The Viking 1 photo of the Cydonia region in Mars’ northern hemisphere taken in 1976. Cydonia is well known for its mesas, knobs and hills. Credit: NASA

NASA recently released a new photo taken by the Mars Reconnaissance Orbiter of the infamous "Face of Mars", a 1.2 mile long, 800 foot high hill or mesa in Mars’ Cydonia region. When first photographed by the Viking 1 spacecraft in 1976, the play of light and shadow combined with the camera’s relatively low resolution revealed a remarkably human-like face that resembled that of an Egyptian pharaoh. It was quickly nicknamed the Face of Mars and caught the attention of wishful thinkers, some of whom became convinced it was a monument built by a long-ago Martian civilization. Nearby "pyramids" and other blocky features on the Cydonia plain were even construed as the remains of an ancient Martian city. I still remember routinely seeing the photo of the Face on the cover of the National Enquirer while waiting in the grocery store line. Such is the power of the Red Planet to incite the imagination.

A photo taken of the "Face" by the Mars Reconnaissance Orbiter in 2007 and recently released. The feature is an eroded mesa 1.2 miles long. Check out the HI-RES version. Credit: NASA/JPL/Univ. of Arizona

We see faces all the time. I see them in clouds, floor tiles, patterns of leaves and shadow, in the spots on the backs of beetles — you name it. It’s natural, but we all know there’s no connection to a real face. But when you want to believe or profit from what others believe, you can choose to ignore common sense. A furor developed over the Mars face, books were published by its extraterrestrial-origin defenders and NASA was accused of covering up evidence of intelligent Martian life. When we eventually returned to Mars with new spacecraft and more sophisticated cameras, the Cydonia region and the Face became targets if only to quell the crazy talk.

Now we have exquisite photos of the feature, and the pharaoh’s visage has been replaced by an old, eroding hilltop on a plain that may once have been the bottom of a long-ago Martian ocean. Be sure to click on the hi-res link above (and then click on the image again when you’re there) to appreciate just how much there is to see in this once enigmatic feature.

And now the two faces together. Compare them and you’ll see how easily light and shadow can suggest a face when the lighting conditions are favorable and resolution is poor. Credit: NASA

Looking to the week ahead we have some attractive lunar alignments in the morning sky and planetary ones in the evening. The International Space Station returns for morning sky watchers. Moonless nights in August are the best time to get out and see the complete summertime MIlky Way spanning the sky from one horizon to the other. Sunsets are earlier now also, meaning you — and your kids — can see the stars in a dark sky before bedtime.

Monday August 2 – evening

This all-sky map shows the Milky Way slicing across the sky from below the W of Cassiopeia in the northeast to the Teapot in the south in early August. It looks like a misty rainbow. All maps creating with Stellarium

Wednesday August 4 – before dawn

The waning moon will be only a few degrees to the right of the Seven Sisters or Pleiades star cluster between about 3 a.m. and dawn Wednesday morning. Look to the east to find them. The sight should be especially nice in binoculars.

Friday August 6 – dawn

The International Space Station (ISS) begins making passes again for the Duluth region. This morning’s will be across the south-southeast sky starting at 4:56 a.m. Central time. Watch for a bright, steady light moving eastward. For times for your town, click HERE.

* Saturday August 7 at 5:23 a.m. A brilliant pass high across the south and southeast.
* Sunday August 8 at 4:17 a.m. Bright but low in the southeastern sky
* Monday August 9 at 4:43 a.m. Brilliant across the south

While you’re out sighting the ISS, turn to face east and you’ll get a preview of winter. The crescent moon forms a nearly right triangle with that season’s brightest red stars, Aldebaran in Taurus the Bull and Betelgeuse in Orion the Hunter.

Saturday August 7 – evening

We’ve got a planet party in the west-southwest sky 45 minutes to an hour after sunset. Although they’ll be near one another all week, Mars, Saturn and Venus form their most compact arrangement Saturday evening. Will they all fit together in one binocular field of view? Give it a try to find out.

A wedge of twilit sky is reflected in Horse Lake in the Boundary Waters two nights ago. Below right are Indian pictographs of a pelican and a canoe (with paddlers and prayer flag) on a cliff overhang on the Basswood River. Photos: Bob King

I’ve spent the past few days with my friend Glenn in the Boundary Water Canoe Area in northern Minnesota paddling through bogs and lakes, studying the rich array of pictographs on the Basswood River along the international border and eating very well. Mosquitos were everywhere but 100% Deet and occasional gusty winds helped to allay their full force.

I see while I was away that an asteroid was found to have a 1 in 1000 chance of hitting the Earth in 2182. Maybe you’ve already heard of this bad boy, which goes by the name of 1999 RQ36. At 1,837 feet across, it’s a mighty big rock, and if it did strike Earth would cause an enormous amount of destruction. The University of Pisa’s Andrea Milani examined the asteroid’s orbit using information from telescopic and radar studies and modeled its future whereabouts. The odds for an impact increase after 2080 as 1999 RQ36′s orbit brings it closer to Earth. Although Milani’s paper appeared in a noted astronomy journal last year, the story just surfaced this week in the mainstream media.

Artist impression of a good-sized asteroid striking the Earth. Smaller objects like meteorites either burn up or break up and are greatly slowed by their passage through the atmosphere before they hit the ground. A larger object like 1999 RQ36, discovered in 1999, would come crashing to Earth at close to its orbital speed and cause widespread destruction. Credit: AP

There are always uncertainties in pinning down an asteroid’s precise orbit.  After a number of observations, astronomers determine a preliminary orbit or set of possible orbits for an asteroid. If one or more of those orbits indicate a close pass by Earth, they may assign a certain probability of impact. The only way to know for sure is to make additional observations and refine the orbit. As the data come in, the number of possible orbits drops from many to several and finally to one very good one. No orbit is set in stone, however. Gravitational effects from the planets and other asteroids, and even the pressure of light from the sun — the Yarkovsky Effect — can push an asteroid farther from or closer into harm’s way.

209 telescopic observations and 13 radar surveys were used to determine the current best-fit orbit for 1999 RQ36. Based on that data, there’s a small chance for a hit 172 years from now. Since this asteroid is now an "object of interest", astronomers will continue to observe it and adjust impact probabilities along the way. In the few earlier cases when asteroids were forecast to make dangerously close passes to Earth, probabilities have always been revised way downward the more data points astronomers have added to their orbits. There’s a lot of time between now and 2182 for revision. If you’d like to keep up with all this scary stuff, check out NASA’s current impact risks website.  

Spirit took this self-portrait when its became stuck in the sand last spring on Mars. It hasn’t been able to move since. Photo: NASA

Meanwhile NASA scientists haven’t heard from the Mars Spirit Rover since March 22. It’s now the middle of winter where Spirit sits stuck in the sand on the Red Planet. Its internal temperature has dropped as low as 67 below Fahrenheit. This winter is the toughest yet for the robotic explorer since it couldn’t get into position to aim its solar panels at the sun to recharge its batteries. Batteries operate a heater that keeps the electronics running inside the craft. Spirit is likely in low-power hibernation mode hanging on for dear life. NASA usually listens for a regular signal beamed out by the rover, but since that’s not been forthcoming, they’re now trying to wake it up by sending commands to reply. So far, there’s been no response. Could this be the end of the line for the little explorer? For more on the story, please see this press release.

Darkness has returned to the evening sky with the late rising of the last quarter moon. While paddling on the lakes, I enjoyed seeing the moon still up in the blue sky after sunrise. The contrast between its dry, sun-baked surface and the wet pliancy of the water dramatically illustrated how strikingly different our two worlds are. The moon’s departure points the way to dark skies for the annual Perseid meteor shower next month. I am so looking forward to kicking back in a lawn chair and watching meteors streak by. I bet you are, too. We’ll be taking a closer look at the shower and how to get the most out of watching it in about a week.

The moon rises last night over Lake Superior and a lucky boater. Credit: Lyle Anderson

With my time committed to other activities in the next few days, I thought we’d take a breezy look at this week’s upcoming astronomical events in one fell swoop. On tap are a playful game of cat-and-mouse among the evening planets, a Jupiter-moon conjunction and a surreptitious star in the north. In addition, we’ll check out the final constellation of the Summer Triangle, Aquila the Eagle.

Tuesday night July 27

Maps created with Stellarium

Venus, Mars and Saturn gather together ever more closely in the western sky during evening twilight. Watch the positions of Mars and Saturn change quickly over the next few days as speedier Mars looks to overtake the ringed planet. Venus is always easy to see nearly due west 45 minutes after sunset. Slide up from Venus to locate the others and keep binoculars handy just in case. If you’re into extreme challenges, try to spot Mercury sitting right next to the star Regulus a considerable distance to the lower right of Venus and very near the horizon (see below).

A lake or prairie horizon to the west-northwest is your best bet for catching Mercury’s close conjunction with Regulus in Leo Tuesday evening. Look about a half hour after sundown.

Wednesday night July 28

Cassiopeia helps to direct you to low-flying Capella nearly due north at nightfall.

One of winter’s brightest stars is poking around the northern horizon in late July. Capella in the constellation Auriga is due north and visible from the northern states and southern Canada a few degrees above the horizon. In late July it reaches what astronomers call lower culmination — its lowest point in the sky. It’s one of the few really bright stars that doesn’t set for skywatchers in mid-northern latitudes. If you have a clear horizon to the north and haze-free skies, look for it around 10:30 p.m. local time.

Thursday night July 29

Altair is the bright star in the head of Aquila the Eagle. It’s accompanied on either side by two stars I’ve always seen as "guardians" or keepers of the eagle named Tarazed and Alshain. The latter is Arabic for peregrine falcon. Tarazed is a 4th magnitude star, Alshain a 3rd and Altair a 1st — a fine group to use to get to know star brightnesses better.

With the moon now waning and soon to exit the evening sky, now’s a good time to add Aquila (AK-will-uh) to your list of summer constellations. Look high in the southeastern sky and use the chart provided to find it. Aquila is Latin for Eagle, and if you connect its starry dots, you’ll find it bears a good resemblance to a stick-figure bird with fully-spread wings. The constellation’s brightest star is Altair, which forms the southern vertex of the prominent asterism the Summer Triangle.

This wide-view chart shows how Aquila connects to the Summer Triangle. Vega at top is nearly at the top of the sky around 11 o’clock in late July.

Friday night July 30

Mars and Saturn are in conjunction tonight to the upper left of Venus. Can you see both without binoculars? This map shows the sky as you look west about 45 minutes after sunset.

Lots happening tonight with planets. Mars are Saturn are less than 2 degrees apart and make a fine, close pair. Mars is much closer to the Earth than Saturn and moving quickly eastward (to the left) in its orbit. Saturn is moving east too, but much more slowly, allowing Mars to overtake beginning tonight. Can you still see Mars’ red color? If you have difficulty with the unaided eye, it should be no problem in binoculars. If you stay up until 11 or so, you’ll catch the waning gibbous moon in the southeast in close company with brilliant Jupiter.

If you look low in the southeastern sky around 11:30 p.m. Friday, you’ll see the moon has a bright companion.

Illustration: Bob King / Hubble photo: NASA/ESA

A few readers have written to ask about an e-mail they’ve received about the planet Mars being closer to Earth next month than at any time in history. Here’s a typical read gathered from snopes.com:

++The Planet Mars will be brightest in the night sky starting in August. It will look as large as the full moon to the naked eye. Be sure to watch the sky on August 27 at 12:30 a.m. It will look like the Earth has two moons. NO ONE ALIVE TODAY WILL EVER SEE IT AGAIN++

Look familiar? Too bad it’s not true. I should say it was true once, sort of. Back in 2003, Mars really was near the Earth, something that happens every 15-17 years. That particular approach was a record breaker because it was the closest in nearly 60,000 years. Mind you, other close approaches are only slightly more distant. You and I wouldn’t notice the difference either with our eyes or through a telescope.

The message goes to compare the Red Planet’s size to the full moon. This unfortunate error is also based on a shard of truth. Through a telescope with modest magnification, Mars did look the same size as the full moon as seen with the naked eye. This is understandable because you’re enlarging its image with magnification. If I had a 2000x eyepiece I could make Mars look as big as the moon tonight. Sure, the planet would be a blurry mess because atmospheric turbulence would also be magnified, but I could do it. Even when closest to Earth, Mars will always look like a brilliant star to the naked eye. It’s just too small to show a disk except in a telescope.

Mars is currently 180 million miles from Earth — more than five times further than in 2003 — and looks like a tiny red dot even in a high power telescope. Because it’s so far away, it’s also not particularly bright, being comparable to the stars in the Big Dipper. Created with Stellarium

Every two years Mars and Earth line up on the same side of the sun which puts them near one another. In 2005, 2007 and early 2010 Mars was near the Earth and bright in our skies. A similar close approach to the one in 2003 will happen again in 2018, but we’ll have to wait until 2287 to squeak past 2003′s record. If we still have an Internet then, the goofy e-mail circulating today will once again be closer to the truth.

Close approaches of Mars and Earth from 2003 to 2018. The reason Mars’ distance from Earth varies every two years is due to its orbit, which is more elliptical (oval) than Earth’s. The sun is "off to one side" for planets with more highly elliptical orbits. As Earth comes round to meet Mars, it’s a little farther or closer to us depending on where it is in its orbit at that time. Illustration: Bob King

Tonight through August, Mars will be a rather dim "star" low in the western sky during twilight. That doesn’t mean it’s worth ignoring. In a telescope maybe, but not with the eye or through binoculars. Tomorrow I’ll bring you up to date with some fun events involving the Red Planet later this week.

Here’s a couple photos from last night’s moonrise and this morning’s sunrise. Hope you got to see either, or better yet, both.

The full moon rises over Lake Superior within the grey band of Earth’s shadow. Photo: Bob King

One sphere gives way to another. Lyle Anderson of Duluth captured this morning’s colorful sunrise from his home along the shore of Lake Superior.

The full moon rises over Lake Superior this past April. Variations in air density near the horizon cause the moon to assume all kinds of warped shapes during rising and setting. The only way to find out what it’s going to do next is to go out and see for yourself. Photo: Bob King

The Full Buck Moon will dump buckets of light on the landscape tonight. It’s named for the time when new, velvety antlers begin to poke from the heads of buck deer. An alternate name — the Thunder Moon — is one most of us can relate to. We’ve had our share of thunder and rain in the Duluth area this summer, but you’ll hear no complaints from me. I haven’t had to water the garden in over a month, and the peas and tomatoes are growing like amazons.

While you’re out this evening, try catching the moonrise. The thick atmosphere near the horizon scatters and absorbs much of moon’s shorter wavelength light (greens, blues) and allows only the oranges and reds to pass through to your eye. It’s fun to watch the moon’s color slowly change from bloody red to pale yellow as it leaves the horizon for the thinner air layers higher up. Its outline changes, too. Close to the horizon, the moon’s shaped like a mango but gradually becomes more circular as it rises. Air at the horizon is very thick and dense compared to that just a few degrees above it. Like a strong pair of prescription glasses, denser air has more refracting or "bending" power than thinner air. The air acts like a lens and refracts or "lifts" the bottom of the moon into the top creating that squishy oval shape.

Moonrise is 8:33 p.m. (16 minutes before sunset) for the Duluth area. Click HERE to get moonrise times for where you live, and remember to find a location where you can see as far down to the southeastern horizon as possible.

Tonight’s full moon is a short distance below (south) of two double stars in Capricornus making them very easy to find in binoculars. First spot the moon and then scoot about one binocular field above it to see the two.Maps created with Stellarium

By good fortune, the moon is only a couple degrees south of and directly in line with two easy double stars you can split in almost any pair of binoculars.  Alpha and Beta Capricorni are right next door to one another in the constellation Capricornus the Sea Goat. Alpha is the top pair and can actually be split with the naked eye, but given the moon’s brilliance, I’d opt for binoculars tonight.  As convincing a double as Alpha appears, it’s an "optical" double or chance alignment of two stars at very different distances. Alpha-1, to the west or right, is 690 light years away, while Alpha-2, the brighter, is only 109. They sure make a pretty pair despite the illusion.

The circle covers several degrees of sky or about one binocular field of view. Very neat that both pairs can be viewed at the same time. Alpha is an optical double star, Beta a true double.

Beta is a real physical double with the fainter 6th magnitude companion orbiting about the brighter. The two are 328 light years from Earth and take about 700,000 years to complete an orbit. In other words, we won’t be seeing Beta’s companion move in our lifetime. Enjoy these sights tonight as you work on your moon tan.

Split Rock Lighthouse, which sits atop a tall cliff on Lake Superior north of Duluth, provided a guiding light for ships and sailors from 1910 until 1969. Today visitors can tour the lighthouse as well as hike and ski in the park. Photo: Bob King

Split Rock Lighthouse near Silver Bay, MN. about an hour north of Duluth is one of our state’s favorite tourist destinations. This year it celebrates its 100th birthday. The lighthouse hasn’t been used as a navigational aid since 1969; these day visitors can tour the building and get a feel for what it was like to be a lighthouse keeper. The Fresnel lens used to focus the lighthouse beam is an elaborate and beautiful piece of glass. Don’t miss a chance to see it if you’re in the neighborhood.

This is a fist-sized hunk of anorthosite, which consists mostly of the light-colored mineral plagioclase (PLA-gee-oh-clays) feldspar. I picked it up at a road cut on Highway 61 in Silver Bay. Feldspar is a light-colored mineral that makes up much of the Earth’s crust. Photo: Bob King

The lighthouse stands on an imposing 130-foot high cliff of grey rock overlooking Lake Superior. An observant eye will notice that the cliff rock stands out from the dark volcanic basalt rock common in the region. It consists instead of a very attractive, crystalline material called anorthosite (an-OR-tho-site). A chunk of anorthosite is a thing of beauty — pale green crystals massed together that sparkle as you turn a piece of it in your hand. It’s a also a mineral Split Rock shares with the moon.

Cool video showing how the moon formed from material remaining from the impact of the early Earth and another planetary body

Yesterday we divided the moon up into two basic types of landscapes: the lunar seas or maria, which are the dark spots that form the face of the "man in the moon", and the rest of the moon called the lunar highlands. The highlands are the original lunar crust that formed 4.4 billion years ago when the entire moon was covered in a magma ocean. How did the moon get so hot? A Mars-sized body is believed to have struck the nascent Earth some 4.5 billion years ago. Material from both bodies was blasted into space where it reassembled to form the moon. Heat generated during formation completely melted the moon’s crust and upper mantle. As the fiery ocean cooled, lighter minerals floated to the top to form the present crust while heavier ones sank below to make the  mantle.

Based on telescopic studies as well as the composition of moon rocks brought back to Earth by the Apollo astronauts, the moon’s pale crust or highlands is made mostly of anothosite, the same material sitting under Split Rock lighthouse. Anorthosite is a silicate rock with lots of calcium and aluminum which gives its pale color. It’s also lighter than other lunar volcanic rocks like those dark mare lavas we examined yesterday. They originated in the deeper mantle and flowed up through fissures to fill the moon’s crater basins a half billion years after the crust solidified.

Genesis Rock photographed by the Apollo 15 astronauts. The white rock was sitting up on a little pedestal of lunar soil as if to say "here I am". The rock is made of anorthosite, and was used to help date the formation of the moon’s crust. Credit: NASA

The oldest moon rocks are anorthosites including the famous Genesis Rock found in 1971 by the Apollo 15 crew at the foot of Mt. Hadley in the lunar Apennine mountains. That bit of crustal rock was dated at some 4.2 billion years. The astronauts James Irwin and David Scott saw its crystals sparkling in the sunlight as they approached the unique white rock. Here’s a snippet of their conversation at the moment of discovery:

Irwin: Oh, man!
Scott: Oh, boy!
Irwin: I got…
Scott: Look at that.
Irwin: Look at the glint!
Scott: Aaah.
Irwin: Almost see twinning in there!
Scott: Guess what we just found. (Jim laughs with pleasure)
Guess what we just found! I think we found what we came for.
Irwin: Crystalline rock, huh?
Scott: Yes, sir. You better believe it.

The Genesis Rock back home in the lab. The cube at right is 10mm across making the rock about 1 1/4" inches long. Credit: NASA

Several slightly older rocks around 4.4 to 4.5 billion years were later found by the Apollo 16 and 17 astronauts. They’re also anorthosites or closely related rocks. In contrast, the lighthouse rocks are dated at a "youthful" 1.1 billion years. Amazing to think what’s under our feet is sometimes over our heads as well. If you’re ever in the neighborhood of Split Rock, take a good look at that cliff. You might just get swept away to the moon.

The waxing gibbous moon has a brush with cirrus clouds Wednesday evening. Photo: Bob King

Suddenly there it was. The moon slipped out from behind tendrils of sunset-lit cirrus clouds as I mowed the lawn Wednesday. Time to let go of the on-off handle and enjoy the sight. Blessed silence, refreshment for the spirit. With the moon approaching full this weekend, we have the opportunity to get to know the lunar seas or maria (MAH-ree-uh) better. The best time to identify lunar features is during twilight when the moon’s glare is not so intense. I invite you to pull up a lawn chair, pop the caps off your binoculars and join me for a bit of exploration.

Tonight you’ll first notice that the moon is not quite round. The left side will appear slightly shaved or blunted. Since we’re still two days from full moon, here’s a little invisible sliver of moon that’s yet to be lit by sunlight. We can’t see it because of the overwhelming brightness of the sunlit moon. The most obvious features are the dark spots known as the lunar seas. They got their name from 17th century astronomers, some of whom thought they were actual bodies of water. The Latin word for sea is "mare". If you look at the names of the maria (plural) you’ll notice quite a few of them have watery names. Now that modern research has determined that lunar rocks do indeed contain at least tiny amounts of water, the names are becoming oddly more appropriate.

Use this photo to help you find some or all of the moon’s major "bodies of water". The black dots are in the centers of their respective lunar seas. The 58-mile-diameter crater Copernicus is circled. All of these features can be seen with the naked eye, but if you have trouble, just use a pair of binoculars. Photo: Bob King

In my opinion, the easiest seas to spot are what look like two big eyes: Serenity and Tranquillity. They’re side by side. You can’t miss the vast dark space along the left side of the moon. That’s the Ocean of Storms or Oceanus Procellarum. Between the pair of "eyes" and the ocean is a large, roughly circular sea called Mare Imbrium or the Sea of Showers. Drop down from there to find the crater Copernicus, a fuzzy white spot, and continue south to the Sea of Clouds or Mare Nubium. The right or western side of the moon features a crisis sea right next door to a tranquil one. Things continue improve as you round the eastern edge with fertility and nectar. Sweet.

The seas are vast sheets of dark lava that poured out from the lunar mantle to fill the basins created from asteroid impacts some 4 billion years ago. Since the filling happened after the most intense bombardment of the moon by solar system debris, they’re relatively crater-free compared to the surrounding lunar highlands (white areas). The highlands are the original crust of the moon that formed over 4 billion years ago from magmas that floated to the surface of the molten moon. Once in place, the crust was battered incessantly by meteorites and asteroids and today consists largely of shattered rocks called breccias (BRECH-uhs). Tomorrow we’ll learn how the most common mineral in the moon’s crust finds its counterpart in a familiar mineral found right here on Earth and in particular at a major Minnesota tourist destination not far from where I live.

I hope you visit many seas in the coming nights. Please feel free to share what you saw with our readers by using the Comments link below.

This artist’s impression shows the relative sizes of young stars, from the smallest red dwarfs, weighing in at about 0.1 solar masses, through low mass yellow dwarfs such as the Sun, to massive blue dwarf stars weighing eight times more than the Sun, as well as the 300 solar mass star named R136a1. Credit: ESO/M.Kornmesser

Big, bigger, scary big. Astronomers at the European Southern Observatory using the Very Large Telescope have pushed the size limit of stars to a new high this month with the discovery of a monster star some 265 times the mass of the sun. Called R136a1, it’s located inside the star cluster R136 165,000 light years away in the Large Magellanic Cloud, a satellite galaxy of the Milky Way.  The upper limit was believed to be 150 solar masses, so this star shatters that record by a mile. Scientists will now be busy re-examining current theory to understand how nature would allow such a beast into the china shop.

Our new heavyweight is located inside a huge, naked-eye gas cloud inside the Large Magellanic Cloud called the Tarantula Nebula . At the nebula’s center is a young, compact star cluster (R136). R136a is in the cluster’s core. Credit: ESO/P. Crowther/C.J. Evans

Normal hydrogen-burning stars like our sun range from 1/10 the sun’s size for red dwarfs to what was thought to be the upper limit of 150 suns for supergiants. Massive stars are nature’s gas-guzzling Chevy Suburbans. They burn energy at such a ferocious rate, the radiation they pour into space takes part of their atmospheres with it. Over its brief million-year lifetime, R136a1 has already lost a fifth of its original 320-sun mass. While it could easily be the winner of The Biggest Loser, it will undoubtedly shed more in the centuries ahead but probably not enough to avoid exploding as a supernova. Unless a star can get rid of enough matter to bring its weight down below about 8 solar masses, it burns through its nuclear fuel until its core collapses and rebounds in a shattering blast. Should R136a1 become a supernova, it would be exceptionally bright and easily visible to the naked eye.

A closeup of the R136 cluster. R136a1 is the brightest star at center. Credit: ESO/P. Crowther/C.J. Evans

R136a is not just big and heavy. It’s also 10 million times brighter than the sun and more than 7 times hotter. Here’s a nice comparison from the ESO press release: "If R136a1 replaced the sun in our solar system, it would outshine the sun by as much as the sun currently outshines the full moon."

Whew, baby, that cooks!

Saturn’s F ring bisects the grandest globular cluster of them all, Omega Centauri, in this photo taken by Cassini on March 29 this year. Hi-res image. Credit: NASA/JPL/SSI

WOW! This photo appeared on NASA’s Jet Propulsion Lab site yesterday and my jaw dropped when I saw it. It was taken by the Saturn Cassini probe of the globular cluster Omega Centauri sparkling 16,000 light away in the distance behind Saturn’s outer F ring. Look closely at the rings where the slice through the cluster. The ring material, which consists primarily of chunks of ice, is sparse enough that many stars shine right through it. Early space and science fiction artists like Chesley Bonestell would paint imaginary scenes from other planets to help us imagine the unearthy vistas our solar system might offer. Isn’t it crazy cool that we now get a near daily dose of the real thing? Photos like these offer us viewpoints no one even imagined. We’ll always need those artists to help us see and understand what’s out there, but it’s nice when it’s supplemented now and again by the real thing.

Powdery with stars, Omega Centauri is easily visible with the naked eye from southern skies. Omega Centauri is the biggest globular cluster in the Milky Way and second biggest among all the globulars in the 50 or so galaxies in our neighborhood called the Local Group. #1 goes to cluster G1 in the Andromeda galaxy. Gigantic hi-res image. Credit: ESO

It’s visible during the spring months in the constellation Centaurus if you live in the southern U.S. I’ve seen it several times from Arizona, where it looks like a fat, fuzzy star with the naked eye. Omega was known in antiquity but cataloged as a star. It wasn’t until English astronomer John Herschel pointed a good telescope at it in the 1830s that we learned it was a cluster. And what a heap of stars it is. Omega contains contains up to 10 million stars in a densely-packed ball 230 light years across. Suns in the core are packed tight as a crowded subway car; their average distance from one another is just a third of a light year. The sky as viewed from a planet orbiting a star in the cluster’s center would be 100 times brighter than Earth’s night sky and filled with hundreds of Venus lookalikes.

The Hubble Space Telescope took this picture of the core of Omega Centauri which is crowded with stars and may harbor a black hole. Credit: NASA/ESA

Omega is 10 times bigger than the average globular cluster and contains muliple generations of stars, something very unusual in almost all other globulars in the Milky Way, which were formed in one fell swoop billions of years ago from large clouds of hydrogen gas. These peculiarities lead astronomers to suspect that Omega is more likely the core of a small galaxy that was pulled toward and eventually merged with our galaxy. Its outer stars and gas stripped away, it now mimics a globular but on a much larger scale. Recent observations indicate there may even be a black hole in Omega’s core whipping around stars at the cluster’s center at speeds much higher than expected. This is yet another galactic trait.

Sunspots are plentiful in the 1089 group as seen in this photo taken this morning. Details: 540mm at f/10, 1/5000 second exposure at ISO 50 with solar filter. Photo: Bob King

I looked at the sun this morning and saw that sunspot group 1089 is still growing quickly. It now looks like a healthy bed of sunflowers just over the sun’s east limb. I refer you to the SOHO (Solar Heliospheric Observatory) page for additional photos. Tomorrow we’ll look at a star almost 300 times the size of the sun.

Clear skies by you tonight? Check out the waxing gibbous moon and Antares in Scorpius the Scorpion. They’ll be near one another all evening and make a pretty sight. Created with Stellarium

This photo was taken by NASA’s orbiting Solar Dynamics Observatory about 2:30 Tuesday afternoon and shows the very active sunspot group 1089. Huge loops of incandescent hydrogen gas larger than Earth arch over the region. This view was taken in the light of extreme ultraviolet which reveals structures invisible in regular, "white light" telescopes.  Credit: NASA/SDO

A new sunspot region is rotating into view along the southeast limb of the sun and it looks like a whopper. Named region 1089, it’s already busting out small to medium-sized flares as it continues to expand in size. If you have a telescope equipped with a safe solar filter, this week will be an exciting one to monitor the group’s development. Based on the photos taken so far, I suspect 1089 will eventually grow large enough to see with the naked eye when viewed through an appropriate safe solar filter.

Region 1089 is seen here at lower left earlier today. This view is closer to the way the sunspot group looks in regular light, the way you’d see it in typical telescope equipped with a safe solar filter. The dark dots are sunspots and the white patches are called faculae. Both are concentrations of the sun’s magnetic energy, but faculae concentrate that magnetic energy in tighter bundles and so appear brighter than sunspots. Credit: NASA/ESA

Sunspots take about two weeks to rotate from the eastern edge of the sun to the west. If flares increase in intensity while the group is nearer the centerline of the sun’s disk, our chances for good northern lights displays increase also. I’ll keep you posted on what’s in store.

These two photos of Jupiter were taken five minutes apart on July 10. The NEB (near top) is dark and colorful in contrast to the faint SEB. Credit: Damian Peach

Like several others who read this blog, I’ve been out in the wee hours observing Jupiter, which now rises shortly before midnight. The best time to see any sky object is when it’s highest in the sky and least affected by dense air, haze and turbulence. For Jupiter that time is currently between 2 and 6 a.m.

Over the past two weeks I’ve observed the planet three times in my 15-inch reflecting telescope and I can tell you this: the South Equatorial Belt (SEB) — the one that disappeared this spring — still shows faint traces of its former self. The North Equatorial Belt (NEB) is hard to miss and looks like a big pink hot dog stretching from one end of the planet to the other. As for the SEB, it’s there but the life’s been sucked out of it. I still see the stripe shape, but it’s faint and very pale grey. To date I’ve only seen the SEB on the side of the planet opposite the Great Red Spot, so it may look different or be entirely missing on the "Red Spot" side. Do we have any other Jupiter belt observers out there who’d like to chime in with their impressions?