The dog-star, Sirius, is the brightest star visible from the northern hemisphere of Earth. This star has been known to humans since thousands of years as it is quite easy to spot in the sky. What to the eye appears as a single star is actually a binary star system, consisting of a white main sequence star of spectral type A1V, named Sirius A, and a faint white dwarf companion of spectral type DA2, named Sirius B. The reason for its brightness is not its intrinsic luminosity but its closeness to earth; at a distance of 2.6 pc or 8.6 light years, Sirius is one of our near neighbors. Sirius A is only about twice as massive as the Sun and, with an absolute magnitude of 1.42, has far less intrinsic luminosity than Canopus or Rigel.
Researchers noticed that Sirius does not move like most other planets. There were irregularities in its orbit and it seemed quite obvious to scientists that it was being affected by an external body. They believed that the other celestial object with a huge mass must be close to it.
It was not until 1862 that Alvan Graham Clark discovered the other object that was affecting Sirius A and named it Sirius B. It was a tiny star close to Sirius but it seemed to be too small have been causing such a large effect on Sirius A.
It was not until 1920 that a scientist, Sir Arthur Eddington, suggested that Sirius B was a star that had collapsed in on it self and took on a density that was not proportionate to its size. It was suggested that a single cubic meter of Sirius B has the mass of 20,000 tons. This explained why it was able to affect Sirius A so dramatically.
Sirius B was finally photographed in 1970.
The Egyptians and the Dogon
The ancient Egyptians called this star Sopdet. The star was worshipped as Sothis in the valley of the Nile long before Rome was founded. The Middle Kingdom of Egyptians based their calendar on the heliacal rising of Sirius, which occurred just before the annual flooding of the Nile and the summer solstice. The hieroglyphic for Sothis features a star and a triangle. Interestingly, Sothis was identified with the great goddess Isis who formed a part of a trinity with her husband Osiris and their son Horus. The hieroglyphic for Sirius was a triangle that suggests that each corner was for each of these gods.
The Dogon tribes of Mali are descendants of the Ancient Egyptians. They know this star as Sigu Tolo. Their religious beliefs claim that Sirius represents a trinity of stars. They have also charted the orbit of Sirius B and various other stars that interact with Sirius A. Dogon drawings show that the correct orbit of Sirius A and Sirius B. They had also determined that a complete orbit of the two stars was over a period of fifty years.
Furthermore, the Dogon beliefs and 400 year old artifacts show that there is a third star, Sirius C, near Sirius A and B. They claim that it has the star is four times lighter in weight than Sirius B that has an orbit that takes four centuries to complete. Scientists are currently debating this because some reports have shown clues of another star near Sirius A that matches the description of Sirius C given the Dogons.
Other than the Sirius system, some Dogon artifacts and priests accurately mention the existence of the rings of Saturn, and the four moons of Jupiter. Both of these facts would be impossible to be known without access to powerful telescopes and equipment.
It remains a mystery of how these primitive tribes came to know about these facts about the universe with no tools at their disposal.
The Dogons claim that their ancestors were visited by beings from outer space who told them about the Sirius stars and the universe. They are said to have landed in North Eastern Africa in a a giant space ship. The visitors apparently told the Egyptians and Dogon ancestors that they came from a planet near Sirius. They call these aliens the Nommo.
Critics claim that the Dogon have been culturally contaminated. There is no solid proof that the religious beliefs that they have existed prior to 1862 when Sirius B was first discovered by scientists. Skeptics also believe in the possibility that the anthropologists, Marcel Griaule and Germaine Dieterlen, who first embedded themselves into the Dogon culture were the cause of the cultural contamination.