Astronomy

The Planet Killer from Star Trek Episode #35
“The Doomsday Machine”

Science fiction gets another chance to get it all wrong.

A study using the Canada-France-Hawaii telescope based in Hawaii confirmed that as the Andromeda galaxy moves through our local cosmic neighborhood, it eats everything in its path—including, eventually, us.

Andromeda grows by pulling galactic companions to it, like spare change down a sewer grate. The astronomers found evidence of this interaction by detecting stars streaming off some dwarf galaxies not fully absorbed by Andromeda. The shape of these streams traces the size and history of the galaxies being pulled in, says MIT astrophysicist Robert Simcoe, and is determined by the mass of the galaxy itself: the larger the galaxy being eaten, the closer the stream will be to its center.

So will Andromeda tear our galaxy apart as it devours us? Not exactly, says Pauline Barmby, one of the study’s authors. read more »

Andromeda Galaxy
Image courtesy of John Lanoue, Wikimedia Commons

The current rage in galactic astronomy is “hierarchical formation” — the buildup of big galaxies by devouring little ones — and the Pan-Andromeda Archaeological Survey (PAndAS) is adding fodder to the flame.

Using the 3.6-meter Canada-France-Hawaii Telescope, PAndAS is digging up table scraps from our nearest spiral galaxy neighbor, Andromeda, in the largest single-galaxy survey of its kind. The observations reveal several previously-unobserved star streams spanning tens to hundreds of light-years, likely leftovers from Andromeda’s previous feedings. Hordes of red giant stars also trace a dim structure 100 times larger than the galactic disk we see with our eyes. Because the astronomers do not detect enough gas in the area to form the stars in situ, the stars must be crumbs captured in previous interactions, claims the team’s Nature paper, lead-authored by Alan McConnachie of the Herzberg Institute for Astrophysics in British Columbia.
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