Researchers have long been interested in the ability to trap and cool molecules to facilitate improvements in ultracold molecular physics and in molecular spectroscopy. Scientists use methods such as laser cooling and cryogenic surface thermalization, but these techniques are not applicable to molecules because of their complex internal energy level structure. Now a group of Harvard University researchers in Cambridge, Mass., has demonstrated a loading technique based on elastic collisions with a cold buffer gas. The team has successfully trapped atomic chromium and europium and demonstrated the technique to magnetically trap a molecular species -- calcium monohydride. Researchers say that because the technique relies on elastic collisions with buffer gas and on the magnetic state of the species, it should be applicable to many atoms and molecules. This method of trapping and cooling atoms could lead to the production of large numbers of ultracold molecules. Immediate applications include high-resolution spectroscopy and studies of cold collisions.