Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

LSU researcher solves ancient astronomy mystery

14.01.2005


An ancient mystery may have been solved by LSU Associate Professor of Physics and Astronomy Bradley E. Schaefer.



Schaefer has discovered that the long-lost star catalog of Hipparchus, which dates back to 129 B.C., appears on a Roman statue called the Farnese Atlas. Hipparchus was one of the greatest astronomers of antiquity and his star catalog was the first in the world, as well as the most influential. The catalog was lost early in the Christian era, perhaps in the fire at the great library in Alexandria.

The Farnese Atlas is a Roman statue, dating to the second century, that depicts the Titan Atlas holding a sky globe on his shoulder. The statue, currently housed in Italy, includes relief figures on the globe depicting the ancient Greek constellations in fine detail. Schaefer has discovered that the constellation figures on the Farnese Atlas are an accurate rendition of Hipparchus’ star catalog. According to Schaefer, the discovery will likely lead to the solution of several long-debated questions.


Indeed, Schaefer’s discovery is already stirring interest among those in the field of astronomy. "The constellations are one of our more enduring intellectual properties, and in antiquity, they turned the night sky into familiar territory. Dr. Schaefer’s clever and disciplined analysis of the oldest graphic representation of the traditional Greek constellations reveals unexpected roots of scientific astronomy in a celebrated work of ancient art," said E.C. Krupp, director of the Griffith Observatory in Los Angeles.

Schaefer, who earned his doctorate from the Massachusetts Institute of Technology in 1983, specializes in astronomy and astrophysics. He has long been interested in the history of astronomy and has written extensively on the subject. He began his examination of the Farnese Atlas statue while conducting research on ancient constellation lore.

Schaefer said that scientists have long held Hipparchus in high regard for his work, which was conducted between 140 B.C. and 125 B.C. He is known for the discovery of the first nova and a process called precession; a theory for the motions of the sun and moon; top-quality planetary observations; and the first-ever catalog of about 1,000 stars. Unfortunately, only one of Hipparchus’ books has survived to today: "Commentaries," which describes the constellation figures in detail. The rest of his written work is known only through the references of later astronomers. For example, Schaefer said, Hipparchus’ star catalog was described in the work "Almagest" by the influential Greek astronomer and geographer Ptolemy, who lived around A.D. 85 to A.D. 165.

The Farnese Atlas – roughly seven feet tall and made of marble – is now in the Farnese Collection in the National Archaeological Museum in Naples, Italy. The statue’s sky globe, which is 26 inches in diameter, shows 41 Greek constellations, as well as the celestial equator, tropics and ecliptic. Art historians have concluded that the statue is a late Roman copy of a Greek original. Schaefer said that the constellations are accurately depicted, so the sculptor must have based his work on some specific astronomical observations. Throughout the last century, Schaefer explained, these observations have been attributed to many sources, but not Hipparchus.

Schaefer said that a number of facts led to the conclusion that the statue’s sky globe was based on Hipparchus’ catalog.

Precession, as discovered by Hipparchus, is a process whereby the stars and constellation figures slowly move with respect to the celestial equator, tropics and lines of constant right ascension. This provides the key to dating the original observations, Schaefer explained, because it means that investigators need only look on the sky globe to see what date matches the constellation positions. Thus, Schaefer traveled to Naples and made the first astronomical analysis of the constellation positions.

For his analysis, Schaefer took his own pictures, because the photographic analysis requires knowledge of the distance between globe and camera. He measured a total of 70 positions on the globe and made a formal mathematical fit to find the best date. Schaefer concluded that the best date for the original observations is 125 B.C. He said that the normal margin of error in this result is ±55 years. In other words, Schaefer said, there is a two-thirds chance that the real date was somewhere between 180 B.C. and 70 B.C.

Schaefer said that the date of 125 B.C. immediately points to Hipparchus’ circa-129 B.C. catalog as the original observational source. Indeed, he said, all previously proposed source candidates are confidently eliminated because they come from time periods that are either too early or too late.

Positioning on the globe is another key indicator of the source, said Schaefer. The positioning of the constellation figures on the Farnese Atlas has a typical accuracy of 3.5 degrees. Schaefer said that such accuracy is essentially impossible to achieve by simple verbal descriptions (as found in the works of other potential sources, such as Aratus or Eudoxus) which are accurate to around 8 degrees. Nevertheless, ancient star catalogs would have the required accuracy. However, it is Hipparchus who is known to have a star catalog created around the correct time, 129 B.C., whereas the next catalog, created by Ptolemy, came much too late, in A.D. 128.

In addition, Schaefer said it is known that Hipparchus constructed many sky globes based on his star catalog. For instance, ancient coins depict Hipparchus seated in front of a globe and Ptolemy writes explicitly of Hipparchus making such globes. Thus, Schaefer explained, a likely scenario is that Hipparchus used his catalog to make an accurate globe, which was later copied exactly by a Greek statue sculptor. Then, the Greek statue was later copied by a Roman sculptor.

The constellations of the Farnese Atlas also contain many specific details that point to Hipparchus as the original observer. Schaefer made a comparison between the Farnese Atlas and all ancient constellation descriptions, including those of Ptolemy and other ancient astronomers and thinkers, such as Hipparchus, Aratus, Eratosthenes, Eudoxus and Homer. All ancient sources other than Hipparchus have many and major differences in their descriptions of the constellations. However, the detailed comparison shows Hipparchus’ "Commentary" to have no differences and many unique similarities.

Thus, the case for Hipparchus’ lost star catalog appearing on the Farnese Atlas is based on:
The derived date of 125 B.C., which matches Hipparchus and rejects all other candidates;
The fact that the accuracy of the sky globe requires a star catalog, and only Hipparchus had created one before A.D. 128;
The fact that Hipparchus is known to have produced working sky globes from his catalog;
The fact that only Hipparchus’ description of the constellation figures matches the Farnese Atlas.

Schaefer said that the discovery of Hipparchus’ lost star catalog on the Farnese Atlas could provide answers to two long-standing questions that have been the source of heated debate: What did Hipparchus use as coordinates and what fraction of Hipparchus’ star catalog made it into Ptolemy’s "Almagest?" Now, Schaefer said, with an accurate representation of Hipparchus’ catalog, researchers can make exhaustive correlations between all constellation figures on the Farnese Atlas and those contained within "Almagest." But, Schaefer said, perhaps the best part of the discovery is "simply that we have recovered one of the most famous known examples of lost ancient wisdom."

Schaefer announced his discovery today, at the American Astronomical Society meeting in San Diego, Calif.

For more information on the discovery, contact Schaefer at 225-578-0015 or schaefer@lsu.edu. Schaefer will be attending the AAS conference until Jan. 13, but will be reachable through messages left at 619-908-5062 or 619-908-5065. The results of Schaefer’s research will be published in the May 2005 issue of the Journal for the History of Astronomy. More information, including Schaefer’s journal paper, is available at http://www.phys.lsu.edu/.

Bradley Schaefer | EurekAlert!
Further information:
http://www.phys.lsu.edu/.
http://www.lsu.edu

More articles from Physics and Astronomy:

nachricht DGIST develops 20 times faster biosensor
24.04.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>