Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
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Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#2The Hubble fork isn't "wrong". It's just a classification scheme. The fork has nothing to do with how spiral structures form or how long they last, it's just a way to quickly describe them.
Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#3The Hubble fork isn't "wrong". It's just a classification scheme. The fork has nothing to do with how spiral structures form or how long they last, it's just a way to quickly describe them.
According to the article, it's a classification scheme that doesn't work. It describes categories that real galaxies don't fit in.
Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#4Huh.
I thought that there was a solid theoretical basis for the density wave hypothesis. But TFA implies that the main constraint was consistency with the Hubble tuning fork diagram.
That would be funny, because I've never really understood the density wave hypothesis.
Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#5The Hubble fork isn't "wrong". It's just a classification scheme. The fork has nothing to do with how spiral structures form or how long they last, it's just a way to quickly describe them.
According to the article, it's a classification scheme that doesn't work. It describes categories that real galaxies don't fit in.
>Hubble's tuning fork has been more or less the standard for a century now. It's done a decent job, but there have been some galaxies that don't fit the pattern. For example, one might have a small bulge but tight arms, or another with a large bulge and fairly open arms. If there's a galaxy that didn't quite fit, astronomers usually used the arm structure to place it in the diagram.
More specificly, it suggests that there are additional categories that should be added.
The fork used 2 variables to come up with 6 combinations: bulge size( with 3 states) and bar presence (with 2 states). A third variable, arm angle, was assumed to be linked with bulge size.
the data suggests that arm angle does not have the relation to bulge size that was assumed.
Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#6I think that [1] is the paper that this is based on. I don't work on dynamics and I found it pretty readable. Most of what is in the article is in sections 3.2, section 4 (discussion) and section 5 (conclusions).
Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#7Given that most cosmology relies on a huge percentage of dark matter, which cannot be detected, and a huge amount of dark energy, with enormous conflicting calculations, I think it's fair to say that astronomers are wrong about a lot of things.
Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#8Given that most cosmology relies on a huge percentage of dark matter, which cannot be detected, and a huge amount of dark energy, with enormous conflicting calculations, I think it's fair to say that astronomers are wrong about a lot of things.
It's hard to do experiments.
It's a limitation of all purely observational sciences.
Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#9Given that most cosmology relies on a huge percentage of dark matter, which cannot be detected, and a huge amount of dark energy, with enormous conflicting calculations, I think it's fair to say that astronomers are wrong about a lot of things.
Just because you cannot detect something does not make you wrong nor does it mean it doesn't exist. What a ridiculous statement.
Re: Battle of the bulges: Have astronomers been wrong about spiral galaxies? (2019)
#10Given that most cosmology relies on a huge percentage of dark matter, which cannot be detected, and a huge amount of dark energy, with enormous conflicting calculations, I think it's fair to say that astronomers are wrong about a lot of things.
Just because you cannot detect something does not make you wrong nor does it mean it doesn't exist. What a ridiculous statement.
> Just because you cannot detect something does not make you wrong nor does it mean it doesn't exist. What a ridiculous statement.
If you cannot detect something, it's can be equally ridiculous to say it exists.