String theory is a theory in physics that views subatomic particles as string-like objects floating in space-time rather than as point-like objects. — American Heritage Student Science Dictionary

In relationships, people spend a lot of time wondering what would have happened if they’d chosen their words more carefully, if their inflection had been different or if they’d followed a different thread of the conversation. Would the situation have changed? Would the ending still have been the same?

British playwright Nick Payne applies string theory to an evolving relationship between two lovers in his awarding winning one-act “Constellations,” which is being performed this week by the School of the Performing Arts at the University of Maine. As the characters replay their encounters throughout the course of the relationship, one new word, one change of inflection, changes the outcome. Just when the scenes begin to get repetitive, Payne tosses in a new twist that grabs the audience’s attention again.

Director Marcia Joy Douglas’ decision to present “Constellations” in the Emera Astronomy Center planetarium, which opened in October 2014, allows theatergoers to collide with time, space and the characters.

The intimate space immerses the audience in the world, and, often the psyches of quantum physicist Marianne and beekeeper Roland to explore the varied ways their love might evolve. The stars, clouds, equations, bees and other things projected onto the round ceiling of the planetarium keep the science and the universe close.

The scenes between Amelia Raphaela Courtney and John Dalton Logan don’t crackle with sexual energy. The duo almost overcome that by their ease and comfort with each other. Their sincerity in the roles give Marianne and Roland a shared purpose — the exploration of their relationship in the greater scheme of this universe and all the other ones.

Logan gives a slightly more nuanced performance than Courtney does, but both are believable. He milks Payne’s dialogue for all its “guyness.” Logan is the shy recluse in one scene, the suave confident suitor in another and the cunning charmer in the next.

Courtney does not reinvent Marianne as often or as successfully. She seems always to be the sometimes shy scientist and never the sly seductress. But her choices complement Logan’s even though her performance is not as skilled as his.

Douglas’ choice to stage “Constellations” in the M. F. Jordan Planetarium was bold and courageous. It challenges her actors, her technical team and the center’s staff. All have embraced her vision and executed it almost perfectly.

This production of “Constellations” is a theatrical experience not soon forgotten.

“Constellations” will be performed at 7:30 p.m. Thursday, 8:30 p.m. Friday, 2 and 9 p.m. Saturday, and 4 p.m. Sunday at the Emera Astronomy Center at UMaine. Tickets are $6 or free with a student identification card. For information, call 581-1341 or visit astro.umaine.edu.