The plump moon will stroll by Jupiter tonight and Wednesday night making the planet particularly easy to find. Binoculars and small telescopes will show all four moons tonight but you’ll seek them in vain during part of tomorrow night. This illustration and the one below were created with Stellarium.

OK, this is weird. Normally I write about things that might nudge you outside for a look-see but this latest happening is the exact opposite.  It’s a total non-event … in a sense. Tomorrow night (Weds) between 11:43 p.m. and 1:29 a.m. Central time none of Jupiter’s four bright moons will be visible alongside the planet. The solar system’s father of the sky will be hard pressed to find his children. Just for a little while.

Jupiter in binoculars tonight (Tues.) around 10 o’clock. I’ve listed the order of its four brightest moons from left to right.

Normally you can see at least a moon or two on either side of the planet. Indeed tonight all four should be visible in a pair of steadily-held binoculars and through any small telescope. Tomorrow night’s a different show. For nearly two hours Ganymede and Europa will be in front of the Jupiter and camoflaged from view. You’ll need a modest telescope to see them against the pale clouds of Jupiter’s equator assuming the air is steady. Io will be tucked behind the planet’s edge and then emerge into eclipse, invisible in the planet’s shadow. Moon #4, Callisto, will also be in eclipse. If you’re used to seeing those familiar little "stars" alongside big, bright Jupiter you might find the moonless view oddly disturbing.

The disappearance of Jupiter’s moons is a rare event that happens only about 20 times per century. The last time was May 21 but that one was only visible in the eastern U.S. and for a very brief time. Observers across the U.S. will witness Wednesday night’s. Plan your outing well since the show will be over at 1:29 a.m. when Io slides out of Jupiter’s shadow and back into sunlight.

A modest telescope at high magnification will show the moon Ganymede and perhaps Europa "hiding" in front of Jupiter at the start of the moonless period. This illustration and the one below are courtesy of Chris Marriott and SkyMap software.

Ready for more? Users with modest-sized telescopes (6 to 10 inches) can enjoy watching the moons Ganymede and Europa and their shadows dot the planet during the moonless time. If you stay up late, you’ll see Europa move off the planet’s face and shine again in a dark sky. How fine a thing it is to watch this solar system in miniature move with the precision of a classic Swiss watch.

In this view at 1:45 a.m. Central time, both Ganymede (G) and Europa (E) and their shadows are visible through a telescope. The easiest shadow to see is Ganymede’s since it’s the biggest.

The waxing gibbous moon shines between the leaflets of a fern during twilight yesterday. Photo: Bob King

The sky was hazy last night and the moon low. These two factors combined to give it a pleasing orange color like a ripe peach or cantalope. We see the moon all the time but how many of us have really focused our eyes on it to see the many features presented before us?

Tonight and the next few nights you can use the little chart below to help you identify some of the moon’s "seas" as well as one prominent crater. The seas or maria (MAH-ree-uh), which is Latin for seas, are the easiest to find. You probably know a few already since they make up the face of the fabled man in the moon. These grey patches were once thought to be actual bodies of water. We know now that they’re large basins hollowed out by asteroid impacts nearly four billion years ago. Not long after, lava welled up from deep cracks and filled the holes with a grey, titanium-rich magma soup which eventually solidified into vast plains.

This photo shows the moon’s phase tonight (Monday) and some of the moon’s numerous grey patches called maria or seas. Illustration: Bob King

You can see most of the lunar seas with just your naked eye. To give you an idea of which are more challenging, we’re going to rate each feature’s visibility starting with the easiest and ending with the hardest. Here they are:

1. Sea of Showers
2. Sea of Tranquillity
3. Sea of Serenity
4. Sea of Clouds
5. Sea of Crisis
6. Sea of Fecundity
7. Sea of Nectar
10. The crater Copernicus

Notice that I placed Copernicus three steps below the Sea of Nectar. That’s because it’s considerably harder to see than the seas and in a class all by itself. Look for a small, isolated white patch between the Seas of Showers and Clouds. Sounds like I’m giving you a forecast, doesn’t it? Remember that this is a naked eye challenge, but after you’ve gone through the list, by all means explore with your binoculars too. Good luck and let us know how it goes.

It’s easy to find Venus shining low in the northeastern sky just before dawn (around 4:30-5 a.m. for northern Minnesota and Wisconsin). With binoculars look just to the left of the planet to see the cluster. Created with Stellarium.

Early morning observers can reach for their binoculars the next couple mornings to catch Venus right next to the bright little star cluster called the Beehive in the constellation of Cancer. The contrast between the impossibly bright planet and the tiny cluster stars should make for a very pretty view.

The three top stars of the Great Square crown the rooftop of a neighborhood house lit by moonlight last night. Details: 24mm lens at f/2.8, 25-second exposure at ISO 800. Photo: Bob King

Chilly last night and great to be out under the stars. The waxing gibbous moon was a studio light in the south bright enough for nighttime portrait work. I grabbed the camera and took this picture of a brick house along my walking path. A couple weeks ago I was struck by how the upper three stars in the Great Square of Pegasus formed a neat starry roof over the earthly one. With the moon for illumination, the photo was easy to shoot.

Have you tried taking photos in moonlight? If not, then get a tripod for that digital camera and wander your neighborhood for places where you can photograph without scaring the neighbors. No one wants a visit from the police in the middle of a time exposure. Set your camera to a higher "speed" like ISO 400 or 800 and make a series of time exposures to see what looks best. The closer to full moon phase, the shorter your times need to be. Moonlight not only provides the light needed to reveal detail in the foreground objects but gives you a rich blue sky background.

We visited Delta Cephei in yesterday’s blog and last night I noticed it was a step below its neighbor Zeta. I estimated Delta’s brightness at 3.8. I hope you’ll be watching with me over the next few nights to see how it fades and brightens again. Delta was the first Cepheid variable star to be discovered and gave its name to the type. All Cepheids experience pulsations and expand and contract like an enormous bellows over a period of days to months (illustration at right).The Cepheids are just one class of variable stars — stars whose light is not constant but varies.

One hundred years ago, astronomers using trigonometry could measure distances out to only a 100 light years or so. After that they had to rely on shaky estimates. Lucky for them, one Henrietta Leavitt would soon make a seminal discovery that would give us a tool to reach out to the galaxies. Knowing distance in astronomy is crucial because without that bit of information, you can’t really know how big or how truly bright something is. Does Vega look bright because it’s a gigantic, hot star or because it’s close? In Vega’s case, the star’s proximity is the main reason for its brilliance.

Leavitt (left) worked as a human "computer" at Harvard College Observatory in the late 1800s through the early part of the 20th century. For 30 cents an hour she studied the observatory’s photographic plate collection measuring and cataloging the brightnesses of stars. In doing so, she discovered several thousand variable stars, including many in the Large and Small Magellanic Clouds. The Clouds are small, irregular companion galaxies to the Milky visible in the southern hemisphere. In 1908 she noticed a pattern among the Cepheid variables in the Clouds — the brighter the star, the longer its period. Recall that Delta’s period is 5.4 days, the time it takes to go from bright to dim to bright again. Leavitt discovered that the dimmest Cepheids in the Clouds had short periods of around a day or two while the brightest took over one hundred days.

Since all the Cepheids concentrated in the small Clouds were essentially the same distance from Earth, once you knew a star’s period you’d also know its true brightness. Leavitt published her findings in 1912. The only thing lacking was the distance to a nearby Cepheid so you could calibrate the scale. Let’s say you knew that Cepheid A in the Milky Way had a period of five days, was 120 light years away and of a certain brightness. Now you find a much fainter Cepheid but with the same period. Since you know the distance to the first one, you just compare the difference in brightness between the two to get the distance to fainter, more remote star. If the Cepheid is in another galaxy, once you know its distance you also know the galaxy’s. A year after Leavitt published her results another astronomer determined the distance to several nearby Cepheids and got the ball rolling.

The relation between brightness and period is called the Period-Luminosity Relationship and it’s one of the greatest discoveries in astronomy. Cepheids are brilliant stellar beacons visible across millions of light years; they provide a crucial yardstick for measuring distances between stars and even galaxies. In quick order astronomers seized on the relationship to uncover the true vastness of the Milky Way. In the early 1920s, Edwin Hubble found the first Cepheids in the Andromeda Galaxy and determined that it was much too far away to be inside the Milky Way as many astronomers believed at the time. Andromeda, thanks to the Cepheids, turned out to be another galaxy altogether over two billion light years from our own. It’s no exaggeration to say that Henrietta’s careful observation of Cepheids opened our eyes to the true scale of the universe.

Edwin Hubble’s photo of the Andromeda Galaxy. Stars marked "N"
are novas (exploding stars). The first Cepheid discovered in the
galaxy is marked "VAR!" at upper right. Hubble originally marked
it as another nova but scratched it out when he realized it was a Cepheid.

(Cepheid animation by Kirk Korista / Western Michigan University. Leavitt photo courtesy of the AAVSO)

The shuttle Discovery launched successfully last night and is now chasing the International Space Station (ISS). It will rendevous and dock with the ISS on Sunday but I don’t have times yet when you might see the two crossing the dawn sky together. If you’re one of those planning on watching the ISS tomorrow, you might be the first to know.

In the meantime you can still enjoy the Milky Way and summer stars tonight since the moon’s not so bright as to spoil the view. I was out last night around 11 walking the dog and surprised at how bright the Milky Way was. For northern hemisphere observers, the moon is currently near the lowest part of its monthly orbital path through the sky and out of the way.

When I turned north and headed back home, the Big Dipper was low in the northwest and looked lazy like a bear settling in for a long nap. Indeed an inkling of the same might be going on in the heads of real bears as August gives way to September next week. How appropriate that the constellation of the Great Bear is in sychrony with the life cycle of the black bear.

Cepheus the King is Cassiopeia the Queen’s husband. They’re both near
near the North Star throughout the summer and fall. Our featured star
Delta is marked B and is just off the king’s right elbow. Credit: Urania’s Mirror

Further up in the northeastern sky was the W of Cassiopeia, now tipped almost on end as if lifted up by helium balloons. From there my gaze floated higher into the realm of Cepheus the King. There at his right elbow I stopped at one of the sky’s most famous stars, Delta Cephei (SEPH-ee-eye).

Delta does not jump out at you. It’s rather dim and couched next to several similarly bright stars, but keep an eye on it over several nights and you’ll see Delta do something very few naked eye stars do: fade, brighten and dim in a regular cycle.

This map shows the sky as you look toward the north-northeast around 9:30 p.m. Delta is at the apex of a compact triangle of stars one outstretched fist above the top right star in the W of Cassiopeia. Maps created with Stellarium.

Delta is the prototype for a class of stars called Cepheid variables. These are unstable giant stars that physically expand and contract. During expansion they brighten, while during contraction they fade. Delta goes through a complete cycle in just 5.4 days, and you can watch the entire huff-and-puff with the naked eye. To help you see the brightness changes we have two able assistants, the neighboring stars of Zeta and Epsilon that together with Delta form a compact triangle. Delta’s rise to maximum takes a day and a half while its fall to minimum happens more slowly over four days.

In this closer view, you can see Delta and its neighbors better. Delta’s brightness changes are easy to track using Zeta and Epsilon. Don’t let the numbers scare you. They’re just a measure of brightness that astronomers use called magnitudes. The bigger the number, the fainter the star. The stars in the Big Dipper are magnitude 2; these are about a magnitude or one level of brightness fainter.

Zeta has a steady brightness or magnitude of 3.6 and Epsilon shines at a fainter 4.2. Delta’s brightness range of 3.5 to 4.4 fits nearly between the two. Last night Delta was on the bright end of its cycle and almost equal to Zeta. That means that several nights from now, it will be closer to Epsilon. Take a look yourself and revel in the knowledge that you’re watching a star physically change right before your eyes. You might feel the same excitement John Goodricke (right) felt when he discovered Delta’s variations in 1784 from his home in England. Goodricke was both deaf and mute and died at the young age of 21, but his discovery of some of the first variable stars won him great honors from the prestigious Royal Society of London.

Astronomers have discovered hundreds of stars like Delta since Goodricke’s time with pulsation times ranging from a few days to months. One of the most famous is the North Star or Polaris in the Little Dipper. Unfortunately the amount of its variation is so slight we can’t detect it with the naked eye. Cepheids, as they’re called, range from five to 20 times the mass of the sun and are very brilliant. Because of their predictable variations and great brightness, astronomers discovered they could be used as yardsticks to measure cosmic distances, a key step in our understanding of the universe’s true dimensions. It all started with Delta.

We’ll look at who made that discovery and how in tomorrow’s blog. For more on Delta Cephei, check out this page on the website of the American Association of Variable Star Observers (AAVSO).

(Goodricke portrait by James Scouler)

The C.O.L.B.E.R.T decal is placed on the Combined Operational Load Bearing External Resistance Treadmill. Credit: NASA/Jim Grossmann

At 10:59 p.m. Central time tonight the space shuttle Discovery will launch on its next mission to the International Space Station (ISS). In addition to to seven tons of supplies, a load of science equipment and a new crew member to drop off at the station, the shuttle will deliver the COLBERT or Combined Operational Load Bearing External Resistance Treadmill. Yes, it’s named after the comedian Stephen Colbert of the Colbert Report. NASA selected the treadmill’s name after Colbert took interest in a NASA online naming poll and encouraged his viewers to submit the name "Colbert.”

COLBERT is a high-tech treadmill to help astronauts exercise aboard the station. Exercise is crucial in space to help counteract muscle and bone density loss due to living in a weightless environment. “The main purpose to the treadmill, of course, is to work out those walking and running muscles that would otherwise go unused up here,” wrote Astronaut Ed Lu in one of his Expedition 7 journals in 2003. The treadmill has special monitoring devices that determine if the exercise is having the desired effects. COLBERT’s top speed is 12.4 miles per hour but the astronauts will typically be running closer to 4-8 mph.

If you’re a regular Colbert Report watcher, I suspect you’ll be getting punchy updates on just how well the treadmill is working. And if you’d like to keep a watch for the International Space Station (ISS), here are some morning viewing times. It’s unclear just yet when the shuttle will dock with the ISS, but when that information becomes available, I’ll update here.

The ISS will look like a bright star traveling from west to east across during the early morning hours. Click here for times for your zip code.

* Saturday Aug. 29 starting at 5:59 a.m. A high, brilliant pass!
* Sunday Aug. 30 at 4:50 a.m.
* Monday Aug. 31 at 5:14 a.m. Another brilliant pass!
* Tuesday Sept. 1 at 4:07 and again at 5:09 a.m.
* Wednesday Sept. 2 at 4:32 a.m.
* Thursday Sept. 3 at 4:56 a.m.

Lyle Anderson of Duluth sent this photo he took early Wednesday morning. While it looks like some kind of UFO, it’s actually a time exposure of a low-flying helicopter. The W of Cassiopeia is at center in this fisheye view of the sky.

The waxing first quarter moon will shine very close to Antares Thursday evening in twilight. This map shows them at around 8:30-9 p.m. as you look southwest. Created with Stellarium.

The moon will cover the star Antares, the bright red-colored star in Scorpius this afternoon for the Northern Minn.-Wis. region at about 4:05 p.m. Two things will make this nearly impossible to see: bright daylight and the moon’s low elevation above the southeast horizon. Skywatchers on the East Coast will have a better chance of seeing the event, called an occultation, through binoculars, or preferably a small telescope, where the moon is higher up.

No matter. The star-moon combo will still be very close together after sunset so keep a lookout for them in the southwestern sky. Many of us get a little thrill to see two bright celestial bodies so close together.

Jupiter wore spots last night (Aug. 26) before midnight. These drawings of the planet’s cloud belts and moon shadows were made using a 10-inch reflecting telescope at 250x. "G" stands for the moon Ganymede; "E" for Europa. These two moons and the shadows they cast on Jupiter’s clouds made for a wonderful night of planet viewing. In the right drawing, notice how white Europa appears compared to grey Ganymede. Credit: Bob King

I got an unexpected thrill last night when I pointed my telescope at Jupiter. Polka dots! The equatorial region of the planet was spotted with the shadows of two moons — Europa and Ganymede — and the little grey disk of Ganymede itself. When a moon passes in front of Jupiter and casts a shadow, astronomers call it a shadow transit. Ganymede, the largest of Jupiter’s four bright moons, casts the biggest shadow. You can easily see it in a very small telescope.

The moons Europa (left) and Ganymede taken by the Voyager and Galileo spacecraft. Europa’s icy crust makes it one of the most reflective moons in the solar system. Ganymede, which is made of a mixture of rock and ice, is considerably darker. Photos: NASA

What was even more amazing was spotting the tiny white disk of Europa as it neared the inside edge of the planet around 11:30 p.m. It was clearly white in contrast to Ganymede, a testament to its icy surface. It blows me away that even modest telescopes can see such things nearly half a billion miles away. It helped that the air was very steady which allowed the sharpest, clearest views of the planet in a long time.

The show didn’t end there. The moon Io popped into view around 11:30 after being eclipsed by Jupiter, and by 12:15 both Ganymede and Europa had departed the disk and sparkled in the dark alongside the planet. Not even Jimmy Fallon could touch this kind of entertainment.

I would posted news of this freckled frenzy in advance but I wasn’t paying as close attention to the comings and goings of Jupiter’s moons as I should have. The next time Ganymede and Europa cross in front of the planet at the same time will be after midnight on September 3. Please visit back next week when I’ll post details.

WASP-18b is so close to the star WASP-18 that it completes one orbit around it in less than a day. Credit: Picture courtesy ESA, NASA, M. Kornmesser (ESA/Hubble), and STScI

There have been more than 370 planets discovered outside the solar system. One of the most recent was picked up by Coel Hellier, a professor of astrophysics at Keele University in England. Called WASP-18b (named after the Wide Angle Search for Planets), this latest find is 10 times bigger than Jupiter and only 1.4 million miles from its star. That’s so close that the star’s powerful tidal forces — think of the moon pulling on the Earth to create the tides — are causing the planet to slowly spiral down into the star. Scientists calculate that this "giant Jupiter" has only a million years to live before it’s fried to a marshmallow crisp. WASP-18b is 325 light years away in the southern constellation of the Phoenix. Learn more about fated world here.

As August looks to September, the familiar figure of Orion the Hunter gains prominence for early morning skywatchers. This photo was taken today at about 5 a.m. Details: 35mm lens at f/2.8, 25-second time exposure at ISO 800. Photo: Bob King

Orion crept up on me from behind this morning. When I turned from the telescope, I felt the tingle of the Hunter’s club raised over my head. Is he back so soon?? The cooler, longer nights have many of us already thinking about fall; seeing Orion at dawn provided even more impetus to relish the ever-shortening days.

Jupiter is one fine bright "star" in the southeast these evenings. Since it’s so easy to identify, we’re going to put the planet to good use finding several more late summer gems. If you go out around 9:30-10 o’clock and look two outstretched fists to the right of Jupiter, you’ll spot two modest stars — Alpha and Beta in the constellation Capricornus the Sea Goat. The top one is actually a close pair of stars with the designations Alpha 1 and Alpha 2. They look like two beady eyes to me, and you can split them without any optical aid. They’re very close but if you stare directly at Alpha, you’ll be pleased to see two stars where before you may have noticed only one. 

Jupiter is the brilliant star in the southeast at nightfall. Two fists to the right of the planet takes you to the optical double star Alpha Capricorni. The green circle at right is an enlargement of the Alpha and Beta area so you can better see Alpha as a double. Two fists to the left of Jupiter will take you to a distinctive group of stars that resembles a jumping jack. To the right of the jack are the two brightest stars in Aquarius, Alpha and Beta. The "nebula" shown is described below. Illustration created with Stellarium.

Alpha is an optical double or a chance lineup of two stars widely separated in outer space. Just below Alpha is Beta, a true double star, where both stars revolve about their common center of gravity. You can’t split Beta with your eye alone but binoculars will do it with ease. Look for the companion immediately to the right and a bit below bright Beta. Most binoculars will easily show both the false and real doubles in the same field of view. It’s a fun coincidence that the two types are right next store to each other.

Now let’s swing two fists to the upper left Jupiter to a compact asterism of stars in Aquarius the Water Carrier I’ve nicknamed the "jack", after the pick-up pieces in the child’s game (right). None of these stars is particularly bright but the shape makes it easier to see than you’d think. Whenever you’re having difficulty spotting a faint star or stars, look around them rather than straight at them. That way you align the most sensitive part of your retina on the subject. You’ll be surprised at how something invisible a moment before will suddenly pop into view.

This photo of the Saturn Nebula was taken by the Hubble Space Telescope. It shows the bright white dwarf at center, ovals of fluorescent gas and two "handles" of additional gas on either side. Credit: NASA/ESA

For telescopes only is the strangely beautiful Saturn Nebula, the shape of which mimics the ringed planet. Also known as NGC 7009, this planetary nebula is 1,400 light years away in the constellation Aquarius. We’ve looked at planetary nebulas before — they’re the "puffed-away" atmospheres of stars that were once similar to our own sun. A tiny, white-hot cinder of a star called a white dwarf resides at the core of these nebulas and excites the gas around them to glow in psychedelic greens and pinks.

Grey clouds skewer the crescent moon around 8:30 Monday night. Photo: Bob King

I caught sight of the thick crescent moon last night just before a mass of grey cloud covered it for good. Our weather tonight looks much more promising for moonwatching although you’ll still need to get out before about 9 p.m. Much later than that and expect to stand on your tippytoes to see it above the treeline.

About two outstretched fists to the left of the moon, Scorpius’ brightest star Antares will become visible by mid-twilight. It’s nodding off in the west these nights as Sagittarius and Capricornus move in to take over the southern sky. Like kings, queens, presidents and prime ministers, every constellation’s dominance is only temporary. Eventually they all move west with the changing seasons and disappear from view.

The moon will be a shiny half-pie Tuesday night in the southwestern sky. You’ll find Antares about two fists to the east. Because the moon is traveling a low arc in the west this time of year, it’s best to observe it before the end of twilight. Created with Stellarium.

Tonight the moon’s terminator, that gently-curved arc that separates the bright, illuminated portion of the moon from the part still in darkness, slices straight across a spectacular trio of craters: Theophilus, Cyrillus and Catherina. The crater rims will glow brilliantly in the early morning sun with bowls still partly steeped in shadow. The terminator is the sunrise line on the waxing moon so anything near it will cast dramatic shadows just as trees and houses do at sunrise here on Earth. The contrast between light and shadow should be strong enough for you to see the crater Theophilus and perhaps the entire trio in a pair of 10 power binoculars. Give it a try and see for yourself. Through a small telescope the chain is one of my top ten coolest spots on the moon.

The striking crater chain of Theophilus, Cyrillus and Catharina will be near the lunar terminator tonight. If you’re clouded out, the next two nights should still provide a fine view. Photo: Bob King

Theophilus is named after an ancient Greek geographer and measures 68 miles across. It fairly fresh as lunar craters go, with a sharp-edged rim and a couple of distinctive central mountain peaks. Theophilus overlaps the much older Cyrillus, which is 61 miles across and named for a 4th century theologian. Scientists determine relative crater age by looking at which craters overlap others (the ones on top are younger) and noting how worn or broken their rims are. Cyrillus’s rim is worn down and much less crisp than Theophilus to the north. The final crater is the chain, Catherina, named for St. Catherine, a Greek theologian and philosopher, is 62 miles across and even more beaten down than Cyrillus.

So we have a neat sequence of craters tonight that show the march of time in the early history of the moon. If you have a telescope, explore the entire moon to see if you can find other craters which hint of their age by appearance and overlap. 

Theophilus up close and personal from the window of the Apollo 16 command module. Can you spot Cyrillus and Catharina above and to the right? Credit: NASA

Mars, Aldebaran and Betelgeuse form a triangle of similarly-colored stellar orbs in the morning sky just before dawn. This map shows the sky as you look east around 4 a.m. Created with Stellarium.

Early risers can see a red triangle in the eastern sky the next couple weeks as Mars slowly moves among the stars of Taurus the Bull and Gemini the Twins. The little planet teams up with two stars of similar color — Aldebaran and Betelgeuse — during the wee hours from 2 a.m. till dawn. Can you see a difference in shading among them? Mars’ color comes from iron oxide (rust) in the dust on its surface while the two stars owe their ruddy complexions to incandescent hydrogen gas. The brightest of the trio is Betelgeuse while Aldebaran and Mars shine with nearly equal strength. That will change this fall and winter as Earth’s and Mars’ orbital motions combine to bring them closer together. Come next January, the Red Planet will shine as bright as Sirius, the sky’s brightest star.

Mars photographed through the telescope this past Sunday morning. Three different filters were used and then combined to make the color images at left. The top row was taken at 5:11 a.m Central time; the bottom at 5:31. Photos courtesy of Larry Owens of Alpharetta, Georgia.

That reminds me. If you’ve been hearing that Mars is making a spectacularly close approach to Earth later this month, it’s not true. That’s an old Internet news item that’s been turning up like a bad penny every year since 2003. Mars is currently far from the Earth and appears like a very tiny gibbous moon in a telescope. Even at high magnification, you’ll need patience to see any detail on its surface.

The Block Island iron meteorite is examined by the Opportunity rover on Mars. Credit: NASA/JPL-Caltech/Cornell University/USGS

Better to enjoy the photographs that are being sent back from the Spirit and Opportunity rovers and the Mars Reconnaissance Orbiter. More images have been taken of the two-foot-long Block Island iron meteorite by Opportunity which has cruised over 10.7 miles since landing on the planet in January 2004. Quite a hike for a remotely operated robot. The color image of the meteorite is strikingly clear and shows twisted metal (right side) and pockmarks either from erosion or from melting as it plunged through the Martian atmosphere.

On the left is a closeup photo of the iron crystal pattern in the Martian meteorite; on the right a slice of an iron meteorite found on Earth. They both show a similar triangular structure. Credit: NASA/JPL-Caltech/Cornell University/USGS; NASA

Take a look at that the odd triangular patterns in the closeup photo. Some form of alien writing perhaps? What you’re seeing is the Widmanstatten (VID-mahn-Shtett-en) pattern (named after one of its discoverers) formed by iron and nickel that cooled into interlocking crystals 4.5 billion years ago. We see the same pattern in iron meteorites found on Earth. I’d like to be up there at this very moment with saw in hand and specimen bag at the ready.

In this wonderfully evocative photo taken by the Mars Reconnaissance Orbriter, we see a dust devil (right of center) in low-angled sunlight creating a dark trail on the Martian surface. The winds of the dust devil blow away the dust, exposing the dark, subsurface rock. The shadow of the dust devil falls to the right. Credit: NASA/JPL/University of Arizona