Saturday, September 05, 2009

Early September ISS Shuttle passes in Chicago

See the International Space Shuttle and the Shuttle together in orbit here in Chicago:

1 comment:

Anonymous said...

Dear Dean W. Armstrong
I was searching the net for ion chamber and radioactivity measurement.
Found your blog and have read your article about “A simple ion chamber to measure radioactivity”.
It is so interesting and useful.
I have a scientific question and I don’t know is it ok to ask you?
If know and possible, please help me.
Let me tell you what is the story.
I live in a historical city. using metal detector to find ancient coins, metals,….
But I have experienced a phenomenon at least strange for me.
Metal detector can find old(ancient)metals more deeper than fresh metals under the soil.
But when I touch the soil or move it or take out that metal from the soil,
Metal detector can not find same target from previous distance.
For example detector can find an old silver coin from 40 cm but if I change or move the soil on top of or around the target or take it out, the detector just can find it from 20 cm.
This is famous between people as “gold gas”,” silver gas”,…
Some times this phenomenon causes false signal or lead to false position.
I don’t know what is this. ionization? electrostatic field?....
Is it detectable by another techniques? is it traceable from far by another instruments?
Some sites named as “ghost wave” or “ghost signal” but no explanation.
I couldn’t find any suitable answer for it.
If possible, would you please direct me?
Thank you
Best regards