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Photo by Nick Hobgood

During the holiday season, even the ocean gets in the spirit! The Christmas tree worm (Spirobranchus giganteus) is a type of polychaete, a group of segmented worms mostly found in the ocean. It lives on tropical coral reefs and resembles a fluffy fir tree adorned with colored ornaments. Each worm has two tree-like appendages that are used to breathe and to catch meals of plankton floating by.

The Christmas tree worms are sedentary, attaching themselves to coral cover that act as their home base. Once attached, they create a calcium carbonate tube that they can then retract into for protection. The fluffy, eye-catching section of the worms that attract divers are small in size, usually not bigger than a few inches, but the remainder of the worm (hiding in its burrow) can be almost twice that size.

Check out more holiday-themed ocean animals and phenomena on the Ocean Portal! 

Photo by Nick Hobgood

A colorful “forest” of Christmas tree worms. Photo by Nick Hobgood

Read more articles about the holidays in our Smithsonian Holiday Guide here

 Learn more about the ocean from the Smithsonian’s Ocean Portal. 

The October 3, 2005 annular eclipse, as seen from Spain. Photo by Abel Pardo López

On Sunday evening, for the first time in 18 years, a solar eclipse will be visible from the continental United States. This won’t be your typical eclipse, either—as in the picture above, from October 3, 2005, the moon will cross directly in front of the sun but block out only a portion of its light, leaving a “ring of fire” that is much thicker than the ring seen during most total eclipses.

Why the ring of fire? Total solar eclipses occur when the moon passes directly between the sun and earth, covering up the sun for a brief duration from our vantage point. Because the moon is currently near apogee—meaning it’s at a point in its orbit that is farther from us than usual—the moon appears smaller in the sky, and thus isn’t large enough to block the entire sun. The result: a bold, shimmering ring of fire, known as an annular eclipse.

Unfortunately, those on the East Coast (including us here at Smithsonian) won’t be able to see the eclipse at all, since the sun will set by the time it will occur. Many residents of Western states will be able to see the ring of fire eclipse during the afternoon or evening on Sunday; others will see a partial eclipse, in which the moon crosses in front of the sun off-center, blocking just one portion of it. This NASA map shows the thin swath of the United States that will be able to see the annular eclipse. If you’re outside it, you can click on your exact location to see what time you should look to the sky to see a partial eclipse.

Although up to 94 percent of the sun’s light will be blocked out by the eclipse, looking at it for even a few seconds with the naked eye can cause permanent harm to your retinas. (Don’t try watching with your smartphone or digital camera, either—it can damage the lens.) Instead, punch a small hole in a piece of cardboard and allow the sun’s light to pass through it, and you’ll see a projected image of the eclipse on the ground. You can also look to the shaded ground beneath a leafy tree to see the shadows turn into circular rings of light.

Watch the video below by Science@NASA for a full explanation of the astronomical phenomenon:

For his 65th birthday, Stephen Hawking took a ride in zero gravity. Photo: Associated Press

On January 8, 2007, scientist Stephen Hawking did something special for his 65th birthday—he took a trip up into zero gravity. He rode in the Zero Gravity Corporation’s modified Boeing 727 jet, which traveled up to 24,000 feet over the Atlantic Ocean off the coast of Florida and performed a series of dips that let Hawking experience a total of about four minutes of weightlesness. Because Hawking suffers from a degenerative nerve disease related to amyotrophic lateral sclerosis, a medical support team was on hand to monitor his blood pressure and cardiac readings. But the renowned physicist held up even better than expected, negotiating for two additional 30-second rounds of weightlessness while in flight.

NASA has been using aircraft to simulate the zero-gravity environment of orbit for decades, and in 2004 the Zero Gravity Corporation became the first company to offer the experience to the general public. The sensation occurs as the plane climbs upward with a very steep pitch and then levels out—a little like the feeling you get at the top of a roller coaster—and lasts about 30 seconds at a time. The price tag: $4,950 plus tax.

Hawking took the flight in order to publicize the possibility of commercial space travel. “I believe that life on Earth is at an ever-increasing risk of being wiped out by a disaster such as sudden nuclear war, a genetically engineered virus, or other dangers. I think the human race has no future if it doesn’t go into space,” he said before the flight. Using the force of commerce, he believes, is the most practical way to eventually make mass space travel a real possibility.

After the flight, Hawking was exuberant, and discussed his hopes to someday fully enter earth’s orbit (Richard Branson, owner of the company Virgin Galactic, has said he will waive the $200,000 fee). “It was amazing. The zero-G part was wonderful, and the high-G part was no problem,” Hawking said. “I could have gone on and on. Space, here I come.”

The rare all-white orca whale was spotted swimming with its pod. Photo by E. Lazareva / Newscom

On a summer morning in 2010, off the coast of Kamchatka in eastern Russia, scientists made a rare discovery. Photos, released earlier this week (and posted on our Retina Tumblr blog) document what may be the first verified sighting of its kind: an all-white adult orca whale. Also known as “killer whales,” orcas are typically a mix of black and white. White members of several other whale species have been seen previously, but so far, the only known white orcas have been young.

This one, nicknamed “Iceberg” by the researchers, sports a six-foot-tall dorsal fin, indicating that it is an adult. The scientists, led by Erich Hoyt of the Whale and Dolphin Conservation Society, are are unsure why this whale has such unusual pigmentation. Although it is mostly white in color, it may not qualify as albino due to some color in the area behind the dorsal fin. One previously known young albino orca, a resident of a Canadian aquarium named Chima, suffered from a rare genetic condition that caused a number of medical complications, but Iceberg appears to be a healthy member of its pod.

Monday's solar eruption at its peak moment. Photo courtesy of NASA

On Monday, NASA’s Solar Dynamics Observatory telescope recorded an awesome sight: one of the most visually spectacular solar eruptions in years. The mass of super-hot gases and charged particles exploded from the east limb of the sun, which is the left side for observers on earth. The false-color image above captures the prominence at its peak, showing charged particles from the sun’s magnetic field rising up from the surface.

Solar prominences occur when these charged particles interact with the sun’s plasma, and are often associated with solar flares, which are momentary brightenings of the sun’s surface. The flare that accompanied this prominence rated an M1.7 on the Richter scale for solar flares, making it a medium-size event, but since it was not aimed toward Earth, it has had no effect on satellites or air travel.

As captured in the video below, some of the particles did not have enough force to break away from the sun, and can be seen falling back toward its surface afterward. Have a look: