Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast: August 6-12, 2012

Globular Cluster M15 from Hubble - Credit: ESA, Hubble, NASA

Greetings, fellow SkyWatchers! While you start your observing week out by watching the Mars Curiosity Landing, be sure to step outside and view the Aquarid meteor shower, too! It’s going to be a grand week for globular cluster studies and breezing along the Milky Way. Whenever you’re ready to learn some more history, mystery and just plain fun things about the night sky, then meet me in the back yard.

Monday, August 6 – Today in 2001 the Galileo spacecraft made its flyby of Jupiter’s moon – Io -sending back incredible images of the surface. For southern hemisphere observers, be on watch as the Iota Aquarid meteor shower peaks on this Universal date.

Tonight our studies of globular clusters continues as we look deeper into structure. As a rule, globular clusters normally contain a large number of variable stars, and most are usually the RR Lyrae type such as in earlier study M54. At one time they were known as “cluster variables,” with their number differing from one globular to another. Many globulars also contain vast numbers of white dwarfs. Some have neutron stars which are detected as pulsars, but out of all 151, only four have planetary nebulae in them.

Now, let us head toward the emerging constellation of Pegasus and the magnitude 6.5, class IV M15 (Right Ascension: 21 : 30.0 – Declination: +12 : 10). Easily located with even small binoculars about four degrees northwest of Enif, this magnificent globular cluster is a true delight in a telescope. Amongst the globulars, M15 ranks third in variable star population with 112 identified. As one of the densest of clusters, it is surprising that it is considered to be only class III. Its deeply concentrated core is easily apparent, and has begun the process of core collapse. The central core itself is very small compared to the cluster’s true size and almost half M15?s mass is contained within it. Although it has been studied by the Hubble, we still do not know if this density is caused by the cluster stars’ mutual gravity, or if it might disguise a supermassive object similar to those in galactic nuclei.

M15 was the first globular cluster in which a planetary nebula, known as Pease 1, could be identified. Larger aperture scopes can easily see it at high power. Surprisingly, M15 also is home to 9 known pulsars, which are neutron stars left behind from previous supernovae during the cluster’s evolution, and one of these is a double neutron star. While total resolution is impossible, a handful of bright stars can be picked out against that magnificent core region and wonderful chains and streams of members await your investigation tonight!

Tuesday, August 7 – On this date in 1959, Explorer 6 became the first satellite to transmit photographs of the Earth from its orbit.

Tonight, let’s return again to look at two giant globular clusters roughly equal in size, but not equal in class. To judge them fairly, you must use the same eyepiece. Start first by re-locating previous study M4. This is a class IX globular cluster. Notice the powder-like qualities. It might be heavily populated, but it is not dense. Now return to previous study M13. This is a class V globular cluster. Most telescopes will make out at least some resolution and a distinct core region. It is the level of condensation that determines the class. It is no different from judging magnitudes and simply takes practice.

Try your hand at M55 (Right Ascension:19 : 40.0 – Declination: -30 : 58) along the bottom of the Sagittarius “teapot” – it’s a class XI. Although it is a full magnitude brighter than class I M75, which we looked at earlier in the week, can you tell the difference in concentration? For those with GoTo systems, take a quick hop through Ophiuchus and look at the difference between NGC 6356 (class II) and NGC 6426 (class IX). If you want to try one that they can’t even classify? Look no further than M71 (Right Ascension: 19 : 53.8 – Declination: +18 : 47) in Sagitta. It’s all a wonderful game and the most fun comes from learning!

In the meantime, don’t forget all those other wonderful globular clusters such as 47 Tucanae, Omega Centauri, M56, M92, M28 and a host of others!

Wednesday, August 8 – Today in 2001, the Genesis Solar Particle Sample Return mission was launched. In September of 2004, it crash landed in the Utah desert with its precious payload. Although some of the specimens were contaminated, some did survive the mishap. So what is “star stuff?” Mostly highly charged particles generated from a star’s upper atmosphere and flowing out in a state of matter known as plasma…

Tonight let’s study one of the grandest of all solar winds as we seek out an area about three fingerwidths above the Sagittarius “teapot’s spout” as we have a look at magnificent M8 (Right Ascension: 18 : 03.8 – Declination: -24 : 23), the “Lagoon Nebula.”

Visible to the unaided eye as a hazy spot in the Milky Way, fantastic in binoculars, and an area truly worth study in any size scope, this 5200 light-year area of emission, reflection and dark nebulae has a rich history. Its involved star cluster – NGC 6530 – was first discovered by Flamsteed around 1680, and the nebula by Le Gentil in 1747. Cataloged by Lacaille as III.14 about 12 years before Messier listed it as number 8, its brightest region was recorded by John Herschel and the dark nebulae were discovered by Barnard.

Tremendous areas of starbirth are taking place in this region; while young, hot stars excite the gases in a are known as the “Hourglass,” around Herschel star 36 and 9 Sagittarius. Look closely around cluster NGC 6530 for Barnard dark nebulae B89 and B296 at the nebula’s southern edge. No matter how long you chose to swim in the “Lagoon” you will sure find more and more things to delight both the mind and the eye!

Thursday, August 9 – Today in 1976, the Luna 24 mission was launched on a return mission of its own – not to retrieve solar winds samples, but lunar soil! Remember this mission as we take a look at its landing site in the weeks ahead.

Tonight we’ll return to the nebula hunt as we head about a fingerwidth north and just slightly west of M8 for the “Trifid”…

M20 (Right Ascension: 18 : 02.3 – Declination: -23 : 02) was discovered by Messier on June 5, 1764, and much to his credit, he described it as a cluster of stars encased in nebulosity. This is truly a wonderful observation since the Trifid could not have been easy given his equipment. Some 20 years later William Herschel (although he usually avoided repeating Messier objects) found M20 of enough interest to assign separate designations to parts of this nebula – IV.41, V.10, V.11, V.12. The word “Trifid” was used to describe its beauty by John Herschel.

While M20 is a very tough call in binoculars, it is not impossible with good conditions to see the light of an area that left its home nearly a millennium ago. Even smaller scopes will pick up this round, hazy patch of both emission and reflection, but you will need aversion to see the dark nebula which divides it. This was cataloged by Barnard as B85. Larger telescopes will find the Trifid as one of the very few objects that actually appears much in the eyepiece as it does in photographs – with each lobe containing beautiful details, rifts and folds best seen at lower powers. Look for its cruciform star cluster and its fueling multiple system while you enjoy this triple treat tonight!

Friday, August 10 – Today in 1966 Lunar Orbiter 1 was successfully launched on its mission to survey the Moon. In the weeks ahead, we’ll take a look at what this mission sent back!

Tonight we’ll look at another star forming region as we head about a palm’s width north of the lid star (Lambda) in the Sagittarius teapot as we seek out “Omega”…

Easily viewed in binoculars of any size and outstanding in every telescope, the 5000 light-year distant Omega Nebula was first discovered by Philippe Loys de Cheseaux in 1745-46 and later (1764) cataloged by Messier as object 17. This beautiful emission nebula is the product of hot gases excited by the radiation of newly born stars. As part of a vast region of interstellar matter, many of its embedded stars don’t show in photographs, but reveal themselves beautifully to the eye of the telescope. As you look at its unique shape, you realize that many of these areas are obscured by dark dust, and this same dust is often illuminated by the stars themselves.

Often known as the “Swan,” M17 (Right Ascension: 18 : 20.8 – Declination: -16 : 11) will appear as a huge, glowing check mark or ghostly “2? in the sky – but power up if you use a larger telescope and look for a long, bright streak across its northern edge, with extensions to both the east and north. While the illuminating stars are truly hidden, you will see many glittering points in the structure itself and at least 35 of them are true members of this region spanning about 40 light-years that could contain up to 800 solar masses. It is awesome…

Saturday, August 11 – On this date in 1877, Asaph Hall of the U.S. Naval Observatory was very busy. This night would be the first time he would see Mars’ outer satellite Deimos! Six nights later, he observed Phobos, giving Mars its grand total of two moons.

Tonight after midnight is the peak of the Perseid meteor shower, and this year there’s not so much Moon to contend with! Now let’s sit back and talk about the Perseids while we watch…

The Perseids are undoubtedly the most famous of all meteor showers and never fail to provide an impressive display. Their activity appears in Chinese history as far back as 36 AD. In 1839, Eduard Heis was the first observer to give an hourly count, and discovered their maximum rate was around 160 per hour at that time. He, and other observers, continued their studies in subsequent years to find that this number varied.

Giovanni Schiaparelli was the first to relate the orbit of the Perseids to periodic comet Swift-Tuttle (1862 III). The fall rates have both risen and fallen over the years as the Perseid stream was studied more deeply, and many complex variations were discovered. There are actually four individual streams derived from the comet’s 120 year orbital period which peak on slightly different nights, but tonight through tomorrow morning at dawn is our accepted peak.

Meteors from this shower enter Earth’s atmosphere at a speed of 60 km/sec (134,000 miles per hour), from the general direction of the border between the constellations Perseus and Cassiopeia. While they can be seen anywhere in the sky, if you extend their paths backward, all the true members of the stream will point back to this region of the sky. For best success, position yourself so you are generally facing northeast and get comfortable. If you are clouded out, don’t worry. The Perseids will be around for a few more days yet, so continue to keep watch!

And speaking of watching… If you’re out late, be sure to watch for a Jupiter/Moon conjunction. What an inspiring bit of sky scenery to watch them rise together! For lucky viewers in the Indonesia area, this is an occultation event, so please be sure to check resources for times and locations in your area.

Sunday, August 12 – Did you mark your calendar to be up before dawn to view the Perseid meteor shower? Good!

Tonight while dark skies are on our side, we’ll fly with the “Eagle” as we hop another fingerwidth north of M17 and head for one of the most famous areas of starbirth – IC 4703.

While the open cluster NGC 6611 was first discovered by Cheseaux in 1745-6, it was Charles Messier who cataloged the object as M16 and he was the first to note the nebula IC 4703 (Right Ascension: 18 : 18.9 – Declination: -13 : 47), more commonly known as the “Eagle.” At 7000 light-years distant, this roughly 7th magnitude cluster and nebula can be spotted in binoculars, but at best it is a hint. As part of the same giant cloud of gas and dust as neighboring M17, the Eagle is also a place of starbirth illuminated by these hot, high energy stellar youngsters which are only about five and a half million years old.

In small to mid-sized telescopes, the cluster of around 20 brighter stars comes alive with a faint nebulosity that tends to be brighter in three areas. For larger telescopes, low power is essential. With good conditions, it is very possible to see areas of dark obscuration and the wonderful “notch” where the Pillars of Creation lie. Immortalized by the Hubble Space telescope, you won’t see them as grand or colorful as it did, but what a thrill to know they are there!

Until next week? Clear skies!

Posted on by Elizabeth Howell

Google’s 5 Most Memorable Space Doodles

Google’s one of those tech companies that makes a big deal about space exploration.

There’s not only the Google Lunar X-Prize, or its maps of the Moon and Mars, or memorable April Fool’s pranks such as the lunar Google Copernicus Hosting Environment and Experiment in Search Engineering (G.C.H.E.E.S.E.)

The Mountain View, Calif.-based search giant often puts space front and center in its periodic “Google Doodles”, which are variations of its logo shown on the site. Google’s been pencilling those since 1998. Over the years the sketches have become more elaborate – and sometimes animated!

After reviewing the space doodles featured on Google’s Doodle site, here are five of the most memorable of them:

May 1-5, 2000 – Google Aliens series

 

This appears to be the first set of space-themed Google Doodles. The drawings are simple – for the most part, they show a UFO flying past or landing on the Google logo. Still, running them in a series over several days was smart, as it encouraged Internet users to visit the young search engine several days in a row to see what was happening next. More eyes on the page is always good for advertising.

Jan. 15, 2004 – Spirit lands on Mars

Mars landings are always big media events, and NASA was in the midst of a bonanza of attention in 2004 as both Spirit and Opportunity successfully touched down on the Red Planet. Thousands of Google users would have been searching out the rovers’ latest exploits. Commemorating Spirit’s landing in a doodle, just as that excitement was at a fever pitch, was a great way for Google to highlight the ability for users to seek out information about the rovers on its own site.

Aug. 9, 2010 – Anniversary of Belka and Stelka spaceflight

The best Google Doodles are those that show you what you don’t know before. In this case, few outside the space community are likely aware of who Belka and Stelka were, and where their spaceflight fits in history. (They were among a series of animal flights flown in the 1960s to determine the risks of space travel to humans.) From Google’s perspective, running a doodle one needs to learn more about encourages users to click on it, generating more page views.

June 15, 2011 – Total lunar eclipse, featuring Slooh

This is a brilliant example of cross-promotion. Astronomy geeks are well-aware of Slooh, a site that turns telescopes to celestial events such as the recent Venus transit of the sun. Google brought the site to the masses through promoting Slooh’s June 15, 2011 lunar eclipse feed right on the home page; the colour of the moon in the logo changed as the eclipse progressed. Google also showed the eclipse on its YouTube channel and on Google Earth, and promoted the Slooh Android app (also hosted by Google.) Slooh mentioned Google’s participation on its own website, too.

Nov. 8, 2011 – Edmond Halley’s birthday

Commemorating Edmond Halley’s birthday is not unique in itself, as Google has singled out other astronomers for the honour – see Ruby Payne-Scott and Johann Gottfried Galle, for example. What makes this sketch memorable is you can barely see the “Google” logo in the doodle. This is a company that is so confident in its brand that it is willing to let its readers fill in the blanks by imagination. (Astute readers will notice Scott’s doodle follows the same principle, but Halley’s doodle did run first.)

What other doodles should Universe Today readers check out? Share your thoughts in the comments.

All images are from Google’s Doodle website.

Elizabeth Howell (M.Sc. Space Studies ’12) is a contributing editor for SpaceRef and award-winning space freelance journalist living in Ottawa, Canada. Her work has appeared in publications such as SPACE.com, Air & Space Smithsonian, Physics Today, the Globe and Mail, the Canadian Broadcasting Corp.,  CTV and the Ottawa Business Journal.

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast: July 30 – August 5, 2012

Greetings, fellow SkyWatchers! It’s big. It’s bright. There’s no escaping it. This week the Moon will be our major point of study, but don’t rule out some bright globular clusters and interesting stars! There’s plenty of history and science to explore, too. Whenever you’re ready, just meet me in the back yard…

Monday, July 30 – Today’s history celebrates the 2001 flyby of the Moon by the Wilkinson Microwave Anisotropy Probe (WMAP) on its way to Lagrange Point 2 to study the cosmic microwave background radiation.

Now that we’re back at Sinus Iridum on the lunar surface, we’ll hop across Mare Frigoris and northeast of the punctuation of Harpalus for a grand old crater – J. Herschel. Although it looks small because it is seen on the curve, this wonderful old walled plain named for John Herschel contains some very tiny details. Its southeastern rim forms the edge of Mare Frigoris and the small (24 km) Horrebow dots its southwest edge. The crater walls are so eroded with time that not much remains of the original structure. Look for many very small telescopic impact craters which dot J. Herschel’s uneven basin and exterior edges. Power up! If you can spot the small central crater C, you are resolving a feature only 12 kilometers wide from some 385,000 kilometers away! Formed in the Pre-Nectarian period, this walled plain could be as much as 4 billion years old…

Now, relax and enjoy the peak of the Capricornid meteor shower. Although it is hard for the casual observer to distinguish these meteors from the Delta Aquarids, no one minds. Again, face southeast and enjoy! The fall rate for this shower is around 10 to 35 per hour, but unlike the Aquarids, this stream produces those great “fireballs” known as bolides. Enjoy…

Tuesday, July 31 – Tonight on the Moon, look south of Mare Humorum is darker Paulus Epidemiarum eastward and paler Lacus Excellentiae westward. To their south you will see a complex cojoined series of craters we’ll take a closer look at – Hainzel and Mee. Hainzel was named for Tycho Brahe’s assistant and measures about 70 kilometers in length and sports several various interior wall structures. Power up and look. Hainzel’s once high walls were obliterated on the north-east by the strike that caused Hainzel C and to the north by impact which caused the formation of Hainzel A. To its basic south is eroded Mee – named for a Scottish astronomer. While Crater Mee doesn’t appear to be much more than simple scenery, it spans 172 kilometers and is far older than Hainzel. While you can spot it easily in binoculars, close telescope inspection shows how the crater is completely deformed by Hainzel. Its once high walls have collapsed to the northwest and its floor is destroyed. Can you spot small impact crater Mee E on the northern edge?

Now, let’s take the opportunity to look at two multiple star systems – Nu and Xi Scorpii.

Starting with Nu about a fingerwidth east and slightly north of bright Beta, we find a handsome duo of stars in a field of nebulosity that will challenge telescopic observers much the way that Epsilon Lyrae does. With any small telescope, the observer will easily see the widely separated A and C stars. Add just a little power and take your time… The C star has a D companion to the southwest! For larger telescopes, take a very close look at the primary star. Can you separate the B companion to the south?

Now let’s hop to Xi about four fingerwidths north of Beta.

Discovered by Sir William Herschel in 1782, this 80 light-year distant system poses a nice challenge for mid-sized scopes. The yellow-hued A and B pair share a very eccentric orbit about the same distance as Uranus is from our Sun. During the 2007 observing year they should be fairly well spaced, and the slightly fainter secondary should appear to the north. Look a good distance away for the 7th magnitude orange C component and south for yet another closely-matched double of 7th and 8th magnitude – the D and E stars.

For the larger scope, this multiple star system does display a little bit of color. Most will see the A and B components as yellow/white, the C star as slightly orange, and the D/E pair as slightly tinged with blue. Be sure to mark your observations for this is one of the finest!

Wednesday, August 1 – Today is the birthdate of Maria Mitchell. Born in 1818, Mitchell became the first woman to be elected as an astronomer to the American Academy of Arts and Sciences. She later rocketed to worldwide fame when she discovered a bright comet in 1847.

For larger telescopes, let’s try a challenging lunar study worthy of your observing skills. Due west of Hansteen you will find a small crater known as Sirsalis near the terminator. It will appear as a small, dark ellipse with a bright west wall along with its twin, Sirsalis B. The feature you will be looking for is the Sirsalis Rille – the longest lunar “wrinkle” presently known. Stretching northeast of Sirsalis and ex-tending 459 kilometers south to the bright rays of Byrgius, this major “crack” in the lunar surface shows several branchings – like a long dry river bed. Geologically forming in the Imbrian period, chances are the Sirsalis Rille is lunar graben. Thanks to Lunar Orbiter images, the evidence points to shifting tectonic plates as the source of this incredible feature.

Tonight, let’s continue our exploration of globular clusters. These gravitationally bound concentrations of stars contain anywhere from ten thousand to one million members and attain sizes of up to 200 light-years in diameter. At one time, these fantastic members of our galactic halo were believed to be round nebulae. Perhaps the very first to be discovered was M22 in by Abraham Ihle in 1665. This particular globular is easily seen in even small binoculars and can be located just slightly more than two degrees northeast of the “teapot’s lid,” Lambda Sagittarii.

Ranking third amongst the 151 known globular clusters in total light, M22 (Right Ascension: 18 : 36.4 – Declination: -23 : 54) is probably the nearest of these incredible systems to our Earth with an approximate distance of 9600 light-years, and it is also one of the nearest globulars to the galactic plane. Since it resides less than a degree from the ecliptic, it often shares the same eyepiece field with a planet. At magnitude 6, the class VII M22 will begin to show individual stars to even modest instruments and will burst into stunning resolution for larger aperture. About a degree west-northwest, mid-sized telescopes and larger binoculars will capture smaller 8th magnitude NGC 6642. At class V, this particular globular will show more concentration toward the core region than M22. Enjoy them both!

Thursday, August 2 – Tonight we’ll fly right by the Full Buck Moon as we continue our studies to have a look at Mu 1 and Mu 2 Scorpii about two fingerwidths north of Zeta.

Very close to the same magnitude and spectral type, the twin Mu stars are easy to separate visually and most definitely worth a look in telescopes or binoculars. They are considered an actual physical pair because they share the exact same distance and proper motion, but they are separated by less than one light-year.

Hanging out in space some 520 light-years away, western Mu 1 is a spectroscopic binary – the very first discovered to have double lines. This Beta Lyrae-type star has an orbiting companion that eclipses it around every day and a half, yet causes no significant visual drop in magnitude – even though the orbiting companion is only 10 million kilometers away from it! While that sounds like plenty of distance, when the two pass, their surfaces would nearly touch each other!

Friday, August 3 – Tonight let’s race ahead of the rising Moon as we continue our studies with one of the globulars nearest to the galactic center – M14 (Right Ascension: 17 : 37.6 – Declination: -03 : 15). Located about sixteen degrees (less than a handspan) south of Alpha Ophiuchi, this ninth magnitude, class VIII cluster can be spotted with larger binoculars, but will only be fully appreciated with the telescope.

When studied spectroscopically, globular clusters are found to be much lower in heavy element abundance than stars such as own Sun. These earlier generation stars (Population II) began their formation during the birth of our galaxy, making globular clusters the oldest of formations that we can study. In comparison, the disk stars have evolved many times, going through cycles of starbirth and supernovae, which in turn enrich the heavy element concentration in star forming clouds and may cause their collapse. Of course, as you may have guessed, M14 breaks the rules. It contains an unusually high number of variable stars – in excess of 70 – with many of them known to be the W Virginis type. In 1938, a nova appeared in M14, but it was undiscovered until 1964 when Amelia Wehlau of the University of Ontario was surveying the photographic plates taken by Helen Sawyer Hogg. The nova was revealed on eight of these plates taken on consecutive nights, and showed itself as a 16th magnitude star – and was believed to be at one time almost 5 times brighter than the cluster members. Unlike 80 years earlier with T Scorpii in M80, actual photographic evidence of the event existed. In 1991, the eyes of the Hubble were turned its way, but neither the suspect star nor traces of a nebulous remnant were discovered. Then six years later, a carbon star was discovered in M14.

To a small telescope, M14 will offer little to no resolution and will appear almost like an elliptical galaxy, lacking in any central condensation. Larger scopes will show hints of resolution, with a gradual fading towards the cluster’s slightly oblate edges. A true beauty!

Saturday, August 4 – As we explore globular clusters, we simply assume them all to be part of the Milky Way galaxy, but that might not always be the case. We know they are basically concentrated around the galactic center, but there may be four of them that actually belong to another galaxy. Tonight we’ll look at one such cluster being drawn into the Milky Way’s halo. Set your sights just about one and a half degrees west-southwest of Zeta Sagittarii for M54 (Right Ascension: 18 : 55.1 – Declination: -30 : 29).

At around magnitude 7.6, M54 is definitely bright enough to be spotted in binoculars, but its rich class III concentration is more notable in a telescope. Despite its brightness and deeply concentrated core, M54 isn’t exactly easy to resolve. At one time we thought it to be around 65,000 light-years distant, and rich in variables – with 82 known RR Lyrae types. We knew it was receding, but when the Sagittarius Dwarf Elliptical Galaxy was discovered in 1994, it was noted that M54 was receding at almost precisely the same speed! When more accurate distances were measured, we found M54 to coincide with the SagDEG distance of 80-90,000 light-years, and M54?s distance is now calculated to be 87,400 light-years. No wonder it’s hard to resolve – it’s outside our galaxy!

As we know, most globular clusters congregate around the galactic center in the Ophiuchus/Sagittarius region. Tonight let’s explore what creates a globular cluster’s form… We’ll start with the “head of the class,” M75 (Right Ascension: 20 : 06.1 – Declination: -21 : 55).

Orbiting the galactic center for billions of years, globular clusters endured a wide variety of disturbances. Their component stars escape when accelerated by mutual encounters and the tidal force of our own Milky Way pulls them apart when they are near periapsis, that is, closest to the galactic center. Even close encounters with other masses, such as other clusters and nebulae, can affect them! At the same time, their stellar members are also evolving and this loss of gas can contribute to mass loss and deflation of these magnificent clusters. Although this happens far less quickly than in open clusters, our observable globular friends may only be the survivors of a once larger population, whose stars have been spread throughout the halo. This destruction process is never-ending, and it is believed that globular clusters will cease to exist in about 10 billion years.

Although it will be later evening when M75 appears on the Sagittarius/Capricornus border, you will find the journey of about 8 degrees southwest of Beta Capricorni worth the wait. At magnitude 8, it can be glimpsed as a small round patch in binoculars, but a telescope is needed to see its true glory. Residing around 67,500 light-years from our solar system, M75 is one of the more remote of Messier’s globular clusters. Since it is so far from the galactic center – possibly 100,000 light-years distant – M75 has survived almost intact for billions of years to remain one of the few Class I globular clusters. Although resolution is possible in very large scopes, note that this globular cluster is one of the most concentrated in the sky, with only the outlying stars resolvable to most instruments.

Sunday, August 5 – Today we celebrate the birthday of Neil Armstrong, the first human to walk on the Moon. Congratulations! Also on this date in 1864, Giovanni Donati made the very first spectroscopic observations of a comet (Tempel, 1864 II). His observations of three absorption lines led to what we now know as the Swan bands, from a form of the carbon radical C2.

Our study continues tonight as we move away from the galactic center in search of a remote globular cluster that can be viewed by most telescopes. As we have learned, radial velocity measurements show us the majority of globulars are involved in highly eccentric elliptical orbits, which take them far outside the plane of the Milky Way. These orbits form a sort of spherical “halo” which tends to be more concentrated toward our galactic center. Reaching out several thousands of light-years, this halo is actually larger than the disk of our own galaxy. Since globular clusters aren’t involved in our galaxy’s disk rotation, they may possess very high relative velocities. Tonight let’s head toward the constellation of Aquila and look at one such globular – NGC 7006 (Right Ascension: 21 : 01.5 – Declination: +16 : 11).

Located about half a fist’s width east of Gamma Aquilae, NGC 7006 is speeding towards us at a velocity of around 345 kilometers per second. At 150,000 light-years from the center of our galaxy, this particular globular could very well be an extra-galactic object. At magnitude 11.5, it’s not for the faint of heart, but can be spotted in scopes as small as 150mm, and requires larger aperture to look like anything more than a suggestion. Given its tremendous distance from the galactic center, it’s not hard to realize this is a class I – although it is quite faint. Even the largest of amateur scopes will find it unresolvable!

Until next week? May all your skies by clear and steady…

Lead image caption: Crater J. Herschel – Credit: Damian Peach

Posted on by Nancy Atkinson

Flags Still Standing at Several Apollo Landing Sites on the Moon

Caption: LROC image showing the illuminated side of the still standing American flag to be captured at the Apollo 17 landing site. Credit: NASA/GSFC/Arizona State University.

Mark Robinson, Principal Investigator of the Lunar Reconnaisance Orbiter Camera (LROC) says the most often-asked questions he gets about the images LRO has taken of the Moon are about pictures of the Apollo landing sites and what is visible. Especially, Robinson said, people want to know if the flags are still standing.

Previously, Robinson has said that while the flag poles are likely still standing, he didn’t think the flags themselves survived the harsh radiation of the lunar surface environment. But new images and video show that at some of the landing sites – Apollo 12, Apollo 16, and Apollo 17 – the flags must still be intact, because they are creating shadows on the surface.

“Personally I was a bit surprised that the flags survived the harsh ultraviolet light and temperatures of the lunar surface, but they did,” Robinson wrote on the LROC website. “What they look like is another question (badly faded?).”


Caption: The flag was captured in this image of the Apollo 16 site with the spacecraft slewed 15° towards the Sun; the shadowed side of the flag is seen by LROC. Credit: NASA/GSFC/Arizona State University.

James Fincannon, a NASA engineer from Glenn Research Center, combined LROC images of each Apollo site taken at roughly the same orientation but with different Sun angles to show the travel of shadows.

“Combined with knowledge of the Apollo site maps which show where the flag was erected relative to the Lander, long shadows cast by the flags at the three sites show that the these flags are still “flying”, held aloft by the poles,” Fincannon wrote.

And so, from the LROC images it is now certain that the American flags are still standing and casting shadows at all of the sites, except Apollo 11. Astronaut Buzz Aldrin reported that the flag was blown over by the exhaust from the ascent engine during liftoff of Apollo 11, and Robinson said that from the images of the Apollo 11 landing site, it looks like he was correct.


Caption: Enlargement of area surrounding Apollo 11 landing site. Credit: NASA/GSFC/Arizona State University

Robinson added that the most convincing way to see that the flags are still there, is to view a time series of LROC images taken at different times of day, and watch the shadow circle the flag (see movie below; the flag is just above the LM descent stage).

Read Fincannon’s story of his research on the flags.

Source: LROC website.

Posted on by Jason Major

Europe’s Plans to Visit the Moon in 2018

The European Space Agency is aiming for the Moon with their Lunar Lander mission, anticipated to arrive on the lunar surface in 2018. Although ESA successfully put a lander on Titan with the Huygens probe in 2005, this will be the first European spacecraft to visit the surface of Earth’s Moon.

Although Lunar Lander will be an unmanned robotic explorer, the mission will be a forerunner to future human exploration of the Moon as well as Mars. Lunar Lander will use advanced technologies for autonomous landing and will be able to determine the best location for touchdown on its own, utilizing lasers to avoid obstacles on the Moon’s surface.

With no GPS on the Moon, Lunar Lander will navigate by digitally imaging the surface on the fly. Landing will be accomplished via thrusters, which were successfully tested earlier this year at a test chamber in Germany.

Lunar Lander’s destination will be the Moon’s south pole, where no exploration missions have ever landed. Once on the lunar surface, the Lander will investigate Moon dust using a robotic arm and a suite of onboard diagnostic instruments, sending data and images back to scientists on Earth for further study.

Watch a video of the Lunar Lander mission below, from launch to landing.

Read more about Lunar Lander on the ESA site here.

Images and video: ESA

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast: July 23-29, 2012

IC 4665 - Credit: Palomar Observatory, courtesy of Caltech

Greetings, fellow SkyWatchers! Are you ready for a week filled with alternative astronomical observing studies? If so, you’ll enjoy looking at some unusual stars and star clusters. If you want to keep things cool, then come along as we mine for lunar ice. Feeling a bit more lazy? Then kick back and enjoy the Delta Aquarid meteor shower or just step out after sunset and enjoy a splendid conjunction! It’s all here… Just head outside!

Monday, July 23 – Tonight we’ll launch our imaginations as we view the area around Mare Crisium and have a look at this month’s lunar challenge – Macrobius. You’ll find it just northwest of the Crisium shore. Spanning 64 kilometers in diameter, this Class I impact crater drops to a depth of nearly 3600 meters – about the same as many of our earthly mines. Its central peak rises up 1100 meters, and may be visible as a small speck inside the crater’s interior. Be sure to mark your lunar challenges and look for other features you may have missed before!

Now, relax and let’s talk until the Moon sets…

As we know most stars begin life in stellar nurseries and end life either alone or in very small groups as doubles or multiple stars. Tonight we can have a look at a group of young stars beginning their stellar evolution and end with an old solitary elder preparing to move on to an even “higher realm.” Open cluster IC 4665 (Right Ascension: 17 : 46.3 – Declination: +05 : 43) is easily detected with just about any optical aid about a finger-width north-northeast of Beta Ophiuchi. Discovered by Philippe Loys de Cheseaux in the mid-1700s, this 1400 light-year distant cluster consists of about 30 mixed magnitude stars all less than 40 million years of age. Despite its early discovery, the cluster did not achieve broad enough recognition for Dreyer to include it in the late 19th century New General Catalog and it was later added as a supplement to the NGC in the Index Catalog of 1908. Be sure to use low power to so see all of this large group.

About three finger-widths north-northeast of IC 4665 is a study that did make Dreyer’s catalogue – NGC 6572 (Right Ascension: 18 : 12.1 – Declination: +06 : 51). This 9th magnitude planetary is very small – but intense. Like the “Cat’s Eye” in Draco, and NGC 6210 in Hercules, this planetary can take a lot of magnification. Those with large scopes should look for a small, round, blue inner core encased is a faint shell. A challenge to find? You bet. Worth the work? Sometimes working for something makes it all the more fun!

Tuesday, July 24 – As our observing evening begins, be sure to look for one of the finest conjunctions of the year! Hovering around the waxing crescent Moon like bees drawn to a hive, you’ll find Mars to the upper right and Spica to the upper left (northwest and northeast respectively). To Spica’s upper right, you’ll find Saturn joining the show, too! This is a very “photogenic” opportunity…

With plenty of Moon to explore tonight, why don’t we try locating an area where many lunar exploration missions made their mark? Binoculars will easily reveal the fully disclosed areas of Mare Serenitatis and Mare Tranquillitatis, and it is where these two vast lava plains converge that we will set our sights. Telescopically, you will see a bright “peninsula” westward of where the two conjoin which extends toward the east. Just off that look for bright and small crater Pliny. It is near this rather inconspicuous feature that the remains Ranger 6 lie forever preserved where it crashed on February 2, 1964.

Unfortunately, technical errors occurred and it was never able to transmit lunar pictures. Not so Ranger 8! On a very successful mission to the same relative area, this time we received 7137 “postcards from the Moon” in the last 23 minutes before hard landing. On the “softer” side, Surveyor 5 also touched down near this area safely after two days of malfunctions on September 10, 1967. Incredibly enough, the tiny Surveyor 5 endured temperatures of up to 283 degrees F, but was able to spectrographically analyze the area’s soil… And by the way, it also managed to televise an incredible 18,006 frames of “home movies” from its distant lunar locale.

Wednesday, July 25 – Today in 1971, Apollo 15 was launched on its way towards the Moon, and we’ll continue our celebration of space exploration and walk on the Moon where the first man set foot. For SkyWatchers, the dark round area you see on the northeastern limb is Mare Crisium and the dark area below that is Mare Fecunditatis. Now look mid-way on the terminator for the dark area that is Mare Tranquillitatis. At its southwest edge, history was made.

In binoculars, trace along the terminator where the Caucasus Mountains stand – and then south for the Apennines and the Haemus Mountains. As you continue towards the center of the Moon, you will see where the shore of Mare Serenitatis curves east, and also the bright ring of Pliny. Continue south along the terminator until you spot the small, bright ring of Dionysius along the edge of Mare Tranquillitatis. Just to the southwest, you may be able to see the soft rings of Sabine and Ritter. It is near here where the base section of the Apollo 11 landing module – Eagle – lies forever enshrined in “magnificent desolation.”

For telescope users, the time is now to power up! See if you can spot small craters Armstrong, Aldrin and Collins just east. Even if you cannot, the Apollo 11 landing area is about the same distance as Sabine and Ritter are wide to the east-southeast. Even if you don’t have the opportunity to see it tonight, take the time during the next couple of days to point it out to your children, grandchildren, or even just a friend… The Moon is a spectacular world and we’ve been there!
Tonight let’s have a look with our eyes first at Delta Ophiuchi. Known as Yed Prior (“The Hand”), look for its optical double Epsilon to the southeast: Yed Posterior. Now have a look in binoculars or a telescope at absolute minimum power for another undiscovered gem…

Delta Ophiuchi is 170 light-years from us, while Epsilon is 108 – but look at the magnificent field they share. Stars of every spectral type are in an area of sky which could easily be covered by a small coin held at arm’s length. Enjoy this fantastic field – from the hot, blue youngsters to the old red giants!

Thursday, July 26 – Long before the Sun sets, look for the Moon to appear in the still-blue sky. As it darkens, watch for shadows on the surface. Have you ever wondered if there was any place on the lunar surface that hasn’t seen the sunlight? Then let’s go searching for one tonight…

Our first order of business will be to identify crater Albategnius. Directly in the center of the Moon is a dark floored area known as Sinus Medii. South of it will be two conspicuously large craters – Hipparchus to the north and ancient Albategnius to the south. Trace along the terminator toward the south until you have almost reached its point (cusp) and you will see a black oval. This normal looking crater with the brilliant west wall is equally ancient crater Curtius. Because of its high southern latitude, we shall never see the interior of this crater – and neither has the Sun! It is believed that the inner walls are quite steep and that Curtius’ interior has never been illuminated since its formation billions of years ago. Because it has remained dark, we can speculate that there may be “lunar ice” pocketed inside its many cracks and rilles that date back to the Moon’s formation!

Because our Moon has no atmosphere, the entire surface is exposed to the vacuum of space. When sunlit, the surface reaches up to 385 K, so any exposed “ice” would vaporize and be lost because the Moon’s gravity cannot hold it. The only way for “ice” to exist would be in a permanently shadowed area. Near Curtius is the Moon’s south pole, and the Clementine spacecraft’s imaging showed around 15,000 square kilometers in which such conditions could exist. So where did this “ice” come from? The lunar surface never ceases to be pelted by meteorites – most of which contain water ice. As we know, many craters were formed by just such impacts. Once hidden from the sunlight, this “ice” could remain for millions of years!

Friday, July 27 – Tonight let’s skip the Moon and take a look at an astounding system called 36 Ophiuchi, located about a thumb’s width southeast of Theta. Situated in space less than 20 light-years from Earth, even small telescopes can split this pair of 5th magnitude K type giants very similar to our own Sun, and larger telescopes can also pick up the C component as well. 36 Ophiuchi B is also known as system 544…because it has what could very likely be a planet in a habitable zone!

Now we’ll have a look at a beautifully contrasting pair of stars – Zeta 1 and 2 Scorpii. You’ll find them a little less than a handspan south-southeast of Antares and at the western corner of the J of the constellation’s shape.

Although the two Zetas aren’t a true physical pair, they are nonetheless interesting. The easternmost, orange sub-giant Zeta 2 appears far brighter for a reason… It’s much closer at only 155 light-years away. But, focus your attention on western Zeta 1. It’s a blue supergiant that’s around 5700 light-years away and shines with the light of 100,000 suns and exceeds even Rigel in sheer power! The colorful pair is easily visible as two separate stars to the unaided eye, but a real delight in binoculars or a low power telescope field. Check them out tonight!

Saturday, July 28 – Tonight let’s continue our studies of the lunar poles by returning to previous study crater Plato. North of Plato you will see a long horizontal area with a gray floor – Mare Frigoris. North of it you will note a double crater. This elongated diamond-shape is Goldschmidt and the crater which cuts across its western border is Anaxagoras. The lunar north pole isn’t far from Goldschmidt, and since Anaxagoras is just about one degree outside of the Moon’s theoretical “arctic circle” the lunar sun will never go high enough to clear the southernmost rim.

On March 5, 1998, NASA announced that Lunar Prospector’s neutron spectrometer data showed that water ice had been discovered at both lunar poles. The first results showed the ice was mixed in with lunar regolith (soil, rocks and dust), but long term data confirmed near pure pockets hidden beneath about 40 cm of surface material – with the results being strongest in the northern polar region. It is estimated there may be as much as 6 trillion kg (6.6 billion tons) of this valuable resource! If this still doesn’t get your motor running, then realize that without it, we could never establish a manned lunar base because of the tremendous expense involved in transporting our most basic human need – water.

The presence of lunar water could also mean a source of oxygen, another vital material we need to survive! And for returning home or voyaging further, these same deposits could provide hydrogen which could be used as rocket fuel. So as you view Anaxagoras tonight, realize that you may be viewing one of mankind’s future “homes” on a distant world!

Now grab a comfortable seat because the Delta Aquarid meteor shower reaches its peak tonight. It is not considered a prolific shower, and the average fall rate is about 25 per hour – but who wouldn’t want to take a chance on observing a meteor about every 4 to 5 minutes? These travelers are considered to be quite slow, with speeds around 24 kilometers per second and are known to leave yellow trails. One of the most endearing qualities of this annual shower is its broad stream of around 20 days before and 20 days after peak. This will allow it to continue for at least another week and overlap the beginning stages of the famous Perseids.

The Delta Aquarid stream is a complicated one, and a mystery not quite yet solved. It is possible that gravity split the stream from a single comet into two parts, and each may very well be a separate stream. One thing we know for certain is they will seem to emanate from the area around Capricornus and Aquarius, so you will have best luck facing southeast and getting away from city lights. Although the Moon will interfere, just relax and enjoy a warm summer night. It’s time to catch a “falling star!”

Sunday, July 29 – Tonight let’s take an entirely different view of the Moon as we do a little “mountain climbing!” The most outstanding feature on the Moon will be the emerging Copernicus, but since we’ve delved into the deepest areas of the lunar surface, why not climb to some of its peaks?

Using Copernicus as our guide, to the north and northwest of this ancient crater lie the Carpathian Mountains, ringing the southern edge of Mare Imbrium. As you can see, they begin well east of the terminator, but look into the shadow! Extending some 40 kilometers beyond the line of daylight, you will continue to see bright peaks – some of which reach 2072 meters high! When the area is fully revealed tomorrow, you will see the Carpathian Mountains eventually disappear into the lava flow that once formed them. Continuing onward to Plato, which sits on the northern shore of Imbrium, we will look for the singular peak of Pico. It is between Plato and Mons Pico that you will find the scattered peaks of the Teneriffe Mountains. It is possible that these are the remnants of much taller summits of a once stronger range, but only around 1890 meters still survives above the surface.

Time to power up! Lather, rinse and repeat until you know these by heart… To the west of the Teneriffes, and very near the terminator, you will see a narrow series of hills cutting through the region west-southwest of Plato. This is known as the Straight Range – Montes Recti – and some of its peaks reach up to 2072 meters. Although this doesn’t sound particularly impressive, that’s over twice as tall as the Vosges Mountains in central Europe and on the average very comparable to the Appalachian Mountains in the eastern United States. Not bad!

Now head about a palm’s width east of our previous study star – Zeta Scorpii – for lovely Theta. Named Sargas, this 1.8 magnitude star resides around 650 light-years distant in a very impressive field of stars for binoculars or a small telescope. While all of these are only optical companions, the field itself is worth a look – and worth remembering for the future.

About three fingerwidths north is true double Lambda Scorpii, also known as Shaula (The Sting). As the brightest known star in its class, 1.6 magnitude Lambda is a spectroscopic binary which is also a variable of the Beta Canis Majoris type, changing ever so slightly in little more than 5 hours. Although we can’t see the companion star, nearby is yet another that will make learning this starhop “marker” worth your time.

Until next week? Ask for the Moon, but keep on reaching for the stars!

Posted on by Nancy Atkinson

Barnstorming the Moon’s Giordano Bruno Crater

Caption: Southern rim of Giordano Bruno crater seen obliquely by LROC. Credit: NASA/GSFC/Arizona State University

At the 2012 Lunar Science Forum going on this week at the NASA Lunar Science Institute, scientist Mark Robinson presented some new stunning images from the Lunar Reconnaissance Orbiter’s cameras (LROC), including this oblique view Giordano Bruno crater, and a wonderful video (below) that allows viewers to “barnstorm” over the crater to witness the stark beauty of this impact basin.

“I could spend weeks and months looking at the preserved materials in the crater,” Robinson said, adding that views like this are helping scientists to understand the impact process. “Until astronauts visit Giordano Bruno, this gives a view about as close as you can get to standing on the surface to the west of the crater.”

Robinson is the Principal Investigator for LROC, and in his talk today said all systems on LROC are working nominally. “That’s NASA-speak for everything is fantastic,” he joked.

With the wide angle camera, LROC has mapped the entire Moon nearly 33 times. “Every map has a different photometric geometry, so this is not a redundant dataset,” Robinson said, adding that the different lighting provides different ways to study the Moon. “And to be able to do follow-up observations, I can’t tell you how great it is.”

Just about every month, the science team is able to take new mosaics of both the north and south pole, and they’ve also found 160 pits – lunar caves – so far. These caves with “skylights” are intriguing because they would offer potential protective habitats for future lunar explorers.

Now in its extended mission, LRO is still going strong, and has provided incredible details of the lunar surface. LRO project scientist Richard Vondrak said since the start of the mission, LRO has uploaded 325 terabytes of data into the Planetary Data System, the digital storehouse for NASA science mission, through June 2012.


Caption: Close-up detail of the rim of Giordano Crater. Credit: NASA/GSFC/Arizona State University

“Thanks to LRO, the Moon’s topography is now better understood than the Earth, since two-thirds of Earth is covered by water,” Vondrak said.
But both scientists agrees LRO is just getting started.

“The Moon is one of the most engaging bodies in the Solar System and we’ve still got a lot of work to do,” Robinson said

Robinson suggests scrolling through all of the details of this beautiful impact crater by looking at the full-resolution version of Giordano Crater — “not to be missed!” he said. Also, the full resolution version of the video can be downloaded here.

Sources: NLSI Lunar Forum, LROC website

Posted on by Nancy Atkinson

Spectacular Views: The Moon Occults Jupiter

Caption: July 15 2012 occultation, taken with Canon 550D on Newton 200/1200 mounted on NEQ6Pro. Credit: Andrei Juravle

Astrophotographers in Northern Africa, Europe and the Middle East were treated to a beautiful sight in the early morning hours of July 15, 2012. A lunar occultation of Jupiter took place just before dawn, as the waning crescent Moon slid in front of the planet Jupiter. Venus was hanging around nearby, too. Several astrophotographers were able to capture the event, and some got a bonus look at Jupiter’s Galilean moons, as well! Above is a lovely image by Andrei Juravle.

More below!

Caption: The Moon, Venus and Jupiter. Credit Thierry Legault.

Astrophotographer extraordinaire Thierry Legault took this great shot of Venus, Jupiter and the Moon from Saint-Cloud, France with a Canon 5D mark II and 135mm lens. But look closely: the satellites of Jupiter are visible:

Caption: A closer look reveals Jupiter’s moons! Credit: Thierry Legault.

And as always, you should check out Thierry’s website for more incredible images.

Caption: Jupiter and the Moon hover over Dolmabahce Mosque in Istanbul, Turkey. Credit: Rasid Tugral.

Caption: Clouds nearly covered the view in Mombaroccio, Marche, Italy. Credit: Niki Giada.


Caption: A series of images of the Moon’s occultation of Jupiter as seen in Saida, Lebanon. Credit: astroZ1 on Flickr.


Caption: Occultation of Jupiter by the Moon as seen from Smolyan, Bulgaria. Credit: Zlatan Merakov.

More images are still coming in, and you can see more on Universe Today’s Flickr page. Thanks to everyone who submitted their gorgeous images!

Posted on by Fraser Cain

Full Moon, 2012

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Here is the schedule for all the Full Moons that will happen in 2012. If you’re going to go skywatching, remember that the best time to see the night sky is when you have a new moon. When there’s a full moon, the dimmer skies are washed out. Please note that all the times listed are in Universal Time.

Full Moon for January, 2012

  • January 9, 07:30

Full Moon for February, 2012

  • February 7, 21:54

Full Moon for March, 2012

  • March 8, 09:39

Full Moon for April, 2012

  • April 6, 19:19

Full Moon for May, 2012

  • May 6, 03:35

Full Moon for June, 2012

  • June 4, 11:12

Full Moon for July, 2012

  • July 3, 18:52

Full Moon for August, 2012

  • August 2, 03:27
  • August 31, 13:58 (blue moon)

Full Moon for September, 2012

  • September 30, 03:19

Full Moon for October, 2012

  • October 29, 19:49

Full Moon for November, 2012

  • November 28, 14:46

Full Moon for December, 2012

  • December 28, 10:21

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Reference:
http://aa.usno.navy.mil/cgi-bin/aa_moonphases.pl?year=2012&ZZZ=END

Posted on by Jason Major

The Moon Is Toxic

As our closest neighbor in space, a time-capsule of planetary evolution and the only world outside of Earth that humans have stepped foot on, the Moon is an obvious and ever-present location for future exploration by humans. The research that can be done on the Moon — as well as from it — will be invaluable to science. But the only times humans have visited the Moon were during quick, dusty  jaunts on its surface, lasting only 2-3 days each before departing. Long-term human exposure to the lunar environment has never been studied in depth, and it’s quite possible that — in addition to the many inherent dangers of living and working in space — the Moon itself may be toxic to humans.

An international team of researchers has attempted to quantify the health dangers of the Moon — or at least its dust-filled regolith. In a paper titled “Toxicity of Lunar Dust” (D. Linnarsson et al.) the health hazards of the Moon’s fine, powdery dust — which plagued Apollo astronauts both in and out of their suits — are investigated in detail (or as best as they can be without actually being on the Moon with the ability to collect pristine samples.)

Within their research the team, which included physiologists, pharmacologists, radiologists and toxicologists from 5 countries, investigated some of the following potential health hazards of lunar dust:

Inhalation. By far the most harmful effects of lunar dust would come from inhalation of the particulates. Even though lunar explorers would be wearing protective gear, suit-bound dust can easily make its way back into living and working areas — as Apollo astronauts quickly discovered. Once inside the lungs the super-fine, sharp-edged lunar dust could cause a slew of health issues, affecting the respiratory and cardiovascular system and causing anything from airway inflammation to increased risks of various cancers. Like pollutants encountered on Earth, such as asbestos and volcanic ash, lunar dust particles are small enough to penetrate deep within lung tissues, and may be made even more dangerous by their long-term exposure to proton and UV radiation. In addition, the research suggests a microgravity environment may only serve to ease the transportation of dust particles throughout the lungs.

Skin Damage. Lunar regolith has been found to be very sharp-edged, mainly because it hasn’t undergone the same kind of erosive processes that soil on Earth has. Lunar soil particles are sometimes even coated in a glassy shell, the result of rock vaporization by meteorite impacts. Even the finer particles of dust — which constitute about 20% of returned lunar soil samples — are rather sharp, and as such pose a risk of skin irritation in instances of exposure. Of particular note by the research team is abrasive damage to the outer layer of skin at sites of “anatomical prominence”, i.e., fingers, knuckles, elbows, knees, etc.

“The dust was so abrasive that it actually wore through three layers of Kevlar-like material on Jack [Schmitt’s] boot.”

– Professor Larry Taylor, Director of the Planetary Geosciences Institute, University of Tennessee (2008)

Eye Damage. Needless to say, if particles can pose abrasive damage to human skin, similar danger to the eyes is also a concern. Whether lunar dust makes its way into the eye via airborne movement (again, much more of a concern in microgravity) or through direct contact from fingers or another dust-coated object, the result is the same: danger of abrasion. Having a scratched cornea is no fun, but if you’re busy working on the Moon at the time it could turn into a real emergency.

While the research behind the paper used data about airborne pollutants known to exist on Earth and simulated lunar dust particles, actual lunar dust is harder to test. The samples returned by the Apollo missions have not been kept in a true lunar-like environment — being removed from exposure to radiation and not stored in a vacuum, for instance — and as such may not accurately exhibit the properties of actual dust as it would be encountered on the Moon. The researchers conclude that only studies conducted on-site will fill the gaps in our knowledge of lunar dust toxicity. Still, the research is a step in the right direction as it looks to ensure a safe environment for future explorers on the Moon, our familiar — yet still alien — satellite world.

Read the team’s paper in full here.

“The Apollo astronauts reported undesirable effects affecting the skin, eyes and airways that could be related to exposure to the dust that had adhered to their space suits during their extravehicular activities and was subsequently brought into their spacecraft.”

– Dag Linnarsson, lead author, Toxicity of Lunar Dust

Top image: Apollo 16 astronaut Charlie Duke with a dust-coated LRV. Side image: a dusty Gene Cernan in the LM at the end of an Apollo 17 EVA. (NASA/JSC)