"The surface of the Earth is the shore of the cosmic ocean... Recently, we've managed to wade a little way out, and the water seems inviting." - Carl Sagan
In response to kororaa's request, here is a picture of the Cat’s Eye Nebula.
In this detailed view from NASA/ESA’s Hubble Space Telescope and NASA’s Chandra X-Ray observatory, the Cat’s Eye Nebula, formally catalogued as NGC 6543, is one of the most complex planetary nebulae seen in space. A planetary nebula forms when Sun-like stars gently eject their outer gaseous layers that form bright nebulae with amazing and confounding shapes.
Observations suggest the star ejected its mass in a series of pulses at 1,500-year intervals. These convulsions created dust shells, each of which contain as much mass as all of the planets in our solar system combined. These concentric shells make a layered, onion-skin structure around the dying star.
The patterns seen around planetary nebulae come as a surprise to astronomers because they had no expectation of episodes of mass loss at the end of stellar lives that repeat every 1,500 years. Several explanations have been proposed, including cycles of magnetic activity somewhat similar to our own Sun’s sunspot cycle, the action of companion stars orbiting around the dying star, and stellar pulsations. Approximately 1,000 years ago the pattern of mass loss suddenly changed, and the Cat’s Eye Nebula started forming inside the dusty shells. It has been expanding ever since.