APOD: Barred Spiral Galaxy NGC 1300 (2020 Jun 11)

[CuriousChimp]

Could the whitening of the background spirals be due to "special" gases and dusts that selectively absorb red and perhaps infrared? Methane andsuch, like the airs of Neptune and Uranus? That would be cool, too.

Thank you, lady, that was an awful lot of work to do to answer what was an off-hand and quite silly question.

You are a good person. I hope you have a lovely Christmas.

[CuriousChimp]

Why would Ellipticals have interior discs of gas? Surely that's a trick Spirals are best known for? Could there be a disc-forming bit of physics that is only apparent over smooth, large-scale regions with little mass density such as galaxies? Something magneto-hydro-dynamic or hydrogen-bondy? Some small influence that only shows up when everything else is stable? Or do we have an explanation for Spirals?

Thank you for putting so much effort into answering a silly notion. You should try being a teacher.

Take care and have a lovely Christmas.

[CuriousChimp]

Reddening is a tricky thing in astronomy, because it's not reliably detectable. That's because it's not true reddening (as with redshift) where sources get shifted in wavelength- something that is obvious spectroscopically, but just a change in the balance of a range of wavelengths.

It's a great, big, huge, complicated Universe and nothing's every as easy and simple as it looks at first glance.

Fortunately, we have people like you to help us find out what's happening and to hep us understand it all; understand it, that is, as far as we can manage.

Thank you and have a nice, warm, happy Christmas. Stay safe out there.