The Reader's Ask

How fast can a sail-powered board go?

Who started the calendar? The Lord's Prayer:

Why do some churches say 'debts,' others 'trespasses'?

How quickly will those controversial smog devices be installed on cars?

Why do crops grow in circles on some farms? How do you measure the pulse rate of an earthworm?

Q How are space shuttles insulated against the cold of outer space? As much as people rely on pink fiberglass, I can't imagine that it's up to the task of space exploration. - Jon Rosenthal, Somers, Conn.

A According to NASA, more than 24,000 silica ceramic tiles as well as silica blankets insulate the shuttle against heat and cold. Black, high-temperature tiles are used on the underside and the nose, while white, low-temperature tiles and blankets protect the upper surface. The blankets are made of two outer layers of woven fabric stitched together in a quilt-like pattern. Temperatures in space range from minus 250 degrees F. to plus 350 degrees F., depending on the shuttle's orientation to the sun. When the shuttle reenters the earth's atmosphere, temperatures go well above 2,000 degrees F.

Q Why do some churches use "trespasses" when saying the Lord's Prayer and others say "debts"?

A It all depends on the denomination, and sometimes on the particular pastor and his congregation. A theologian from the United Methodist Church explains that there are three versions of the Lord's Prayer. One uses "trespasses," one uses "debts," and the third uses "sins." Trespasses was incorporated into the prayerbook of the Anglican church, and the version using debts found its way into non-Anglican traditions, which explains why Presbyterians primarily say debts. Trespasses can be traced to the Tyndale Bible around 1525, one of the earliest and best English translations. Tyndale may have chosen the word trespasses because it's found in a passage immediately following the Lord's Prayer in Matthew. Debts appears in the King James Version (1611), and two other translations of the same era. A representative of the Presbyterian Church of America says debts was popularized during the Westminster Assembly in the 1600s. The version using "sinners" is part of an ecumenical text that the Methodist theologian says simply makes it clear that trespasses and debts are sins.

Q I'm interested in the calendar. When was it started? BC? AD? When was Jesus really born? - Lois Jo Deitrick, Las Vegas.

A Our current calendar evolved slowly. The Julian calendar, developed by Julius Caesar (45 BC) and his adopted son, Octavian (Augustus), gave us the order of months and number of days per month. It worked well for a long time, but by 1500 its use of leap years had thrown it off by 13 days. To correct the problem, Pope Gregory, advised by astronomer Christopher Clavius, deleted 10 days from October 1582 and modified the leap year rule. Henceforth, any year ending with 00 must also be evenly divisible by 400 to warrant the extra, 29th day in February. The Gregorian calendar remains in use today. The number of years since Jesus' birth was the work of 6th-century scholar Dionysius Exiguus. While calculating dates for Easter, Dionysius got the idea of starting with Anno Domini 1, or the year of Jesus' birth. But he apparently got it wrong. Jesus' birth now is estimated to have occurred between 7 BC and 3 BC.

Q I've read that the new anti-smog devices to be installed in some 1998 model cars could pose a fire hazard. What's the story?

A The Environmental Protection Agency has given the green light to the new antismog equipment. The coffee-can-sized mechanisms are designed to catch vapors that ordinarily escape from a gasoline tank as new fuel is pumped in. News reports indicate that some safety experts are concerned that the vapor-recovery systems increase the risk of explosion or fire in crashes. These on-board refueling vapor-recovery systems, known as ORVR, do not have to pass the same federal safety standards as other fuel system parts. The EPA has required that the devices be installed in 40 percent of all 1998 models and 100 percent of all cars in 2006. US companies are conforming promptly to the government's demands. All Chrysler-built 1998 models will have them, as will most Ford and General Motors cars and trucks. Vehicles made for sale in the United States by foreign manufacturers must also meet the standards.

Q Recently, when flying from New York to Dallas, I noticed interesting patterns on the farmland below. The area appeared to be almost geometric in its exact arrangement of circles, circles-within-circles, squares, etc. What crops are planted in this area, and what purposes are served by this neat arrangement of the land? - Betty Salem, Laguna Hills, Calif.

A Usually the squares or rectangles are either property lines or simply how farmers divided up their land. It's easier to drive a tractor in a straight line. The circles are probably the result of center-pivot irrigation. When driving through farmland, you often see sprinklers with long arms and many wheels extending out from a central point. The arms are sometimes up to a quarter-mile long, and are attached to a central well or water source in the middle of a field. Thus, the crop grows in a circle shape. The different colors are crops in different stages of development.

Q What is the fastest speed ever achieved by a windsurfer?

A The Guinness Book of Records reports that the "Yellow Pages Endeavour," a trifoiler, reached 46.25 knots (53.19 miles per hour) over a 500-meter timed run on Oct. 26, 1993, near Melbourne, Australia. This is the fastest speed ever recorded on water under sail. The craft's designers say the Endeavour could theoretically reach 54 knots (62 m.p.h.) without compromising the crew's safety. The women's record, achieved on a simpler boardsailer, is 40.38 knots (46.44 m.p.h.) by Babethe Coquelle of France in 1995.

Q I am a ninth-grade biology student and would like to do my science project on how temperature affects the pulse rate of an earthworm. What is the best way to take an earthworm's pulse? - Sean McLoughlin, via e-mail.

A An earthworm has five "hearts." Biologists recommend viewing the earthworm under a dissecting microscope. Don't try to "feel" the pulse. You'll be able to see the hearts beating and do a direct count. Biologists point out, however, that to view the hearts, you'll need to apply a fairly strong light to see inside the translucent body of the worm. And the light itself could raise the worm's body temperature. Being cold-blooded, the worm's metabolic rate, and thus its heartbeat, will rise as its temperature goes up. If possible, use a water flask heat shield, or consider using red or orange light. Another tip: It's easier working with small worms, since they are more transparent.

Q What is the earliest-known artistic depiction of Christ Jesus?

A Christian art expert Gertrude Gracesill says that because early Christians opposed pictorial representations of Jesus, he was portrayed mainly by symbols such as the lamb, the fish, the cross, and other sacred monograms until the 3rd century. "The earliest [AD 313] figural representation of Christ shows him as a young shepherd, a classical beardless hero," she says. Scholars believe the earliest preserved portrait of Jesus is a wall painting done in the 4th century in the catacomb of Commodilla, Rome. Later representations of Jesus, similar to those of Oriental pagan philosophers, depict him as a bearded teacher. Other early drawings of Jesus were offensive to Christians. For example, a 3rd-century depiction of his crucifixion shows an unknown person standing in prayer in front of the cross with Jesus shown having the head of a donkey.

The Reader Responds

Dear Editor:

I refer to "The Readers Ask" (Aug. 27, 1997) section on Prince Charles. The article mentioned him in connection with the HMS Bronington, but the ship is not the aircraft carrier from which he flew. In fact, Bronington is the mine hunter that Prince Charles was the captain of in 1976, his only naval command. The ship was retired from the Royal Navy in 1988. Bronington, launched in 1953, is a wooden-hulled ship, 150 feet long with a 28-foot beam. The ship became a museum in 1992 and is open to the public on weekend afternoons during the summer at Trafford Wharf. Visitors are guided by a taped commentary, parts of which were recorded by Charles.

- G.A. Errock, Cheshire, England

Let Us Hear From You

Readers are invited to submit questions to: The Readers Ask, TCSM, One Norway Street, Boston, MA 02115. Or e-mail queries to: Research for this page was provided by Kristina Lanier and John Christian Hoyle, Monitor staff interns. Question

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