A recent survey of stars conducted with the Spitzer Space Telescope is convincing astronomers that our Milky Way Galaxy is not just your ordinary spiral galaxy anymore. Looking out from within the Galaxy's disk, the true structure of the Milky Way is difficult to discern. However, the penetrating infrared census of about 30 million stars indicates that the Galaxy is distinguished by a very large central bar some 27,000 light-years long. In fact, from a vantage point that viewed our galaxy face-on, astronomers in distant galaxies would likely see a striking barred spiral galaxy suggested in this artist's illustration. While previous investigations have identified a small central barred structure, the new results indicate that the Milky Way's large bar would make about a 45 degree angle with a line joining the Sun and the Galaxy's center. DON'T PANIC ... astronomers still place the Sun beyond the central bar region, about a third of the way in from the Milky Way's outer edge.
This artist's rendering shows a view of our own Milky Way Galaxy and its central bar as it might appear if viewed from above. An arrow indicates the location of our Sun. Astronomers have concluded for many years that our galaxy harbors a stellar bar, though its presence has been inferred indirectly. Our vantage point within the disk of the galaxy makes it difficult to accurately determine the size and shape of this bar and surrounding spiral arms.
New observations by the GLIMPSE legacy team with NASA's Spitzer Space Telescope indicate that the bar-shaped collection of old stars at the center of our galaxy may be longer, and at a different orientation, than previously believed. The newly-deduced size and angle of the bar are shown relative to our Sun's location. Our Milky Way galaxy may appear to be very different from an ordinary spiral galaxy.
Also available showing with our Sun's position: