This segment of light suspended in space is actually an entire galaxy, spanning 35,000 light years across and containing billions of stars. We just happen to be looking at it almost perfectly edge-on.
The edgewise shot of NGC 4452, a disk galaxy in the nearby Virgo Cluster, was shot recently by the Hubble Space Telescope. All those dots in the background? Those are galaxies too.
But as amazing as this image is, NGC 4452 isn't especially unqiue; our very own Milky Way is thought to be about this thin, too. Hope you're sucking in your gut. [APOD via Geekosystem]