11 June 2004

Puzzle 'Toon thoughts

Editor,

Thanks, Forrest. In my opinion, part of solving problems (puzzles, science...) is creating tools to help find the solution. Knowing what is out there to help you is key. Maybe I can come up with some more puzzles that forces the solver to create some tools either on the computer or otherwise.

Brian Mansfield

Brian sent this in response to this about his Puzzle 'Toon of 4 June 2004: "Brian, Very nice solution. I especially like the way you used the spreadsheet to find the solution. Thanks for another great contribution. Forrest. This is published with Brian's permission. Editor.

Time machines

I enjoyed the poignant writing of Mr. Mims's responses to time machines [see "Forrest Mims' World of Science," 30 January 2004, www.sas.org/E-Bulletin/2004-01-30/mimsci/index.html].

However, he could have pointed out that, due to the speed of light, that the real time machine would be an optical telescope that would show distant planets many years previous to the current events of the planet. If we had a telescope in space that was millions of light years from Earth, we would see the evolution of hominids.

Regards,

Douglas Graham

An observer at the telescope would see Earth as it appeared when photons of light emitted from the Earth reached the telescope. Thus, if the telescope is 1,000,000 light years from Earth, the observer would indeed see the Earth as it appeared 1,000,000 years earlier. However, the observer would have to be at the distant telescope and not on Earth. For unless there is a method of sending signals from the distant telescope to Earth at much faster than the speed of light, signals sent by the telescope to Earth would also require 1,000,000 light years to arrive, thus canceling any time machine effect. Editor.

Satellite weather images

Dear Forrest,

Several people have mentioned to me that the following statement in my article ["Direct reception of satellite weather images," 4 June 2003, www.sas.org/tcs/weeklyIssues/2004-06-04/feature1/index.html] caused some confusion:

"If you live in the Northeastern United States like I do, the NOAA 12, NOAA 15 and NOAA 17 polar orbiting satellites zip overhead several times a day making real-time observations of weather."

Actually, this is accurate but incorrectly worded.  It would be equally correct if you live on Geronimo Creek, Texas, or in China or Russia or anywhere else in the world for that matter. 

I will admit to using a very poor and confusing choice of words in that statement.  Someone may get the false impression that the NOAA satellites only fly over the Northeastern United States. That is definitely incorrect!  They cover the entire globe.  My apologies if I had caused any confusion.

Mike Dziekan
Connecticut Analytical Corporation

Thanks, Mike, for the clarification. Because I have been comparing ozone and haze measurements made by satellites with those made by my homemade ground instruments for 15 years, this slipped right by. Looks like you and I are kindred spirits when it comes to satellite monitoring! Editor.