Wonder-inducing ring galaxy image

[jim mcnamara]

From https://phys.org/news/2018-01-image-hubble-cartwheel-galaxy.html

The attached article explains the proposed origin of this nifty ring galaxy.

 

[Bystander]

" shock waves " How?

 

[jim mcnamara]

I do know there are stars that have recently gone nova, and have a ring of high energy particles expanding out into space surrounding them. Possibly this is what is meant. What I do not get is why the small "nucleus" galaxy looks, well, undisturbed, especially if it were the object that created "shock waves" and blown a galaxy apart...

None of this rules out bad journalism in the phys.org article. I will try to find the original from NASA.

Shock waves is a circular link, BTW.

 

[Bystander]

small "nucleus" galaxy looks, well, undisturbed, especially if it were the object that created "shock waves" and blown a galaxy apart...

"Bad journalism?" Nah, couldn't be.

 

[jim mcnamara]

This is a NASA discussion of Hoag's Object - a ring galaxy like the cartwheel galaxy pictured above.

https://www.nasa.gov/multimedia/imagegallery/image_feature_1747.html

 

[phyzguy]

I think the model is that a shock wave is propagating out from the center of the galaxy. As the shock wave travels through the gas surrounding the galaxy, it compresses the gas and triggers a wave of star formation. The bright blue ring you are seeing is from newly formed hot blue stars at the peak of the wave of star formation. Since these hot blue stars are very short-lived, you only see them where the star formation is currently occurring.