Monthly Archives: December 2011

GRAIL moon mission lets students snap lunar closeups

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The first quarter moon is an ideal place to point your new telescope or binoculars. Photo: Bob King

Sometimes it’s cloudy for so long you’re surprised at the change in the moon’s phase since it was last clear. Thanks to almanacs and apps we can always know and see the moon’s phase. I suppose that will have to do for now, since clouds stubbornly remain in the forecast.

Tonight the moon will be a near perfect “half” as it enters first quarter phase. You may also notice that the moon is much higher in the sky than a few months back at this phase. That’s because the angle of its path up from the western horizon in December and January is much steeper – it gets high in a hurry. Higher altitude also makes this 2,160 mile wide ball of rock all that more inviting for observation.

Did you get a new telescope for Christmas? Yes? The first thing you should point it at is the moon. The next few nights are the best for seeing hundreds of craters and craggy peaks along the terminator, the boundary marking the line of advancing lunar sunrise. Here the sun is low and shadows long, and even low magnification will reveal a stunning amount of detail. Crater forms and mountain ranges are even visible in 7x binoculars.

Artist concept of GRAIL mission. Grail will fly twin spacecraft in tandem orbits around the moon to measure its gravity field in unprecedented detail. Credit: NASA

The moon is the apple of NASA’s eye this weekend as the twin Gravity Recovery And Interior Laboratory (GRAIL) spacecraft make their way to lunar orbit. GRAIL-A should enter orbit sometime today with GRAIL-B following on New Year’s Day at 4:05 p.m. CST. Once at the moon, each of the twin probes’ orbits will be refined until they’re nearly circular and only 34 miles high. You could never get away with a 34 mile-high-orbit around Earth; the satellites would quickly burn up in our atmosphere. On the airless moon, it’s possible to come down very close to the surface. And the closer you get, the more detailed the measurements and photographs you can make.

The purpose of the mission is to map the moon’s gravity field to determine what’s going on beneath the moon’s crust. When the science phase begins in March 2012, the spacecraft will transmit radio signals to each other precisely defining the distance between them as they orbit in formation. Subtle variations in the pull of gravity over different areas of the lunar globe will change the distance between the GRAIL probes. Measuring those changes will help scientists create a map of the moon’s interior.

The moon's farside (left) is much more heavily cratered than the nearside (right), the side we see from Earth, which has many more lava-filled lunar "seas". Credit: NASA

One of the biggest questions NASA hopes to answer is why the lunar farside crust is thicker and the surface more saturated with craters than the nearside. The mission also has a fun participatory side. GRAIL will carry four “MoonKAMS“, which middle school students can use in collaboration with their teachers to take pictures of the moon. Students choose a specific location on the moon’s surface and request the GRAIL satellites to snap a photo of it. They sure didn’t have stuff like this when I was in junior high.

One of the MoonKAM cameras that students will use to photograph the moon. Credit: NASA/Sally Ride Science

MoonKAMS stands for ‘Moon Knowledge Acquired by Middle school students’. The project is being led by Sally Ride, America’s first female astronaut. Ride joined NASA in 1978 and flew aboard the space shuttle Challenger in June 1983 on the shuttle program’s 7th mission. She was also the first woman to use the robotic arm in space to retrieve a satellite.

Some 2,100 schools have already signed up but there’s room for more. Teachers can click HERE to register to participate. And yes, it’s free. More information HERE. Tomorrow I’ll have an update on GRAIL’s progress. Meanwhile, as you gaze at tonight’s first quarter moon, consider the excitement of this next mission to “see” into its dark innards.

Biggest, best astronomy events coming in 2012

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Comet Garradd photographed on November 28, 2011 with a wide-field 8" telescope. Credit: Michael Jaeger

2011 is nearly out of breath. This past year we’ve seen two close asteroid flybys – 2011 MD on June 27 and 2005 YU55 on November 8, the Dawn spacecraft’s successful mission to Vesta, a total lunar eclipse in December, the return of Venus to the evening sky,  and two big satellites – UARS and Roentgen – fall back to Earth. The sun also cooked up some big flares in 2011 and sparked two spectacular auroral displays for mid-latitude skywatchers this fall.

Comet Elenin, the comet we all expected would brighten to naked eye visibility, went poof! Given all the doomsday talk surrounding this hapless hunk of ice, its disappearance was sweet irony. Meanwhile Comet Lovejoy, which many expected to vaporize during its searingly close approach to the sun earlier this month, survived and became one of the prettiest comets in years for southern hemisphere skywatchers. I love surprises.

What lies ahead for 2012? Below you’ll find a selection of interesting astronomical events to look forward to in the coming year.

January 4 – Quadrantid meteor shower: We’ll have more details on this shower in the coming days, but this will be the year’s first meteor shower with 50-100 meteors visible per hour in the early morning sky just before dawn. No moon will interfere.

Mid-Feb through March – Comet Garradd: The only bright, easily visible comet predicted for 2012. Garradd will move from Hercules into Draco in February and remain visible around 6th magnitude in binoculars all night long high in the northern sky for observers at mid-northern latitudes.

Mars and its north polar cap. Credit: Damian Peach

March – Mars at opposition and near Earth: About every two years, Mars and the Earth closely approach one another as they line up together on the same side of the sun. This happens on March 3, when Mars will be 62.6 million miles away. Because the Red Planet is farthest from the sun at nearly the same time, it won’t make an especially close approach to Earth. Still it will shine at magnitude -1.2, nearly as bright as Sirius and make an inviting telescopic target.

March 13 – Jupiter-Venus close conjunction: The sky’s two brightest planet pair up for a tour de force in the western sky during evening twilight. They’ll be within three degrees of each other that day and visited by the crescent moon on March 25-26.

Annular eclipse over Urbana, Illinois on May 10, 1994. Photo: Bob King

May 20 – Annular eclipse of the sun: The eclipse path crosses Oregon-California border, Nevada and much of the western U.S. An annular eclipse is like a total solar eclipse in that the moon passes directly in front of the sun, but like trying to cover a pan with lid too small, the moon’s disk is too small to cover the sun. This happens when the moon is at the far end of its orbit around the Earth at the time and appears smaller than at other times. No need for disappointment. What you see instead is a spectacular ring (annulus) of sunlight around the black disk of the moon. Don’t pass up the chance to drive or fly to see this.

The last transit of Venus photographed from Tower, Minn. through a low power telescope with solar filter. Photo: Bob King

June 5 – Transit of Venus: A very rare event! Venus will look like a small black disk when it passes directly in front of the sun during afternoon hours for North America. Venus transits come in pairs – the last one was in June 2004. Very few people will be alive for the next pair of transits on December 11, 2117 and December 8, 2125. You can watch the progress of the planet across the sun’s face with a safe solar eclipse-style filter. No telescope needed!

August 6-20 Curiosity Rover lands on Mars: Sometime in mid-August, the latest, greatest Mars rover will land on the slopes of a mountain in Gale Crater and begin looking for signs of the planet’s wetter past. Expect lots of great science, photos and videos to come streaming back to Earth.

A bright Perseid meteor. Credit: Kohle Kredner

August 12-13 Perseid Meteor Shower: 2011′s full moon this year snuffed out many of the fainter Perseids. In 2012, conditions will be much better with little to no interference from the waning crescent moon. Lay out a warm blanked and expect to see around 60 meteors per hour.

November 13 – Total eclipse of the sun: Visible across northern Australia but since the path is mostly over ocean, most people wanting to see this eclipse will probably book cruises in the South Pacific.

December 13-14 Geminid Meteor Shower: With no moon at all to spoil the show, the 2012 Geminids should be wonderful with up to 100 meteors per hour zipping overhead.

Naturally, we should also expect the unexpected in the coming year. A bright new comet could be discovered, we might finally contact E.T. or identify an Earth-sized extrasolar planet in a star’s “habitable zone”. A meteorite could land in your front yard or fossils found on Mars. The world might even end – well, that’s not going to happen, but I guarantee 2012 will wrap up richer in wonders than it began.

Jupiter’s moons reappear out of thin air tonight

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Mercury and Antares about 45 minutes before sunrise tomorrow morning low in the southeastern sky. Maps created with Stellarium

Early morning risers can see the planet Mercury shining on the level with Antares, the brightest star in Scorpius the Scorpion tomorrow morning low in the southeastern sky at dawn. Depending on exactly when you go out to look, the sky will be lit with twilight, so bring binoculars just in case. The map above is drawn for around 7:15 a.m. local time. Mercury, located in the constellation Ophiuchus, will shine about a half magnitude brighter than Antares, a red supergiant star. Can you see the color difference between the two? Through a telescope, the planet looks like a very tiny version of the waxing gibbous moon.

First Europa and then Io reappear at the times shown after being eclipsed by Jupiter's shadow. Each takes several minutes to fully emerge into sunlight. The black dots are the moons in shadow; the white as seen in sunlight. Shadow outline is approximate.

Tonight Dec. 29 Jupiter’s moons are once again at center stage. Anyone with any kind of telescope will be able to watch the amazing sight of two moons materializing from empty space as they leave the planet’s shadow and reappear in sunlight. Europa and Io are hidden in Jupiter’s shadow before 6:45 p.m. Central time, but a minute or two later, Europa slowly reappears a little more than one Jupiter-diameter to the east of the planet. Faint at first, it will soon brighten as the entire moon gradually exits the dark shadow. If we could see it up close, we’d watch the shadow slips across Europa’s disk much like the Earth’s shadow during a total lunar eclipse.

The same happens to the moon Io about 40 minutes later a bit closer to the planet. Be sure to start watching both these “eclipse reappearances” 5-10 minutes BEFORE the times shown, so you can watch and appreciate the full transition from invisibility to return to normal brightness. By the time they’re finished, Jupiter will have two “new” moons compared to the hour before. I hope you get to see it. Oh, just to be sure you know where to find Jupiter in the first place, it’s that very bright “star” high in south at nightfall.

Meet the sun’s ruby persona; minor auroras possible tonight

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A pink Christmas ornament reflects a night scene including several bright stars two nights ago. I reversed the image left to right, so sky directions are "normal" with east to the left as you face south. Details: 200mm lens at f/2.8, ISO 1600, 30-seconds. Photo: Bob King

Christmas may be over, but my experimenting with ornaments-as-fisheye-lenses has only begun. While the photo didn’t quite work out as I wanted, it still gives you an idea of what the starry sky looks like reflected in a cheap glass sphere. The ornament recorded the Winter Triangle – the three stars in the shape of a little equilateral triangle in the center – Orion’s Belt and his Sword and some of Gemini, Auriga and Taurus. The brightest star is Sirius (at bottom) with Procyon to its upper left and Betelgeuse at upper right. I plan to go out again on another night (or two) and try again. Focus wasn’t easy and the slightest breeze during the exposure blurred the image. The surface of the globe appeared very smooth to the eye, but subtle imperfections caused the stars to look bloated.

The sun photographed in the deep red of hydrogen light with a Lunt LS60 solar scope on December 11, 2011. Credit: John Chumack

The sun sent a couple CMEs or coronal mass ejections our way a couple days ago that are due to arrive today (Dec. 28) and tomorrow. Observers in the northern states and higher latitudes should keep an eye out for minor auroral storms. The sun has been very quiet lately with few large spots and significant flares. It would be nice to get back into the swing of things again. We’ve still come far from where we were a year ago when sunspots and auroras alike were extremely rare.

In the photo above, amateur astronomer and astrophotographer John Chumack used a special device called a hydrogen alpha filter to filter out all the colors of sunlight except for a very narrow slice of deep red. This allowed him to photograph a layer of the sun’s atmosphere immediately above the blinding white photosphere we see with our eyes on sunny days. Called the chromosphere or ‘color sphere’, it’s only about 1,200 miles deep and dominated by the red emission of hot hydrogen gas. Because its light is weak, it’s completely overwhelmed by the much brighter photosphere or ‘light sphere’, home to sunspots and most of the heat and light we receive from the sun.

The chromosphere is a layer of gas above the photosphere and below the sun's corona. It's the realm of prominences, spicules and flares. Credit: NASA/ESA/Image Editor

The chromosphere is home to prominences, huge plumes of incandescent hydrogen gas suspended above the edge of the sun by invisible magnetic fields. When silhouetted in front of the sun, they resemble dark snakes or caterpillars and are called ‘filaments’. Sometimes you’ll witness a filament extending beyond the sun’s edge as a prominence. Unstable solar magnetic fields can fling prominences into space in the Earth’s direction sparking auroras. Several nice examples of each show in John’s photo.

60,000 to 70,000 spicules carpet the sun at any one moment. They're jets of hot solar plasma in constant motion. Credit: NASA

Through an H-alpha filter the sun is carpeted by tiny spicules, which are spike-shaped jets of gas several thousands miles long that shoot upward through the chromosphere at 18 miles per second and last only 10 minutes. They look like fine fur and are best visible when viewed in profile along the edge of the sun’s disk. And while solar flares, those huge storms that can propel CMEs our direction, occur in multiple layers of the sun’s atmosphere from photosphere to chromosphere to corona, they’re most easily and frequently visible in the chromosphere. No wonder some of us happily fork over big $$$$$ for the pleasure of getting to know the sun’s ruby persona.

Pink prominences in the chromosphere are visible during a total solar eclipse. Credit: Luc Viatour

Only during a total solar eclipse or momentarily during an annular eclipse, when the moon blocks the photosphere from view, can we safely look at prominences and spicules in the ‘color sphere’ without a special filter. The next easy-to-reach total eclipse for Americans will occur on August 21, 2017 along a narrow track from South Carolina to Oregon.

Jupiter in polka dots, a bear stands on its tail and Venus Act II

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There will be shadow transits of both Ganymede (moon III) and Europa (moon II) over Jupiter's clouds tonight. During the times shown, the Great Red Spot will rotate onto the front of the disk - a bonus! South is at top and east to the right as viewed in most telescopes. Illustration created with Claude Duplessis' Meridian software

Got a telescope? Tonight two of Jupiter’s moons will briefly cast shadows on the planet at the same time. Ganymede, also known as Jovian moon III, starts the fun when its shadow takes its first tiny bite from the planet’s eastern limb at 8:08 p.m. CST. Add an hour if you live in the Eastern time zone and subtract two hours if you live on the West Coast.

For nearly two hours, the shadow will travel across Jupiter’s southern polar region until it slides off the disk at 9:57 p.m. Ganymede itself will lie to the left of Jupiter as shown on the diagram above. Both moon and shadow move westward due to Ganymede’s orbital motion around Jupiter. When using the diagram as a guide, remember that it shows a much enlarged view of the planet. The scale will be smaller at scope-side.

Meanwhile, beginning at 9:52 p.m., Europa’s shadow makes its first appearance along the eastern limb to begin its journey across Jupiter’s south temperate region. That means from 9:52 until 9:57 p.m. both moons’ shadows will be visible at either end of the planet, an uncommon happening. At the same time, the pale pink Great Red Spot will be in full view. While you’ll only need a small to medium telescope and 60x to see the black pinhead shadows, the Red Spot is a low contrast feature that shows more clearly at 100x or higher.

The performance is over at 12:17 a.m. when Europa’s shadow exits, stage west.

This map shows the sky facing north around 10 p.m. local time. The top stars of the Dipper's bucket point to Polaris, the North Star. Cassiopeia, now looking more like the letter 'M' instead of 'W', is high in the northwestern sky. Created with Stellarium

Many of you don’t own a telescope, so let’s turn our attention instead to the Big Dipper. If you poke your head outside just before the 10 o’clock news, you’ll find it standing on end in the northeastern sky. Yes, its slumbers along the northern horizon last fall are coming to an end with a bit of grandstanding worthy of a circus act. The handle of the Big Dipper represents the tail of Ursa Major the Greater Bear. As the sky clock turns and the hours glide by, the bear climbs higher and higher in the sky as if using its tail as a spring. By dawn,  it’s nearly overhead.

The International Space Station continues making easy-to-see passes over the U.S. and Canada during the early evening hours this week. Below are times for the Duluth, Minn. region to watch for it. For times for your city, log in to Heavens Above or type your zip code into Spaceweather’s Satellite Flybys page. The station, like many satellites, travels from west to east across the sky.

* Tonight Dec. 27 starting at 5:58 p.m. across the northern sky. Very bright!
* Wednesday Dec. 28 at 5:01 p.m. “          ”
* Thursday Dec. 29 at 5:41 p.m.  “          ”
* Friday Dec. 30 at 4:44 p.m. in bright twilight across the north. Second pass at 6:20 p.m. when the station rises in the northwest and becomes nearly as bright as Venus before disappearing in Earth’s shadow near the top of the sky
* Saturday Dec. 31 at 5:24 p.m. High pass in the north – very bright!
* Sunday Jan. 1 at 6:04 p.m. high in the southern sky. Another bright one

The moon and Venus tonight (left) and a photo taken of them last night at dusk (right). Photo: Bob King

Finally, if missed last night’s pairing of the thin crescent moon and Venus, they’ll be back together tonight just as close but in a different arrangement.

Flaming rocket upstages Santa; satellite falls on Cosmonaut Street

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Video showing the re-entry of the Soyuz rocked stage over Germany

A Russian Soyuz rocket stage used to lift a crew of three astronauts to the International Space Station last week burned up in spectacular fashion over Germany, Belgium, the Netherlands and France on Christmas Eve at dusk as it re-entered Earth’s atmosphere. Re-entering rocket stages and other man-made debris look nearly identical to flaming meteors, but there’s a difference. Meteors travel from 10-40 miles per second and flame out in a matter of seconds. Man-made space debris usually moves more slowly through the sky, because it’s scraping the upper atmosphere at less than 5 miles per second.  If you’re lucky enough to see a re-entry, the display can last up to 2-3 minutes.

Frame grab from another Youtube video of the Soyuz rocket burnup. Click to watch video

In unrelated development, the Russian communications satellite Meridian failed to reach orbit when launched on December 23 due to a failure in a Soyuz rocket. The satellite plummeted back to Earth just minutes later, landing in the Novosibirsk region of central Siberia. In a twist of irony that sounds more like a joke written for a late-night talk show host, a 20-inch spherical fragment of the satellite crashed into the roof of a home on Cosmonaut Street in the village of Vagaitsevo. Although Andrei Krivoruchenko and his wife were home at the time, no one was injured. By the way, many websites are confusing the satellite failure with the Christmas Eve Soyuz rocket stage re-entry. The two are not connected.

It’s been a long and difficult year for the Russian Roscosmos space program with the loss of five satellites, a Progress supply ship bound for the space station and the Phobos-Grunt Mars probe stuck in orbit and expected to fall back to Earth in mid-January. Even more worrying, with the end of the space shuttle program, the only ticket to the space station is aboard the Soyuz spacecraft propelled by similar Soyuz rocket boosters.Vladimir Popovkin, the head of Roscosmos, commented on Russian state television that the space industry was in crisis. He placed the blame on the loss of specialists from the program after the collapse of the Soviet Union in the 1990s.

John Burt looks at Comet Lovejoy through binoculars this morning (Dec. 26) from Gisborn, New Zealand. The photographer John Drummond estimated the tail at 27 degrees long and 3 degrees wide at the fainter end. No head was visible. Credit: John Drummond

Comet Lovejoy continues to make southern observers lose sleep every clear morning. I understand their sacrifice every time I see another photo of this fabulous object. Skywatchers across Australia and other southern hemispheric realms can spot the comet in the east in a dark sky before dawn.

Although the headless wonder has faded to around 4th magnitude, the tale has grown to 25 degrees or longer – taller than the outline of the constellation Orion – and remains easily visible. Northerners will have to wait about 4 weeks until Lovejoy shows up in the evening sky. More northern northerners like those of us in Minnesota won’t get our chance until the end of January-early February. I’ll take whatever scraps are left over just for the sake of “touching” this storied comet.

Don’t forget to keep an eye on the southwestern sky after sunset tonight December 26. As twilight deepens, Venus and a thin crescent moon will share the scene together – a beautiful sight.

Season’s greetings from Comet Lovejoy and the rest of the gang

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ESO optician Guillaume Blanchard captured this wide-angle photo of Comet Lovejoy just two days ago on December 22. Comet Lovejoy has been the talk of the astronomy community over the past few weeks. It was first discovered on 27 November by the Australian amateur astronomer Terry Lovejoy . Click for a LARGE version. Credit: G. Blanchard / ESO

There are so many excellent photos out there of Comet Lovejoy, but this one, taken at the European Southern Observatory’s Paranal Observatory in Chile stands out not only for the comet but for everything else it shows including the Milky Way’s two brightest companion galaxies, a famous dark nebula and the zodiacal light.

If you follow the Milky Way up to the right, the first dark patch you bump into is the Coal Sack, a prominent cloud of interstellar dust thick enough to block the more distant background stars. To the eye, it looks like a missing piece of the Milky Way. If stars were embedded in the nebula, their light would reflect off the dust and cause it to glow. Then we’d see it a bright, reflection nebula. Nearly touching the Coal Sack on the upper right is the compact, four-starred constellation Crux, better known as the Southern Cross.

The Coal Sack (left), is located 600 light years away within the Milky Way. The Southern Cross is outlined at right. Credit:ESO/S.Brunier

Now take a look to the lower right of the Milky Way between the two observatory  buildings. Those two fuzzy blobs are satellite galaxies of the Milky Way called the Large and Small Magellanic Clouds and only observable from southern latitudes. The Large Cloud is 160,000 light years away; the Small is 200,000.

To the left of the comet is a faint, finger-like glow called the zodiacal light. This is another cloud of dust but one created by generations of comets. Heated by the sun, a comet’s dirty, dusty ice vaporizes and is driven back to form a tail. Material from the tail is spread along the comet’s orbit and diffuses into a stream of dust over time.

With thousands of comets coming and going over the eons, dust has built up in the plane of the solar system. Illuminated by sunlight, we see it as a cone or finger of soft light at early dawn or dusk. The name ‘zodiacal’ tells us the dust is concentrated along the zodiac, a belt of sky that includes famous 12 constellations, which, you guessed it, is centered on the plane of the solar system.

Venus at Christmastime

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Venus shines over a conifer-studded ridge near Little Marais, Minn. this past Tuesday around 5 p.m. Photo: Bob King

I got off the hiking trail at 5 p.m. after a fiery sunset this week. One lone spark still burned in the blue. Venus, the planet named for the goddess of beauty and love has returned to the evening sky for the holidays and beyond. After a slow climb in the west  all fall, it’s now unmistakeable at dusk and challenges mighty Jupiter for dominance. Yes, Jupiter still has the edge in altitude, but Venus is currently three times brighter with more to come.

Venus is well up in the southwestern sky during evening twilight in late December. Maps created with Stellarium

While driving home after my hike, I watched Venus carefully through the windshield and noticed that it twinkled. Hey, planets aren’t supposed to twinkle, right? That’s a star thing.  Well, if the planet is relatively low in the sky and its apparent diameter particularly small, turbulent air can make it quaver just the same. And since the love planet is 124.6 million miles from Earth -  near its maximum distance of 162 million -  its disk is tiny and more easily pushed around than Jupiter’s, which is nearly quadruple the size.

The apparent sizes of Jupiter (left) and Venus compared now and next May. Size is a matter of distance. Venus' phase changes as well during the time.

Notice I said the planet’s “apparent” diameter. That’s how big it looks from Earth. Jupiter’s still relatively close to us and intrinsically brighter, because it’s covered in bright clouds and much larger than Venus. That will change next spring when Jupiter is on the opposite side of the sun from Earth and a good bit further off. Its apparent size will shrink by a third. Meanwhile Venus, which continues getting closer to Earth all along, will be nearly twice as big as its rival next May. And so the mighty shall fall!

Through a telescope magnifying around 75x and up, Venus looks like a miniature waning gibbous moon.

Venus is now high enough above the horizon haze to see its phases in a small telescope. The best time to observe it is as soon as possible after sunset, when the planet’s highest in the southwest. That way you avoid the detail-destroying glare for which Venus is famous. I think you’ll be struck by how tiny it looks … and how brilliant.

Keep an eye on Venus over the next few months, and you’ll be able to watch it grow bigger as its phase lessens to a “quarter moon” and then crescent. The less of Venus there is, the larger it appears. That’s because the planet revolves around the sun inside Earth’s orbit. When at full phase, it’s on the opposite side of the sun from Earth. At crescent and new moon phase, it’s between the sun and Earth and brushes by our planet at a distance of only 27 million miles. That makes Venus the closest planet to our own.

The crescent moon and Venus will hang together in the southwestern sky on Monday, December 26. The map shows the view around 40 minutes after sunset.

There’s another reason to keep an eye on Venus. On December 26, the day after Christmas, a “newborn” crescent moon will appear right alongside it. A gift to us all – if a bit belated – from the cosmos.

Enjoy the ornaments of the firmament this season!

Spectacular video of Comet Lovejoy from space station

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Comet Lovejoy is visible near Earth’s horizon in this nighttime photo by NASA astronaut Dan Burbank, Expedition 30 commander, onboard the International Space Station. The blue arch of morning twilight rims the Earth below the comet; the green band is airglow. Click photo for hi-res version. Credit: NASA

I was just made aware of this picture the moment I wrapped up today’s astro blog. Time to re-open the store! The photo was taken on December 21 from an altitude of about 240 miles. Is there a more eloquent statement about the beauty of our universe?

Now take a look at the video: