Explanation:
Gazing out from within
the Milky Way, our own galaxy's true structure is difficult to discern.
But an
ambitious survey effort with the
Spitzer Space Telescope now
offers convincing evidence
that we live in a large galaxy distinguished by two main
spiral arms
(the Scutum-Centaurus and Perseus arms)
emerging from the ends of a large central bar.
In fact, from a vantage point that viewed our galaxy
face-on,
astronomers in distant galaxies
would likely see
the Milky Way
as a two-armed barred spiral
similar to this
artist's illustration.
Previous investigations have identified
a smaller central barred structure and four spiral arms.
Astronomers still
place the Sun about a third of the way in from
the Milky Way's outer edge, in a minor arm called
the Orion Spur.
To locate the Sun and identify the Milky Way's newly mapped features,
just place your cursor over the image.
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