Introduction In nursing particularly, absolute competence is a must…

A spiral galaxyin the process of forming that’s somehow appearing at an earlier developmental stage than it should be based on its distance?

An interacting pair of galaxies which we can’t disentangle yet?

An Sa,SB, SBc type spiral masquerading as an SO type spiral? Could the central-bulge-size-spiral type law be wrong at least in this case?

Whichever turns out to be the case a great image and great set of questions. Love to hear what BA’s friend finally says.

Finally, stars like galaxies are termed ‘later’ or ‘earlier’ regarding spectral type with no (or very tenuous?) evolutionary connection – for example Vega (type A0) is termed an earlier spectral type than Altair (A7), Tau Ceti (G8) is of “later” spectral type than our Sun (G2) and in the whole system spectral types O-F are generally termed ‘early’ and F-M (or now T~L?) described as ‘late.’ As I understand it anyhow.

Stars and galaxies do evolve and transform from one type to another but in complex ways and not just from “early” to “late” … Galaxies often change (esp. via merger) from “late” spiral types to “early” ellipticals. (Our Milky Way will merge with M31 Andromda and undergo this shift.)The same can occur with stars too. Eg. the star that became Supernova 1987A moved from being a “late” type red supergiant to an “early” type blue supergiant star before blowing itself apart.

Misleading word use perhaps? But still useful as a descriptive term if you understand the underlying concepts?

( But was Mark in “Airplane!” with Leslie Nielsen? )

Ivan.

“What is it?”

“It’s an interogative statement designed to elicit information, but that’s not important right now!”

On a different tack now, what about the common depiction of the curved space ie. the saddle? Is our ‘line of sight’ confined to the curvature of space– our ‘straight’ view is actually curved. In other words, can we not really see across that curve? Only along the curved plane, as though it was a light pipe?

If so it would imply that light is reflected off that boundary. Of course the angles would remain small, and what would the boundary be made of? Gravity again?

Ivan. (obviously I’m trying to wear out my Question Mark key, don’t you think?)

And would Gravity rule the idea out anyway?

Ivan.

I’m reminded of this question because I use the view in a nearby store window when reversing into a parking space. If available, it does give a different view.

Ivan.

Maybe I should not get out as much.

Ivan.

Arthur comments (inter alia): “My left arm’s floating away. How am I going to operate my digital watch now?

You may remember that this joke was set up by an earlier line, in which the narrator tells of “a backwater planet in the outer western spiral arm of the galaxy, whose ape-descended inhabitants are so amazingly primitive that they still think digital watches are a pretty neat idea.”

Not too long ago, the BBC adapted the later Hitchhiker’s Guide books for radio. One change is that the narrator now says, “they still think custom ringtones are a pretty neat idea.”

One thing I’ve always loved about you and this site is your “kid in a candy store” attitude to new things you’ve yet to figure out.

This serves as a good counterargument to those creationists and other anti-science types who claim that scientists ignore or dismiss evidence contrary to their preconceived notions, or that scientists are just spouting the party line in order not to jeopardize the untold millions they get in grants.

It seems that not a year goes by in which I don’t read a science news article that quotes a scientist as saying, “This discovery overturns our theories! I have no idea what’s going on! This is so-o-o cool!”

By the way, in the photo above, it looks as though the dust is all in a flat area, but the stars are in a lens-shaped distribution. It looks as though the thickness of the bright area is about a third of its width. Is that a photographic effect, or are there stars 10,000 ly from the plane of the disk?

Possible? Or only merely probable?

Ivan.

“Later”-type spiral galaxies (Sc, as opposed to Sa) have more open and well defined spiral arms. S0 galaxies are even “earlier” than Sa galaxies. (The terms “later” and “earlier” are unfortunate, and nowadays refer only to whether it’s further left or further right on the Hubble Tuning Fork Diagram.)

Also, “later”-type spiral galaxies have a smaller bulge compared to “earlier” type spiral galaxies. Sa galaxies like the Sombrero Galaxy have big bulges. The Milky Way is an Sbc galaxy, so has a smaller bulge. (Actually, the MW is an SBbc, because it does have something of a central bar.)

That’s how you can tell that this galaxy is an S0 or Sa, as opposed to a later-type galaxy. It’s got that big prominent bulge. A type Sb or thereabouts galaxy seen edge on would look more like NGC 891.

-Rob

‘Fraid you missed the pop-culture reference there. It’s from the Hitch-Hiker’s Guide to the Galaxy. After Ford and Arthur are rescued by the infinite-improbability-drive ship, before normality is restored, Arthur comments (inter alia): “My left arm’s floating away. How am I going to operate my digital watch now?”

I do wonder though if we cannot discern spiral arms in NGC 5866 because of the foreshortening effect caused by the huge distance between object and subject, a factor well known in photography, we are using a pretty big telephoto lens! We would be looking at maybe three or four cross-sections of those arms, so the expected spaces between the arms would be backed up with another arm section and then probably another after that.

If radar or doppler could be used at this distance to give reasonable evidence, well and good, but I won’t be around in 88,000,014 years to confirm or deny the proposition. You are wondering why it will take the extra fourteen years? Have you ever known any government to set up committees, debate, approve, vote finance, do it all again in the next administration, build the instruments, and then have recriminations and inquiries for such things as who authorised the truckload of $250 hammers. Yeah, it will take 14 years.

But then again there may be other evidence learned astronomers can determine for sure that there are/are not spiral arms. I’m sure there is ample evidence out there of both types.

Um, do globular clusters have arms too?

Ivan.

Remember, we see it as it was 44 million (I think) years ago. So it probably has one of those red LED watches that eats batteries.

How is it going to operate its digital watch now?

Perhaps it recently underwent an interaction of some sort that will form arms, but the arm formation is in process and the arms haven’t really sorted themselves out yet.

This photo is so cool. I’m just pleased with myself if I can take a reasonably attractive photo of a landscape or sunset. It’s awe inspiring that those talented among us can take such fantastic photos of entire galaxies millions of lightyears away!