…would have to be this one, which was buried on page A9 of Tuesday’s New York Times:
A previously unrecognized galaxy appears to be merging with the Milky Way, bringing hundreds of thousands of stars into our home galaxy that no one has noticed until now, astronomers said Monday. A survey of the northern sky has detected a huge and diffuse structure within the confines of the Milky Way that does not seem to fit in with other parts of the galaxy that contains our solar system.
Robert H. Lupton of Princeton University told a meeting of the American Astronomical Society that the large, faint collection of stars rises almost perpendicular to the flat, spiral disk of the Milky Way. The most likely interpretation of the structure, the astronomer said, is that it is a dwarf galaxy that has been merging with our galaxy….
The latest study, which has been submitted to The Astrophysical Journal for publication, shows that the Milky Way is still changing and evolving, said Mario Juric, a Princeton graduate student who is the principal author of the report. “It looks as though the Milky Way is still growing, by cannibalizing smaller galaxies that fall into it,” Mr. Juric said in a statement.
New galaxies falling into ours? To me, that’s news. Then, buried underneath that mind-bending revelation came this one:
Reporting at the same meeting, another group of researchers said they had an explanation for a mysterious warp in the disk of the Milky Way that has baffled scientists for decades.
Leo Blitz, professor of astronomy at the University of California, and his colleagues Evan Levine and Carl Heiles charted the warp and found evidence that it is a ripple or vibration set up by two small galaxies that circle the Milky Way. These satellite galaxies, called the Magellanic Clouds, cause vibrations at certain frequencies as they pass though the edges of the Milky Way, the researchers said.
It was previously believed, Dr. Blitz said, that the Magellanic Clouds, with their combined mass being only 2 percent that of the Milky Way, were too small to influence their neighboring galaxy. However, he said, when the Milky Way’s dark matter is taken into account, the motion of the small galaxies can create a wake that influences the larger one.
Dark matter, invisible material that accounts for most of the universe’s mass, is 20 times more massive in the Milky Way than all visible material, including stars. According to a computer model created with Martin Weinberg, an astronomy theorist at the University of Massachusetts, Amherst, dark matter spreading from the Milky Way disk with the gas layer can enhance the gravitational influence of the Magellanic Clouds as they pass through it.
A wake?? Better get out the seasick pills. With apologies to Mark Twain: Everybody talks about dark matter, but nobody ever does anything about it.