1. ## Weird question about nebulae

I was just wondering if nebulae show movement when viewed? Ive seen countless photos of nebulae like M42, M57 etc, but not having seen one for myself I got to wondering what the view was like. Or are they just too far to show any kind of movement. By movement I mean the gaseous filaments swirling in the view.

2. ## Re: Weird question about nebulae

There is movement over time but nothing that you will see visually while viewing.

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Cyclops (03-05-2018)

No movement.

5. ## Re: Weird question about nebulae

Everything in the sky is moving in one or more directions. Most of things are moving pretty fast too.
Take M81 Bode's Nebula a nice spinning spiral galaxy. It's diameter is roughly 90,000 light years across.
To get the circumference we multiply the diameter by Pi 3.1416 (C=D*Pi).
The circumference is 282,744=90,000*3.1416
So traveling at the speed of light it would take the outside parts of M81 282,744 years to make one revolution.
It's actually spinning at something more like 10% the speed of light, so it really takes something like 2,827,440 years to make a single revolution.

If you where able to look at it long enough, say a thousand years or so you might be able to perceive a very small amount of motion. But looking at it for a few seconds, minutes, hours or even days you will never be able to perceive any motion.

6. ## Re: Weird question about nebulae

No movement apparent, that is why astrophotography frames can be taken in the order of over 90 minutes and nothing is blurred. If you have really really good tracking

It would require exposures dated hundreds if not thousands of years apart to show any change.

7. ## Re: Weird question about nebulae

Originally Posted by UlteriorModem
It would require exposures dated hundreds if not thousands of years apart to show any change.
Have a look at this, only 10 years.

https://www.astrobin.com/327338/?page=2&nc=iotd

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j.gardavsky (03-06-2018),KathyNS (03-05-2018),not_Fritz_Argelander (03-06-2018),yobbo89 (03-06-2018)

9. ## Re: Weird question about nebulae

Originally Posted by Hondo
Have a look at this, only 10 years.

https://www.astrobin.com/327338/?page=2&nc=iotd
Now that is cool! It appears to be growing!

10. ## Re: Weird question about nebulae

That's a very cool picture.
M1 has been expanding for just under 1,000 years. So 10 years is about 1% of it's life span.

There are other objects like the Blinking Nebula (NGC 6826) that give the appearance of changing while you watch them.

11. ## Re: Weird question about nebulae

Originally Posted by Cyclops
Now that is cool! It appears to be growing!
Well there you go, sit a your eyepiece for 10 years observing M1

12. ## Re: Weird question about nebulae

YES! They DO show movement!

Not in the way like seeing horses running, as the sizes of nebulae is so blooming big, it takes a long time for spatial distances to become obvious.

But if you are able to interpret what you are looking at, there is A LOT of movement going on!

Have a look through this Hubble tour of the Eta Carina nebula, yes even if you cannot see Eta Carina from northern latitudes. This tour shows what all the different features are all about not just in this nebula, but also EVERY other nebula too. If you understand the forces at play, what the shadows are saying, what the colours are indicating, and what the light is revealing, then you will see that there is a lot of movement going on in ALL nebulae:

HubbleSite: Video - Carina Nebula: A Hubble Image Tour

Once you understand what going on in the Eta Carina nebula, you can will see M42 in a totally different way. It is a giant bubble that is being blow by the Trapezium cluster. The Fishmouth dark protrusion that points towards the Trapezium is a huge dark pillar that harbours dozens upon dozens of protostars. The different streamers we see are bands of different densities of material, and the colours have to do with emission and reflection spectral lines. There is a lot of movement in M42.

M57 is another bubble, being blown out by a star that is going through its death throes! The colours here indicate a more complex chemistry at play due to the make up of the parent star. While the image appears static to us, the movement is there, though it takes a more abstract way from us to interpret this movement.

Just provoking a different way of thinking

Alex.

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not_Fritz_Argelander (03-06-2018)

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