Search found 121 matches

by cosmo_uk
Sat Feb 08, 2014 6:49 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: What can be learnt from star colors?
Replies: 21
Views: 1469

Re: What can be learnt from star colors?

"An issue that can't be ignored is that "color" means many different things. In stellar photometry, it is a scalar typically derived as the ratio or difference in intensity across two adjacent parts of the spectrum (e.g. B-V)"

Well indeed but I decided not to go into that!
by cosmo_uk
Sat Feb 08, 2014 6:21 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: What can be learnt from star colors?
Replies: 21
Views: 1469

Re: What can be learnt from star colors?

Also as Annmentions you can use the average colours of stars in different regions of the sky to make a pretty decent statistical dust map of the Milky Way (using a very large dataset like SDSS)
by cosmo_uk
Sat Feb 08, 2014 6:19 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: What can be learnt from star colors?
Replies: 21
Views: 1469

Re: What can be learnt from star colors?

Good question Ann. Some of you guys are being a bit dismissive of colour, a colour magnitude diagram (basically HR) can tell you a lot. As you all rightly say the colour is due to the temperature (in the main) as stars are approximately Black Body emitters (OK not all of them and strong absorption f...
by cosmo_uk
Tue Oct 29, 2013 5:20 pm
Forum: The Communications Center: Breaking Science News
Topic: Most Distant Galaxy Ever, Found Using Keck
Replies: 13
Views: 5758

Re: Z8_GND_5296 - Furthest Galaxy Discovered

As Chris says this was from a deep survey CANDELS I think. So basically they image the sky in many different filters and then look for faint galaxies with certain properties ie brighter in some filters than others. In this case they were probably looking for 'drop outs' galaxies that have a break in...
by cosmo_uk
Tue Oct 29, 2013 12:23 pm
Forum: The Library: Information Desk and Educational Resources
Topic: What do you think this object is?
Replies: 9
Views: 19543

Re: What do you think this object is?

Well, there's a Green Pea in it. And it looks like either a merging pair of ellipticals, or perhaps a foreground lensing effect splitting the one elliptical galaxy into two. I can't tell if all these are in one galaxy cluster or not. If so, I'd guess the Green Pea is not part of the cluster, since ...
by cosmo_uk
Mon Oct 28, 2013 4:55 pm
Forum: The Library: Information Desk and Educational Resources
Topic: What do you think this object is?
Replies: 9
Views: 19543

Re: What do you think this object is?

Looks like a Brightest Cluster/Group Galaxy to me. Largest galaxies in the Universe sit in the middle of huge potential wells. From the spectra its showing line emission (particularly all that OIII) so it probably has an accreting black hole in it (AGN) and maybe some residual star formation
by cosmo_uk
Fri Nov 07, 2008 11:34 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Could Dark Matter Possibly Be . . .
Replies: 315
Views: 32167

Re: Could Dark Matter Possibly Be . . .

Whenever I receive a directed 'spam' email to my university account from an 'independent researcher' (I'm trying to be nice here!) they always include a copyright symbol next to some unknown laboratory - in case I copy their work I guess! - its the calling card of the crank
by cosmo_uk
Mon Oct 27, 2008 9:01 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Do You Have A Favorite Telescope
Replies: 7
Views: 1279

Keck :)
by cosmo_uk
Sat Jul 19, 2008 8:43 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Planet Earth?
Replies: 21
Views: 5028

Duran Duran may help with this query:

Bop bop bop bop bop bop bop bop this is planet earth

Bop bop bop bop bop bop bop bop calling planet earth

Bop bop bop bop bop bop bop bop looking at planet earth

Bop bop bop bop bop bop bop bop this is planet earth
by cosmo_uk
Fri Sep 07, 2007 10:03 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Origins of the UNIVERSE
Replies: 829
Views: 154214

This new hole is not at odds with LCDM cosmology. MM said whereas plasma cosmology "predicts" a universe that is threaded and full of "holes" as well. As far as I am aware no one has ever used plasma cosmology (pc) to predict anything. If it was possible to model the universe wit...
by cosmo_uk
Sun Sep 02, 2007 7:19 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Origins of the UNIVERSE
Replies: 829
Views: 154214

well the MACS clusters are at z=0.5 ish and (i should know i've spent the last 2 years studying them!!) this is around 9 billion years after the big bang so thats plenty of time to form a relaxed cluster. so far to my knowledge the furthest cluster known is at z=1.45 from the XCS survey, this is rou...
by cosmo_uk
Wed Aug 29, 2007 2:48 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: APOD Cafe
Replies: 1
Views: 1315

APOD Cafe

As Harry suggested I have no authority on this forum but why don't we let people say what they like in this (and only this) thread as long as its not spam. therefore if craterchains et al want to discuss alien warfare and MM wants to chat 'iron sun' they can do so here: moderators delete this if you...
by cosmo_uk
Thu Aug 09, 2007 10:43 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Is there any way ...
Replies: 1
Views: 1391

yes the sdss navigate tool you included http://cas.sdss.org/dr6/en/tools/chart/navi.asp (edit: the explore tool gives all available SDSS information on the selected object. photometry, spectra, redshift) and the Nasa Extra-galactic Database (NED) http://nedwww.ipac.caltech.edu/ the latter gives all ...
by cosmo_uk
Sat Jul 21, 2007 11:50 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Is the moon gray or is the picture colorized (20 July 2007)
Replies: 30
Views: 11146

dited afterthought: Why isn't Mars as pockmarked by craters as the moon?
weathering from the atmosphere (wind, dust storms etc), volcanic activity and perhaps at some point in the past, flowing water, all act to clean the surface of craters just like on earth
by cosmo_uk
Fri Jul 20, 2007 1:09 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Is the moon gray or is the picture colorized (20 July 2007)
Replies: 30
Views: 11146

because it was all done for £5 in a basement in kent :) or it could be to do with how optical instruments (cameras or eyes) work when presented with a very bright object in the field such as the surface of the moon compared to the very faint stars. camera would be set to a daylight aperture and expo...
by cosmo_uk
Wed Jul 04, 2007 8:54 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Radiometric dating
Replies: 23
Views: 6964

you're clearly not looking at the right evidence!

forget carbon dating what about fossils in sedimentary rock which takes millions and millions of years to form? Or have you found a way of speeding up geology?
by cosmo_uk
Tue Jul 03, 2007 10:05 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Scientists should know grammar.
Replies: 12
Views: 4338

well done
by cosmo_uk
Mon Jun 25, 2007 10:31 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: A Hole in Mars (APOD 28 May 2007)
Replies: 109
Views: 38819

huge worms like off the tremors? That would explain lines and holes :)
by cosmo_uk
Fri Jun 22, 2007 9:18 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Ceres and Vesta (APOD 22 June 2007)
Replies: 11
Views: 4241

Well for a start hubble has no "great images of stars", stars have such a small angular size on the sky that they are unresolved point sources. The fact that they can look big in images is due to there intensity, point spread, diffraction etc. To my knowledge there are no resolved stars th...
by cosmo_uk
Wed Jun 13, 2007 1:41 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Origins of the UNIVERSE
Replies: 829
Views: 154214

I was not aware of such case(s), and I would appreciate a reference describing them. I'm talking about normal common elliptical galaxies - they do not contain a great deal of gas/plasma or dust and have negligible new stars to make any more. Put simply they are thought to be formed by the merging o...
by cosmo_uk
Wed Jun 13, 2007 9:51 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Origins of the UNIVERSE
Replies: 829
Views: 154214

...and back to my previous question - what about galaxies with no/negligible gas/plasma? How come they can be at high redshift?
by cosmo_uk
Tue Jun 12, 2007 3:41 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Origins of the UNIVERSE
Replies: 829
Views: 154214

So you're saying that huge superclusters of normal elliptical galaxies at high redshift are actually nearby and small :) Are they just a collection of globular clusters compared to local clusters which are a collection of ellipticals? :) If you've ever seen the perspective episode of Father Ted with...
by cosmo_uk
Tue Jun 12, 2007 9:21 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Origins of the UNIVERSE
Replies: 829
Views: 154214

Another question I'd be interested to hear the plasma/arp view on. What about high redshift non-quasars? my own personal research is the study of normal boring ellipticals at redshift 1. For those of you not familiar with cosmology redshift 1 is half the age of the Universe at around 7 billion years...
by cosmo_uk
Mon Jun 11, 2007 9:24 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Origins of the UNIVERSE
Replies: 829
Views: 154214

Dear cosmos_uk: In stead of replying to Arp's cogent objection (re Quasar Redshift) and my suggestion of an intrinsic redshift, I get an ad-hominëm attack from you. What a sad bag of arrogance ("I know it all") and ignorance ("I need not to look because I know it all") are you. ...
by cosmo_uk
Sun Jun 10, 2007 8:33 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: CME watch.....
Replies: 28
Views: 6317

Hey MM

Its nice to see you doing some live research on this thread. I'll keep my eye on it.

Cosmo