Search found 13 matches

by keshlam
Sun Aug 15, 2010 8:04 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Layered Hills in Arabia Terra on Mars (2010 Aug 15)
Replies: 31
Views: 6364

Re: APOD: Layered Hills in Arabia Terra on Mars (2010 Aug 15

Actually, there's a simple initial test: Do all the hills in the same area have steps at about the same heights (allowing, if necessary, for some possible distortion by uneven uplift)? Or, if they're uneven, is the bias minor and consistently in a particular direction? Either would tend to confirm t...
by keshlam
Sun Aug 15, 2010 7:43 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Layered Hills in Arabia Terra on Mars (2010 Aug 15)
Replies: 31
Views: 6364

Re: APOD: Layered Hills in Arabia Terra on Mars (2010 Aug 15

I tend to agree that what I'd suspect if I saw this on earth -- ignoring human activity -- is sedimentary layers being eroded away by slowly receding water, perhaps with harder and softer layers alternating (which tends to result in undercutting and collapse, thus leaving relatively sharp-edged plat...
by keshlam
Wed Feb 03, 2010 11:32 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: P2010 A2: Unusual Asteroid Tail ... (2010 Feb 03)
Replies: 35
Views: 6029

Re: P2010 A2: Unusual Asteroid Tail Implies... (2010 Feb 03)

It looks like a Klingon Battlecruiser... ... or perhaps an old-fashoned bottle-with-fins rocket. If so, the vapor trail would mark the path of its retrorocket exhaust (which it would have been falling into, after all) and the bright spot at the tip of the "fin" is actually light from an a...
by keshlam
Sun Jan 31, 2010 5:16 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The Mysterious Voynich Manuscript (2010 Jan 31)
Replies: 238
Views: 69393

Re: The Mysterious Voynich Manuscript (2010 Jan 31)

The hoax or alchemy proposals seem equally plausible to me. Expensive hoax, in time invested... but given the price it might have commanded, perhaps worth the effort. I don't entirely buy the assertion that the text is too statistically consistent to be fake; I can produce glossolalia which sounds p...
by keshlam
Tue Oct 13, 2009 4:13 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Giant Dust Ring Discovered Around Saturn (2009 Oct 13)
Replies: 19
Views: 3151

APOD: Giant Dust Ring Discovered Around Saturn (2009 Oct 13)

The insert graphic makes it appear that the new ring is orbiting on a significantly different plane than the others. True, or just a presentation artifact?

http://apod.nasa.gov/apod/ap091013.html
by keshlam
Tue Aug 04, 2009 6:14 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: A Triple Sunrise Over Gdansk Bay (2009 Aug 04)
Replies: 338
Views: 56106

Re: Cause of Triple Sunrise (APOD 2009 August 4)

Re not being in a straight line: Float glass is not optically flat to begin with, and large panes are a lot less rigid than folks may be assuming. We don't normally notice any distortion, but I can more easily believe there's enough to account for a bit of misalignment than that there's an atmospher...
by keshlam
Tue Aug 04, 2009 4:36 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: A Triple Sunrise Over Gdansk Bay (2009 Aug 04)
Replies: 338
Views: 56106

Re: Cause of Triple Sunrise (APOD 2009 August 4)

I'm still leaning toward reflection due to one detail: the slight flare seen at the bottom of the middle solar disk echos that seen at the bottom of the brightest image, which appears to be a horizon/mirage effect, even though it appears slightly higher in the sky. I may be missing something obvious...
by keshlam
Wed Jul 29, 2009 12:20 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Devil's Tower (2009 July 29)
Replies: 17
Views: 5698

Re: "Devil's Tower"

Re naming: "Devil's" does sound disrespectful to some (how would you feel if one of your holy sites was colloquially called Devil's Whatever?), so I'd have liked to at least see the alternate name mentioned. Not a big deal for me, but it seemed worth pointing out.
by keshlam
Wed Jul 29, 2009 4:33 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Devil's Tower (2009 July 29)
Replies: 17
Views: 5698

Devil's Tower (2009 July 29)

I've been told that the local tribes object to that name for the hill, and would prefer that it be referred to as Bear Lodge. Since hearing that, I have tried to comply -- they _were_ here first, after all. I know, I know, fewer people would recognize it by that name... but I think a bit of a cultur...
by keshlam
Wed Jan 21, 2009 3:05 pm
Forum: The Observation Deck: Latest Sky Photography
Topic: Proposed APOD: Obama Inauguration Satellite View
Replies: 1
Views: 1246

Proposed APOD: Obama Inauguration Satellite View

At the risk of slashdotting their server ... this is just too good an image not to share. Satellite view of the inauguration crowd. My, that's a lot of surprisingly-well-behaved people! http://www.geoeye.com/CorpSite/gallery/detail.aspx?iid=220&gid=1 (OK, it isn't astronomy or earth science. But...
by keshlam
Tue Jan 13, 2009 4:40 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Unusual Light Pillars Over Latvia (2009 Jan 12)
Replies: 176
Views: 191184

Re: Unusual Light Pillars Over Latvia (2009 January 12)

pmanson: I agree, that simulation does look a lot like what we're seeing in the photo.
by keshlam
Mon Jan 12, 2009 5:41 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Unusual Light Pillars Over Latvia (2009 Jan 12)
Replies: 176
Views: 191184

Re: Unusual Light Pillars Over Latvia (2009 January 12)

I'm trying to think through the optics of this image... and I have more questions than answers. The lights aren't pointed upward, so the "columns" presumably aren't actually columns per se, but are instead a lensing effect of the ice crystals between the light and viewer -- like lens flare...
by keshlam
Tue May 16, 2006 12:50 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD 15th May 06
Replies: 40
Views: 12287

Typo in text: "Mar's northern hemisphere"

Try either Mars' or Mars's.

(Although I do know someone named Mar, commenting about the amount of sunlight reaching an individual's northern hemisphere is generally considered impolite...)