Galileo, Venus and the church


Earth-shaking scientific discoveries do not grow on trees. Changing the world takes dedicated effort and the leisure time to pursue the often tedious and always arduous tasks of observation and experimentation.

In the meantime, our best and brightest have to eat and support both their families and their research efforts. These days, scientists are often employed by universities, but they can ill afford to support pure research. Everyone involved is in an unending quest for support from private and public sources.

In that regard, things haven’t changed much in the past 400 years. Only the sources of outside funding have changed. Such was the case when Galileo was the first person to point his “optik tube” at the sky in a systematic, scientific way.

In doing so, he changed the universe for every human who has lived since. He also had to depend on rich patrons and the approbation of the Catholic Church. Unfortunately, his discoveries came into conflict with basic church dogma. Galileo was faced with an unenviable dilemma: Wait to announce his discoveries or yield to the personal urgency of announcing them to the world.

In the coming months, you’ll be able to experience with binoculars or a small telescope one of Galileo’s groundbreaking work. His discovery of the phases of Venus provided the first real evidence for the radical notion, first suggested by Nicholas Copernicus, that the sun and not Earth was at the center of things. If your boss told you to keep silent about your discoveries, what would you do?

Look west during deep evening twilight. Venus is the brightest object in the nighttime sky besides the moon. Its blazingly white brilliance makes it easy to see why our ancient forebears believed that the planet was the goddess of love and beauty.

The heavens may have been the abode of the gods, but humans and the ground we walk on were the center of the physical universe. Everything else – sun, moon, planets, and even stars – revolved around Earth.

As Galileo observed Venus night after night, an evidentiary crack began to appear in the Earth-centered philosophy that had dominated astronomy for thousands of years.

Try it for yourself. Right now, a small telescope or binoculars show the planet shrinking from its “half Venus” phase. Venus has moon-like phases because it travels more rapidly around the sun than we do. The sun’s light thus hits it from a constantly changing angle. Such gyrations are difficult ­– although not impossible – to explain if sun and Venus travel around Earth.

Observe Venus at about the same time every evening as often as our cloudy central-Ohio sky permits. Venus slowly shrinks to a thinner crescent. Simultaneously, the planet moves closer to Earth, and its crescent eventually becomes visible in binoculars.

By early August, Venus is a scant 30 million miles away. The planet may be only an Earth-sized 8,000 miles wide, but because of its relative proximity, the sharpest-eyed stargazers will see its razor-thin crescent with their unaided eyes alone.

On one level, Galileo’s observations are a well-meaning failure. The phases of Venus provide no definitive, mathematical proof of the sun-centered model.

However, Galileo knew he was on to something important. He announced this and other discoveries too quickly to satisfy the Catholic Church. He was forced to recant his claim that Earth orbits the sun under threat of excommunication.

His “punishment” was house arrest under the supervision and with the financial support of the church. There he performed his groundbreaking experiments that led to Isaac Newton’s laws of gravity. Galileo had indeed changed the world in a way he never could have foreseen. It took both the animus and the patronage of the Catholic Church to make it happen.

Up and Coming at Perkins Observatory

• “Astronomy and Galileo” — Galileo played the patronage game as well as anyone until his observations came into conflict with religious dogma. On Thursday, July 2, Ohio Wesleyan dean and professor Barbara Andereck will give some insight into the process. Her talk “Astronomy, Rhetoric and Philanthropy: Connections between Delaware, Ohio, and Florence, Italy,” will begin at 8 p.m. at Perkins Observatory. We’ll do a bit of stargazing afterward, including a look at the crescent Venus if the sky is clear. Please call 740-363-1257 for more information and to reserve tickets.

• “Celebration of the Sun” — During July, the lack of early-evening darkness makes evening programs difficult. At Perkins Observatory, we embrace the daylight by observing, discussing and celebrating the sun with a series of three Saturday afternoon programs. They run from 4 to 6 p.m. on July 11, 18 and 25. Please call 740-363-1257 for more information and to reserve tickets.