Scientists Working to Map the Local Group, a 'Neighborhood' of Galaxies Housing the Milky Way and Andromeda
ByAny scientist knows that space has endless an endless reach, but now experts in the field are trying to map out other galaxies within 35 million light years of Earth.
According to a press release, that is the objective of a York University team, who published a study Tuesday in Monthly Notices of the Royal Astronomical Society.
The Earth lies somewhere in the Milky Way Galaxy; an orbit partner with the Andromeda Galaxy in a "neighborhood" known as the Local Group. Spanning three million light years, the Local Group could very well be one of many galaxy neighborhoods in the endless expansion of space.
"All bright galaxies within 20 million light years, including us, are organized in a 'Local Sheet' 34-million light years across and only 1.5-million light years thick," study lead author Marshall McCall, a York physics and astronomy professor, said in the release. "The Milky Way and Andromeda are encircled by twelve large galaxies arranged in a ring about 24-million light years across - this 'Council of Giants' stands in gravitational judgment of the Local Group by restricting its range of influence."
Of the 14 Local Group giants, 12 resemble the Milky Way and Andromeda's spiral galaxy shape, with flattened disks known to encourage star formation. The other two are called "elliptical galaxies" and sit on opposite sides of the Council.
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"Thinking of a galaxy as a screw in a piece of wood, the direction of spin can be described as the direction the screw would move (in or out) if it were turned the same way as the galaxy rotates," McCall said in the release. "Unexpectedly, the spin directions of Council giants are arranged around a small circle on the sky. This unusual alignment might have been set up by gravitational torques imposed by the Milky Way and Andromeda when the universe was smaller."
The study should have implications on how scientists think about the limits of the Local Group and other neighboring galaxies other than the Andromeda. It should also shed light on the formation of the Milky Way.
"Recent surveys of the more distant universe have revealed that galaxies lie in sheets and filaments with large regions of empty space called voids in between," said McCall. "The geometry is like that of a sponge. What the new map reveals is that structure akin to that seen on large scales extends down to the smallest."