Using Shadows To Measure the Geysers of Enceladus

The Bad Astronomer writes "A lot of folks are posting about the amazing new pictures of the icy moon Enceladus returned from the Cassini spacecraft. However, one of them shows the shadow of the moon across the geyser plumes. This has been seen before, but I suddenly realized how that can help determine the geysers' locations, and I thought Slashdot readers might be interested in the general method."

Comments

Nerdy-purdy!

[Cazekiel]

Icons of this. It shall be done.

Gorgeous, gorgeous.

Re:I want my 5 minutes back

[Anonymous Coward]

Here's your five minutes back. The balance of eternity is for people that understand how wondrous this is.

By the way, you are wrong about the "Slashdot whore" part, just so you know. Sites like "Bad Astronomy" qualify as being one of the main reasons Slashdot was created.

Beautiful.

[robably]

Seeing the images, running us through the thought process - lovely. More stories like this, please. It was fascinating and wonderful.

Two serious questions:

[Anonymous Coward]

1) What sort of freaky small time window and lighting conditions do they need to get a picture at a range of 185 km, and can they do it consistently? That's insanely close for how fast this spacecraft is traveling across the surface of the moon, and for the lighting conditions.

2) Unrelated, but what the hell are those things at lower left (and two of them crossing in upper-mid-to-upper-right)this pic from a more more sane 17000 km? Ridiculously long crater chains from ejecta, or something rolling/bouncing "downhill"? Seems weird that it could roll "downhill" through a crater without altering its path, so I'm leaning towards crater chains from ejecta, but they seem pretty wildly extended for crater chains, yet are too varied in direction to suggest faults. Where was this relative to the "tiger stripes"?

Least comments ever.

[DeionXxX]

This article has the least comments I've ever seen for an article on the homepage. Only 16 comments after 7+ hours. What's happening with Slashdot??

Re:I want my 5 minutes back

[jd]

No, he CAN'T have his five minutes back - you know the rules, no refunds on Slashdot except through the complaints department.

"The Bad Astronomer" has been around long enough, and has enough credibility, that anyone who claims he's a karma whore is de-facto neither a nerd nor a geek and should gerroff our collective lawns.

Obvious Geometry is indeed Obvious. This guy, Euclid, wrote some of the Obvious Geometry down and used it as a teaching manual. Nobody had done that before. Everyone in his time knew the rules he was describing (Archimedes regarded them as insultingly simple), but few had understood the fundamentals (what was axiomatic, what was derivative) and absolutely nobody had thought of actually explaining things before. The result of him doing so caused the number of mathematicians and their skills to explode. The learning curve had become dramatically shallower.

This is really no different. Sure, it's basic but the learning curve of WHY it works, HOW it works and WHEN/WHERE it can be used is NOT common knowledge. This makes teaching the relationship of maths and astronomy a cakewalk. I have no objections to more people seeing why geometry and maths are relevant (a common complaint is that they aren't ever used anywhere, but that's because nobody explains why, yes, they are). I regard it as the sole opportunity for turning the world into people who can think for themselves.