We live in a galaxy1 known as the Milky2 Way -- a vast conglomeration3（聚集，团块） of 300 billion stars, planets whizzing around them, and clouds of gas and dust floating in between. Though it has long been known that the Milky Way and its orbiting companion Andromeda are the dominant4 members of a small group of galaxies5, the Local Group, which is about 3 million light years across, much less was known about our immediate6 neighbourhood in the universe.Now, a new paper by York University Physics Astronomy Professor Marshall McCall, published today in the Monthly Notices of the Royal Astronomical7 Society, maps out bright galaxies within 35-million light years of Earth, offering up an expanded picture of what lies beyond our doorstep.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, says McCall. 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 judgment8 of the Local Group by restricting its range of influence.McCall says twelve of the fourteen giants in the Local Sheet, including the Milky Way and Andromeda, are spiral galaxies which have highly flattened9 disks in which stars are forming. The remaining two are more puffy elliptical galaxies, whose stellar bulks were laid down long ago. Intriguingly10, the two ellipticals sit on opposite sides of the Council. Winds expelled in the earliest phases of their development might have shepherded gas towards the Local Group, thereby11 helping12 to build the disks of the Milky Way and Andromeda.McCall also examined how galaxies in the Council are spinning. He comments: 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 if it were turned the same way as the galaxy rotates. Unexpectedly, the spin directions of Council giants are arranged around a small circle on the sky. This unusual alignment13（队列，成直线） might have been set up by gravitational torques imposed by the Milky Way and Andromeda when the universe was smaller.The boundary defined by the Council has led to insights about the conditions which led to the formation of the Milky Way. Most important, only a very small enhancement in the density14 of matter in the universe appears to have been required to produce the Local Group. To arrive at such an orderly arrangement as the Local Sheet and its Council, it seems that nearby galaxies must have developed within a pre-existing sheet-like foundation comprised primarily of dark matter.Recent surveys of the more distant universe have revealed that galaxies lie in sheets and filaments15 with large regions of empty space called voids in between, says McCall. The geometry（几何学） is like that of a sponge. What the new map reveals is that structure akin16 to that seen on large scales extends down to the smallest.
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1 galaxy n.星系；银河系；一群 参考例句： The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。 The company has a galaxy of talent.该公司拥有一批出色的人才。
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