Things to see while waiting for the storm to hit

A very thin moon only a day and a half past new appears in the southwestern sky shortly after sunset this evening. Created with Stellarium

* UPDATE 10:30 p.m. CST: The Kp index, which measures magnetic activity and the potential for auroras, reached storm levels of 5 this afternoon but has since dropped to an “active” but non-storm level of 3 for the past six hours. Earlier, auroras flickered over Scotland, northern Ireland, Scandinavia and the Arctic regions. For now, they appear to have moved further north into Canada. I’ve heard of no sightings YET from the northern U.S. Let us know what you see. Thanks!

While we’re waiting for the hoped-for light storm, let’s look ahead to things we can see and predict with certainty. Tonight for instance, you can stand outside and face southwest a half hour after sunset to see a temptingly delicate crescent moon in the west below Venus. It’ll be so thin that in bright twilight, it’s barely there. By tomorrow night the 25th, watch for the moon to thicken a bit and brighten further as it scooches up next to Venus.

Comet Garradd shows a pale green coma and two tails in this photo taken on January 16. Ion tail to the upper right (n.west) and dust tail (east). Credit: Erik Bryssinck

Remember Comet Garradd from last summer and fall? With the staying power of a marathon runner, it’s returned to the morning sky still clicking through the stars of Hercules the Strongman. No moon will spoil the darkness for the next 10 nights, so you may want to go out for a look.

Garradd will be easy to pinpoint thanks to some handy guide stars, and at magnitude 6.5-7 it’s bright enough to see in binoculars. A few mornings ago the comet was a small ball of glowing fuzz in 8×40 binoculars, while a look through my 15-inch scope made my eyeballs smile. At low power, the pale green coma with two soft, diffuse tails sticking out either end was a beautiful sight. I figured it was time to share.

Find Vega and then use the star Gamma in Draco and draw an imaginary equilateral triangle that includes Comet Garradd. The map shows the sky facing east around 5 a.m. local time.

The best time to observe Comet Garradd is when Hercules is highest in the east before the start of dawn or around 5-5:30 a.m. You can start by finding the bright star Vega of Summer Triangle fame in the east-northeast. From there, navigate up to the trapezoidal pattern of stars nicknamed the “Keystone” of Hercules. One side of the Keystone features the sumptuous globular cluster M13. The comet lies along the other side and moves slowly northward in the coming weeks. Let us know if you have success in seeing it.

Use this detailed chart to pick your way to the comet with binoculars and telescope. Star shown to 7th magnitude. Positions are at 5 a.m. Central time every five days. Created with Chris Mariott's SkyMap software

Big solar storm, possible auroras on the way

The M9-class solar flare (upper right) photographed around 10 p.m. Sunday night by NASA's Solar Dynamics Observatory in ultraviolet light. Credit: NASA

A large, long-duration M9-class flare that began around 10 p.m. Central time Sunday January 22 blasted a supercharged cloud of plasma called a coronal mass ejection in Earth’s and Mars’ direction. Traveling at 4.5 million miles per hour, it’s expected to arrive tomorrow morning (Jan. 24) though it could arrive 7 hours earlier or later. Earlier would mean late tonight for the U.S. and Canada. The flare, one of the most powerful in the current solar cycle, originated in the same sunspot group as the earlier flare that spawned last night’s auroras.

The NOAA Space Weather forecast calls for periods of severe and major geomagnetic storming on both January 24 and 25 with calm conditions returning late on the 26th. What does this all mean? Well, for one, sky watchers in the northern U.S. are almost certain to see a great show of northern lights. A big storm also could blackout radio communications between airplanes crossing polar regions (flights are rerouted), damage sensitive satellite electronics, affect the accuracy of GPS devices and overload power grids, particularly those in Canada, Alaska and the northern states.

The auroral oval photographed via satellite in ultraviolet light. The oval is a permanent feature in Earth's ionosphere but shrinks or expands in response to plasma clouds arriving from the sun. Credit: NASA

I’ll be monitoring the progress of the storm as I hope – like you -  that skies will be clear. Here are a few other useful websites you might want to check out to stock your info larder:

* Real-Time auroral oval. This site shows you the position and extent of the “crown” of strong auroral activity in the Earth’s north polar region called the auroral oval. If you’re under the oval, you see the aurora every dark night of the year. Normally this glowing green donut stays way up in the Arctic, but if you see the oval expand southward into the U.S., it’s time to drop what you’re doing and head outside to look for northern lights.

The storm of streaks is from an image taken by SOHO's coronagraph are caused by high-speed protons from the current storm hitting the the camera's sensor. Credit: NASA/ESA

* 3-day Kp index. Indicator of magnetic activity in the Earth’s magnetosphere or magnetic bubble. If the index bar is yellow with a value of 4, activity is increasing. If the bar is red with a reading of 5 or higher, chances of seeing an auroral display is very good — at least from the northern U.S.
* POES auroral oval plot. Data from the POES satellite is used to create an image of the auroral oval. If the oval is large, red and near the region where you live, you have a good chance of seeing northern lights.
* Aurora FAQ. Lots of answers to your questions.

After checking the data this evening, I can already see that activity levels are going up and the storm is starting. How exciting. It’s almost like a summer thunderstorm when you were a kid – a little scary but you knew you were safe. That’s true with this geomagnetic storm too. We’ve been through ones like it before. While there may be some disturbances as described above, the most pain you and I will show for it are a few lost hours of sleep and stiff necks from craning our heads skyward.

Stop back for more information as the story develops.

Mars shifts gears as it approaches Earth

Aurora borealis over northern Norway last night. Credit: Øystein Lunde Ingvaldsen

Last night’s aurora graced the skies of Canada, Alaska, Scandinavia and even Ireland. Perhaps you saw it, too. We were cloudy in my town but that won’t stop me from sharing a striking image shot by Øystein Lunde Ingvaldsen of northern Norway. A combination of good weather and lots of activity made for a powerful display. The effects of the solar flare will taper off tonight, but it now appears we’re in for round two.  A burst of particles from another large flare late on Jan. 22 will reach Earth sometime tomorrow and produce auroras that likely will reach down into the U.S. I’ll have more on this in tomorrow’s blog.

If you could float in space above the plane of the solar system, this is how Mars and Earth would look during late January. Shortly before the two planets make their closest approach to each other at opposition on March 3, the Red Planet appears to stop and move backwards in the sky. Illustration: Bob King

We normally see Mars (and all the outer planets) move eastward through the sky as they orbit the sun, but something odd happens around the time of opposition. That’s when Earth and the Red Planet are lined up on the same side of the sun and closest to one another.  This tete-a-tete occurs every two years and will again this year on March 3. As the two planets combined orbital motions bring them closer together, Mars has been steadily brightening and appearing larger over the past few months. It currently outshines every star of the night except Sirius and Canopus.

The planet Mars retrogrades or "backs up" through the constellation Leo beginning tomorrow. Created with Chris Marriott's SkyMap

As we approach the March opposition,Earth, which is closer to the sun and moves faster than Mars, slowly overtakes the slower planet. From our perspective, we see Mars appear to slow down, stop and “put it in reverse”, moving to the west for a time. When an outer planet appears to stop moving in the sky, we say it’s “stationary”. For Mars that happens tomorrow January 24. Slowly at first, but then with increasing speed, Mars backs up to the west as Earth passes. Think of passing a slower car on the freeway. As you move into the left lane and accelerate, the car appears to be moving backwards as you zoom by. Astronomers call this backwards movement retrograde motion.

Mars will retrograde through early April as it inches its way northward toward Leo’s brightest star Regulus. Once Earth and Mars have sufficiently separated, Mars will resume its usual eastward motion among the stars. To see a wonderful animation of how it all happens, please click HERE and press the RUN button.

This animation shows how ancient astronomers explained retrograde motion. Each planet moved in a smaller circle superimposed on its larger orbital circle. (Animation from Dr. Stephen J. Daunt's Astronomy 161 website at Univ. of Tennesee, Knoxville.)

Retrograde motion confounded ancient astronomers given the accepted model of the solar system at the time with Earth at the center and all the planets, including the sun, revolving around it. To explain how a planet could back up and make an about face, they had to postulate separate, smaller circular orbits called epicycles (left) superimposed on the planet’s main orbit. This gears within gears approach eventually became so complicated, logical-minded folks figured there had to be another way. Enter Nicholas Copernicus, who helped clean up the mess when he published his sun-centered solar system theory in 1543, but that’s another story.

Astrophotographer Tunc Tezel combined many images of Mars taken before, during and after opposition in 2003 to show its wonderful loop-de-loop movement in the sky. A similar but flatter loop is made by the much more distant planet Uranus, seen at right. Credit: Tunc Tezel

There’s a nice little benefit that comes with retrograding. Mars’ eastward motion means it outpaces the natural earlier rising time of stars with each passing night. Regulus and Leo rise much earlier now than they did a couple months ago. Mars meanwhile has been “running away” to the east during much of this time, delaying its rising time and requiring sky watchers to stay up late to see it. No more. The planet will soon be moving west and rising slightly sooner than the stars, making it easier to see during earlier evening hours.

Aurora alert tonight

A flare from sunspot group 1401 kicked out a CME - coronal mass ejection - in the Earth's direction on Jan. 19. Its arrival today has sparked auroras. Credit: NASA/ESA

It’s overcast here in Duluth, Minn. and looks to remain so overnight, but if you live in the northern U.S. or Canada, seeing an aurora tonight is a distinct possibility. As of 4 p.m. Central Time, the Kp index, a measure of how active or disturbed the Earth’s magnetic field is, has climbed into the “red zone” with Kp=5. That means a geomagnetic storm with accompanying auroras is in progress. Looking at the real-time aurora map, you can see that Siberia, Scandinavia, Scotland, and Greenland and parts of northern Canada are already under a cap of northern lights.

POES satellite map of aurora at 3:29 p.m. CST today. Credit: NOAA

The map at right was made with data from the Polar Operational Environmental Satellite (POES) and shows high magnetic activity (aurora) across much of the far north. The red arrow indicates where it’s local noon.

If there’s any chance for a clear sky at your house, pop out for a look tonight. There’s no moon in the sky, so it’s an ideal time to watch an auroral display — assuming it keeps on coming.
** Update 1: Aurora is still active this evening as of 8:30 p.m. CST but appears to be north of 50 N. latitude into Canada. It’s early yet.
** Update 2: If it were clear in northern Minn., my hunch is that aurora would be visible in the northern sky at this hour (11 p.m. CST). Activity is still up and aurora appears to be out across a good part of Canada.

Winter binocular tour of the Milky Way mansion

In and around the bright Winter Hexagon (outlined) are 11 deep sky objects bright enough to see in just a pair of binoculars. The blue circle guide is about 5 degrees across, the field of view of a typical pair of binoculars. The map covers the entire southern sky from horizon to overhead. Created with Stellarium

Not long ago we visited the Winter Hexagon and all the bright stars concentrated in the southern sky this season. This great abundance of jewels is the real reason why the stars seem to be so much brighter compared to the other seasons. That’s not all. Tucked in and around the Hexagon is one of the greatest concentrations of bright deep sky objects visible anywhere in the sky.

Deep sky objects are everything that’s up there besides the stars and solar system offerings – all the galaxies, star clusters and nebulae in the universe. Hunting up the brighter ones in your binoculars will give you a deeper appreciation for the richness and diversity of our Milky Way and a taste of what lies beyond. It’s like going to the next level in a video game only you’re looking at real things. Much better.

My pair of 8x40 binoculars. Photo: Bob King

And yes, I do mean binoculars. From a moderately dark sky, you should be able to see all 11 of the “M” objects I’ve plotted on the map above.  Just to be sure, I did a reality check Friday night with an inexpensive pair of Nikon Action Touch 8×40 binoculars, which are very middle-of-the-road as far as light gathering power and magnification. With no moon to brighten the sky and moderate light pollution in the south, I didn’t have to strain to see any of them. Several, like M42, M45, M41 and M37 were even visible with the naked eye.

“M” stands for Messier as in Charles Messier, an 18th century French astronomer who compiled a catalog of 110 fuzzy and starry patches he stumbled across while hunting for comets. Because he only used a small 4-inch telescope, Messier discovered most of the sky’s brightest and prettiest deep sky objects. His comets have been mostly forgotten, but the Messier catalog has become the night sky’s hit parade.

Like many beginning astronomers, I became acquainted with the Messier objects after first looking at the moon and bright planets. A few were too faint to see from my suburban Chicago home, so I’d bring the telescope along when our family would vacation in northern Wisconsin and make good use of the dark sky. By the late 1960s, I’d seen them all.

Photos of four of our Messier objects taken through the telescope. Open clusters are loose groups of bright, young stars formed from gas and dust in the Milky Way's spiral arms. The blue disk in M46 is the planetary nebula NGC 2438, visible in a telescope.

In astronomy, once you’ve seen something once doesn’t mean you’re done. You return to see that cluster or galaxy again and again just as you would a favorite photograph, painting or book. Should you buy a larger telescope, you’ll eagerly point it at each Messier once more to see what new details might be revealed. I’ve been in the hobby for nearly fifty years and still look at the Orion Nebula (M42) nearly every clear winter night.

The Orion Nebula or M42 is just below Orion's Belt (top) in the middle of his "sword". In this time exposure it looks pink but through binoculars the nebula appears as a misty patch dotted with several stars. Photo: Bob King

Of the 11 deep sky objects plotted, all are found within the Milky Way galaxy. 10 are open clusters — assemblages of young stars born from clouds of gas and dust called nebulae and held together in bunches by their mutual gravitational attraction. The remaining object is the Orion Nebula, is a cavernous gas-dust cloud 1350 light years from Earth and 24 light years across located directly below his famous “three-stars-in-a-row” belt.

Within its folds and swirls, new stars and planetary systems are congealing as I write this. In the remote future, the dust will be gone, leaving a rich cluster of stars much like the other Messier objects on our list.

By far the easiest Messier object is M45, better known as the Seven Sisters Star Cluster or the Pleiades. That you can find with your naked eye, but don’t pass up the chance to see it in binoculars. You’ll be amazed at how many more stars are hiding there just below the naked eye limit.

This photo, taken Friday night, shows the constellation Canis Major the Greater Dog with three Messier clusters. The dog's head is the triangle at upper left; his feet stick out to the right side of and below Sirius. Photo: Bob King

The map shows the star clusters as fuzzy spots, and that’s just what they look like at first glance. If you take care to focus your binoculars sharply, you’ll have no problem seeing individual stars in several of them. The easiest to resolve into tiny pinpoints are M41, M44 (also called the Beehive Cluster), M47 and M35. M46 and M50 are fainter and may take a little (but just a little) more effort to see. M41 is a particular favorite of mine, because it looks so sparkly and rich compared to its more “spread out” appearance in the telescope.

In this illustration of the Milky Way galaxy based on recent findings, many of the bright clumps represent open star clusters in its spiral arms. This image is copyright Mark A. Garlick and has been used with permission. Please do not use this image in any way whatsoever without first contacting the artist - thanks! www.space-art.co.uk / www.markgarlick.com

From a dark sky, you’ll even see the faint band of the winter Milky Way streaming down from near Capella at the top of the sky through Gemini and eastern Orion and past Sirius. Many of the clusters are situated within our galaxy’s spiral arms. If we could zoom away from our galaxy and look back, they would stand out as bright clumps like lights  strung around a Christmas tree. We live in a grand place – put on your coat and come tour the mansion overhead.

Astronauts in perpetual twilight as space station returns to view

This picture of the Earth's terminator, the fuzzy boundary between day and night, was taken from the window of the space station recently. The astronauts on board will spend a lot time in the coming week flying over this zone of perpetual twilight. Credit: NASA

Astronaut Don Pettit’s latest blog entry from his current stay aboard the International Space Station (ISS) is an interesting one. Pettit, a flight engineer, describes this time of year as one of perpetual twilight for him and his fellow astronauts. Twice a year around the time of the solstices, the orbit of the ISS nearly parallels the Earth’s terminator. In his own words:

“For a period of about a week, we live in what seems like perpetual twilight, being in neither full daylight nor full night. Our orbit follows the terminator, so that the space station is constantly sunlit. From this vantage I can see both day and night simply by swiveling my head from left to right. But the night is not really dark, and the day is lit by low-angle rays from the sun.”

It almost sounds like a description of our winter except for the 24 hours of sunlight part. Pettit describes other peculiarities:

How many layers of blue can you see in this photo taken from the ISS recently? Credit: NASA

“The Moon sets in a counterintuitive way. From this vantage it moves nearly parallel to the horizon. Once I saw it slowly set, only to reappear in a few minutes. The Moon was visible for nearly the whole orbit. The night side is equally fascinating. The atmosphere on edge glows with a vibrant electric blue. Did van Gogh paint this scene? I can see at least five, maybe six distinct layers of blue—perhaps a visual display of the classic atmospheric strata.”

We can imagine Don musing out the window during his down time, because the space station is making a new series of bright passes in the morning sky  The times listed below are for the Duluth, Minn. region. For your town, please click HERE and enter your zip code or log on to Heavens Above, which includes sky maps for every pass. The ISS moves from west to east and typically appears as bright as Jupiter. Its large orange-colored solar panels give the craft a yellow hue.

* Sunday morning Jan. 22 beginning at 6:16 a.m. across the northern sky. Very bright!
* Monday Jan. 23 at 6:54 a.m. similar to above
* Tuesday Jan. 24 at 6 a.m. Appears out of Earth’s shadow below and west of the North Star
* Wednesday Jan. 25 at 6:38 a.m. Another pass across the north
* Thursday Jan. 26 at 7:16 a.m. in twilight. A high,brilliant pass — peak magnitude -3.0!
* Friday Jan. 27 at 6:21 a.m. in the northern sky
* Saturday Jan. 28 at 6:59 a.m. straight across the top of the sky. Another brilliant appearance!

A very "old" crescent moon punctuates the twilight sky earlier this morning seen from Duluth. Photo: Bob King

I wish I could say you’ll have the company of the crescent moon when you’re out ISS-gazing, but by tomorrow it’ll be too low in the east before sunrise to see from Duluth. Floridians and others in the Sun Belt might still catch a glimpse of it. The following day the moon will be new and then coast back into the evening sky.

This morning was calm, cold and very clear. Saturn’s rings and moons and Mars’ north polar cap were stunning in the telescope. As the temperature sank to -14, I watched the star Altair finally clear the treeline in the east to complete the Summer Triangle. Yes, it’s back! Anytime you want to see what the starry future holds, just look up at dawn. It’s a whole different world up there.

Warming up for Valentine’s Day, Eros flies by Earth

A video compiled of still images taken by the NEAR spacecraft in 2000-2001. The asteroid rotates end over end once every 5 hours and 16 minutes. Credit: NASA

With Valentine’s Day approaching, get into the spirit early by consulting with Eros, Greek god of love, now touring the constellation Sextans in the evening sky.

Asteroid 433 Eros was the first near-Earth asteroid (NEO) ever discovered back in 1898. Some NEOs zip just thousands of miles from our planet, but Eros will only come as close as 16.6 million miles or about 70 times the distance of the moon on January 31. That still makes this approach the closest since 1975 and the best until January 2056.

While it can shine as brightly as magnitude 7.0, this time around Eros will range between magnitude 8.6-9.0. That’s a little fainter than Neptune, so you’ll need good binoculars or a small telescope to see it. My 8×40 binoculars can reach down to 9th magnitude under dark skies. The key to seeing faint objects is keeping the instrument steady. You can mount your binoculars on a tripod, hold them atop a fence post or car roof or simply brace yourself against a wall.

A reconstruction of Eros using images from NEAR-Shoemaker. Stony meteorites called L4 chondrites might be derived from the rocks on the asteroid. Click image to see many more photos and animations. Credit: NASA

Eros is a rocky asteroid measuring 21 x 7 x 7 miles and shaped a bit like a slipper. The Near-Earth Asteroid Rendezvous-Shoemaker (NEAR) probe visited the asteroid and settled into orbit around it on – get this – Valentine’s Day 2000. The following January it passed within 1.5 miles of Eros’ surface snapping many closeup pictures of the cratered landscape. Then in mid-February NASA mission controllers gently brought it to the surface where it rests to this day. The last signals from NEAR were received on February 28, 2001 before it was shut down.

There is no air on Eros and temperatures range from a daytime high of 212 degrees (water’s boiling point) to a nighttime low of 238 below. Because of its small size and mass, a 200 lb person would weigh just two ounces there. Pick up and throw one of its many rocks at just 22 mph and it would escape into space never to return.

Wide field map showing Leo, Mars and your key star Rho Leonis around 10:30 p.m. local time facing east. Maps created with Stellarium

To spot the cruising space island, you’ll need to be out around 10:30 p.m. local time when the constellation Leo along with the planet Mars are up in the eastern sky. Locate the bright star Regulus at the bottom of the sickle-shaped head of Leo. About four degrees to the lower left of Regulus you’ll see a fainter 4th magnitude star named Rho Leonis. Once you find Rho, you can use the detailed map below to star hop to Eros.

The faintest stars shown on the map are about 9th magnitude or a little fainter than the asteroid, which shines at about magnitude 8.7 from now through mid-February.

Eros is moving fast enough that you can easily its motion to the south night after night. With a telescope magnifying around 100x, its movement is detectable in just an hour or so. In both instruments, Eros will look exactly like a star, since it’s too small and too far away to show a shape. I wish you luck in love in the coming weeks!

This detailed map shows Eros in relation to Rho Leonis as it tracks south in the next couple weeks. The positions shown are around 10:30 p.m. CST and won't vary much over a few time zones on a particular night. North is to the upper left, the way you'd see it facing Leo around 10-11 p.m. your local time.

Subzero sun and a glimpse into the future

The sun rises through a bank of lake fog on Lake Superior near the Lester River on a bitter cold Thursday morning here in Duluth, Minn. Photo: Bob King

It wasn’t easy to feel the sun this morning with 19 below zero and a sharp northwest wind. No matter what the season, the sun’s brilliance remains the same, but you’ll strain to sense the warmer side of its personality on days like today. When the thermometer scrapes bottom in my town, Lake Superior exhales foggy breath just like people do. We call it lake steam or ice fog. Colder air blowing over the warmer open water suddenly drops in temperature; the water it’s carrying condenses into millions of wispy vapors. The swirls combine into clouds that rise into a tidal wave of steam in the distance. Raw, menacing, ethereal – pick your adjective. We love the apparition and consider it one of the many intangible reasons we choose to live here.

Photo of the sun taken at noon CST today by the Solar Dynamics Observatory. Several sunspot groups are visible including the lively 1401. Credit: NASA

After a period of doldrums, solar activity is picking up again with several picturesque and magnetically active sunspot groups dotting the sun’s face. In particular, Region 1401 has a busy, complicated mix of magnetic polarities (north and south magnetic poles) that’s been responsible for an ongoing series of flares. Once the group rotates more directly into our line of sight, we might see some effects on Earth. Meanwhile material from a January 16 coronal mass ejection (CME) is expected to touch our planet starting late tonight through the 20th. That means an increased chance for northern lights for observers at higher latitudes. If you live in the northern U.S. or southern Canada, it’s worth checking the northern sky both nights.

The Ring Nebula in the constellation Lyra is a classic example a planetary nebula. The remaining white dwarf is at center is the size of Earth but contains 1.2 x the mass of the sun. Credit: NASA/ESA

The sun is a middle-aged star with about five billion years of an active, exciting life remaining before it runs out of nuclear fuel. In the year 5,000,000,001 A.D. – give or take – the sun will sheds its outer layers to reveal a carefully kept secret – a tiny, compressed core called a white dwarf star. Though only as big as the Earth, a white dwarf is twice as hot and so fantastically dense that a teaspoon of the stuff would weigh as much as an elephant. Surrounding the dwarf will be a butterfly or ring-shaped cloud of gas astronomers call a planetary nebula. The name comes from its resemblance to the round shape of a planet.

The scenic cloud are the remains of the sun’s outer layers that will be expelled by powerful stellar winds during its tumultuous transition to white dwarfdom. Every time we observe a planetary nebula through our telescopes, we see the sun’s distant future.

ESO's Visible and Infrared Survey Telescope for Astronomy (VISTA) captured this unusual view of the Helix Nebula, a planetary nebula located 700 light-years away. The left picture was made through infrared filters. The telescope's infrared vision reveals strands of cold nebular gas that are mostly obscured in visible images of the Helix. Click to enlarge. Credit: ESO/VISTA/J. Emerson

European astronomers released a brand new photo today of the Helix planetary nebula in the constellation Aquarius taken in infrared light. The main ring of the Helix is two light years across and glows due to excitation from strong ultraviolet light emitted by the white dwarf at center. Each of the fine strands radiating from the nebula’s center span the size of our solar system and is composed of hydrogen molecules. To learn more about the Helix, please click HERE.

Assuming the Earth survives until the time the sun becomes a white dwarf, we’ll still revolve around it as always, but what we call “sun” will be only a pinpoint of white fire in a twilight-dark sky.

Father-daughter-Jupiter conjunction, aurora video and more

The thin crescent moon will pair up with Antares, the heart of the scorpion tomorrow morning at dawn. This is an ideal time to see the earthlit portion of the moon. Created with Stellarium

Mid-January. It’s cold here in northern Minnesota. While I wouldn’t pass up a cozy hour next to the wood stove, I’m drawn outside on even the bitterest of clear nights for yet another look at the winter stars. Jupiter’s still high in the southwestern sky and you can’t beat Orion charging up from the east. Shoot a line through his three belt stars toward the horizon and you’ll run right into the sky’s brightest star, Sirius.

Last night, while I peered through the telescope under a dark, rural sky, my daughter called me from downtown Minneapolis. Her sky was clear too, though orange and sapped of starlight. We shared the only “star” the two of us could both see at the same time – Jupiter. Like a communications satellite, the planet connected us across the miles.

Tomorrow morning there’s a nice conjunction of the thin crescent moon and Antares, the brightest star in Scorpius. Only a sliver of moon will be lit by sunlight. The remainder – the dusky, gray disk – glows from twice-reflected sunlight called earthshine. Some of the light reflected from our shiny planet bounces off into space, is picked up by the moon and then reflected back to our eyes.

Because the moon returns reflected rather than direct sunlight, earthlight has a dim, ghostly quality. All you need is an open view to the southeast around 6-6:30 a.m. at the start of morning twilight and the willpower to stand out in the cold to see it. I wake up very quickly when I step out the door in January. Coming back inside a warm house never felt better after you’ve gazed at the winter sky.


Time lapse sequences of photographs taken with a special low-light 4K-camera
by the crew of expedition 28 & 29 onboard the International Space Station from
August to October, 2011. Credit: Image Science & Analysis Laboratory,
NASA Johnson Space Center

I’ve posted aurora videos taken by the astronauts on the International Space Station before, but they’ve typically been brief. This one is five minutes long and features not only the quivering lights but cool flybys of cities and flashing thunderstorms. If you’re more in the mood to stay indoors tonight, this is for you. In order of appearance on the video are:

1. Aurora borealis pass over the U.S. at night
2. Aurora borealis and eastern U.S. at night
3. Aurora australis from Madagascar to southwest of Australia
4. Aurora australis south of Australia
5. Northwest coast of United States to Central South America at night
6. Aurora australis from the Southern to the Northern Pacific Ocean
7. Halfway around the World
8. Night pass over Central Africa and the Middle East
9. Evening Pass over the Sahara Desert and the Middle East
10. Pass over Canada and Central United States at Night
11. Pass over Southern California to Hudson Bay
12. Islands in the Philippine Sea at night
13. Pass over Eastern Asia to Philippine Sea and Guam
14. Views of the Mideast at night
15. Night Pass over Mediterranean Sea
16. Aurora borealis and the U.S. at night
17. Aurora australis over Indian Ocean
18. Eastern Europe to Southeastern Asia at night

Witnessed fall of Tissint Mars meteorite stirs excitement

A fragment of Tissint, the newest Martian meteorite to land on Earth, photographed on January 4 this year. It's covered in glistening black fusion crust created from melting of the outer surface layer during its fiery fall through the atmosphere. The last Martian meteorite seen to fall was Zagami in 1962. Credit and copyright: Abderrahmane Ibhi

A meteorite from Mars is a rare bird indeed. There are only about 60 known. A witnessed fall of a Martian meteorite is rarer still. The last time it happened was on October  3, 1962 in Nigeria when the 40 lb. Zagami meteorite landed about 10 feet away from a farmer who was chasing cows from his field. Fifty years later another piece of Mars came zinging through the sky, this time in Morocco.

At about 2 a.m. local time July 18, 2011 nomads and military personnel south of Tata, Morocco were awakened by sonic booms and a bright light from a large fireball. One eyewitness reported that the meteor turned from yellow to green and split into two pieces. Three months later in October, nomads found fresh, black fusion-crusted stones about 30 miles south of the village of Tissint. French meteorite hunter Luc Labenne was guided to the site of the fall by local meteorite hunters. He gathered up several samples and sent two grams worth for testing to Brigitte Zanda and Violaine Sauter at the National Museum of Natural History in Paris. They determined the crust was very fragile and fresh, good indications that it fell recently. Labenne then sent more pieces to an American researcher who confirmed their Martian origin.

This Tissint fragment from the Macovich Collection of Meteorites displays a beautiful black crust contrasting with a pale interior dotted with several dark crystals. The cube is 10mm across. Click image to see more. Credit: Darryl Pitt

The meteorite was officially named Tissint this week by the Meteoritical Society, but you might still see earlier references to its informal names Tata, Tanzrou and Foumzgit on some online sites. Either in the air or when it hit the ground (probably both), the new space rock shattered into many small fragments with weights ranging from about one gram to 987 grams. Few complete stones were found in the approximately 7 kilograms or 15.4 lbs recovered. The interior is pale gray dotted with occasional olivine crystals. As you might expect, the discovery and sale of pieces have been hot topics in both the meteorite collecting community and among scientists eager to study one of the freshest Mars rocks they’ll ever get their hands on.

Tissint is an igneous rock called a shergottite, named after the Shergotty meteorite that fell in India in 1865. Shergottites crystallized from hot magmas on Mars between 150 to 500 million years ago and were later ejected into space by large meteorite impacts. Their most likely sources are the young volcanic regions of Mars like the vast Tharsis Plateau, home to Olympus Mons, the biggest volcano in the solar system.

Rocks at the Mars Pathfinder landing site. Although covered by red iron oxide dust, the rocks themselves are gray. Credit: NASA/JPL

Most meteorites are 4.5 billion years old and date from the earliest days of the solar system, when asteroids were colliding and coalescing to form the planets. So while shergottites’ ages sound old, they’re very young by planetary standards and could only have formed relatively recently on a volcanically active planet other than Earth. That plus their particular chemical makeup and the trapped gases they contain that match those measured by the Viking and and other Mars landers clinch their Martian connection.  Shergottites come in several varieties; ones rich in pretty green olivine like this one are classified as olivine-phyric types.

A 147g Tissint meteorite with spectacular fusion crust and slightly oriented shape. Credit and copyright: Chladni's Heirs

You might think meteorites from Mars would be red – or god forbid, green – based on the planet’s overall color, but they’re far more drab. The red is iron oxide dust blown by Martian winds across the planet. It coats everything, but the rocks themselves are gray, mostly volcanic rocks.

Dr. Carl Agee, director of the Institute of Meteoritics at the University of New Mexico in Albuquerque, describes glassy melt pockets in Tissint, perfect for holding trapped gases and other Martian morsels. Melt, a sign of heating from impact and shock, will help tell us the story of the meteorite’s past – its catastrophic excavation, long journey through space and fiery delivery to Earth.

Best of all, a freshly-fallen stone has minimal weathering. This is truly pristine material. Whatever researchers find when they drill deep inside the new Tissint meteorite, whether that be signs of water or organic compounds, it’ll be the real deal from Mars, not contamination from Earth’s sticky hands.

For more on Mars meteorites, click HERE for the complete list and HERE for in depth information.