(left to right): REIDAR HAHN/FERMILAB; R. JAY GABANY/COSMOTOGRAPHY; Kay Nietfeld/picture-alliance/dpa/AP Images

Top stories: ‘the God particle’ father, rivers of stars, and Nobel winners

Leon Lederman, father of ‘the God particle,’ dies

Leon Lederman, the Nobel Prize–winning physicist and passionate advocate for science education who coined the term “the God particle,” died this week at age 96. Lederman also headed the team that discovered a particle called the bottom quark and led the Fermi National Accelerator Laboratory in Batavia, Illinois, one of the world’s eminent high-energy particle physics laboratories, for more than a decade.

Streams of stars reveal the galaxy’s violent history—and perhaps its unseen dark matter

Stellar streams, the filamentous remains of galaxies and star clusters that long ago fell into the gravitational grasp of the Milky Way, are ushering in a new era of “galactic archaeology,” letting scientists rewind the cosmic clock to reconstruct the assembly of the Milky Way. The streams, 60 of which have been discovered so far, are also being used as exquisitely sensitive scales to measure the galaxy’s mass and to reveal the presence of dark matter.

Cancer immunotherapy pioneers win medicine Nobel

James Allison of the University of Texas MD Anderson Cancer Center in Houston and Tasuku Honjo of Kyoto University in Japan have won the Nobel Prize in Physiology or Medicine. Both discovered ways to remove the immune system’s “brakes” that prevent it from attacking cancerous cells. These discoveries led to immunotherapies that have revolutionized the treatment of certain types of cancer, causing previously untreatable tumors in some patients to shrink to almost nothing.

Newly discovered ‘goblin’ world hints at the presence of Planet Nine

Far beyond Pluto, astronomers have found a new dwarf planet that follows the most distant orbit yet confirmed, reaching some 2300 times farther from the sun than Earth’s. Nicknamed “The Goblin” thanks to its discovery around Halloween 2015, the dwarf planet joins a small group of extreme solar system objects whose orbits hint at tugs from a hypothesized, but not yet observed, Planet Nine, hidden in the fringes of the solar system.

Bacterial injections into tumors show early promise for treating cancer

Certain live bacteria seem able to stall tumor growth when injected into cancerous lumps, researchers reported this week. The injections appear to activate an immune response that also targets the tumor. Despite lingering questions about the approach’s safety, such injections have generated enough interest to be included in a new clinical trial combining bacteria with an established immune therapy known as a checkpoint inhibitor.