Astronomical illiteracy. Science educators are saying, `Let's get Sirius.'

WHY is the earth hotter in the summertime? Everyone knows that - right? Isn't it because then the elliptical orbit of Earth takes us closer to the sun? Yeah - closer to the sun. That's the ticket! If that's your answer - you're wrong. But talk to Phil Sadler and you won't feel so bad.

Mr. Sadler is working on a project at the Harvard Center for Astrophysics which is designed to breathe new life into the teaching of astronomy in public schools. Most students, most people, today don't know even the basics about astronomy - planetary motion, celestial configurations, distances, magnitudes, he says. Most are heavenly illiterates.

Sadler dramatically proved his point last year when he took a camera crew into the closely cropped Harvard Yard during June commencement - right up to the beaming students in caps and gowns, newly ushered into the ranks of the certainly educated. He asked them why the earth is hotter in summer. Only 1 in 20 got it right. (It's not, as most students thought, the distance of the earth from the sun; it's hotter because the tilt of the earth allows more direct light and longer days.)

The graduates also flunked the other basic question Sadler asked: What causes the phases of the moon? (It's not a shadow from the earth; rather, the lighted side of the moon turns away.)

``Kids hear about astronomy in elementary school, junior high, and high school,'' says Sadler, a former Apple Computer/Silicon Valley whiz kid. ``But they still don't get it. We've got a lot of science teaching going on, but not a lot of science learning.''

One problem is a decades-long deemphasis on astronomy as a serious subject. Only 10 percent of US high schools offer astronomy as a course - for about 50,000 students, compared with 500,000 who take physics. No high school astronomy textbook exists. And 60 percent of astronomy teachers have no training in the subject.

Project STAR, funded through the National Science Foundation, represents a major effort to change that. (STAR stands for ``science teaching through its astronomical roots.'') It's one of several new grass-roots efforts around the country to improve students' knowledge of the heavens. Already field-tested in 30 schools, when complete in 1991 STAR will be a year-long, full-blown astronomy course focusing on three areas: the nature of light (how light helps determine distance, size, and temperature); the laws of nature (physics); and space and time (seasons, motion, scale, distance). Only the space and time segment is complete.

STAR's main feature is its hands-on approach. Students do a lot of individual work: For three months they keep a picture journal of the position and time of the sunset. They plot the course of the moon for 10 evenings in a row. Using clear molded plastic and a tiny globe (cost: 10 cents) they build an Earth-centered celestial sphere and chart the motions of the sun. Paper towel tubes and a simple plastic lens (cost: 5 cents) are used to build a telescope.

``For the first time in their lives, a lot of my kids went out and actually watched the moon,'' says Hal Coyle of Framingham (Mass.) North High school, who is helping to develop and test STAR. ``It's hard to believe, but a lot of them hadn't done that.''

``The important thing is for students to predict the outcome of experiments,'' Sadler says. ``That way, if the experiment comes out differently, they have to change their ideas - explain why. To just tell them how experiments come out doesn't do the job.''

``I'm addressing things I've never addressed before,'' says teacher Mark Petricone of Billerica (Mass.) High, a STAR field-tester. ``I'm making the kids think about the way things work. It's not a bunch of facts that make them feel like hotshots - like how many moons Saturn has or how far it is to the sun. It's the underlying stuff.''

STAR is aimed as much at teaching the principles of science - method, observation, analyzing fallacies - as teaching astronomy. Universal principles used in other fields of science, such as the inverse square law for the propagation of light, are repeated throughout the course.

``About 41 percent of our high-schoolers don't take any science at all,'' says Sadler's colleague Darrel Hoff, referring to last month's national assessment of science learning by the Educational Testing Service (ETS) in Princeton, N.J. ``That's our target audience.''

The ETS ``Science Report Card'' concludes that ``the content and structure of our school science curricula are generally incongruent with the ideals of the scientific enterprise,'' and it recommends more laboratories, open-ended questions, and better-prepared teachers.

STAR's combination of teacher training, experiment-laden workbooks, films, class activities, and computer software fits the need, Sadler thinks: ``We could reach every high school in the US.''

Kenneth Brecher, an astrophysicist at Boston University, agrees that STAR will make inroads. ``It's neat - and cheap. That's important,'' he says. ``In the real world of schools, there ain't any money.'' Dr. Brecher thinks STAR software designed for the Apple Macintosh desktop computer - which shows full-color 3-D simulations of the moon's orbit, the phases of Venus, colliding galaxies - is a real breakthrough. ``That would've required a mainframe 15 years ago.''

Until the 20th century, astronomy was taught regularly as one of the seven classical liberal arts.

The progressive schooling ideas of the '20s, however, stressed social adjustment and personal skills. Astronomy, seeming old-fashioned and impractical in that context, slipped further in the public schools.

``For over 50 years the average educated US citizen was largely illiterate in astronomy,'' says astronomy historian Jeanne Bishop.

Andrew Fraknoi of the Astronomical Society of the Pacific, in San Francisco, which sponsors an annual astronomy workshop for 200 teachers, says astronomical literacy introduces students to a world beyond their own peer culture. ``It's the geography of the universe,'' he says, adding that the concept of ``scale'' is a good starting point:

If the distance between Earth and the sun is the distance across a typical living room, how far is it between Earth and the next closest star? Dr. Fraknoi asks local students. Students usually say it would be from their living rooms to somewhere across town, or down the block. The actual distance is from San Francisco to Chicago.

``That really blows their minds.''