More Junkmail from Bob!
Monday, February 28, 2000
Important Stuff.
Imagine a world with lots of big volcanoes. In fact, they're so big that they shoot lava 190 miles high. The atmosphere is mostly sulfur dioxide. There is enough radiation to kill people and some computers. This is a moon that orbits a large planet. The gravitation fluctuations from surrounding bodies are enough to cause the surface to distort more than 300 feet as it orbits the planet once or twice a day.
As this moon orbits, it passes through the planet's magnetic lines of force generating a huge electric current causing lightning in the planet's upper atmosphere. The magnetic field pulls about a ton of matter from the moon every second, creating a large plasma torus on the planet's surface and a huge aurora in the atmosphere.
Pretty unbelievable huh?
In the year 1610, an Italian guy named Galileo discovered Io, Jupiter's third largest moon. That's the place I've just described. Io is a little bigger than our moon, and a little farther from Jupiter than our moon is from earth. It's the most volcanically active place in the solar system. In the 1960's I think they named computer input/output operations after this moon.
Last week, the Galileo spacecraft flew by Io, only 124 miles away! That's impressive, considering how far away it is and how big the moon is. It's also pretty amazing that Galileo is still working great more than 10 years after its launch in October 1989.
The factors limiting Galileo's longevity are its plutonium supply and money. It generates electricity from plutonium generators. If you have an irrational (or rational) fear of radiation, don't worry. Galileo is far enough away that it won't hurt you, although the radiation from Jupiter, not Galileo, would fry you pretty quick if you were there. There are about 300 people working on the Galileo project at NASA, and they have to beg to Congress for funding every two years.
Galileo takes pictures and transmits them back to earth at the amazing transmission rate of about 160 bits per second. By comparison, your modem is probably capable of 56,000 bits per second. The computers on Galileo are 1989 vintage, but they had to be specially made to stand up under space travel and Jupiter's radiation. This means that they weren't even as fast as the personal computers in 1989. They have 8-bit microprocessors about as fast as the Apple II from the late 70's, and that's SLOW. But they still work!
The data from last week's pass will be available in October or November. On July 3 the Galileo spacecraft made a pass within about 78,000 miles of Io. Here's a picture from that fly by, in visible colors. Io is yellow! It's the sulfur.
io.jpg
Here's a 1 megabyte hi-resolution image of the same thing:
iobig.jpg
They expected Galileo to work for about 2 years after it started orbiting Jupiter, but it's been going strong since it arrived in 1995. We hear in the news a lot about NASA failures, but successes like Galileo get overlooked a lot of the time.
NASA has a really good web site on Galileo:
http://www.jpl.nasa.gov/galileo/index.html
The NEAR spacecraft is a satellite, but it's a satellite around a 21-mile long asteroid. NEAR stands for Near Earth Asteroid Rendezvous. It was launched a little over 4 years ago and has finally made it to its target asteroid.
Near Earth Asteroid 433, called Eros, ranges between about 105 and 165 million miles from the sun -- that's a little outside earth's orbit to a little outside Mars's orbit. It qualifies as a near earth asteroid because it comes within 121 miles of the sun. At 21 miles long, it's one of the larger asteroids in the area.
A 100-lb. person on Eros would weigh about an ounce. Or a 50-kg person would weigh 30 grams (unless I messed up that higher mathematical calculation.) Escape velocity on Eros is a stunning 22 miles per hour! Escape velocity is the speed that an object leaves orbit. If you threw a golf ball fairly easily on Eros, it would fly off into space. You could throw it really easy and it would either orbit or come back down.
They launched NEAR in 1996 and it headed up into the sky and left earth's orbit. It was supposed to enter orbit around Eros a year ago last December, but when they fired the thrusters NEAR stopped communicating for a day or so. After some panicking on Earth, NEAR finally reset itself but they had to wait a year to try it again. It worked this time. It's the first time a spacecraft has orbited an asteroid.
Here are some good Eros photos:
eros9.jpg
eros7.jpg
eros8.jpg
Here's an mpeg movie of Eros rotating. (It's 3.7 meg so it will be a little slow downloading):
eros.mpeg
It looks a lot like a big rock with craters. Maybe that's because that's what it is. I think it's got a lot of metal in it compared to earth rocks, though.
NEAR is a couple hundred miles or so from Eros now, but they're going to gradually take it down to a 20-some mile orbit. That should really get some detail.
I think integer sequences, the "what comes next" problems, are interesting. A guy named Neil at AT&T Research has a really neat web page -- you give it some integers in a sequence, and it tells you what comes next and why. I tried it with 1, 8, 27, 64, and 125, the cubes of 1, 2, 3, 4, and 5. It came up with:
The cubes: a(n) = n^3
0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 1000, 1331, 1728, 2197, 2744, 3375, 4096, 4913, 5832, 6859, 8000, 9261, 10648, 12167, 13824, 15625, 17576, 19683, 21952, 24389
Denominator of sum of -3 th powers of divisors of n.
1, 8, 27, 64, 125, 6, 343, 512, 729, 500, 1331, 432, 2197, 343, 375, 4096, 4913, 648, 6859, 4000, 1323, 2662, 12167, 384, 15625, 8788, 19683, 2744, 24389, 125, 29791, 32768, 3993, 19652, 6125, 46656,
Digits d in decimal expansion of n replaced with d^3.
0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 10, 11, 18, 127, 164, 1125, 1216, 1343, 1512, 1729, 80, 81, 88, 827, 864, 8125, 8216, 8343, 8512, 8729, 270, 271, 278, 2727, 2764, 27125, 27216, 27343, 27512, 27729, 640, 641, 648, 6427, 6464, 64125, 64216, 64343
Cubes with at most three different digits.
0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 1000, 1331, 2744, 3375, 8000, 27000, 46656, 64000, 238328, 343000, 778688, 1000000, 1030301, 1331000, 5177717, 7077888, 8000000, 9393931, 27000000, 64000000, 343000000, 700227072
Cubes lacking the digit zero in their decimal expansion
1, 8, 27, 64, 125, 216, 343, 512, 729, 1331, 1728, 2197, 2744, 3375, 4913, 5832, 6859, 9261, 12167, 13824, 15625, 17576, 19683, 21952, 24389, 29791, 32768, 35937, 42875, 46656, 54872, 59319, 68921, 85184, 91125, 97336, 117649, 132651, 148877
Cubes of palindromes
0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 1331, 10648, 35937, 85184, 166375, 287496, 456533, 681472, 970299, 1030301, 1367631, 1771561, 2248091, 2803221, 3442951, 4173281, 5000211, 5929741, 6967871
Cubes containing no pair of consecutive equal digits
0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 1728, 2197, 4096, 4913, 5832, 6859, 9261, 10648, 12167, 13824, 15625, 17576, 19683, 21952, 24389, 29791, 32768, 35937, 39304, 42875, 50653, 54872, 59319, 68921, 79507, 85184, 103823, 132651, 140608
Cubes whose digits occur with the same frequency.
0, 1, 8, 27, 64, 125, 216, 512, 729, 1331, 1728, 2197, 4096, 4913, 5832, 6859, 9261, 10648, 13824, 19683, 24389, 32768, 42875, 54872, 68921, 205379, 238328, 287496, 328509, 389017, 421875, 438976, 592704, 681472, 804357, 912673, 2460375
Cubes containing no palindromic substring except single digits.
0, 1, 8, 27, 64, 125, 216, 512, 729, 1728, 2197, 4096, 4913, 5832, 6859, 9261, 10648, 13824, 15625, 19683, 21952, 24389, 32768, 35937, 42875, 50653, 54872, 59319, 68921, 79507, 85184, 103823, 132651, 185193, 205379, 274625, 287496, 328509
Cubes whose digits do not appear in previous term.
1, 8, 27, 64, 125, 343, 512, 4096, 5832, 64000, 91125, 300763, 941192, 3375000, 8489664, 13312053, 86444696669696, 100175333300307, 488224224494488, 510657175657000, 2233398984434344, 5177717000000000, 6393843393228864
This supports my complaint I had when I took achievement tests in school, that there were lots of correct answers to the "what comes next" problems.
Here's Neil's web site:
http://www.research.att.com/~njas/sequences/
Quote of the week: "I know that there are people in this company don't like to work here. As soon as I find out who you are, you will be fired."
Day trading is buying and selling stocks, holding them only for a day or a few days. Can you really make money day-trading? I've read once that 77% and once that 80% of day traders end up losing money. There are two things in your favor when you day-trade:
1. The stock market usually goes up
2. Stock prices usually fluctuate back and forth.
There are four things against you when you day-trade:
1. There is a commission on each trade. It's small, but if you have enough trades it becomes significant.
2. The spread between the bid and the ask price of a stock is effectively a commission.
3. If you buy stock on margin (like good day-traders are supposed to), you have interest have to pay in addition to commissions.
4. Like most gambling, when you run out of money you have to stop.
Here's an article that poo-poos day-trading:
http://www.latimes.com/business/cutting/techwr/20000225/tCB00V0255.html
The pictures of today I took behind my house yesterday. There's a trail from my house to Pryor Creek, about half a mile. There are some beavers that live in the creek. When you go there at night they'll wham the water with their tails really loud. It scared me the first time it happened. Maybe that's why they do it. Here are some pictures of some beaver work:
beaver.htm
... and some other pictures:
trail.htm
In Arizona you can vote in the Democratic primary election online! Well, you can if you live in Arizona:
http://nytimes.com/cnet/CNET_0_4_1558656_00.html
On the campaign trail....
at Bob Jones University: "Catholics are baaaad. Vote for me."
George W. Bush, in Massachusetts: "Catholics are good, except for the ones in South Carolina. And the Kennedy's, of course. And that fuel oil Gore wants to give you is coming from Texas, so vote for me."
Reporter: "What about the Catholics in Texas?"
Bush: "We don't have any Catholics in Texas. But if we did, they'd be big Catholics. Vote for me."
McCain: "George W. Bush is a sick slimeball who has the unmitigated gall to campaign negatively. You can see it on my web page
http://www.mccain2000.com: 'Desperate Texas Governor Brings Negative Sleaze Campaign to Old Dominion.'"
Reporter: "But you're calling George W. Bush a sick slimeball and a sleaze. Isn't that negative campaigning?"
McCain: "No, those are the facts. Shut up and vote for me."
I think more negative campaigning would be good -- it might help these guys be accountable. And it's a LOT more entertaining.
Al Gore: "Whoever you are, if I get elected you'll get FREE MONEY from the federal government. Just put your group's name on this list and we'll get you some cash. I'll buy your vote!"
Reporter: "But with the Republican Congress, won't you have trouble with some of these pork barrel projects?"
Al Gore: "You obviously don't understand politics. And I invented the internet. Vote for me."
Bradley: "Vote for me."
Reporter: "Are you still running??"
(g) 2000, All wrongs deserved. Unauthorized copying of Junkmail is viewed with severe apathy. If you want to read old Junkmails, which would make you a very strange person, you can got to
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