Sunday, October 08, 2006

In Case Details Disappear in the News

I just heard the news this evening that North Korea apparently set off an underground nuclear device this Sunday. According to SFGATE.COM the test was conducted at 10:36 a.m. (9:36 p.m. EDT Sunday) near the city of Kilju (or Kilchu -- depending on your translation). The article went on to say that the USGS hadn't detected any seismic activity in that area, possibly because their sensors weren't sensitive enough.

Oddly, does report a 4.2 magnitude earthquake occuring at 01:35:28 AM UTC (same time as reported test) at the coordinates 41.31N 129.11E at a depth of 0 km, which is roughly the position of Kilju City. FWIW, a 4.2 magnitude earthquake would be about 2kt of TNT worth of energy, although this would only be seismic movement, not necessarily total energy. I haven't found any more information on the relationship of seismic energy to nuclear yield yet, so if anyone has information, please comment.

I took another gander at the USGS world earthquake information site, and I noticed that at about 10:15pm EDT the USGS earthquake network now lists the North Korean earthquake. It's good to know the information is now coming in.

Monday, October 02, 2006

Rovers Racing at Furlongs per Fortnight

About two weeks ago, there was an announcement on the bbc website regarding the upcoming arrival of the Opportunity Rover to Victoria Crater in some two weeks time. The NASA manager in charge of publicity for that day seemed to be really excited by the announcement which made me wonder if the Rover was really cruising or what, since two weeks was a pretty long time when you got to thinking about it. And it was from this point that my mind went off on a tangent.

As anyone with too much time on their hands will tell you, two weeks is the same amount of time as a fortnight. A fortnight is an archane, nigh unto useless unit for time measurement. Yet an even more archane and therefore more useless unit of velocity is the elusive furlong per fortnight, which is about 1cm/minute or 0.000372 miles/hour. A furlong is a distance of exactly 220 yards or just about 200 meters for you metric users. It just so happened that two weeks ago, it appeared to be roughly the distance between the Rover and Victoria Crater according to a map on the Rover's website. There was real serendipity at work here. I was really excited by my discovery and felt compelled to share the news with JPL's Rover Team until I discovered some disturbing news.

A bit more research revealed that many creatures, generally renown for their lack of speed and some renown for their general lack of movement, easily exceeded a furlong per fortnight when cruising along. Creatures you'ld think could easily be passed up by a mechanical wonder like the Mars Rover could beat the Rover handily in a race. Being engineers and all, I thought the Rover Team might want to know. Sadly, no response was forthcoming. :-(

The text of my e-mail follows...


I couldn't help but hear the news that the Opportunity Rover was just 2 weeks away from Victoria Crater. According to your website's map of the Opportunity Rover's path, it appears to be about 200 meters distant from the crater. By my calculations, this means that the rover is travelling at just about one furlong per fortnight. Byron Jones, one of the rover mission managers was quoted on the BBC website as saying, "We're ready to hit Victoria with everything we've got." Which sounded just a bit too enthusiastic for a vehicle that is hurtling towards it's goal at a velocity that wouldn't make a snail break a sweat. In fact, a snail can even go as fast as 80 furlongs per fortnight, so by comparison, the Opportunity rover is stupidly slow. A worse comparison yet is the three-toed sloth which cranks up to something close to 400 furlongs per fortnight. So if the rover was travelling as fast as a sloth, this might be really exciting news. Of course in comparison to the flora rather than fauna, the rover is about 31 times faster than the maximum bamboo growth rate (18" or 45cm per day), so that is saying something.

Congratulations on a job well done with the Opportunity and Spirit rovers.