Tonight, for the August 2 science news, I'm
going to change the format once again to a layout that I think
will improve it for everyone. I have been stockpiling news items
so that on the weekends, I could present 50 new articles a day
when nothing was coming in. I've also squirreled away what seemed
to me to be some of the more interesting articles so that the
weekends wouldn't be a letdown. The problems are
(1) I'm accumulating articles faster than I can I can publish them, including some of the more interesting articles that never see the light of day;
(3) some of the news becomes stale before it"s presented; and
(2) I'm making more work for myself by copying articles to a backlog page and then re-copying them to the Science News page.
Consequently, what I'm going to do, beginning tonight, is to present all the articles I collect each day, however many that may be, and then issue on weekends whatever I find. There are some weekend updates, and I'll publish those, but it means that the number of articles won't be fixed, but will fluctuate from day to day, depending upon how much is available. This should have the benefit of providing you with more, and more timely news. Anyway, we can try it and see how it works.
Tonight, I'm including a part of my backlog, so there will be a greater number of articles in tonight's news than usual. Hope you enjoy them!
7/31/2001: The "Word(s) of the Day" have been modified to make them multiple choice so that over time, they can contribute to vocabulary quizzes..
7/30/2001: On the 24th of June, I mentioned,
"A couple of years ago, NASA's Marshall Flight Center conducted a "tethered satellite" experiment employing a 20-kilometer-long wire to generate electricity using the Earth's magnetic field. Before the wire was fully deployed, it mysteriously snapped in two. Tonight, I ran into Dr, Nobie Stone, the scientific principal investigator for the project, and my former co-worker. Nobie told me that the reason the tether broke was because of the 3,500 volts it had generated.. Although the Earth's magnetic field is small---0.5 gauss---the tether is so long---2,000,000 centimeters---and the satellite moves so fast---8 kilometers or 800,000 centimeters---per second, that high voltages, and kilowatts of power can be generated. The wire was about 1/16th of an inch in diameter, and was insulated with teflon. At some point, as the onboard winch was unreeling the wire, a spot on the wire with a nick in its teflon insulation passed through the eye of the cross-feeder that was paying out the wire. With 3,500 volts on the wire, a dielectric breakdown occurred. An arc formed, with about 1 ampere of current flowing from the wire back to the satellite. The teflon vaporized and formed a plasma, which finished the job of melting the wire.
"At that point, our conversation was interrupted. As he turned away, Nobie mentioned that you could run current the other way, into the wire, and use it as an electric motor to propel the wire (and presumably, the satellite). I didn't get a chance to ask about the logisitcs of the situation, but I will the next time I see him. How practical is this for spacecraft propulsion, and if it's very practical, what are NASA's plans for employing it? (It would transfer momentum to the Earth through the Earth's magnetic field.) "
I called Nobie that night but didn't hear back from him. Last week, his wife, Margaret, explained that they had had to rush Nobie's 90-year-old aunt to the Emergency Room that night, and that's why he didn't call me back. Tonight, I asked him about using a tether as an electric motor in the Earth's one-half gauss magnetic field to accelerate a satellite out of Earth orbit. Nobie explained that it can possibly be done. It requires hanging weights on both ends of the wire so that it will remain upright and taut during the acceleration, with the lower weight feelng a slight net-gravitational- orce and the upper weight responding to a slight net-centrifugal force. He said that it's not one of the most hotly-pursued propulsion technologies, but that it is in the running.
Sorry. Haven't had time for additional "Colonizing Mars" updates today.
Dan Thompson has finished his "Sherlock Holmes Adventures on the Red Planet" story. As you'll soon see, Dan is an accomplished author, illustrator, and much more. His stories on his "Mars" website are only the tip of the iceberg.
7/29/2001: Tonight's updates to "Colonizing Mars" are shown in green.