Still an astrophysical mystery, the evolution of the bulges in <a href="https://en.wikipedia.org/wiki/spiral_galaxies" class="extiw" title="en:spiral galaxies">spiral galaxies</a> led astronomers to the edge-on galaxy <a href="https://en.wikipedia.org/wiki/NGC_4710" class="extiw" title="en:NGC 4710">NGC 4710</a>. When staring directly at the centre of the galaxy, one can detect a faint, ethereal <i>X</i>-shaped structure. Such a feature, which astronomers call a <i>boxy</i> or <i>peanut-shaped</i> bulge, is due to the vertical motions of the stars in the galaxy's bar and is only evident when the galaxy is seen edge-on. This curiously shaped puff is often observed in spiral galaxies with small bulges and open arms, but is less common in spirals with arms tightly wrapped around a more prominent bulge, such as NGC 4710.
NASA, ESA, and P. Goudfrooij (STScI)
<ul><li><a rel="nofollow" class="external free" href="http://www.spacetelescope.org/images/heic0914a/">http://www.spacetelescope.org/images/heic0914a/</a></li>
<li><a rel="nofollow" class="external free" href="http://hubblesite.org/newscenter/archive/releases/2009/30/image/a/">http://hubblesite.org/newscenter/archive/releases/2009/30/image/a/</a> (<a rel="nofollow" class="external text" href="http://imgsrc.hubblesite.org/hu/db/images/hs-2009-30-a-full_jpg.jpg">direct link</a>)</li></ul>