Trajectory of Smith Cloud

This diagram shows the 100-million-year-long trajectory of the Smith Cloud as it arcs out of the plane of our Milky Way galaxy and then returns like a boomerang. Hubble Space Telescope measurements show that the cloud, because of its chemical composition, came out of a region near the edge of the galaxy's disk of stars 70 million years ago. The cloud is now stretched into the shape of a comet by gravity and gas pressure. Following a ballistic path, the cloud will fall back into the disk and trigger new star formation 30 million years from now.

About the data

The HST data were taken from proposal 13840 : A. Fox and K. Sembach (STScI), F. Lockman (NRAO/Green Bank), B. Menard (Johns Hopkins University), N. Lehner (University of Notre Dame), A. Hill (Haverford College), K. Barger (Texas Christian University), F. Heitsch and D.V. Stark (University of North Carolina, Chapel Hill), M. Rahman (Johns Hopkins University), and R. Benjamin (University of Wisconsin, Whitewater).

The science team for these findings includes: A. Fox (STScI), N. Lehner (University of Notre Dame), F. Lockman (NRAO/Green Bank), B. Wakker (University of Wisconsin, Madison), A. Hill (Haverford College), F. Heitsch (University of North Carolina, Chapel Hill), D.V. Stark (University of North Carolina, Chapel Hill/Kavli Institute, Kashiwa, Japan), K. Barger (Texas Christian University), K. Sembach (STScI), and M. Rahman (Johns Hopkins University).