Posers! Cirrus clouds catching twilight’s bright western glow and perhaps a bit of moonlight resemble noctilucent or night-shining clouds. Hints of pink and a more fibrous form gave them away. The REAL noctilucents were much lower in the sky. Photo: Bob King
Since about 4 a.m. this morning, the Kp index, an indicator of geomagnetic activity and aurora borealis, has been pinned at “4″ or just below the minor storm level. The gusty solar wind we talked about yesterday is already rattling its cage, making auroras a possibility for the northern states and Canada tonight. Members of our local Arrowhead Astronomical Society spotted the lights very early this morning from Duluth’s Canal Park. Again, one caveat – the moon is 3/4 full, bright and sets late. Its light may well swamp the aurora’s unless the display is relatively bright.
Close up of true noctilucent clouds glowing pale blue very low in the northern sky last night June 29. At 50 miles high and composed of ice crystals, they’re Earth’s loftiest clouds. Photo: Bob King
Last night, patchy cirrus clouds did an excellent job pretending to be noctilucent clouds. They glowed white well into twilight and had a fibrous texture, but there was something not right about their ever-so-faint pink tinge and lack of “waviness” so prevalent in true noctilucents. By 10:45 p.m. (about 1 3/4 hours after sunset) the cirrus were exposed as impostors when I finally noticed the real item much lower in the northern sky.
Jupiter (top) and Venus shine in the eastern sky over Lake Superior during morning twilight June 30. The two were about 6 degrees apart. In the coming weeks they’ll draw closer together and be joined by the crescent moon. Photo: Bob King
Have you felt the pull of Venus and Jupiter yet? I finally gave in this morning and arose at dawn for a face-to-face with the two luminaries. They made a most tranquil sight over the big lake around 4 a.m.
Jupiter through a 14-inch telescope on June 20 photographed by Philippines amateur Christopher Go. The wide appearance of the North belt (top) I saw was a combination of the NEB and the further north, narrower belt called the North Temperate Belt.
Back at home, I looked at each in the telescope. Venus was again a crescent but with its horns pointed west, opposite of how we saw it last in the evening sky. Jupiter fluttered about in turbulent air making it difficult to see much detail. I managed the South Equatorial Belt (SEB) – a dark, easy-to-see stripe – and noticed the odd appearance of the North Equatorial Belt (NEB), which looked pale and unusually wide.
Jupiter’s northern hemisphere has been in meteorological upheaval since the planet’s returned to view in the morning sky.
July begins tomorrow. Mark your calendar for a grand conjunction of the two planets and crescent moon on the morning of the 15th.
A coronal hole shows up as huge dark patch in this photo taken this morning in ultraviolet light by NASA’s Solar Dynamics Observatory. Holes are places where the sun’s magnetic field opens up and allows pent up solar wind to escape. Electrons and protons in the wind can cook up auroras in Earth’s upper atmosphere. Credit: NASA
The sun giveth in so many ways. A high speed wind of particles from a large hole in its outer atmosphere is streaming toward Earth right now and will put the squeeze on our planet’s protective magnetic bubble wrap tomorrow June 30 and Sunday.
Flaring sunspot groups currently crossing the sun will also contribute to the disturbance.
That puts at least minor auroral storms back in the forecast, so be on the lookout. One downer. A bright moon could dilute their visibility.
A NASA-funded researcher has been studying a recently discovered phenomenon called “portals” that connect the sun’s magnetic field with Earth’s, allowing the solar wind direct entry to our upper atmosphere, where it can spark auroras and other geomagnetic storm effects.
Earth’s magnetic field lines (pink) tie in directly with the sun’s (yellow) at portals located in the sun-facing side of our planet’s magnetic bubble. The resulting connection sends solar wind particles straight into the upper atmosphere. Credit: NASA
The sun’s magnetic field, which is bundled with the solar wind’s blizzard of electrons and protons, hooks up with Earth’s at so-called X-points, creating an uninterrupted path between our planet and the sun’s atmosphere. Portals are cylinder-shaped and located about 20,000 miles from Earth toward the sun. Approximately every 8 minutes a portal open up and the two fields connect, allowing particles access to Earth. Most X points are small and come and go quickly, but some are as big as the Earth and long-lived.
When Earth’s and the sun’s fields cross at the X point (right) material can follow our planet’s magnetic lines of force (blue) down into the polar atmosphere to create auroras. Credit: NASA
Earth’s magnetosphere staves off much of the sun’s solar wind, but like a mole in the CIA, a portal allows the wind to get in through the front door. Don’t get too alarmed about them – the sun’s wind’s been blowing for billions of years. No matter how it ultimately enters Earth’s inner sanctum to bless and curse us with geomagnetic storms, we’re still protected by our atmosphere from any direct particle hits.
Photograph of the northern auroral oval during an active geomagnetic storm, when Earth’s magnetic field is energized by particles flowing in the solar wind. Credit: NASA
Scientists are coming to understand that the auroras we so enjoy are stoked by more often by the solar wind popping through portals then trickling around the edges of Earth’s magnetosphere. To learn more, take a look at NASA’s videoon the topic.
A glory, created by scattering of sunlight among the water droplets in a cloud, surrounds the shadow of a plane. Credit: Wiki
Plan on flying somewhere this summer? If it’s sunny and you’re lucky enough to sit on the side of the plane opposite the sun, take a close look out the window. On the clouds below, you might just see the plane’s shadow surrounded by shimmering rings of color called a glory.
The rings resemble a little corona like you sometimes see around the moon at night. Glories form in lower clouds made of water droplets; you’ll often see them after the plane breaks through a lower cloud deck into sunlight.
A corona around the moon is also caused by diffraction. Glories involve refraction (bending of light into the water droplets), reflection (light reflected back out toward the observer’s eye) and diffraction. Credit: Andrew Kirk
Coronas and glories are both caused by a process called diffraction. Sunlight shines into the droplets and is reflected back toward the person sitting in the plane. One the way to their eyes, the cloud’s minute droplets interfere with light’s progress, scattering or diffracting it in many directions. The scattered light rays bump into and interfere with each other to create a series of concentric rings.
Since white light is made of all the colors of the rainbow, we see individual colors separated out across the rings -red on the outside and blue inside.
Smaller water droplet sizes mean bigger, brighter glories. Since clouds don’t always have consistent droplet sizes, glories shrink and expand while you watch as if alive. Glories can also change in size as your altitude rises or drops during a flight. These targets of colored lights are one of nature’s more alluring sights – don’t miss the chance to see one if you’re traveling by air.
Planet Earth seen from the top down. Ocean scientist Norman Kuring pieced together this composite image of Europe, Asia, North Africa, and the entire Arctic. It was compiled from 15 satellite passes made by Suomi-NPP on May 26, 2012. Click for hi-res version. Credit: Norman Kuring, NASA/GSFC/Suomi NPP
NASA just released a very cool picture of planet Earth seen from a new perspective – looking down over the North Pole and Arctic. Scientist Norman Kuring of NASA’s Goddard Space Flight Center stitched together satellite photos to create this view of Earth looking down from 70 degrees north, 60 degrees east (western Siberia). If summer’s heat is already getting to be too much, click on the photo for a larger version and cool off.
Noctilucent clouds above the Tibetan Plateau photographed on June 13, 2012 by astronauts aboard the International Space Station. Also known as polar mesospheric clouds, they’re formed of ice crystals some 50 miles high – nearly at the edge of outer space. Click for hi-res version. Credit: NASA
Back on June 13 I wrote about a nice display of night-shining or noctilucent clouds visible in northern Minnesota during late evening twilight. Turns out ground dwellers weren’t the only ones watching the northern sky that night. Space station astronauts flying over Tibet looked out the window and snapped the photo above of the same delicate clouds from a much higher perspective.
June and July are the best months to watch for the elusive sight. I usually start checking the northern sky for the first faint traces of the clouds about an hour and a quarter after sunset.
We first meet young Luke Skywalker, hero of the Star Wars movies, on the desert planet Tatooine on the fringe of the Galactic Republic. Luke worked on his Uncle Owen’s “moisture farm” but like any future Jedi knight, he knew he was destined for greater things. At the end of the first scene, Skywalker gazes skyward toward that planet’s two suns, pulled toward a fate he could only guess.
The fictional world Tatooine, Luke Skywalker’s home world in the Star Wars movie series. Credit: Star Wars/George Lucas
As far as planets go, Tatooine will always be one of my favorites. The exotic dual sunsets, wild expanses of desert and cool architecture of the future left a wonderful impression when I first saw Star Wars back in 1977.
American film producer George Lucas filmed scenes for his fictional planet at various locations across the real deserts of Tunisia. As for the name Tatooine, it was adapted from the Tunisian city Tatahouine, an oasis town in southern part of that country.
Roadside sign in the town of Tatahouine. There are several spellings for the name in common use. Credit: Alain Bachellier
In the film, it’s pronounced “tatoo-een” but the locals call it “tat-ween”. Although Lucas didn’t film any scenes in the city, the landscape there and across the deserts of Tunisia were the inspiration for Luke’s homeland.
A typical fragment of the Tatahouine meteorite – this one weighs 1.2 grams. Notice the green color and black shock veins. Penny shown for scale. Photo: Bob King
Tatooine/Tatahouine boasts yet another outer space connection. 81 years ago to the day on June 27, 1931 at 1:30 a.m. local time, a fireball exploded above the Tunisian desert 2.5 miles northeast of Tatahouine. Soon after the fall, local Bedouins collected hundreds of small meteorite fragments that peppered a hillside.
Vesta’s south pole is face on in this picture taken by Dawn. The dark area at center is a tall mountain peak. Scientists suspect the weird appearance of the polar region is due to an impact with another asteroid. Credit: NASA/JPL-Caltech
What they plucked from the dust was a rare, green-colored meteorite found deep within an asteroid’s crust called a diogenite. Many years later, scientists identified the Tatahouine meteorite’s true home – the asteroid Vesta – by analyzing light reflected from the meteorite and the asteroid. They were a close match.
More recently, the Dawn space probe, which has been keeping an orbital eye on Vesta for months, confirmed that Tatahouine and other diogenite meteorites originated on this little world. A likely scenario for Tatahouine’s delivery to Earth involved a massive impact on the asteroid. Chunks of crustal material were sent flying into space where they drifted for some 38 million years before finding their way to our planet on a tepid June morning in 1931.
Known informally as Tatooine, Kepler 16b orbits a pair of stars in the Milky Way. Credit: NASA
Evidence for the power of the impact can be seen in the web of black shock veins of melted rock created instantaneously upon impact. The large orthopyroxene crystals give Tatahouine a unique green color found in few meteorites.
Since the meteorite shattered into thousands of small pieces, tourists to the area can still find fragments to this day. Tatahouine fragments look “naked” or without the typical black fusion crust coating many other meteorites. It blew to bits at a very low altitude, too late and moving too slowly for air friction to melt the exterior of each small piece.
In 2011 NASA announced it had found the first planet in orbit about a double sun like the fictional Tatooine. Named Kepler 16b, the Saturn-mass planet orbits orange and red stars with a period 229 days. With temperatures ranging from 100 to 150 below F, this gas giant Tatooine sadly couldn’t host Jabba the Hut and the delightful cantina pictured in Star Wars.
Watch the local planets tonight in the southwestern sky at nightfall. Mars and Beta Virginis, also known as Zavijava, will be a tight pair. Created with Stellarium
Before we depart planets alien and otherwise, take a look tonight in the moon’s direction. To its left you’ll see the ever-present pair of Saturn and Spica. Right of the moon is Mars, which will be very close to the 3rd magnitude star Zavijava in the constellation Virgo tonight. Can you split the two apart with you eye? If not, enjoy this temporary “double star” in binoculars.
The mystery object in Ophiuchus seen last month. It looked like a 3rd magnitude star (one level fainter than the Big Dipper stars) that “didn’t belong” there. Photo: Bob King
One night last month while setting up the telescope for a night of observing I noticed a “new” star in the southern constellation Ophiuchus. I first thought it was a satellite but it appeared stationary and didn’t fade away. Hmmmm. Could this be a new nova? It was in the Milky Way band where most novae (explosive outbursts of stars) are discovered. Just in case the object proved to be something interesting, I fired off a few photos.
Close up view of Ophiuchus and Galaxy 11. In 30 seconds time, the satellite barely moved while the stars show obvious trails from Earth’s rotation. Photo: Bob King
The longer the light remained the more excited I became until I noticed that it was moving very slowly to the east. Well, there went my novae hypothesis. The mystery object soon began to fade; five minutes later was barely visible to the naked eye.
Feeling slightly deflated, I realized I’d been watched a long, slow flare from a satellite. The sun, satellite and my spot on the hill were lined up just right for sunlight to reflect off an antenna and back to my eye.
Later that night I fished around and discovered my nova was Galaxy 11, an active communications satellite serving both the U.S. and Brazil.
Galaxy 11 is a communications satellite in geosynchronous orbit around Earth.
Galaxy 11 relays TV programming like the Celebrity Shopping Network and National Geographic to widely separated points on Earth.
Most of the satellites we see like the space station are in low-Earth orbit or LEO. Being relatively close to the planet they circle around it faster than the Earth rotates. That’s why we see the 240-mile-high space station cross the sky in only five minutes. Every 90 minutes it completes another orbit.
A satellite in geostationary orbit (shown above) remains in exactly one spot in the sky. Credit: Francisco Esquembre
The farther a satellite is from Earth, the slower it moves across the sky. If you ever see one slowly creeping its way through the heavens, you know it’s much higher than the space station located some 240 miles up in LEO.
It’s possible to send a satellite far enough away – 22,236 miles to be exact – so that it appears to stay fixed or nearly so in just one place in the sky, hovering over the planet like an all-seeing eye.
Birds at this towering altitude are said to be in geosynchronous orbit. You may have also heard of geostationary satellites. Geostationary is a more specific term and refers to a satellite in a geosynchronous circular orbit directly over the equator. These remain in exactly the same spot in the sky; geosynchronous satellites are in slightly inclined orbits and remain in the same small area of sky.
Arthur c. Clarke at his home in Colombo, Sri Lanka in 2005
It was the late science fiction writer Arthur C. Clarke who in 1945 first suggested that a global communications network would be possible using three equally spaced geostationary satellites orbiting above Earth’s equator. NASA finally tested Clarke’s idea in 1963, and lo and behold in 2012 we can hardly live without them.
Geosynchronous satellites are essential for TV broadcasting, satellite radio, weather forecasting and global communications.
Most geosynchronous satellites are faint because they’re far away and require binoculars or a telescope to see. One in while however they flare in sunlight like Galaxy 11 and become easily visible with the naked eye.
Illustration showing space debris and active satellites orbiting Earth. Geosynchronous satellites responsible for relaying communications around the world define the distinct outer ring. The dense inner circle are satellites in low Earth orbit. Credit: NASA
It’s a real treat to bump into a geosynchronous satellite in the telescope. They hang out near the celestial equator in the sky. Once found, a “geosync” stays put in the field of view while all the other stars drift by, carried along by Earth’s rotation. Even though I didn’t discover a nova that May night, I’m remain in admiration of Clarke’s genius and mankind’s ingenuity.
The sun is nearly blank around 8:30 a.m. (CDT) today with only one obvious sunspot group to the lower left. With few spots, don’t expect much much auroral activity … then again, you never know. Credit: SDO/NASA
I will never figure out the aurora. Most of the time there’s a clear connection and forecast indicating that a flare or coronal hole on the sun will have a certain probability of zinging the Earth’s magnetic field. That might precipitate a display of the northern lights anywhere from the high Arctic to as far south as Arizona.
Like the weather forecast, sometimes space meteorologists get it wrong though not for lack of trying. Nature does not always follow expected pathways despite the best available data and computer modeling.
Around 12:30 this morning (June 25) the northern sky was aglow with a very low green arc and faint, streaky rays. Details: 35mm lens, f/2.8, ISO 2000 and 30-second exposure. Photo: Bob King
Last night northern lights were not in the forecast. The Kp index slumbered around 2 and space weather experts predicted quiet conditions. I even checked the POES satellite map to gauge the extent of the auroral oval and found it nestled far to the north above Hudson Bay. So why did the aurora make an appearance?
The low green arc shows up well in this 30-second exposure with the camera pointed due north around 1:30 this morning. Photo: Bob King
The northern sky up to about 20 degrees (two fists) glowed with colorless, amorphous light punctuated by occasional faint rays that rose like wisps of smoke from a smouldering campfire. This went on until at least 2 0′clock.
The Earth “wears” a crown of aurora borealis centered on magnetic north and south called the auroral oval. This photograph from space shows the southern oval over Antarctica. Credit: NASA
After scratching my head about the matter this morning, I decided to call Joe Kunches, a space scientist at NOAA’s Space Weather Prediction Center. He boiled it down to this: even though aurora wasn’t in the forecast, the constant wind of electrons and protons streaming off the sun (solar wind) “always causes some level of activity in Earth’ s polar atmosphere.”
Electrons in the wind excite the atoms of the upper atmosphere to give off characteristic auroral greens, reds and purples.
This permanent aurora is called the auroral oval; it normally resides in the high Arctic (and Antarctic) but expands further south over the U.S. during periods of enhanced solar activity.
Given dark skies and no moon, conditions were ideal to see even a minor aurora last night. Still, we both remained puzzled as to why the aurora was visible as far south as Duluth when magnetic indicators and satellite maps showed it residing far to the north in the oval.
“You shouldn’t have seen it,” Kunches joked. With that, we both had a good laugh.
Lichen on a boulder near the Cross River in northern Minnesota. Photo: Bob King
What’s crusty, grows on bare rock and appears barely alive? Lichens. Many also grow on trees, but you’d be hard pressed in northern Minnesota to find a rock face not spattered with pale green, yellow and orange lichens.
These amazing creatures are a happy marriage or symbiosis of fungi and algae. The fungus provides a home for the algae; the algae provide food for the fungus via photosynthesis.
Expose-E held trays filled with organisms. Installed on the space station in 2008, it was returned to Earth in 2009. Results were recently published in the Astrobiology Journal. Credit: ESA
In 2008 scientists with the European Space Agency (ESA) sent the suitcase-sized Expose-E to the space station filled with 664 organic compounds and a variety of living organisms to see how they’d survive exposed to the vacuum and radiation-filled environment of space. Here on Earth the atmosphere not only provides essential air for respiration but serves to shield living things from dangerous cosmic rays and the full brunt of UV or ultraviolet radiation from the sun.
The samples were exposed to open space for 18 months. While insulated to a degree by the space station, the assortment experienced airlessness, “hard” ultraviolet radiation, cosmic rays and temperatures constantly rising and falling between 10 and 104 degrees F.
Samples of Xanthoria elegans (sunburst lichen) from Spain were exposed to the extremes of outer space for 18 months and then resuscitated when returned to Earth. Credit: ESA
So who came out on top? The lichens of course! Xanthoria elegans, an attractive orange lichen gathered from the mountains of Spain, “were the best survivors we know”, said René Demets, a biologist working in ESA. They put themselves into “off mode” while waiting for better days to return. Once returned to Earth, the symbionts roared back to life after a good soak in the water. Think of the healing power of a hot shower after a physically demanding day.
Expose-E orbits the Earth on the International Space Station’s European laboratory module Columbus. Credit: ESA/NASA
Water vaporizes almost immediately from living things exposed to the vacuum of space. Only animals and plants capable of carrying on in extremely dry conditions can tough it out. Besides lichens and some dried plant seeds, tardigrades (also called water-bears), brine shrimp and larvae of an African midge are the only animals known to survive the means streets of outer space.
All this talk of living things surviving outside the planet’s protection may have you wondering if life might not have come from elsewhere. Maybe as bacteria tucked under the stony skin of a meteorite. It certainly seems possible.
Of course there are two ways to tango. Life on Earth could have been launched by asteroid impact into outer space to potentially seed other planets. Seeing how common invasive species are – everything was once an invasive species, right? – I wouldn’t be surprised at all if life hitched a ride to parts unknown by the most unlikely paths.
I’ll often see lichens on my walks and wonder if they’re dead or alive, especially after a long dry spell. Some of them crumble away at the touch. Next time I’ll have more faith.
To read the complete set of articles on the Expose-E mission, click HERE for the May 2012 issue of Astrobiology Magazine.
The Summer Triangle is right on schedule with the season. Watch for the trio of Vega, Deneb and Altair across the eastern sky at nightfall.
The Summer Triangle invites our eyes to explore the eastern sky at nightfall. At dusk you’ll see Vega first, shining highest and brightest of the three stars that form the apexes of the triangle.
The others are Deneb in Cygnus the Swan (better known as the Northern Cross) and Altair in Aquila the Eagle. Vega heads up the small constellation Lyra the Harp.
All three are first magnitude or brighter; connect them by imaginary lines and you’ll make a triangle spanning 3 1/2 fists held at arm’s length or about 35 degrees.
Like the proverbial “X marks the spot” on a pirate treasure map, the Summer Triangle points sky watchers to a celestial hoard of star clusters, double stars and dark and bright gas clouds of all shapes and sizes. Many of these require a telescope or binoculars to see best, but not the Milky Way. All you need are your eyes and a dark sky.
The Northern Cross is outlined in the photo above. A bright patch of Milky Way stars occupies the bottom half of the cross, while a dark lane of interstellar dust clouds splits the Milky Way down the middle. The dust blocks the light from more distant stars giving the galaxy a patchy texture. Photo: Bob King
The triangle corrals a particularly bright portion of the galaxy. The section in the bottom or southern half of the Northern Cross can even be glimpsed from suburban areas. As a kid living near Chicago years ago, I used to get up before dawn during the spring and summer months to catch sight of the Milky Way from Cassiopeia to as far south as Aquila. Why get up early? I’d heard that unnecessary city lights were turned off after midnight.
Other galaxies are bisected by clouds of interstellar dust along the mid-section. This is ESO510-G13. Dust is silhouetted against the galaxy’s many billions of stars. Click to see more Hubble galaxy photos. Credit: NASA/ESA/Hubble Space Telescope
Last night a few of us were out in the driveway Summer Triangle gazing around 11 o’clock. The big patch in the Northern Cross was very easy to see as was the Great Rift or apparent splitting of the Milky into two broad forks. What appears as empty space between them are really dark clouds of interstellar dust shed by previous generations of exploding and evolving stars.
The rift’s true nature took centuries to fathom. Only by the early 20th century did astronomers come to understand they’d been looking at dust all along and not empty space between the stars. Modern telescopes operating in the infrared and radio regions of the spectrum can now “see” into the dust and detect multitudes of stars slowly forming within the cold, dense cores of the clouds through gravitational collapse. Dust that was shed by stars long gone will one day become a new generation of stars as gravity coaxes the ashes to burn once again.
Our Milky Way galaxy is shaped something like a pancake. Where the butter is there’s a bulge in the disk where the stars are more concentrated.
The sun and planets are situated in the plane of our pancake-shaped spiral galaxy about 2/3 of the way from the center to the edge. Put yourself inside a pancake for a moment and imagine the Earth 2/3 the way from the butter to the edge.
There’s a lot more pancake (dough) between us and the center compared to looking straight up or down through the thin cake. In the real Milky Way, there are lots more stars between us and the center compared to looking up or down through the galaxy. The stars stack up along our line of sight to create a thick band of hazy starlight in the eastern sky we called the Milky Way. In other directions, the stars aren’t nearly so concentrated and simply appear as scattered jewels across the sky. The reason the stars look hazy is because most of them are so faint and far away their light mushes together into cloudy masses.
A 2-day-old lunar crescent floats above the Wild Ricing Moon sculpture on the UMD campus Thursday night. Details: 400mm lens at f/6.3, 1/100-second, ISO 400. Photo: Bob King
Sharp as honed knife. That was last night’s moon. I grabbed a couple photos of it posing pretty with a sculpture on the University of Minnesota-Duluth campus and then took off for the countryside to commune with the mosquitos while waiting for the sky to grow dark enough to see the planet Mercury. I finally spotted it 50 minutes after sunset shining faintly to the moon’s north.
Tonight the moon will still be an inviting crescent just three days old and barely out of the cradle. Even a cellphone camera will be adequate to frame a lunar scene during twilight. There’s enough light at dusk for cameras to auto-focus on distant objects like the moon and allow photos without blur from vibration or shaking.
Make a survey of your town for cool spots to compose an image of the low-hanging moon in the western sky with an interesting scene in the foreground. It might be a building, a flagpole, neon sign, a particular tree, church steeple, bridge – you name it. If you live near a body of water and the night is calm, the moon’s reflection is well worth swatting bugs to record. The sculpture photo was shot about 15 minutes after sunset with “plain vanilla” settings of f/8, 1/100 second and ISO 400. Sure, my newspaper provides me with a 400mm lens, but the image would have worked almost as well with a standard 200mm or even 150mm lens.
The moon was near setting yesterday evening when Mercury (upper right) finally appeared about 6 degrees to its upper right. Details: 150mm lens at f/6.3, 1/15 second at ISO 800. Photo: Bob King
In late twilight, when the moon glows more brightly against the sky, most cameras will automatically sense the low light, open the lens wider and expose longer. Those things will eliminate most shake, but if you do notice blurring, hold your phone or camera up against something sturdy. Just keep it away from your beating heart of you’ll end up with curious double images on every pump. Those with adjustable settings can play around a little more by changing the shutter speed or lens opening (f/stop), checking the results and trying again to hit the mark.
During late twilight this evening, when the moon is low, look up to the left across the southwestern sky to find the gentle arc of Regulus, Mars and Spica-Saturn. The arc spans about 70 degrees or seven fists at arm’s length. Created with Stellarium
We had 10 inches of rain in Duluth this week and everyone was out with their cameras and phones documenting the crazy flooding, sinkholes and the raw power of nature. Those tools are perfect for capturing nature’s quieter side, too – like a crescent moon fading to orange.
Mercury and the crescent moon low in the western sky 40 minutes after sunset and about 6 degrees apart. Created with Stellarium
Let’s start with a quick reminder that the thin crescent moon will be low in the western sky during twilight this evening. Look several degrees (two or three fingers held at arm’s length) to its upper right to spot the planet Mercury. Since I’m writing much later than usual, I hope you’ll still have time to catch sight of them both.
Through a telescope at magnifications of 50x and higher, Mercury will look like a very tiny half moon.
Shackleton Crater, named after Antarctic explorer Ernest Shackleton is located at the lunar south pole. Because the moon’s axis is only slightly tilted, the crater’s floor is in perpetual shade. The average temperature there is 300 below zero F. Credit: NASA
The floor of the crater Shackleton, located in the chill shade of moon’s south pole, appears to harbor 22 percent ice among its rocks. That’s the story according to data from NASA’s Lunar Reconnaissance Orbiter (LRO). The craft shot laser beams into the 3-plus billion year-old dusty dark crater interior and measured the brightness of the light reflected back. The results showed that parts of the floor and walls are brighter than those of nearby craters, consistent with the presence of water ice.
Elevation (left) and shaded relief (right) image of the 12.5 mile-diameter crater Shackleton. The structure of the crater’s interior was revealed by a digital elevation model constructed from over 5 million laser elevation measurements made by the LRO. Credit: NASA/Zuber, M.T. et al., Nature, 2012
Shackleton might be one of the solar system’s best places to keep ice cream from melting. Because the tilt of the moon’s axis is a scant 5 degrees compared to Earth’s more generous 23.5 degrees, sunlight only grazes the rims of craters at the north and south poles. Their interiors remain in near-permanent shadow, making them ideal environments for preserving water and other ices that may have been delivered by long-ago comets.
Earth was bombarded by comets, too. That water has long since become one with the rivers, oceans and what pours from your faucet. To read more about Shackleton’s bounty of ice, click HERE.