Monday, October 19, 2009

Gravity thought experiments

For some reason (probably reading my son "The Magic School Bus Lost in the Solar System"), I started wondering about gravity. I was wondering why my sensation of gravity is just being pulled down, and not to the sides as well. I guess the mass to either side of me in the Earth is roughly equal and thus cancels itself out. Which made me wonder how something would fall if you happened to be standing on the edge of a hemisphere, or if there was a cylindrical space running through the center of the Earth. In the later case I would have thought that something might fall down past the Earth's center overshoot, and them fall back, oscillating until it eventually came to rest a the center. Not sure about the hemisphere example. Seems like something dropped might actually fall diagonally. Of course the natural rest state of objects large enough to have noticeable gravity is a sphere, so such toroidal or hemispherical objects would not occur without some kind of intervention. The funny thing about gravity is that all matter attracts other matter. I don't notice being sucked towards the computer because it has so little mass, but the mass of the Earth is huge and sucks me towards it. I wonder if there are objects in the universe massive enough for gravity to be noticed, but in different shapes so that the force of gravity is felt in directions other than straight down ...?

Tuesday, October 6, 2009

SmartFM Mobile Study Dictionary Upgrade

So I released an upgrade (1.0.1) of the SmartFM android client, adjusting the media type for audio uploads (although the AMR uploads are still only audible on the phone and not the main site) and disabling the voice input when the google speech recognition package is not available. This latter was in response to a marketplace comment from Zom-B about force closing on voice button.

Of course this makes me want to say a few things about the marketplace comments, which are potentially a great resource, but are kind of odd in that they can be signed under any name, and there is no way to reliably communicate back with the people who made the comments. For example, originally SuaveAfro made the comment that the app should support downloading other people's lists. I replied to SuaveAfro in my own comment explaining that that functionality was included. Subsequently SuaveAfro became Havoc, and so I updated my own comment accordingly, but that moved my comment away from the one it was referring to. I guess the solution is that I should update my comment to reflect whatever is my response to the most recent comment, but it seems less than optimal. Would be nice if the commenting framework could link directly to a discussion forum on that app, but I guess that's overkill. Comments are a simple solution - would be nice if they were at least linked to a user's email so I could have a fighting chance of getting responses back to users who are unlikely to look at the comments again after their first download ...