Search found 10 matches

by ruidh
Wed Oct 31, 2007 3:53 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: How do Martian craters survive? (APOD 22 Oct 2007)
Replies: 2
Views: 1903

Re: How do Martian craters survive?

Something has always puzzled me about Martian craters. Given that they are very old, and that there is so much dust/soil all over the place, why aren't the craters filled to the rim? Clearly, it's because the volume of dust on Mars isn't sufficient to fill all of the craters. And I'm not at all sur...
by ruidh
Fri Sep 07, 2007 1:56 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Lunar Eclipse (APOD 30 August 2007)
Replies: 19
Views: 7729

Actually, I'm more interested in this sentence from today's APOD. "The Moon was up continuously for 14 days in August -- when viewed from the South Pole." Why isn't the moon continuously visible from the South Pole? The Sun isn't continuously visible because the axis of rotation of the Ear...
by ruidh
Mon Oct 03, 2005 3:00 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD Oct.03, 2005 Hyperion
Replies: 44
Views: 15592

Re: Hyperion

It looks like a spent comet nucleus that was captured by Saturn. That would explain its chaotic orbit and dessicated appearance. And especially when they talk about the extremely low density. Hyperion "has a density so low that it might house a vast system of caverns inside." I'm reminded...
by ruidh
Fri Aug 26, 2005 6:56 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Relationship of indentations and age of object.
Replies: 2
Views: 2831

Re: Relationship of indentations and age of object.

My question is whether scientists can tell how old an object is from looking at it and inspecting the number of "hits". Is this an emperical judgement or is it an experienced guess? I think its fairly obvious that if you start with an uncratered surface and objects hit it now and again, t...
by ruidh
Tue Feb 08, 2005 2:02 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Which satellite is this?
Replies: 193
Views: 199596

It's a bug? :D

The fuel dump sounds plausible if the mechanics can be shown to work out right. Also related to the satellite, presumably, it had an upperstage to take it to geosynchronous orbit. Could we be seeing that?
by ruidh
Mon Feb 07, 2005 9:32 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Strange streak discussion: 2004 Dec 7 APOD
Replies: 2124
Views: 537793

Is it time to lock this thread? There hasn't been a substantive contribution in quite a while.

It's a bug.
by ruidh
Mon Jan 24, 2005 2:54 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD January 24
Replies: 2
Views: 4192

APOD January 24

What did they mean by this "Both the riverbed and lakebed were thought to be dry at the time the image was taken but contained a flowing liquid - likely methane - in the recent past."? I followed the link but it didn't seem to mention anything like this. Is the prevailing view that the pro...
by ruidh
Mon Jan 24, 2005 2:49 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Light on distant bodies
Replies: 14
Views: 8635

They don't use color cameras, they take multiple photos from the same camera with different filters and superimpose the layers with color correction to create the colored image. Not on this probe they didn't. The original poster was right. They took a greyscale image and applied a single color to i...
by ruidh
Tue Jan 18, 2005 8:55 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: how about some early interpretations of the hyugens pictures
Replies: 2
Views: 3630

Panda's Thumb posted a discussion about some of the early opinions on the findings. The dark stuff appears to be some kind of spongy substance with a crusty surface and not a liquid ocean.

http://www.pandasthumb.org/pt-archives/000747.html
by ruidh
Mon Jan 10, 2005 8:35 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: Strange streak discussion: 2004 Dec 7 APOD
Replies: 2124
Views: 537793

To Victor, You make a good point about the orange blob being enclosed in a 8x8 square, which I think is puzzling. But the feature I've enclosed in the orange rectangle covers the corners of two 8x8 squares with an identical color, and is about the same color as the square where the orange blob is. ...