View Full Version : Discussion: Dust Galaxies Discovered

2003-Jul-16, 05:47 PM
SUMMARY: An Australian astronomer has discovered 20 galaxies that contain mostly gas, rather than stars - revising the definition of "galaxy". These galaxies are giant discs of gas, tens of thousands of light-years across, and contain the mass of billions of sun, but for some reason their hydrogen hasn't coalesced into stars like regular galaxies. The discovery of these gas galaxies will help astronomers better understand what it takes for a galaxy to form.

Comments or questions about this story? Feel free to share your thoughts.

2003-Jul-16, 06:15 PM
Lets say there is an exoplanet there with live like ours there, and if you want to make a Messier-cataloge, its gonna be huge :blink:

2003-Jul-16, 11:59 PM
As I understand it most galaxies have massive to super massive black holes in them. I can't help but wonder if these large black holes exist in dust galaxies to.

2003-Jul-17, 04:47 AM
Or, if they don;t have black holes in their centres, does that suggest that star formation is dependant on the formation of black holes? :unsure:

2003-Jul-17, 05:46 AM
Wow, that's an interesting idea, considering the other discovery announced today.

Emil V Cseko
2003-Jul-17, 09:46 PM
The are no such things as 'dust galaxies'. Astronomers see something new is space and put their interpretation on it. Pity computers cannot talk to tell them what they see. There are no galaxies without stars. What this astronomer saw is something else altogether. For more info. on galaxies please get in touch with me at ecseko@intas.net.au

2003-Jul-17, 10:23 PM
How can you know there are "no dust galaxies"? What if someone finds one, and all the evidence supports this discovery? It's strange to make a blanket statement.

Even if your theory suggests that dust galaxies are impossible, you need to find evidence that disproves his theory.

Brad Warren
2003-Jul-18, 02:53 AM
Hello, my name is Brad Warren, the astronomy student who has been exploring these particular galaxies at the Mount Stromlo Observatory in Canberra Australia. It is great to see that so many people have an interest in my research and astronomy in general!

Let me just clarify that these galaxies are gas (not dust) dominated, and that we still see stars in them and even spiral and bar structures like much larger more star dominated galaxies. We are yet to find any truely "starless" galaxies, but we should never say we won't. Most of the hydrogen gas in most galaxies has over the course of the life of the Universe been converted to stars, leaving only a small amount to form new stars. Our sample of galaxies haven't done this. The next step in my research will be to try and work out why.

The lack of a black hole is an interesting suggestion. Massive black holes are believed to be common at the centres of large galaxies (spirals like our own and even larger giant ellipical galaxies). But whether they exist in these small ("dwarf") galaxies is still not certain. Another explanation may be that there has been no outside stimulation (such as a passing neighbour galaxy) which might cause the gas to clump into stars. Or something inside the galaxy which has held the gas apart.

Have fun exploring our Universe...