It takes sunlight 8.33 minutes to travel the 93 million miles between the sun and the earth.

That was one of the facts Ron Thompson shared with students and adults Monday at the second lecture in an ongoing series on astronomy hosted by Cape Elizabeth High School teacher Kerry Kertes. The series is open to the public. Thompson’s lecture focused on the sun, using his own photography to illustrate solar phonemena.

“It was quite informative,” said Dave Mulqueeney, 45, of Scarborough, who also attended last month’s presentation on finding new planets by Paul Howell. He said he particularly enjoyed Thompson’s slides on heightened solar activity, such as solar flares, and its effect on Earth and the aurora borealis.

Several other members of the public joined Kertes’ astronomy class for the lecture. John Honess, 51, of Cape, said he enjoyed the presentation. “It is always good to re-familiarize yourself with information learned in college,” he said.

Thompson, a founding member of the Southern Maine Astronomers created in the summer of 2005, used slides in coordination with his presentation that unveiled the secrets of the sun with pictures taken through filters on a telescope. The 9:30 a.m. presentation that was scheduled to take place at the town hall was held instead in Kertes’ classroom because of an absent technology assistance technician.

“Never look directly at the Sun,” said Thompson at the start of his lecture. He said it is important to stress safety when dealing with the sun because once damage is done to the eyes, there is little help available to reverse it.

With marvelous photos and facts, Thompson weaved a tale about the closest star to Earth. The stupendous scale when dealing with cosmic beings is always difficult for people to wrap their heads around, and Thompson attempted to bring the size back to Earth.

“It would take 330,000 Earths to equal the weight of one sun,” he said. It would take 1 million Earths to fill the volume of the sun. The sun is 93 million miles away and it takes sunlight 8.33 minutes to reach Earth, he said.

The facts, while comparable to Earth, are still large when people usually measure distance with inches, feet and miles.

The sun, a small star, is about halfway through its lifespan of 10 billion years, making it 5 billion years old, said Thompson, and the surface of the sun is 6,000 degrees Kelvin. Atomic particles from the core of the sun take about 170,000 years to travel the 700,000 kilometers to the surface.

Thompson, a Portland native who lives in Falmouth with his wife, Carole, said astronomy has interested him since watching the Sputnik take off in 1957, when he was a freshman in high school. He bought a telescope and a National Geographic subscription for his daughter, Dawn, when she was 9, which rekindled his passion for space. That was more than 25 years ago.

In 1959 Thompson received his license for a ham radio and has worked with telecommunications throughout his life. He said the sun’s interference with communications through cosmic particles peaked his curiosity into the dynamics of Earth’s closest star. He is one of the only members of the Southern Maine Astronomers with a hydrogen alpha telescope, which is designed for observing the Sun, and that is why he was chosen to give a presentation on the star.

While delivering his lecture, Thompson stressed several times as he showed pictures of the Sun that it is only through recent inventions that amateur astronomers have been able to take pictures of the star.

“It looks like an orange, doesn’t it,” said Thompson of one of the photos.

Thompson explained how the sun could disrupt Earth’s electronic communications. Coronal ejaculations – sun bursts – drive atomic particles toward the Earth. While most atomic particles are deflected by the magnetosphere – a giant, magnetic orb protecting Earth – some pass through, disrupting atmospheric transmissions, such as radio and television waves.

The magnetosphere is what points a compass north or south. It comes down toward the Earth at the North Pole. There, solar particles pulled toward Earth react with the atmosphere and are visible as the phenomenon known as the northern lights.

Thompson said a special space satellite that orbits in a small circle between the sun and Earth, called the Solar Heliospheric Observatory, monitors the sun and warns Earth when a burst of atomic particles is headed toward the planet. This allows for satellites to be turned away from the sun for protection.

Thompson did three lectures Monday. He said he enjoyed giving the presentations and received a lot of positive feedback. Thompson said the data surrounding the sun is often mind-boggling and still keeps him in awe.

Next month Kirk Rodgers will be giving a presentation on the mythology behind the constellations. A date has not yet been set but will be posted on Kertes’ Web site: http://capedistrict.learningnetworks.com/Pages/HS_Teachers/Website_KeKe/index

A picture of the Sun taken by amateur astronomer Ron Thompson.A looping prominence on the Sun superimposed with an Earth to scale for size comparison. Sun secrets unveiled at Cape High