The Ring Nebula is one of the most famous celestial objects because of its delicate beauty. That shimmering oval of rainbow colors has popped up everywhere from dorm-room posters to book jackets to album covers to just about every TV backdrop in the history of sci-fi. But it is more than mere eye candy. The Ring is also fascinating for what it tells us about our future.
Middleweight stars like the sun expand and cool in their old age, briefly turning into red giants. After the red giant stage, the outer layers puff off, leaving behind a white dwarf: a dense, super-hot stellar cinder. Those puffed-out layers glow brightly before they disperse. That is exactly what we are seeing in this brand-new Hubble image of the Ring Nebula, along with the video interpretation of that image–a snapshot of what will happen to the sun as it runs out of nuclear fuel in about 5 billion years. The Hubble data also add a completely new twist to what astronomers know about the Ring. For the first time, researchers can get an accurate, three-dimensional understanding of the structure of the nebula.
Put that information together with other images taken using different filters and imaging techniques, and scientists have an incredibly detailed picture of how a sunlike star dies.
For comparison, I’ve collected a greatest-hits gallery of recent images of the Ring Nebula taken by other telescopes and satellites, each created using different techniques. You will notice that there is quite a bit of variation here: Most of these pictures little resemble the space-lollipop that has become an astronomy pop-culture staple. That is because the complexity of the nebula itself. It contains many types of atoms in many different states of ionization, each emitting in its own characteristic way. By choosing to zero in on a particular wavelength (or range of wavelengths) of radiation, astronomers can highlight specific elements, temperatures, and densities of the Ring Nebula.
Look at the Ring Nebula with your own eye through a good-size telescope (you’ll need at least 8″ of aperture under dark skies) and you will walk away with yet another impression. Because of the selective sensitivity of the human retina, the Ring Nebula will appear as a faint, diaphanous greenish-gray oval. That is a useful reminder that the colors of space are highly subjective. Each type of image is truthful in its own way, but none of them have a unique claim on representing what the Ring “really” looks like.
Click on each thumbnail for an explanation of how it was created and what it shows; then watch the video for the full story about the dying gasps of a sunlike star.
And be glad that all this action is all unfolding far away. Before the sun produces a beautiful nebula of its own, it will have either baked the Earth to a crisp or swallowed and digested our planet entirely. If any living things are around to see the sun’s version of the Ring Nebula, they will probably be watching from another star system many light years away.
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