Health/Science calendar

The Achilles' heels of cancer Dr. William Hahn of the Dana-Farber Cancer Institute will talk about the genetic weaknesses of cancer cells and how researchers are applying genomic tools to improve cancer diagnosis and treatment. At 6 p.m., in the Broad Institute auditorium, 7 Cambridge Center. Go to broad.mit.edu/outreach/midsummer.

Science on TV The next edition of NOVA scienceNow looks at leeches, the search for extraterrestrial intelligence, stem cells, and marine bioluminescence. At 9 p.m., on Channel 2. Go to pbs.org/wgbh/nova/sciencenow.

Ocean wild Photojournalist and underwater wildlife photographer Brian Skerry will share his photographs and stories of his journeys as a photographer for National Geographic magazine. At 7 p.m., at the Mass Audubon Visual Arts Center, 963 Washington St. Cost: $15 at the door. Call 781-821-8853, ext. 102, or go to www.massaudubon.org/visualarts.

Butterfly wings and snail shells Biologist Nipam H. Patel of the University of California at Berkeley will look at new research into wing patterning in butterflies and shell shape in snails as examples of the stunning diversity of life on earth. At 8 p.m., in the Lillie Auditorium, 7 MBL St., Woods Hole. Go to mbl.edu.

Star party The Harvard-Smithsonian Center for Astrophysics will bring out its big telescopes to tour the star clusters of the Milky Way and its neighbors, at 8:30 p.m., at Hopkinton State Park, 268 Cedar St. (Route 85). Weather permitting. Call 617-495-7461.

Events may be sent to healthscience@globe.com.