April 20, 2014

Review: The Secrets of Triangles by Alfred S. Posamentier & Ingmar Lehmann.

Available for Pre-Order Now!

This week, we delve into the fascinating world of mathematical geometry. Wait! Wait! Come back! We promise not to be too mathy for this week’s review… well, OK, I know that we say that during every math book review, but this time, we promise… [Read more...]

Astro-Challenge: Hunting Przybylski’s Star.

Looking south from 28 degrees north an hour after sunset in mid-June.

(Click image for full view; created by the Author in Starry Night).

This week, we turn the astronomical spotlight on a seemingly ordinary star with an extraordinary tale. Often in visual astronomy, simply understanding the amazing facts behind a speck of light at the eyepiece can give it a special significance. Take last week’s transit of Venus, for example. Yes, it was merely a black dot taking almost 7 hours to cross the Sun. Not as splashy or dramatic as a total solar eclipse, sure, but the rarity and the historical significance was part of the fun. Same goes for some previous targets we’ve tracked down in the column, such as white dwarfs and quasars. Sure, you can read the astrophysical journals, but we always like to see this stuff in person. This week, we’d like to introduce you to a star that stubbornly defies astrophysics; Przybylski’s Star.

Located in the constellation Centaurus, this 8th magnitude star just scrapes above the southern horizon about 14 degrees in elevation for northern hemisphere observers around 30° north on June nights about an hour after local sunset. Fans of this site will remember our hunt for another famous Centaurus object, the massive cluster Omega Centauri. Both are visible in late spring/early summer months from mid-to-low northern latitudes, and if you’re around Miami area, you might just be able to nab the northern-most star Gamma Crucis of the Southern Cross asterism in the late spring time as well.

But it’s the non-descript Przybylski’s Star that we’d like to turn your attention (and perhaps your telescope) towards this week. This star is an enigma in terms of its chemistry. It was Antoni Przybylski that first noted the anomalous nature of this star in 1961. About 4 times the mass of our Sun, this star has abnormally low abundances of iron & nickel in its spectra and instead displays high amounts of exotic metals such as uranium, thorium, yttrium and a whole slew of other lanthanides. The fusion process runs out at iron, and all of these heavy elements had to have been forged  in supernovae sometime in the distant past… just what’s going on with Przybylski’s Star? This odd mixture puts the star in a rare category known as an Ap or Bp star, or stars with a high abundance of exotic metals, of which only 35 are known. These stars are well off the main sequence of the Hertzsprung–Russell diagram, and would fall “off the chart” past Delta-Scuti type variables and technetium laden stars. Pryzbylski’s star also displays a mind bogglingly fast pulsation rate of 12 minutes, discovered in 1978.

The star also displays another bizarre trait that may give some clues as to its troubled past; its moving at a slightly higher than usual velocity of about 24 kilometers per second with respect to neighboring stars. To give you some perspective, our own Sun is moving about 20 kilometers per second roughly towards Vega. Could Przybylski’s star have bared witness to several supernovae early in its career, salting it with heavy elements and ejecting it at high velocity? Whatever the case, Przybylski’s star is an astrophysical oddity worth hunting down in the Centaurus region. Its located 6.5° degrees northwest of Delta Centauri and its coordinates are;

Right Ascension: 11h 37’ 37”

Declination: -46° 42’ 35”

Przybylski’s star is about 370 light years distant.

Oh, and the second great mystery (and usually the first question we receive!) is “how the heck to you pronounce Przybylski?” Well, ye ole Internet search turns up a Polish pronunciation of Sh-eh-bel-skEE, though we always welcome a correction on our rusty Polish!

Review: Destination Mars.

On sale now!

Early this August, a historical event will occur. A rover launched last Thanksgiving weekend will descend via sky crane to the surface of Mars. After the first “six-minutes off terror,” the Mars Science Laboratory will be ready to do some serious science on the Red Planet. [Read more...]

Update: A Transit of Venus Seen ‘Round the World.

Our cloudy view! (Photo by Author).

One of the top-billed events for 2012 & this century occurred yesterday of June 5th, 2012 as Venus transited the Sun for the last time until 2117. The event lasted for about 6 hours and 40 minutes and more individuals saw this rare celestial event online and in person than ever before. Just think, in 2004, social media was non-existent, and actually streaming something live to a web audience was a dicey affair.

Our rig on weather standby! (Photo by Author).

We did savor a few very brief glimpses of the transit through clouds here from Astroguyz HQ, and even managed to snap a very few quick pics which we were pleasantly surprised to see actually contained the transit! (See intro pic) Like many, we were surprised to see how large Venus actually appeared against the disk of the Sun, at about 1 arc minute across. Put Earth at the same distance, and it would appear similar!

Anyhow, we thought we’d run a very brief selection of transit shots from worldwide & beyond today:

The transit as seen from the ISS. (Credit: NASA/Don Pettit(@astro_pettit):

(Credit: NASA/JPL)

Don Petit got the 1st photos of the transit of Venus as seen from the International Space Station yesterday… It’s interesting to note clicking through the Flickr stream that the orbital motion of the ISS is apparent in the rotation of the pics!

Andrew Symes (@FailedProtostar) from Ottawa, Canada:

 

Clay Davis (@Claymdavis) from Santa Fe, New Mexico:

An Ingress Video from NASA-SDO;

Ramiz Qureshi (@ramizq1) from Karachi, Pakistan:

Ramiz noted that as the transit rose through the haze as seen from Pakistan, the transit could actually be seen with the naked eye! How many ancient transits of Venus were seen but unrecorded prior to to 1639?

Rob Sparks (@HalfAstro) from Tucson, Arizona:

a solar projector;

And the transit as seen in Hydrogen Alpha;

Michael Rector (@AdirondackAstro) from Plattsburgh, New York:

Like many astronomical events, a single impression struck me. Here I sat on “transit vigil” in my backyard, awaiting a fleeting glimpse through clouds with a battery of instruments. Around me, dogs barked, cars honked, and the usual neighborhood noises could be heard, just like any other day on the planet Earth. But here was something unique very quietly occurring overhead, there for anyone who sought it out. How much of beauty, truth, and the just plain bizarre swirls around us everyday, obvious to our concerns?

All pictures were used with the authors permission; thanks to all who contributed and made this Transit a truly worldwide astronomical affair!

 

Astro-Event: Venus in Transit.

The 2004 transit of Venus as seen by NASA’s TRACE spacecraft.

(Credit: NASA/LMSAL).

It’s almost upon us. If skies are clear next Tuesday June 5th-6th, you’ll be able to witness one of the rarest events in astronomy; the transit of Venus across the disk of the Sun. This event lasts almost seven hours and spans over three quarters of the world. A good swath of humanity (the largest ever) will see at least a portion of the transit… and unlike the annular eclipse a few weeks ago, you don’t have to be along a narrow track to see the action. If you can see the Sun from 22:09:41 UT June 5th to 04:49:31 UT on June 6th, you can see at least a portion of the transit. This stands not only as the top astronomical event of 2012, but one of the great astronomical events of the 21st century.

How rare is a transit of Venus? Rarer than an eclipse at a Korn concert; the last transit occurred in 2004, but the last one before that occurred in 1882. And the next one doesn’t occur until 2117, so it’s pretty safe to say that no one alive today will see that far off future transit, unless they perfect the technique of preserving heads in jars like in Futurama. In the current epoch, transits of Venus occur in pairs eight years apart that are separated by alternating spans of 105.5 and 121.5 years. This stems from the fact that 13 Venusian orbits (which has a sidereal year of almost 225 Earth days) very nearly equals 8 Earth years; in 2020, you can expect Venus to very nearly mimic its spring 2012 celestial path, but instead miss the edge of Sun by 24’. In the 20th century, no transits of Venus where seen.

Maps of the 2012 transit courtesy of Eclipse-Maps. (Click to enlarge).

This is will only be the 7th transit of Venus to be observed since Kepler realized they occurred in the 17th century. If Venus orbited squarely across the ecliptic, a transit of Venus would be a much more frequent affair, occurring at every inferior conjunction about 19.5 months apart. But since Venus’s orbit is tilted in respect to our own to the tune of 3.4°, transits are much more infrequent as it “misses” the solar disk. In fact, roughly every 4 years before or after a transit, the opposite occurs and Venus passes its maximum separation of about +5° degrees above or below the Sun and can actually be tracked through inferior conjunction, as occurred in 1998, 2009 and will be possible again in 2015 & 2017.

Planning ahead; an 1883 map of the 2012 transit by R. A. Proctor.

(Public Domain image courtesy of Eclipse-Maps).

Alas, Kepler never lived to observe the 1631 transit, and the first successful observation of the transit of Venus goes to Jeremiah Horrocks in 1639. Since that time, the race was on as expeditions fanned out all over the globe to accurately measure the ingress and egress of the planet and measure the scale of the solar system; such adventures are recounted in the fascinating books The Transit of Venus by William Sheehan & John Westfall and The Day the World Discovered the Sun by Mark Anderson. These were some of the first truly international scientific collaborative efforts and they make for a fascinating snapshot of the history of astronomy.

Historical sketches depicting the aureole and black drop effect. (Public Domain).

So, what can you expect to see next week? Well, observers in North America will catch the transit as the Sun is setting; this is a Pacific-based event with the maximum point (where the Sun will be at the zenith during the transit) a few hundred miles south east of Japan. Continuing westward, the Sun will appear ever lower in the morning sky on the 6th as the transit is occurring; Europe, the Middle East and north eastern Africa will witness the transit as the Sun is rising.

The crucial contact times of the transit (numbers corresponding to the map above) are;

June 5th (all times are worldwide and in Universal Time)

1- 22:09 ingress (exterior contact)

2- 22:27 ingress (interior contact)

June 6th:

01:29 Mid-transit

3- 04:31 egress (interior contact)

4- 04:49 egress (exterior contact)

As you can guess, the most “action packed” times will be when Venus first slides onto the solar disk and later slides off. Watch for the “aureole effect” or a ghostly halo encircling Venus as it enters the solar disk. Long reported by observers, it was only recently photographed for the first time during the 2004 transit. Venus has a substantial atmosphere, and this phenomena is caused by sunlight being refracted towards us through it. No aureole is seen, for example, when airless Mercury transits in front of the Sun. Incidentally, Mercury last transited the Sun on November 8th, 2006 (the only transit we’ve seen thus far)  and will next transit the Sun on May 9th, 2016. It will also just miss the Sun by <8’ later this year (more on that in November!)

It’s interesting how the transit pairs also serve as a “snapshot” of the technology of the day; for example, photography was barely in its infancy in 1882. Recently, the plates of David Peck Todd were stitched together into a charming “animation” of the 1882 transit. Even in modern times, off-the-shelf tech has grown immeasurably since the 2004 transit and I don’t doubt that some amazing photos will be flooding the ‘Net next week. It’s amazing to think that prior to 2004, very few images of the transit of Venus existed!

Another elusive phenomenon to watch out for is known as the Black Drop Effect. As Venus enters and exits the disk of the Sun around the time of interior contacts, a slight “elongation” or extension between the disk of Venus and the limb may be seen. More of an optical illusion, this effect has vexed astronomers of yore in their attempts to get ultra-precise timings of ingress and egress. What compounds the problem is the effect of limb darkening on the edge of the Sun. Can you do better than these olden-time observers? Sketching the black drop may be a fun project as well.

This transit will pass about 9’ from the center of the Sun’s disk, and the transit cord is 25’ long. Venus will appear about 1’ arc minute in size (the largest any other planet can appear from the Earth) and be moving at a rate of 1’ per every fifteen minutes and appear 1/32nd the angular diameter of the Sun. Venus passes aphelion on July 11th, 2012.

A peek at our “transit rig”… (Photo by Author).

All of the safety rules that were laid out during the May annular eclipse still hold true for this transit. Do not look at the Sun with the unaided eye or with a filter that’s not approved for solar viewing; projection or a filter that fits snuggly over the aperture end of the telescope are the best bet. We have made several homemade solar filters over the years using Baader filter paper; ten years after our initial 30$ purchase and six filters later, and we still have half a sheet left! In fact, this is how we’ll be observing, along with our trusty hydrogen-alpha PST scope;

Solar viewing glasses (NOT sunglasses!) and #14 welder’s glass are also approved for safe use. One caveat is in order; unlike an eclipse, viewing the transit of the Sun via a pin-hole projection will be difficult; a pinhole camera effectively has a focal ratio of about 100 to 1, and the projected image when focused will be extremely tiny; building a pin-hole mirror is your best bet.

Eclipse (or Transit) viewing… safety first!

(Image courtesy of Chou Hui-Chi @SumiKeiKi).

Transits of Venus also occur in seasons that, in the current epoch, fall either in June or December. The 2004 & 2012 pairing happens in June, while they are bracketed with December transits in 1874/1882 and 2117/2025. The path of this transit is most similar to the June 3rd, 1769 transit witnessed by Captian Cook’s expedition from Point Venus, Tahiti and will next have similar circumstances on June 9th, 2255. Incidentally, single (i.e. non-paired) transits can occur, as happened in 1396 and will occur again on December 18th, 3089. Eclipses also occur in lettered series similar to eclipse saros cycles, with the current actives series being “E” (2004) and “F” (this year’s). This current cycle wraps up with a brief polar transit on December 14th, 2854 AD.

As with the annular eclipse, several satellites will be able to see this historic event; although ESA’s SOHO satellite will miss the transit, NASA’s SDO, JAXA’s Hinode, and ESA’s PROBA-2 will all be watching as Venus transits the Sun. Though most of these will be doing their observations for pure “gee whiz” value, Hubble will be testing a technique for “teasing out” the spectra of sunlight streaming through the Venusian atmosphere by staring at Tycho crater on the waning gibbous Moon during the transit. Refining said technique may go a long way towards identifying exoplanet atmospheres.

And speaking of SOHO, the ESA satellite’s LASCO C/3 camera will be a great place to watch Venus “take the plunge…” it also passes just 0.26° degrees from the planet Mercury in the closest planet-planet conjunction of the year just days before the transit on June 1st. When is the last evening prior to the transit that you’ll be able to see Venus?

It’s also always interesting to attempt to nab a transit of the International Space Station in front of the Sun while Venus transits. 1st accomplished in 2004, your best bets for this transit look to be around the 23:42 UT pass over South East Asia and Australia;

A first look at the ISS path during the the transit of Venus ~23:42UT.

(Created by the author using Orbitron).

CALSky should have accurate path tracks for those who plan to chase the twin shadows of the ISS and Venus up by the end of this coming weekend.

Weather is always a crapshoot for most of the month of June. Although this year’s transit favors the sunward-tipped northern hemisphere, hurricane/typhoon season begins on June 1st and got off to an early start this year. Drier climes such as northern Australia and the United States south west have the best viewing opportunities, while areas such as the Asian Far East and our own home state of Florida offer chancier prospects.  The good news is, you only have to be able to see the Sun to see the transit; pristine skies aren’t required. Areas that have the transit directly overhead have the best chances of a clear view, while regions that have the transit rising or setting risk low cloud cover. Of course, a transiting Venus on the horizon with an interesting foreground is much more photogenic!

As of this writing, weather prospects for Astroguyz HQ in Florida look to be at about a 75% chance of cloud cover, which is typical for Florida skies in summer afternoons. Doubtless, the weather forecast will flip-flop all the way up to show time the evening of June 5th. Some good weather sites to watch for accurate cloud cover predictions and Skippy Sky and Clear Sky Chart.

Solar activity as of May 29th (Photo by author).

Solar activity is also another big question mark; while we’re rolling towards solar max for cycle #24 next year, the Sun as of late has only exhibited minor activity (see image). A dynamic, sunspot-speckled Sun would make for excellent photos, and most of what’s on the Sun’s disk currently will still be present during the transit about a week from now… the equatorial regions of the Sun rotate once every 22 days. Still, it’s always possible that a huge active sunspot region will make its presence known just before show time!

Interested in replicating those observations of yore? In 2012, the transit of Venus meets social media as an Australian-based group seeks to replicate the determination of the astronomical unit via the Delislean method at Transit 2012. The method is simple; follow @venusobs, register at their site, and note in internal/external ingress/egress contact times that are visible from your location and tweet ‘em to #venusobs. If enough measurements are gained worldwide, a fun and historical experiment will be replicated… I plan on using WWV radio for accurate time signals. Just imagine if Cook had had Twitter!

Stranded on the wrong side of the world (or socked in with clouds) and want to watch the transit live? The solar observing Global Oscillation Networking Group (GONG) will have the transit in its worldwide sights. Many live broadcasting sights will crop up towards the weekend, but this is your best bet!

Want to see something truly weird? If you head to Mars in 2086, you can see a transit of Earth, the Moon… and Phobos!:

Finally, don’t forget to simply observe this uber-rare spectacle and have fun. The transits of Venus serve as a collective snapshot of where science and society is and what we hope to gain from such a rare celestial dance. As we noted in our July 2012 Sky & Telescope focal point article, it’s sobering to wonder what the world might be like in 2117. Watch this space for our after-action report on the final transit of Venus for this century, and follow us on @Astroguyz at Twitter for all the latest updates!

 

Review: Two Essential Transit of Venus Books!

This week, we’re going to break from convention and we’re giving you an early review and a shoutout of two fine and indispensible resources for the upcoming transit of Venus on June 5th-6th. This is the last such transit of our sister world for this century, and over the years we’ve reviewed two fine books on this unique event: The Transits of Venus by William Sheehan & John Westfall and The Day the World Discovered the Sun by Mark Anderson. [Read more...]

Astro-Event: The First Lunar Eclipse of 2012.

The partial phase of the December, 2010 total lunar eclipse. (Photo by Author).

(Note: I know, we promised a post on Xi Ursae Majoris this week; upcoming events prompted a last minute scheduling change. Trust me, it’s in the pipeline for July!)

A little over 24 hours prior to the big ticket transit of the planet Venus on June 5th-6th is another interesting astronomical event, perhaps less sexy, but worth noting. [Read more...]

The Elusive Wow by Robert H. Gray.

On sale now!

Nothing fires the scientific imagination like the search for extraterrestrial intelligence. And likewise, no discovery would have further implications to our own existence and what it means to be human. Plus, it would just be darned interesting to get to know something about them. How unique are we?

[Read more...]

Review: The Quantum Universe by Brian Cox & Jeff Forshaw.

On sale now from Dacapo Press!

Quantum physics is perhaps the most arcane field of research out there today. It’s a field where particles pop in and out of existence, actions happen at a distance, and cats in boxes appear to be both alive and dead depending on the actions of the observer. Although there has been much written on the odd world of quantum physics, there are very few books out there for the curious layperson. [Read more...]

AstroEvent: Exploring the Lunar Apennines & Ina Caldera.

Ina Caldera as seen from LRO. (Credit: NASA).

Whew! With yet another “Super-Moon” weekend has come and gone, and lunar exploration can now be safely left up to those who know and love the Moon. This week, as said Full Moon gives way to waning gibbous, I’d like to draw your attention to a famous mountain range on the edge of the Mare of Imbrium. The Lunar Apennines or Montes Appenninus lie at the edge of a volcanic scarp and feature some of the largest peaks on the Moon rising as high a 5 kilometers above the surrounding terrain (there’s no sea-level on the Moon). [Read more...]

Review: From Here to Infinity by Martin Rees.

Out in June from Norton Books!

The early 20th century was a high time for science. As challenge after challenge was met head-on and the Age of Steam gave way to the vacuum tube and the unlocking of the energy of the atom, it seemed as if progress was unstoppable. Would we be living on Mars and commuting by pneumatic tube by 1999? [Read more...]

Astro-Event: A Meteoric Weekend!

We bring you this week’s installment of the astronomy event of the week a few days early to get “eyeballs on the sky” for the first good meteor shower of spring 2012. The Lyrids, generally a lesser shower with rates around 10 per hour, may just be worth watching out for this year. [Read more...]

AstroEvent: Mercury Down Under.

Mercury to the east as seen from Sydney, Australia on the morning of April 18th.

(Created by the author in Starry Night).

This week’s post goes out to my Astro-Hommies in the southern hemisphere. All too often, astronomy journalism has been accused of being northern hemisphere-centric, US East Coast to be precise. This week, we break with the ranks that are touting the April morning elongation of Mercury as the “worst of 2012, don’t bother” and demonstrating that, depending on your point of view, it may well be the best!

This largely has to do with the current angle of the morning ecliptic before sunrise. For northern hemisphere observers, it is currently very shallow to the horizon. This changes, however, as you venture farther south. It is Fall in Australia, South Africa and South America, and the morning ecliptic is nearly perpendicular to the horizon. I’ve ventured five times south of the equator (not counting a winding mountain road in Ecuador that criss-crossed the equator a dozen plus times!) and felt it bizarre to my northern-based brain to see the Sun transit to the north, or see familiar constellations hanging upside down!

But anyway, this situation bodes well for sighting +0.5 magnitude Mercury this week about a half hour before sunset. In addition, the waning crescent Moon will be about 12° degrees away on the morning of the 18th and just 3 days prior to New. The exact timing of greatest western elongation for the fleeting world is April 16th at 17:00 UTC at 27.5° degrees from the Sun. This is the greatest elongation Mercury achieves in 2012, and very nearly the farthest that it can achieve from the Sun at 27.8°. The reason for this is that Mercury reaches greatest elongation only days after passing aphelion, or its farthest point from the Sun on April 15th at 5:00 UTC. Mercury’s orbit has an eccentricity of about 0.2 or 20%, making its orbit noticeably elliptical and causing evening and morning apparitions of the planet to vary greatly in terms of angular distance.

The tiny 8” arc second disk of Mercury will display a maximum illumination area on April 18th at 2:00 UTC, and is headed from crescent phase to 50% illumination on the 21st. (half phase isn’t precisely on the 18th because Mercury’s orbit is also tilted 7° degrees relative to the ecliptic.

Other mercurial events to watch for are a conjunction with +5.9 magnitude 3.4” arc second Uranus 2.1° degrees apart on April 22nd, 2:00 UTC, and a conjunction next month on May 22nd with Jupiter at 07:00 UTC just 0.4° degrees apart. Yes, this will be very close to the Sun only about 6° degrees away, but note that Jupiter, Mercury, and the Moon will all be within a five degree circle during the annular eclipse only two days earlier! More on this next month… be sure to physically BLOCK the Sun if trying to make this sighting; the eclipsed Sun evening during annularity is brighter than most people realize! And speaking of which, this week is also an excellent time to attempt those daylight Mercury sightings using a similar technique… (OK, we’ve never accomplished this, either!)

Superior conjunction and non-transit of the Sun for Mercury occurs on May 27th. Incidentally, the next transit of Mercury will on May 9th, 2016 and will be visible from North America…. There are 12 transits of Mercury remaining for this century, and curiously, a near “miss” less than 8’ arc minutes from the Sun this year on November 17th… could an active Sun reach out and give us a prominence transit?

Finally, another unique event involves the inner most world on August 15th of this year, when Venus & Mercury reach greatest elongation within 24 hours of each other… more on this to come this summer!

Review Space Chronicles by Neil DeGrasse Tyson.

On sale now!

Neil deGrasse Tyson is on a mission. That mission might best be described as assuring the citizens of today’s modern technological society maintain scientific literacy and feed their wonder for the universe.  And if that’s the mission, then this week’s review, Space Chronicles: Facing the Ultimate Frontier is the space aficionados’ manifesto. [Read more...]

Astro-Event: A Tax Day Return of Saturn.

Saturn in January 2004. (Photo by Author).

Not looking forward to April 15th and the U.S. deadline to file taxes? It is in trying times like these that one can look to the skies for solace and the return of our solar system’s most resplendent planet to evening skies. Yes, we’re talking about Saturn as it reaches opposition later this weekend on Sunday April 15th at 18:00 Universal Time, or 14:00 Eastern Standard Time. [Read more...]

Review: Under the Radar by W.M. Goss & Richard X. McGee.

Out from Springer Press!

Among the well known personalities of science there lies those who have labored quietly but have an equally interesting story to tell. This week, we take a look at Under the Radar, a biography of the first woman in radio astronomy, Ruby Payne-Scott out from Springer Press. [Read more...]

AstroEvent: In Search of the Solar Birthplace.

Cancer & M67.

(Photo-graphic by Author; M67 image courtesy of 2MASS/UMass/IPAC-Caltech/NASA/NSF).

A mystery lurks in the heart of the Crab. This month, as the Moon passes Full on March 6th and begins to once again leave the late evenings to us dark sky observers, I’d like to turn your attention to a non-descript open cluster in the constellation Cancer. Just a few degrees below the ecliptic plane and the Beehive Cluster (M44, also known as Praesepe) and about 1.8° degrees west of Alpha Cancri lies M67, a +6.1 magnitude open cluster located about 3,000 light years away. Composed of roughly 1,400 stellar members packed into a space about 10 light years across, this open cluster bucks the trend of early destruction and dispersal that is often the future fate of younger clusters such as the Pleiades and the Hyades and has an estimated age of 3.2 to 4.8 billion years. If that age range sounds familiar, that’s because our very own Sol and our solar system is estimated to be around 4.6 billion years old. This age relationship has placed M67 at the center of some controversy in recent years as a potential “birth-place” of, well, us. This cluster has escaped scattering largely because of its high inclination orbit around the galactic disk (note its position in the sky versus the Orion spur of our galaxy) and there is some conjecture that M67 is even the remnant of a small dwarf galaxy similar to one of the Magellanic Clouds.

But other factors make it attractive as our possible parent stellar nursery. In order for our solar system to have remained intact early in its history, the density of the cluster had to be such that a system-disrupting stellar encounter closer than 400 astronomical units (about ten times the Pluto-Sun distance) would have been improbable. Some evidence for such a far-out encounter early in our solar system’s history exists in the relatively placid orbits of the inner-planets versus the elliptical tilted orbits presented by modern day Trans-Neptunian & Kuiper Belt Objects.

M67 passes this bar, plus there’s something more. Abundances of beryllium, aluminum and iron isotopes found in asteroids suggest that in addition to spallation from cosmic ray bombardment, the solar system witnessed a massive supernova event within a third of a light year distant early in its history, “salting” the solar nebula with heavy elements. The abundance of heavy elements, known as the “metallicity” of our Sun (remember, astronomers think of every element except hydrogen and helium as “metallic”) is much higher than the ancient population stars found in ancient globular clusters. In fact, the exceptional abundance of such elements as carbon, nitrogen, and oxygen in our solar system is why we’re here to ponder this to begin with. Think of the metallic abundance in the barcode-looking spectra of the Sun as a stellar “finger-print” that just might link us to our kin…

Then in 2010, a study published by astronomers working at the University of Uppsala, Sweden published findings of a star in M67 named M67-1194 which has been found to be the most “Sol-like” star yet. Could it be a long lost cousin of our Sun? It has also been noted that from above the galactic plane, the orbits of Sol and M67 are nearly identical, both being about 27,000 light years out from the galactic core. M67 would have hosted several massive stars that would have been supernova candidates early in its history, and perhaps an early encounter with such as star would have flung us out of our home…

There are, however, problems with this scenario. First, although M67 and Sol have similar orbits around the Milky Way, it has been estimated that we’ve journeyed 27 times around the galactic center versus M67’s 17. Note that some of those parameters such as the cluster’s age aren’t precisely known, and only work if you accept the upper age limit. Also, M67 is currently 1,350 light years above the galactic plane versus our 20-90 light years; a recent study by Barbara Pichardo, Edmundo Moreno and Christine Allen published in the Astronomical Journal earlier this year demonstrates that the relative velocity between Sol and M67 is in the order of 20 kilometers per second; any said encounter sufficient to fling us out of the cluster would have also disrupted the nice, orderly inner solar system we see today and doomed Earth to a wondering ice-ball existence.

Add to that sobering scenario, sending our solar system from a cluster in a highly inclined orbit to a sedate one within the galactic habitable zone via a chance encounter is highly unlikely… or perhaps it was a 1 in a million cosmic shot that led to why we’re here as a sentient blogging species?

But whether M67 is our long lost home or not, it provides a fascinating study of where a solar system like ours could have came from; Astronomer Simon Zwart of the University of Amsterdam estimates that 10 to 60 of our Sun’s siblings may still lie with 320 light years of our solar system as we mutually revolve about the galaxy. A great many others will have been dispersed, and the odds are that our birth cluster no longer exists or lurks in a part of our galaxy obscured from view. The European Space Agencies’ Gaia mission to refine stellar positions and motions may help to pinpoint these stars, and is slated for launch in 2013. Whatever the case is, M67 makes a great binocular target spanning about 15’ arc minutes in northern hemisphere spring nights, and really comes of its own in a low power telescopic field littered with 10th magnitude stars. Its coordinates are;

Right Ascension: 08Hours 51.4’

Declination: +11° 49’

Do open clusters like M67 lead to radio telescope-building, IPad-loving civilizations? What’s the early history of our solar system, and how typical is it? Should the mantra for searching for life in the universe be “follow the metals?” Heady stuff to ponder as you show off this unassuming cluster with a fascinating tale to tell!

Review: Proofiness by Charles Seife.

A Statistical Classic!

Depressed by the fact that yet another U.S. election year is upon us? I know, another full calendar year of pundits, polls and predictions. And while much of the political posturing may predictable, you can also expect the mainstream media to once again assail us with impressive looking charts and predictions. [Read more...]