Galaxies are filled with gas

[Brian G Turner]

Apparently, galaxies don't contain enough matter to account for their spin - one of the drivers behind the idea of "dark matter".

However, I wonder how much those same astrophysicists have underestimated the amount of gas to be found in galaxy - as these two stories from this week highlight:

Hidden pockets of turbulent gas fuel stars in far-off galaxies

Gargantuan gas reservoirs have been spotted around multiple distant galaxies, where they can provide fuel for new stars — contrary to accepted theory. A powerful radio telescope in the Chilean desert unmasked the gas, which sheds new light on how galaxies can extend their star-forming eras.

and: Spiralling galaxy arms spread oxygen around for future planets

Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. It arises mainly in massive stars, which forge the element during their brief lives and then cast it into space when they explode.

But a galaxy’s spiral arms also help spread the wealth, says I-Ting Ho at the Max Planck Institute for Astronomy in Heidelberg, Germany.

He and his colleagues have measured oxygen levels throughout a galaxy named NGC 1365 located 60 million light years away in the constellation Fornax. It has two gargantuan spiral arms joined together by a bar of older stars, all embedded in a huge disc of stars and interstellar gas and dust. As viewed from Earth, the galaxy rotates clockwise, but most of the stars and gas revolve faster than the spiral arms themselves.

Ho’s team has discovered that oxygen is 60 per cent more abundant in the spiral arms than in gas that has just passed through them.

“To the best of our knowledge, this is the most extreme case so far,” Ho says. In contrast, using older instruments, astronomers have failed to detect any variations in oxygen levels as one proceeds clockwise around most spiral galaxies.

We can’t see our galaxy from the outside, so it’s harder to do this in the Milky Way. Nevertheless, there are hints of such variation in our galaxy too.

 

[Alexa]

They should study better, to the best of their knowledge, our galaxy first and have more than hints before claiming such results in a galaxy located 60 millions light years. Sometimes, I really think these studies worth nothing.

 

[Vertigo]

Sometimes it's easier to study other galaxies instead of our own. With the Milky Way it's often hard to study, for example, the composition of a particular spiral arm when we have to look through all the rest of the galaxy to see it. Whereas when viewing a galaxy that is well above or below our galaxy's ecliptic we don't have to look through all the mass of our own galaxy to see it.

In the first article they actually say: "We can’t see our galaxy from the outside, so it’s harder to do this in the Milky Way. Nevertheless, there are hints of such variation in our galaxy too."

 

[Alexa]

Those *hints* from the end of the 2nd quote pushed me over the edge and rant about these studies.