Here is your weekly reminder of Psalm 19–the Helix Nebula, also known as the Eye of God.

The Helix Nebula. Credit: NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner (STScI), and T.A. Rector (NRAO)

This is my favorite nebula. It’s a planetary nebula (PN), so-called because astronomers hundreds of years ago, looking through their not-so-good telescopes, thought these might have been planets. They were wrong, but the name stuck. A PN is actually the cast-off outer layers of a dying low-mass star like our Sun. (High-mass stars die in spectacular light-shows called supernovae.) In the very center of the Helix Nebula you can see the glowing core of the dead star in the process of becoming what’s called a white dwarf.

The Helix Nebula is one of the closest PNs to Earth, and if it were bright enough for you to see it with the naked eye, it would span a distance across the sky almost as big as a full Moon. It looks like a bubble from our vantage point, but that’s a bit of an illusion–we’re really looking at two disks oriented nearly perpendicular to each other.

Astronomers discovered mysterious “cometary knots” appearing to radiate from the center of the nebula in a spoke pattern, and later found these same knots in other PNs. To give you some perspective on the size of the Helix, each knot, excluding the tail, is about the size of our solar system.

“Close-Up of the Helix Nebula” by NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner (STScI), and T.A. Rector (NRAO)