# The Cat's Eye Nebula

by skyshrimp
Tags: nebula
 P: 6 I'm just learning about space. The Cat's Eye nebula looks very energetic at the core. I can see what looks like plasma firing off chaotically from the center star. If this was video footage, would what we see in this still Hubble photo move rapidly (like solar flares seen in footage from our Sun), or would the said video footage be static?
 Mentor P: 11,576 The nebula formed in a timescale of 1000 years, and has a diameter of several light years now. To observe changes, you have to wait years. A video would be completely pointless - and I think this image was a long-term observation anyway (= light was collected for a significant amount of time, minutes or even hours).
Mentor
P: 11,501
From wiki here: http://en.wikipedia.org/wiki/Cat%27s_Eye_Nebula#Age

 The angular expansion of the nebula can also be used to estimate its age. If it has been expanding at a constant rate of 10 milliarcseconds a year, then it would take 1000 ± 260 years to reach a diameter of 20 arcseconds. This may be an upper limit to the age, as ejected material will be slowed as it encounters material ejected from the star at earlier stages of its evolution, as well as the interstellar medium.[21]

P: 6
The Cat's Eye Nebula

 Quote by mfb The nebula formed in a timescale of 1000 years, and has a diameter of several light years now.
One side of the explosion has the exact shape as the other but in reverse. How can a 1k yr old explosion that's several light years in diameter do that? You'd think it would be a gradient, uniformed explosion considering the immense size. Even the plasma looking 'blue' center has defined shapes similar to water refraction seen in swimming pools. That's why I assumed it was once moving faster than when Hubble received the still shot.
 Mentor P: 11,576 Why does it look surprising that an explosion can have a symmetry, without having a full spherical symmetry? Note that stars always have an axis of rotation - they are not spherically symmetric, but they have two equivalent sides.

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