Opening Friday. Get an up-close look at the aftermath of 50 years of space flight in “Space Junk 3D,” the newest IMAX film at the Denver Museum of Nature and Science. Debuting Friday, “Space Junk” explores a very modern problem: The increasing amount of debris orbiting our planet, largely from old rockets and satellites. The film studies the issue from the ground and in orbit, including the danger of collisions—both manmade and natural. Friday’s premiere event, at 8 p.m., features a post-movie panel with Don Kessler, former head of NASA’s Orbital Debris Program. Regular showtimes through Oct. 4: 10:30 a.m., 1 p.m., 3 p.m., 5 p.m. daily, with additional 7 p.m. shows on Fridays and Saturdays. Denver Museum of Nature and Science, 2001 Colorado Blvd.; 303-370-6000. Tickets for tonight are $15 for adults, $8 for kids; regular showing prices are $10 for adults, $8 for juniors, seniors and students. Museum members receive a discount. dmns.org

Through Sunday. Didn’t get enough Celtic cheer on St. Patrick’s Day? Throw on some green and head to the Colorado Irish Festival. The celebration of all things Emerald Isle takes over Littleton’s Clement Park all weekend, with three stages of live music, Irish dance competitions, a cultural village and kids’ area. Sports fans will want to check out the slate of Gaelic games like hurling and camogie, too. Bonus: Arrive between 5 and 6 p.m. tonight and get in for free. 5-10 p.m. tonight; 10 a.m. to 10 p.m. Saturday; Sunday starts with Mass from 9-10 a.m., festival follows from 10 a.m. to 7 p.m. Clement Park, 7306 W. Bowles Ave., Littleton. Tickets: $10 per person on Friday; $15 per person on Saturday and Sunday, $10 for seniors age 65 and older, military and students. Kids age 12 and younger are free every day. Tickets available at the gate or at TicketsWest outlets at King Soopers stores. coloradoirishfestival.org

Kathleen St. John