• This is a big week for the Portland Symphony Orchestra.

At 7:30 p.m. Tuesday, the PSO with Robert Moody at the helm presents a program titled “The Planets.” Moody has long been fascinated with the idea of space and space travel, and has assembled a program of music that includes John Williams’ score from the movie “Close Encounters of the Third Kind,” John Adams’ punchy composition “Short Ride in a Fast Machine” and the British composer Gustav Holst’s epic “The Planets.”

The program has no intermission and runs about 75 minutes. The orchestra will be accompanied by a chorus, which will perform underneath the stage, out of sight of the audience.

At 7:30 p.m. Saturday and 2:30 p.m. Nov. 14, vocalist Steve Lippia will join the PSO for a Pops concert featuring the music of Frank Sinatra. Lippia, who lives in Las Vegas, has made a career reinterpreting the Great American Songbook, and specializes in music made famous by Sinatra.

Both concerts are at Merrill Auditorium. Tickets are available through PortTix; 842-0800 or www.porttix.com

Portland Stage continues its run of John Cariani’s new play “Last Gas.” It’s about the little “what-ifs” that we all experience, and explores the notion of lost opportunities and relationships not pursued. The play is full of humor, but has a serious side.

Directed by Sally Wood, “Last Gas” opened on Friday and continues through Nov. 21 with performances at 7:30 p.m. Wednesday to Friday, 4 and 8 p.m. Saturday, 2 p.m. Sunday and additional performances at 7:30 p.m. Nov. 16 and 2 p.m. Nov. 18. Call 774-0465 for tickets or visit www.portlandstage.org

At Bates College in Lewiston, four musicians from the Chamber Music Society of Lincoln Center with perform at 7:30 p.m. Nov. 14 in the Olin Arts Center Concert Hall, 75 Russell Hall. Tickets cost $10 and $14.

Pianists Gil Kalish and Wu Han will perform Bela Bartok’s Sonata for Two Pianos and Percussion and George Crumb’s “Music for a Summer Evening,” both of which are monumental pieces. They will be joined by percussionists Daniel Druckman and Ayano Kataoka.

Wu Han is one of classical music’s most prestigious pianists, and serves as co-artistic director of the Lincoln Center’s Chamber Music Society.