I'm in a inside childrens playground in Nowra (2 hours south of where we live) and while Dirkie is experimenting with slides and friction and Hanorah is trying to put matching blocks together, thanks to the powers of 3G and a laptop I can still can do some of the things I want to do (Which isn't writing weblog entries :-)
Right now I'm streaming the pre-launch video of the launch of the STS-127 Space Shuttle mission. According to the e169-stats program, it downloads about 600 kilobytes per minute. Per hour that is 36 megabytes. Per day that is 864 megabytes. With less than 24 hours to go for the scheduled launch tomorrow at 09:36 AM Sydney time (we're playing the waiting game now), this will cost me less than 1/5th of my monthly total. If I would leave it on for the next 24 hours that is.
Right now the video is the Space Shuttle on the launchpad with not much happening - Now and then a bird flies by, somebody walks in front of a light etc. It must be very cheap MPEG encoding: Just send one full frame and nearly zero-length update frames.
Yay go STS-127!
The Voyager space probe, launched in 1977 and at this moment happily traveling outside our solar system, gets its electrical power via the heath caused by the decay of plutonium.
Since the half-life of plutonium, and the elements it decays into, is known, "aliens" can use it determine the age of the space craft.
At least that was until today, when I read the following article: Evidence for Correlations Between Nuclear Decay Rates and Earth-Sun Distance:
Unexplained periodic fluctuations in the decay rates of 32 Si and 226 Ra have been reported by groups at Brookhaven National Laboratory (32 Si), and at the Physikalisch-TechnischeBundesandstalt in Germany (226 Ra). We show from an analysis of the raw data in these experiments that the observed fluctuations are strongly correlated in time, not only with each other, but also with the distance between the Earth and the Sun. Some implications of these results are also discussed, including the suggestion that discrepancies in published half-life determinations for these and other nuclides may be attributable in part to differences in solar activity during the course of the various experiments, or to seasonal variations in fundamental constants.
If this is true (for real, the reality, ...) then the "aliens" will have a hard time figuring out the age of Voyager!
In addition to repeating long-term decay measurements on Earth, measurements on radioactive samp les carried aboard spacecraft to other planets would be very useful since the sa mple-Sun distance would then vary over a much wider range.Not limited to any knowledge in this field (besides the principles about decay of elements and their halflife, taught at science classes at high school), this is very intriguing stuff!