Search found 20 matches

by starman
Tue Mar 20, 2012 11:46 pm
Forum: The Library: Information Desk and Educational Resources
Topic: Titan is "64%" Earthlike?
Replies: 48
Views: 11555

Re: Titan is "64%" Earthlike?

I think I'm even more pessimistic than you are when it comes to any sort of life being able to function on super-cold Titan. Why? Titan seems every bit as hospitable to life as Earth. What does the temperature matter, as long as you have energy sources (which Titan has in abundance), and liquid sol...
by starman
Tue Mar 20, 2012 11:30 pm
Forum: The Library: Information Desk and Educational Resources
Topic: Telescope use
Replies: 2
Views: 2404

Re: Telescope use

1) Is the scope properly collimated? (collimation is the act of aligning the mirrors accurately) 2) Is the finder scope properly aligned with the main scope? i.e., are they both pointing straight at the same point in the sky? Dobsonians are traditionally 'fast' short-focal length scopes, so accurate...
by starman
Fri Dec 30, 2011 3:10 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: In Wolf's Cave (2011 Nov 19)
Replies: 9
Views: 4256

Re: APOD: In Wolf's Cave (2011 Nov 19)

That blue star is probably a 'runaway'. Close by is another runaway star (PV Cep) ploughing through a nebula. Runaway stars are typically associated with violent events such as supernovae. It's possible that there was a huge Supernova event not far from here (I'd say 'near' the star xi Cep - near in...
by starman
Fri Dec 30, 2011 2:48 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Pleiades to Hyades (2011 Nov 17)
Replies: 23
Views: 3487

Re: APOD: Pleiades to Hyades (2011 Nov 17)

Just a few comments: that "104 solar masses" in the nice article about T Tau should (of course) be 10-to-the-power-four (10,000) solar masses! I'm sure that the reflection nebula around the Pleiades is a remnant of the parent gas cloud from which they formed. The Pleiades is a young cluste...
by starman
Fri Dec 30, 2011 2:35 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: HH 222: The Waterfall Nebula (2011 Oct 24)
Replies: 34
Views: 6163

Re: APOD: HH 222: The Waterfall Nebula (2011 Oct 24)

Also, notice there are several Polar outflows from forming stars (the small, slightly triangular jobs - there's a bright one at the bottom). Maybe the shape of the waterfall itself is caused by the presence of a massive but unseen star, itself probably in the throes of formation and not yet hot enou...
by starman
Wed Dec 21, 2011 12:48 pm
Forum: The Library: Information Desk and Educational Resources
Topic: My entry level telescope.
Replies: 14
Views: 7877

Re: My entry level telescope.

It may now be too late but I'd say that a 100mm reflector is just on the border of being some good. You would be better going for a minimum of 150mm for newtonians. It also depends on what you want to observe. Me, I observe only variable stars (quite often faint ones, 16th magnitude and suchlike). S...
by starman
Sat Sep 17, 2011 2:44 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: HH 47: A Young Star Jet Expands (2011 Sep 05)
Replies: 23
Views: 3970

Re: APOD: HH 47: A Young Star Jet Expands (2011 Sep 05)

If you want to see a serious bit of protostar fun, try googling images for XZ Tauri. One set of images show matter ballooning out of it over the course of a relatively short timeframe. Herbig-Haro jets are collimated streams of ejecta from the poles of a rapidly-rotating young star. Whilst none are ...
by starman
Sat Sep 17, 2011 2:32 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: J102815: A Star That Should Not Exist (2011 Sep 07)
Replies: 44
Views: 6255

Re: APOD: J102815: A Star That Should Not Exist (2011 Sep 07

Lithium is actually the signature of a very young star, since once the core fusion process kicks off, Li is rapidly destroyed. So, find Li in a star's spectrum and you've got a YSO. Incidentally, as an honours graduate in English/Linguistics, I think all this faffing about with Fewer/Less is an irre...
by starman
Sat Sep 17, 2011 2:23 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The Bubble and M52 (2011 Sep 14)
Replies: 16
Views: 3039

Re: APOD: The Bubble and M52 (2011 Sep 14)

With reference to the 'angular size anomaly' it's necessary to remember that the bubble nebula in the photo may well extend out beyond the visible part you can see. What would be better is an image taken in the IR. The OB-association near M52 is very large and dynamic. It spills over into Cepheus ne...
by starman
Thu Aug 18, 2011 5:28 pm
Forum: The Library: Information Desk and Educational Resources
Topic: Can i watch proxima centuri from anywhere on the earth?
Replies: 7
Views: 5564

Re: Can i watch proxima centuri from anywhere on the earth?

Proxima Centauri is so far away from its 'mother' stars, alpha Centauri A and B, that it takes 1 million years to make an orbit! I have seen alpha and beta Centauri from Hawai'i (Big Island), but South of the equator is best as the stars are then higher up the sky. Proxima is also what is known as a...
by starman
Thu Aug 18, 2011 5:22 pm
Forum: The Library: Information Desk and Educational Resources
Topic: My entry level telescope.
Replies: 14
Views: 7877

Re: My entry level telescope.

Hi, Sorry - it looks as though you've bought what is essentially a toy telescope. These things are as ubiquitous as horse doodoos and just as smelly. You would be far better off returning it (if possible) and spending the money on a pair of binoculars. 10 x 50 would be good, and it would be nice to ...
by starman
Wed Jan 05, 2011 4:27 pm
Forum: The Library: Information Desk and Educational Resources
Topic: James Clerk Maxwell and I agree about the nebular hypothesis
Replies: 4
Views: 1103

Re: James Clerk Maxwell and I agree about the nebular hypoth

Hi Doug, Several points of "gravity sinks" ARE often created - in fact, that is the norm, giving rise not only to double and multiple stars, but also star clusters such as the Pleiades. If you know anything about maths (please ignore this bit if you don't!) think of these 'gravity sinks' a...
by starman
Sun Oct 17, 2010 12:57 pm
Forum: The Library: Information Desk and Educational Resources
Topic: What was it?
Replies: 9
Views: 724

Re: What was it?

A few years back I was travelling by bus from the rural village where I live into Norwich (UK). It was December and the sky was dark (about 7.30pm local time). Suddenly the whole sky became virtually day-bright for a few seconds. I can remember saying to the bus driver "either that was a meteor...
by starman
Fri Aug 20, 2010 9:49 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: IRAS 05437 2502: An Enigmatic Star... (2010 Aug 09)
Replies: 39
Views: 6695

Re: APOD: IRAS 05437 2502: An Enigmatic Star... (2010 Aug 09

This looks strangely like one half of a T Tau bipolar outflow - excess material from a forming star is being blasted out at its poles and then causing shocks/illuminating interstellar material in the immediate area. There will be another outflow from the opposite pole but if the star is tilted towar...
by starman
Fri Aug 20, 2010 9:25 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Pelican Nebula Close Up (2010 Aug 19)
Replies: 26
Views: 3908

Re: APOD: Pelican Nebula Close Up (2010 Aug 19)

"It would be great to see a star forming"... well, now you can! Within the past few days, a new star has appeared in this very region! And a new star, not a nova. Actually, a formerly very faint star (18-19m) has just increased by about 5 magnitudes because the circumstellar disc that enci...
by starman
Mon Aug 09, 2010 11:17 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Why the LHC might have destroyed the Earth
Replies: 8
Views: 3823

Re: Why the LHC might have destroyed the Earth

Sorry - this makes no sense. What does 'it's too scientific' mean? Science can't destroy anything any more than (say) literary criticism can - it's just a method of seeing something. It's not in itself a concrete thing so clearly can't destroy anything.
by starman
Tue Jul 13, 2010 1:50 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The Milky Way Over Pulpit Rock (2010 Jul 05)
Replies: 34
Views: 3428

Re: APOD: The Milky Way Over Pulpit Rock (2010 Jul 05)

Great photo, Alex. You could spend a few moments and imagine this could be taken from a probe that landed on a distant rocky/water planet light years away from earth. The Sun being the yellowish star below Alpha Centauri. Mario (or "alpha Centaurus" if you go down the no-Latin route) Inci...
by starman
Mon Jul 12, 2010 2:20 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The Milky Way Over Pulpit Rock (2010 Jul 05)
Replies: 34
Views: 3428

Re: APOD: The Milky Way Over Pulpit Rock (2010 Jul 05)

Great photo, Alex. You could spend a few moments and imagine this could be taken from a probe that landed on a distant rocky/water planet light years away from earth. The Sun being the yellowish star below Alpha Centauri. Mario ... or if you adopt the "English" version, Alpha Centaurus ;-...
by starman
Mon Jul 05, 2010 11:51 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: T Tauri wind verses the solar wind
Replies: 8
Views: 937

Re: T Tauri wind verses the solar wind

Hi Doug, Certainly the higher-end mass star formation process isn't as fully understood as the solar-mass end. One possibility is that since high-mass stars are invariably confined to the galactic equator regions, where there is more ISM (and more stars) then perhaps the high-mass stars are produced...
by starman
Mon Jun 21, 2010 9:56 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: T Tauri wind verses the solar wind
Replies: 8
Views: 937

Re: T Tauri wind verses the solar wind

Yes, I think that's the case. I am sure that YSO wind speeds have been calculated. Best thing to do is find a tech site and if you can search, put in "P Cygni profile" - P Cyg stars have especially energetic winds and a whole class of spectral characteristics have been named after them (ev...