1) If Omega Centauri is reclassified as a dwarf galaxy does that make it the nearest dwarf elliptical or is the Saggitarius dwarf or another of those captured shredded dwarfs actually closer?

2) If it is a galaxy won’t it join the list of just a handful of galaxies visible to the unaided eye – the two Magellanic Clouds, Andromeda, Triangulum – M33, & now the Omega Centauri dwarf galaxy? Has the Local Group of galaxies gained a new member and, if so, where does Omega Cen sit in the heierachy – would it be the smallest dwarf or is it larger than some of the other very faint dwarfs?

3) Can Omega be considered as being *both* a galaxy and a globular cluster (like eg. Ceres = largest asteroid & dwarf planet) or would we it be better to say instead that it used to be an independent galaxy but has since been transformed via capture (?) into a globular cluster? Can a galaxy be part of another galaxy and how long should it be before a smaller galaxy is considered fusedinto or a component partof a larger galaxy?

4) To be a galaxy does Omega need to boast globular clusters of its own? Does it have – or are there any signs it might have had – its own orbiting globulars or extended stellar halo or even dark matter halo? Which leads on to the question of : Should the IAU be trusted to define what a galaxy is after their botch-up with Pluto!

5) Is it the only object like this or could there be more – both around our galaxy and inside others? What are the implications for other globulars and their evolution? Could there be two separate populations or types of globulars – those that used to be separate galaxies and those that were always part of their primary galaxy?

Medium-size black holes, if I have this straight, may have eaten all the matter nearby them and become invisible. But there would be way more of the very small mass ones. But Professor Hawking says that if so, then they’re gone.

“Anything that isn’t big enough to be called what it could be should be called Plutoid. Global clusters can henceforth be called plutoid galaxies.”

But they’re _already_ called globular clusters & perhaps in some cases dwarf elliptical galaxies! We don’t need to add to the nomenclature confusion!

Pluto’ll always be a planet to me – I think the IAU got that very wrong.
I’d be quite happy to call Pluto, Eris and perhaps even Ceres & Charon planets without the qualifier of “dwarf”. After all a dwarf star is still a star! & the classical planets is an even sillier bit of terminology – seems to me the useful way of applying that is to the 5 original unaided eye “wandering stars” – Jupiter, Venus, Mars, Mercury & Saturn.

If we need to classify planets generally, I’d suggest we use the descriptives :

Terrestrial or rocky eg. Earth, Mercury, Mars,Venus

Gas giant or Jovian eg. Jupiter & Saturn

Ice giant or Neptunean eg. Ouranos & Neptune

Ice dwarf eg. Pluto, Eris, maybe Ceres, Sedna, Varuna etc ..

I really believe the IAU made a serious error inthis definition area at their Prague 2006 (?) meeting & needs to review and correct it with something like the suggested system above.

“I got the feeling that this thing is within the Milky Way, although once I re-read the article I couldn’t find it. Maybe because it says that the Milky Way has over 100 of these orbiting it. Anyway, where is this dwarf galaxy located?”

Omega Centauri – like other globular clusters – is in the Milky Way’s galactic halo; meaning it orbits in a high, slow orbit travelling a long way above and below the galactic disk in which our Sun orbits. If the Milky Way’s disk was two saucers placed together, theglobulars would be little ballbearings on strings whirling up and downpast the plane of the table!

In the sky, Omega Cen is in the constellation Centaurus which is a southern hemisphere one surrounding the Southern Cross & probably not too visible anywhere much north of Florida. Luckily, I live in Adelaide, South Australia! We get the two best globulars – Omega Centauri &47 Tucanae, the Magellanic Clouds, Canopus and Alpha Centauri (which with Beta Centauri makes thepointers to the Southern Cross), the Coalsack nebula, the Jewel Box cluster, Eta Carinae and more .. Definitely the better of the two hemisphere’s for astronomy!

You may wish to check out James B. Kaler’s website – he has photos of all the various constellations there & heaps of info. on them and especially the various stars. I’m pretty sure he’d have Omega Centauri marked on there – its actually visible to unaided eyesight in any reasonably dark sky. (hence its Bayer or Greek letter designation.)

“HL Tau is only 520 light years away, giving us a pretty good view. The disk and star are only 100,000 years old, which is incredibly young to be seeing something like this! For comparison the Earth is 6000 (struck through) 4.6 billion years old.”

So … um.. your first answer for Earth’s age is to write 600 years old? Only then do you reconsider it?

Surely not!

I’d reckon that first you think 4.6 billion – the scientifically derived and valid figure then you decide to be “smart” by writing 6000 & striking it through.

To be honest I’m really not sure why ..

Okay, we can poke fun at Kreationists and hammer home again and again that they’re wrong but really I’m not sure that this tactic, esp.applied when the topic has nothing whatsoever to do with the creationists nonsense is really a good idea.

Thanks for the news & blog. Great site!