The Milky Way meets a sausage

Eight to ten billion years ago, thus, in its youth, our Milky Way apparently had a fateful encounter: it crossed paths with another, significantly smaller galaxy. The researchers who discovered this gave the smaller galaxy the name “Sausage Galaxy,” but this is perhaps a little unfair, because in reality it had a similar elliptical shape as the Milky Way.
The name “Sausage” came from the way the collision was proven. To do this, astronomers examined the distribution of velocities of the stars in the Milky Way. This showed that a sausage-shaped group of stars with similar patterns of motion is moving through our Milky Way – and these stars are the remnants of the former dwarf galaxy.

It wasn’t especially small, however. It had a mass of approximately ten billion Suns (Miky Way: 900 billion) and was even big enough to drag along a pair of open star clusters. The collision must have torn quite a hole in the disk of the Milky Way, and probably led to the formation of its central bulge.

Artist’s rendering of the two galaxies before the collision (picture: V. Belokurov (Cambridge, UK); Based on image by ESO/Juan Carlos Muñoz)

 

If you look at the distribution of star motions in the Milky Way, you can see the sausage shape of the stars that originated from the other galaxy (picture: V. Belokurov (Cambridge, UK) und Gaia/ESA)

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BrandonQMorris
  • BrandonQMorris
  • Brandon Q. Morris es físico y especialista en el espacio. Lleva mucho tiempo preocupado por las cuestiones espaciales, tanto a nivel profesional como privado, y aunque quería ser astronauta, tuvo que quedarse en la Tierra por diversas razones. Le fascina especialmente el "qué pasaría si" y a través de sus libros pretende compartir historias convincentes de ciencia ficción dura que podrían suceder realmente, y que algún día podrían suceder. Morris es autor de varias novelas de ciencia ficción de gran éxito de ventas, como la serie Enceladus.

    Brandon es un orgulloso miembro de la Science Fiction and Fantasy Writers of America y de la Mars Society.