There are numerous theories, but no definitive answer, as to who built the stone tower, and why.

NEWPORT - The origins of the Newport Tower, located at Touro Park, continue to intrigue and mystify historians, researchers and regular folks the world over. Was it built by the Vikings or the Chinese? Is it a mini Stonehenge? Is it just a mortar and stone structure that served no real purpose?

Astronomer William S. Penhallow of Charlestown, professor emeritus at the University of Rhode Island, will give an informative lecture, "Astronomical Alignments in the Newport Tower," on Thursday, Jan 25, at the Seaman's Church Institute. For more than 15 years he has studied the tower and he'll present those findings to the public using models, a globe and an astrolabe — a practical instrument developed by the Greeks, elaborated on by the Arabs and used extensively during the Middle Ages.

"I'm going to try to emphasize that the case of the Newport Tower is a cold case like you see on TV these days," Penhallow explained. "It hasn't really been solved. Here you have a structure above ground that shows great intelligence. It wasn't built haphazardly. You've got the eight pillars that were laid out very precisely. The random openings are not random at all. They were carefully worked out."

Two main theories about the tower's origin are that it was simply a windmill built by Newport Gov. Benedict Arnold in the late 1600s or it was a creation of the Vikings.

However, Penhallow said it is far more complicated than the Arnold theory. He said about 12 to 15 years ago, a Danish group came to Newport and did a photogrammetric study. It involved the use of sophisticated equipment in an attempt to find the unit of measure the builders used. From the survey, it was found that it was not measured in feet.

Since all colonial structures in New England were built using feet, that would eliminate anything having to do with Arnold, Penhallow noted.

The Viking theory came to be because of a runic inscription on a stone on the tower which is quite controversial.

"This runic stone implied they (the Vikings) built it," said Penhallow. "I think it was a religious site and someone in 1100 or 1200 left the runic stone around to mark the location. Someone came around between 1300 and 1500 and used that stone not even knowing there was an inscription on it in the building of the tower. They covered it over with pargeting (like stucco) and wasn't aware it was there."

Penhallow, 73, said the purpose of the tower was to determine the motions of the sun, moon and stars in a general, religious background. And that's coming from a man who earned a master's degree in physics from the University of Maine and began his career at URI in 1959.

Since then he established the Quonochontaug Observatory at the college in 1987, taking part in the international tracking of Halley's Comet, and opened the Frosty Drew Observatory at Ninigret Park in Charlestown in 1988. It was there that the public observed the collision of the fragments of Comet Shoemaker-Levy with the planet Jupiter.

The lecture is sponsored by Tempus Fugit, of which Helen Farrell Allen, a Wakefield historian, is principal. She said the organization was founded in 1994 with the mission of alerting people to the importance of early American history.

The Newport Tower was mentioned in the book "1421: The Year China Discovered America" (2002), by Gavin Menzies. Last year the Chronognostic Research Foundation of Tempe, Ariz., tested the area around the structure but was unable to excavate directly under it. The foundation found nothing earlier than 1600 to 1700, but Penhallow feels they did not dig in the correct place.

Penhallow said his interest was piqued by the tower because of its link with navigation, position and religion. He said an interesting possibility is that it was built by Knights Templar, a religious group formed at the time of the Crusades.

"Again, what I'm trying to do is show it's an open question," he said. "We don't know for sure. We need more continued work on it. This group (that built it) was interested in colonizing the New World."

Astronomical Alignments in the Newport Tower lecture

Where: Seaman's Church Institute, 18 Market Square

When: Thursday, Jan. 25; 7 p.m.

Cost: Donation

Info: 782-6248

By Marilyn Bellemore

mbellemore@ntwlive.com