If Richard Conn Henry has his way, and he concedes he almost certainly won’t, the coming year will be the last with 365 days.

The Johns Hopkins University physicist and astronomer has devised a better calendar, he believes, than the one that has sufficed for more than four centuries.

The alternative might sound drastic, if not far-fetched: Some months would lose a day. Others would gain one. Leap years would be abolished in favor of a weeklong “mini-month” tucked between June and July every five or six years.

And most years would end after 364 days.

But the result, Henry said, would be a stable calendar that would make for more convenient planning.

Under his scheme, if you were born on a Tuesday, your birthday would always fall on a Tuesday. Christmas would always be on a Sunday, the Fourth of July on a Wednesday. Election Day wouldn’t be determined by calculating “the first Tuesday after the first Monday” in November. It would always be Nov. 8.

Henry, who is director of the Maryland Space Grant Consortium when he’s not trying to manipulate time, has joined a long line of would-be calendar reformers who date back to Julius Caesar and beyond.

Among their efforts: the Thirteen Moon Calendar, the Ecliptic Calendar, the Long-Sabbath Perennial Calendar and the 60-Week Calendar.

Unlike many of his predecessors, however, Henry initially was motivated by his own convenience a few years ago when he realized that each season, he taught the same courses at Hopkins. He used the same textbooks. He assigned the same homework. Yet he always had to change his syllabus to reflect the new year’s dates.

At first, he thought, that’s just the way it has to be. Then, he said, “I made a dreadful mistake: I looked into it.”

Under Henry’s proposal, developed using a complex computer program he devised, 30 days hath January, February, April, May, July, August, October and November. All the rest have 31.

“I am heartbroken over Halloween, because I love Halloween,” he said, referring to the fact that Oct. 31 no longer would exist.

The Gregorian calendar used in the United States and much of the Western world was instituted in 1582 by Pope Gregory XIII. He modified a calendar Julius Caesar had adopted in 46 B.C. to bring it into sync with the seasons. Ten days were dropped that year — Oct. 15 directly followed Oct. 4 — and the rule for determining leap years was altered.

Leap years are necessary every four years for one maddening reason: An Earth year has an uneven number of days.

Henry’s calendar would eliminate leap years altogether and institute a seven-day period he has dubbed “Newton Week,” in honor of Sir Isaac Newton. Newton Weeks would occur irregularly: in 2009, 2015, 2020, 2026, for starters.

“I would like everybody to have a paid vacation on Newton Week,” Henry said. “It comes so rarely — every five or six years — let everybody have a week and have a good time.”