagonally. (None of our country's largest cities will see it, alas.) A less spectacular partial eclipse will be visible to 500 million people in the other parts of the US and North America.

Astronomers expect tremendous media and public interest in the eclipse and it is not too early to start thinking about how and where best to see it. Eclipse enthusiasts are already busy reserving lodging and viewing space in the narrow region where the total phase can be seen.
The non-profit National Science Teachers Association (NSTA) is making available a popular-level introduction to help explain the eclipse and how to view it. The free 8-page booklet, which I helped write, is available at:http://www.nsta.org/…/f…/solarscience/SolarScienceInsert.pdf
Feel free to share this free booklet with anyone who might be interested.
The eclipse information comes from a new book for educators, entitled Solar Science, which I had the pleasure of writing with my long-time colleague and friend Dennis Schatz. It includes 45 hands-on learning experiences (and lots of background information) about the Sun, the Moon, the sky, the calendar, the seasons, and eclipses. You can see the full table of contents and some sample activities at:http://static.nsta.org/files/PB403Xweb.pdf
Shameless shopping hint: The book could be a wonderful gift for a teacher, a museum or nature center educator, a park ranger, or an amateur astronomer interested in public outreach. See:http://www.nsta.org/store/product_detail.aspx…
But quite separate from the book, please enjoy the free booklet, and, if you can, think about getting to the total eclipse path as part of your summer planning for next year. The image below, by French photographer Luc Viatour, gives you just a taste of how spectacular a total eclipse can be:


NASA is also planning activities and a national website for the eclipse, as is the American Astronomical Society, the main professional organization of astronomers.  I'll let people know when such other resources are available.  In the meantime, the free booklet from NSTA has an eclipse map and information about what will be visible when from many parts of the U.S.  At the end, there are links to sites where you can see very detailed maps of the eclipse path and even commentary about typical August weather at each place.

Wednesday, January 20, 2016

There is a Possible Super Earth in the Outer Solar System


Out there, way beyond the Sun's family, astronomers have discovered thousands of planets orbiting other stars. Among these alien planets, we have discovered a significant number of "Super Earths" -- planets more massive than our Earth but less massive than the smallest giants in our solar system, Uranus and Neptune. Our solar system has no such Super Earths, but many other systems do; they may be quite common.
Now, Michael Brown and Konstantin Batygin at Caltech, propose that we might just have a Super Earth in our solar system, but so far from the Sun, it takes between 10,000 and 20,000 years to make one orbit! (Pluto, for comparison, takes about 250 years.)
Brown and Batygin have been examining the orbits of icy chunks way beyond Pluto, in the region we call the Kuiper Belt. There are several chunks out there, including one Brown discovered in 2003, called Sedna, that move in an oddly aligned way. After testing many computer models to explain their odd orbit, their best model indicates there could be a planet 10 times the mass of our own Earth, whose stronger gravity is affecting the motions of many objects out where it orbits. Just a few of the affected chunks have been discovered so far and the planet itself has NOT be seen.
So this is a somewhat daring hypothesis, which the two astronomers explain in this brief video: https://www.youtube.com/watch?v=6poHQ2h00ZA
Please note that our image is a painting that Caltech commissioned. No one knows what this Planet Nine looks like.
Now here is the human side of the story. Michael Brown led the team that discovered Eris, the dwarf planet that is the same size as Pluto, in 2005. When he discovered it, he told his wife that he had just discovered a tenth planet and she had made a good decision in marrying him. Alas, instead of being acknowledged as the 10th planet, Eris caused astronomers to rethink the status of Pluto, and remove it from being the 9th planet. Brown was gracious about it, but you can imagine how disappointing it all was for him.
So now Brown may have "discovered" (or at least predicted) a real new planet. He is already nicknaming it "Planet Nine" and it's so big, no one will be able to call it a dwarf! If it is confirmed one day, he can go back to his wife and tell her, "Well, maybe I only discovered a dwarf planet before, but now I have discovered a real planet at last." Not a bad thing to discuss over dinner!
You can see a video where Brown discusses his role in the Pluto and Eris story at: https://www.youtube.com/watch?v=7pbj_llmiMg


Brown and Batygin

Thursday, December 31, 2015

Pluto Stamps to Debut in 2016


The U.S. Postal Service is going to release the set of two Pluto and New Horizons stamps in 2016 that you see pictured here. There has been an interesting connection between stamps and the Pluto mission.
In 1991, back when Pluto was still a planet, the U.S. issued a set of stamps showing close-up photos from space missions to all the planets except Pluto. The Pluto stamp was a drawing, and said "Not Yet Explored." This stamp so annoyed Alan Stern and and other astronomers who had been arguing for a Pluto mission, it gave them new energy to pressure NASA to approve a Pluto flight.
In 2006, just before New Horizons was launched, the scientists put one of those annoying stamps aboard the spacecraft and it was thus part of the mission that flew by Pluto last July. Having a U.S. stamp eventually leave the solar system amused the Postal Service people, and the new stamp of what Pluto actually looks like (with that nice heart shaped feature) is the happy result.
The Postal service is also planning to issue another set of stamps of the 8 planets (not including any pesky dwarfs this time) and a Star Trek commemorative series. See the full information at: https://www.nasa.gov/…/postal-service-honors-nasa-planetary…
Happy New Year to Fans of the Solar System and Stamp Collectors Everywhere! May your heart find fulfillment in the year ahead, just like Pluto's did..

Sunday, December 6, 2015

The Best Picture from Pluto So Far


The New Horizons spacecraft, which flew by Pluto in July, is slowly continuing to send back the images and data it took. The latest batch contains some of the most detailed close-up pictures of Pluto we have ever seen and they are fascinating!
Let’s take a look at the most intriguing new picture for a minute. We are seeing the greatest detail the spacecraft cameras were capable of. In a scene about 50 miles wide, we can make out details as small as half a city block. We see the shoreline of the Sputnik plains (part of the giant heart-shaped feature that caught everyone’s attention on the early pictures.)
The “rocks” that make up the mountains in the upper left are made of water – which is harder than rock at Pluto’s freezing temperatures. Some of these mountains are more than a mile and half high, with some of their sides bright with ice and others coated in a darker material that we are still learning about. This darker material may fall out of the sky, when ultraviolet light from the distant Sun causes chemical changes in Pluto’s thin atmosphere.
Notice how abruptly and cleanly the mountain end and give way to the softer, nitrogen-rich ice that makes up the Sputnik plains. In that ice, you can see huge but subtle cell-like structures. What makes up and drives this cell-like structure is still being debated by astronomers. Material in and around these cells may be moving up or down, like the cells you see when you boil miso soup. (If you've never boiled miso soup, ask a Japanese friend to tell you about it.) Cold nitrogen and methane ice might behave similarly when it is heated by the slightly warmer insides of Pluto and the faint heat of the Sun.
In an earlier photo, you can see some dark hills poking up at the boundary between cells, so this is very complicated terrain we are looking at. See the picture below. 
But just enjoy looking at the alien vista New Horizon’s cameras revealed. Pluto is not simple or boring!



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: https://www.youtube.com/watch?v=pf9PjFQIpzU

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: http://www.seti.org/supportus



(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:http://www.seti.org/…/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.