This is “Looking UP! in southern Colorado,” from the Colorado Springs Astronomical Society. I’m Hal Bidlack, and there are lots of reasons to look up!
Did you know there is a vast ghost cheerio floating in space above your head right now? It’s true! It’s called the Ring Nebula, and it’s a spectacular and amazing thing to see. You’ll need a telescope to see it, so check out the calendar at CSastro.org for an upcoming star party.
The Ring Nebula is both beautiful and haunting to look at. It truly looks like, well, a ghost cheerio. In astronomical terms it is a planetary nebula, a term that isn’t exactly correct because it has nothing to do with being a planet. Years ago, when this type of object was spotted by earlier astronomers it looked vaguely planet – like, and the name stuck.
But planetary nebulas, like the Ring Nebula, are actually the signposts of long dead stars.
Long ago, a star not much bigger than our own sun, about 2000 light years away, was running out of hydrogen fuel in its core. Over the course of many, many years the battle between gravity and nuclear fusion cause the star to expand and contract. About 4000 years ago things got way out of hand, and in a final expansion the star blew a vast shell of gas out into space, leaving behind a tiny white dwarf star. This white dwarf has enough energy to illuminate the expanding bubble of gas, and because we see this bubble face on, the edges appear thicker, giving it the appearance of an expanding ring in space. And this bubble of gas is expanding at almost 1 million miles per day. Over the next few thousand years, the Ring Nebula will slowly grow about 50% larger, and then will fade away and the gases will disperse through space, vanishing from view.
And this is the fate of our own sun, when it runs out of fuel. It will swell into a giant star and then contract, several times over, until ultimately blowing vast spheres of gas out into space, becoming a beautiful planetary nebula for observers on other worlds. The Earth, of course, will be destroyed, but it’s okay – we’ve got a few billion years to get ready.
If you’d like to take a closer look at the ring nebula or any of the other wonderful and amazing things in the sky, please visit KRCC.org or CSASTRO.org for a link to information on our monthly meetings and our free public star parties!
This is Hal Bidlack for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!