North America to See An Eclipse of the Blue Moon January 31

On Wednesday morning, January 31, residents of North America (and particularly those on the west coast) will experience a rare triple event:

* The full moon will enter the Earth’s shadow and show a total eclipse (turning the full moon into a dark reddish disk)

* This will be the second full moon in the same month – something we call a blue moon

* And it will be a “supermoon,” where the Moon is full just as it’s closest to our planet Earth (this last thing by itself is not especially rare; in fact it will be third “supermoon” in a row).

Having all three together is unusual. The last time we had a blue moon totally eclipsed in the U.S. was more than 150 years ago.

Here are the times of the eclipse of the Moon on the morning of January 31 in different U.S. time zones:

Eclipse Circumstance                  Pacific Mountain Central Eastern

Partial eclipse begins                 3:48 am 4:48 am 5:48 am 6:48 am
Total eclipse begins                   4:52 am 5:52 am 6:52 am ---
Total eclipse ends                      6:08 am 7:08 am ---         ---
Partial eclipse ends                    7:11 am ---         ---         ---

--- means that Moon has already set (is below the horizon)

You can see that in the eastern half of the U.S., the full Moon sets before the total eclipse or just as the eclipse is getting good, but in the western half of the U.S., some or all of the eclipse will be ready to delight those who can get up early (before the Sun does) that morning.

If you are planning to get up to see the last part of the total eclipse, there is one other factor to keep in mind. The eclipsed Moon is setting in the west as the Sun is rising in the east. That means you have to have a clear sight-line toward the western horizon for the eclipse. If buildings or trees block your view in that direction, you could miss the event. So scout out the location where you plan to be in advance. (Maps and charts can be seen at: http://www.skyandtelescope.com/obser…/january-lunar-eclipse/ )

Note: Only the total eclipse turns the Moon an eerie dark red (because of the bending of red light in the Earth’s atmosphere.) Once the total eclipse is over, the reddish effect that eclipse fans like (and the media call a "blood moon") will be gone.

Our remarkable photo, by Elias Politis, shows a 2011 lunar eclipse sequence over the Acropolis in Greece. Click on the image to see it larger.

Two Million Free Eclipse Glasses through Libraries (and a Free Booklet)

As you may know, there will be a rare eclipse of the Sun on August 21, 2017, and it will be visible throughout the United States. A spectacular TOTAL eclipse will be seen on a narrow path (about 70 miles wide) from Oregon to South Carolina. The rest of the U.S. and North America will see a PARTIAL eclipse, where only a part (but a substantial part) of the Sun is covered by the Moon. To look at the Sun when part of it is showing, special (but not expensive) glasses are required or you could damage the sensitive tissue in your eyes.

Millions of people will need glasses on August 21, and for the last year I have been grappling with the issue of how to get glasses to as many people as possible. Now, I am delighted to tell you that several astronomy colleagues and I have been able to get funding for glasses to be distributed through public libraries nationwide.

Thanks to the generosity of the Gordon and Betty Moore Foundation near San Francisco and Google, two million safe eclipse glasses will be made available through public libraries. Each library will get a supply of glasses to share free of charge and a booklet all about the eclipse and how to explain it to the public. The booklet, which I wrote with my colleague Dennis Schatz, is now ready and can be downloaded free at:

http://www.starnetlibraries.org/EclipseGuide/

The first part of the booklet explains all about eclipses, the August eclipse and when and how it will be visible in different parts of the country, and how to observe it safely. It's written for beginners in science, so we hope everyone can benefit from it. The second part consists of information to help librarians plan public programs around the eclipse.

You could do your city or town a big favor by taking the booklet or just its web address in to your local library and encouraging them to participate in the eclipse and the glasses giveaway. Libraries can register for the program (through the STARNet Library Network at the Space Science Institute) at the website: http://www.starnetlibraries.org/2017eclipse/

If, for some reason, your library can't participate in the program, there is information in the booklet on how to get eclipse glasses from the companies that manufacture the certified safe glasses that will protect you and your family's eyes. This spring is the time to make plans for where you will be and what you will do when the eclipse arrives on August 21.

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.

A Dark Spot on the Sun Seething with Energy

Many of you in North America who saw the partial eclipse of the Sun last Thursday may have noticed a nice dark spot under the eclipsed part of the Sun.  The full "active region" (that the visible spot is part of) is bigger in area than the giant planet Jupiter and has become the largest such feature on the Sun in 24 years.

With the kind permission of the photographers, I am posting here a beautiful close-up of the area, by Randall Shivak and Alan Friedman.  Look how wonderfully complex it is!

The darker regions on the Sun are called sunspots; they look darker because they are slightly cooler than the Sun's visible surface layer. The Sun is made entirely of seething hot gas, where the atoms are so hot, they easily lose their electrons.  This makes our Sun highly magnetic, and as it spins, its magnetic zones get all twisted up.  It's those twisted regions that appear to us as active regions.

Astronomers have already observed some "flares" -- sudden releases of extra energy -- from this region, but they haven't been sent in our direction in space.  The region is now facing the Earth as our Sun does its slow rotation.  So we may get some extra high -energy particles coming our way in days to come (or not -- weather from the Sun is as hard to predict as weather on Earth.)

For a nice movie of this region "crackling" with magnetic energy as the Sun rotates, see: http://apod.nasa.gov/apod/ap141022.html

New Evidence that We Live in a Space Bubble

Many people enjoy talking about their neighborhood, and how well they've come to know it. But do you know much about the "neighborhood" that our Sun and its planets hang out in? New evidence from an instrument launched aboard a NASA rocket has confirmed that our cosmic neighborhood really is a big bubble.

We have known for some time that our solar system sits inside a region which is emptier than the typical neighborhood in the Milky Way Galaxy. This "Local Bubble" (as it is called) is about 300 light years across, meaning light would take 300 years to cross it. Our diagram shows the bubble and some of the bright stars that are located in it. (The stars that looked brightest to our ancestors are the ones that wound up getting names. Many of the names we use today are Arabic translations of ancient Greek names.)

The Sun is actually located in a region that has a bit more loose gas and dust that the bubble. We call our slightly denser region the "local fluff." You can see the local fluff and other slightly denser regions inside the big bubble in yellow on our picture.

But what made this bigger bubble that we sit inside? Our best idea was that the violent explosions of giant stars ("supernovae") carved out this emptier region perhaps 10 or 20 million years or so ago. Some astronomers were not convinced of the exploding-stars origin of our bubble and thought that we might be fooled by some ways that our Sun's wind (the flow of atomic particles boiling off our star's surface) is interacting with the material in the fluff.

A new instrument, which looked for x-rays that come from collisions of atoms in deep space, was launched in 2012 aboard a rocket and got to spend five minutes above the Earth's atmosphere, where cosmic x-rays can be monitored. The data collected from those five minutes (!) was enough for the astronomers to confirm that the violence of exploding stars was the major contributor to the signs of the local bubble.

The exploding stars were not close enough to the Sun and the Earth to hurt life on our planet significantly -- after all, life on Earth thrived earlier than 10 million years ago and still thrives today. But it's clearer and clearer to astronomers that exploding stars have a lot to do with the geography and chemical makeup of our Galaxy. They not only made the bubble we find ourselves in, but we also know that it is the death of these stars that recycles the elements they get to make in their hot centers. This enriches the neighborhood with atoms like carbon, oxygen, and nitrogen -- the chemical building blocks of life as we know it. (Just about every atom of calcium in your bones, for example, was actually once inside a star that later exploded.)

By the way, our cosmic bubble is by no means unique. Other bubbles have been discovered near and far, blown by countless other star explosions over the 13 billion-year history of the Milky Way Galaxy.

For more technical details about this research, see the nice Science@NASA newsletter at: http://science.nasa.gov/science-news/science-at-nasa/2014/26aug_localbubble/

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.

A Possible Sister Star that Formed with Our Sun

Astronomers now know that stars, like people, tend to be sociable. Stars are often born and hang out in groups -- double stars, triple stars, star associations, and star clusters.  Yet our Sun is a single star, surrounded only by its family of planets and moons, but no sibling star to keep it company.  Was it always this way?

In recent years, it's become clearer that our Sun could well have formed in a loose group of thousands of stars, when it first "clumped" out of the gas and dust (raw material) of the Galaxy some 5 billion years ago.  If our mother cluster was indeed just loosely held together by the mutual gravity of the stars, in all that time, the stars could have drifted apart -- as many families do in the busy course of life. 

So we have been on the lookout for the Sun's now far-away sisters. This past week, a team of astronomers, headed by Ivan Ramirez of the University of Texas, announced that they might have found our first long-lost sibling. 

There are perhaps as many as 400 billion stars in our Milky Way Galaxy.  How can we possibly find our sisters in that huge and anonymous crowd?  After all, there are no star birth certificates on file at county offices and no little tags that hang around a star's neck.  The search involved two factors: First they looked for stars that have the same chemical make-up as the Sun (they consist of the same proportion of elements) -- which you'd expect from stars born in the same"womb."  And then they searched for stars whose motion could be calculated backwards in time and would have placed them close to us 5 billion years ago. 

Sorting through 30 possible candidates identified by other groups of astronomers after painstaking work, Ramirez' group came up with exactly one star that fit all the criteria.  Called by its catalog number, HD 162826, it's 110 light years away now, in the constellation box called Hercules.  (See the map.)  It has 15 % more mass than the Sun, and so it is a little brighter and a little hotter than our star. (In astronomy jargon, it's a Type F star, while our Sun is Type G.)

It turns out that HD 162826 has been searched for planets for the last 15 years, and so far, no planets have turned up.  But the kind of search it has been subjected to can't find small (Earth-like) planets. So the we have a long way to go before we can decide it the star has a planetary system around it or not.

Future surveys, allowing us to analyze the make-up of fainter stars, could well turn up other family members out there.  For now, astronomers will keep a far closer eye on this one possible sister star and follow it as it goes about its life.  Who knows, one day, someone from there may just respond to the equivalent of a cosmic blog post.

"Rain" on the Sun: Remarkable Video

Scientists working with the Solar Dynamics Observatory (SDO) -- a Sun-observing mission in space -- have released a wonderful new video of activity on our home star.  I recommend you view it on a nice screen and enjoy the speeded-up action:

http://www.nasa.gov/mission_pages/sdo/news/coronal-rain.html

When the active, seething, magnetic outer layers of the Sun erupt from time to time, they release vast loops and flows of charged particles.  You may have seen iron filings or small nails trapped by a home magnet and aligned into rounded patterns.   In the same way, the Sun's magnetic influence captures some of these particles and they flow back downward toward the Sun along huge rounded loops. Scientists have nicknamed this downward pouring of hot particles "coronal rain" -- after the outermost layer of the Sun, its corona (or glowing crown).

Launched in 2010, SDO is in an orbit 22,000 miles above the Earth, where it can monitor the constantly changing face of the Sun.  The movie you will see was taken on July 19, 2012 and is speeded up so each second you are seeing is six minutes of real time on the Sun.  The music, of course, is added by the film-makers (there is no sound in space), but it's very atmospheric and lets your imagination really accept the down-pouring of charged particles as a kind of rain.

Bear in mind, though, that the round filaments of hot charged particles returning to their home on the Sun are each much longer that the size of planet Earth (which is shown briefly on the video for scale.)  The temperatures that generate the glow in these images are around 90,000 F (50,000 C).  The energies in these burst and showers of particles dwarf our puny activities on Earth, yet are routine for the Sun.