The Front Cover (97k JPEG)
A GLIMPSE OF OUR FUTURE
John Dubinski of the University of Toronto and Lars Hernquist of the Harvard-Smithsonian Center for Astrophysics simulated an encounter between the Milky Way and the Andromeda galaxy on NPACI’s Blue Horizon. This image shows the galaxies about 4 billion years in the future. The results of the encounter are catastrophic—the two galaxies eventually merge, but spray billions of stars into the lonely depths of interstellar space in the process. Each model galaxy contains 10 million particles of normal matter (stars and gas) and is surrounded by a halo of 2 million particles of dark matter, for a total of 24 million interacting mass points. The image shows the stellar masses as particles of constant brightness; if star formation caused by hydrodynamic shocks in interstellar gas were depicted, the galactic cores and spiral arms would be brighter. For more information, see It's the End of the Galaxy as We Know It.