October 21, 2014

Sirius B and the Curious Case of the Dogon.

The ever-controversial star Sirius. (Photo by Author).

Every beginning astronomy student learns that Sirius is the brightest star in the sky. This brightness is apparent, as Sirius is a spectral type A1V star located relatively close to our solar system at about 8.6 light years away. Much myth and lore surrounds this star, but none is stranger that the mythology of the Dogon people. Incorporated into the mythos of these people that inhabit the plains of Mali is a bizarre tale of Sirius, which they call Sigi Tolo. They claim that the star has a small unseen companion in a 50 year orbit that they call Po Tolo. This companion star is tiny but dense, so dense that all the men in the world could not lift it. The mystery deepens as they also go on to claim that Jupiter has four large moons, and that Saturn has a ring “like that seen sometimes around the Moon, but different…” All of these claims are basically true. Sirius has a companion star, a white dwarf known as Sirius B discovered in 1862 by Alvan Graham Clark. This star is made up of degenerate matter, making it extremely dense, about 1×109 per kg/m^3. And the knowledge of Jupiter and Saturn has been around since Galileo first turned his crude telescope to the heavens…

The Dogon People…

(Credit: Martha de Jong Lantink’s Flickr photostream on a Creative Commons 2.0 License).

So, what’s going on here? Why would an isolated tribe have knowledge that technology only revealed to western eyes in the past few centuries? A quick search around the Internet of the Dogon and Sirius reveals no shortage of theories involving ancient alien contact. The modern pedigree of this tale can be traced back to a 1976 book by Robert Temple entitled The Sirius Mystery. Remember, the 1970’s was a time when Eric von Daniken and his Chariots of the Gods was in vogue, and archeologists were seeing space-helmeted aliens everywhere. Temple based much of his book on the writings of anthropologist Marcel Griaule, who spent time with the Dogon off and on from 1931 to 1956. And much of that particular legend comes from an interview with local Dogon wise man Ogotemmeli. You get the picture. Further research with the Dogon has revealed either no trace of the legend or discrepancies with the tale. For example, they also state that there is a third star in the Sirius system they call Emme ya Tolo, which is the opposite of Po Tolo in that it is both “big and light” but no other star has yet to have been found. Also, as with any sole source, it’s tough to say how much bias there may have been on the part of the recorder… it’s easy to lead a subject, even subconsciously, to the data that we might want to hear. In addition, some confusion exists on whether Ogotemmeli was referring to Sirius or the bright planet Venus in reciting the tale.

The orbit of Sirius B. (Adapted from Burnham’s Celestial Handbook).

In 1979, Carl Sagan proposed that the information might have been given to the Dogon by an external source, albeit a terrestrial one. Keep in mind, the legend coming to light in the 20th century wasn’t really giving us any new information about Sirius; psychics perform this feat all the time when they claim to have predicted events that have already happened. When we look at ancient myths and lore, we need to be mindful of the creativity of the human mind; after all, what would archaeologists thousands of years from now make of a Star Trek episode? That we somehow had warp drive and phaser technology? A true myth having some sort of predictive power would be far more compelling. Does this mean that the discovery of a red dwarf star around Sirius, as was spuriously reported in the 1990’s, would lend some credence to the tale? While interesting, I don’t necessarily believe so, as red/brown dwarf stars are quite common in the cosmos; for example, it’s not totally ruled out that our own sun may have a dim unseen companion!

Like white dwarfs, red dwarfs are common throughout the cosmos. (Credit: NASA/H. Bond).

What Sagan proposed is that the knowledge was passed on by a visiting explorer in the late 19th century, and incorporated into the Dogon mythos by the time Griaule did her interview. The image is compelling; an explorer eager to tell the “primitives” about the triumph of western science, imparting new information to the Dogon about their honored star. Keep in mind, another ancient African people, the Egyptians, based their calendar on the Sothic cycle and the helical rising of the star Sirius. Perhaps, said explorer had a telescope on hand to show them Jupiter and Saturn for good measure.

The original Dogon Sirius diagram. (Credit: Bad Archaeology).

But do any historical expeditions fit the bill? Well, there was in fact a total solar eclipse that passed over the region of modern day Mali on April 16th, 1893, and several expeditions were indeed in the area; these expeditions would have been well-equipped with astronomical gear and astronomy and curiosity about the heavens would have been on the forefront of everyone’s minds. And yes, Saturn had just passed opposition and Jupiter would have been an early evening target in the months leading up to that date.

Jupiter at dusk in April 1893. (Created by the Author in Starry Night).

And the diagram purported to be centuries old? Well, keep in mind that it only bears a passing resemblance to an elliptical orbit; it looks a lot like an egg, which symbolizes re-birth and is prevalent in the mythos of many cultures (witness the “Easter eggs” of western culture; a throwback to pure paganism!) The original diagram sketched out by Ogotemmeli shows several other curious objects within the egg; later commentators have edited them out making the case for Sirius B to seem more conclusive than it really is. And keep in mind that we see the orbit of a binary star system generally tipped to our line of sight between either edge-on and face on; it would relatively easy to find several “matches” to the Dogon diagram in the sky.

The total solar eclipse of 1893. (Credit: Fred Espenak, NASA/GSFC).

While I think the Dogon case is more interesting than most, I don’t find it compelling as a sign of ancient extra-terrestrial contact. Keep in mind, this is still giving us knowledge that we already knew; exacting knowledge, such as a chant that encoded how to build a functioning hyper-drive, for instance, would be much more inexplicable and compelling. The final fact often cited is that the Dogon believe in a heliocentric, or Sun-centered solar system, a fact that took us centuries of denial to realize. In this case, I believe that the Dogon should be recognized as astute observers of the sky; anyone can arrive at this conclusion as the Greeks initially did by merely studying the naked eye motions of the heavens and not allowing pre-conceived notions of how the world should be to cloud their judgment. All too often, we fail to give credit to the ingenuity of ancient cultures where credit is due. These people knew the sky far better than the average citizen does today and relied on it as a natural clock. Perhaps such intimate knowledge of peoples like the Dogon should be viewed for what it really is, rather than attributed as merely given to them from afar.

16.02.11: The Tyche Files.

The realm of the outer solar system; here be hypothetical worlds? (Credit: NASA).

Something kept floating around our astro-radar yesterday as we busily wrote about comet flybys, launches, and wacky space weather. Titles like “New Solar System Planet!” and “Solar Companion Found!” kept making a spurious appearance from unverified sources. [Read more...]

Astro-Challenge: Groombridge 34; a Nearby Red Dwarf Pair!

Groombridge 34; the finder chart. The circle is approx a 1 degree field of view. (credit; Stellarium).

Groombridge 34; the finder chart. The circle is approx a 1 degree field of view. (credit; Stellarium).

Sure, everyone’s heard of Alpha Centauri, but have you ever heard of… Groombridge 34? We came across this little known binary red dwarf pair while perusing Burnham’s Celestial Handbook last month during our write up for M31. Also in the constellation Andromeda, Groombridge 34 is a unique system; a pair of red dwarf flare stars relatively close to our own solar system. At 11.62 light years, its the 16th closest stellar system to our own. The separation of the two stars are about 147 Astronomical units (A. U.s) (for reference, Pluto is about 50 A.U.s from the sun!) in a estimated 2,600 year orbit. [Read more...]

Astro-Challenge:Spy a White Dwarf!

Can you see Vulcan? (Photo by Author).

Can you see Vulcan? (Photo by Author).

This week, I’m going to introduce you to a unique but fascinating multiple star system, and one that’s definitely worth seeking out as it’s a good study in comparative stellar evolution; Omicron Eridani. This one will require a telescope of about 4′ aperture or greater, a go-to scope or a good finder chart, and patience. But the quarry is worth it; for Omicron Eridanus B is a white dwarf, the most easily observable in the sky, paired with C, a red dwarf star! Omicron Eridani is a triple star system, about 16.5 light years distant. The primary star, a K type main sequence star, is visible to the naked eye at a magnitude of about +4.5. Known to the Arabs as Al Keid (“the Egg”), [Read more...]