While I realize you are making a whimsical statement that I can agree with (I've never seen an aurora either), in case somebody out there doesn't know the real reason auroras show up at high latitudes (Canada etc) is that when the charged particles from the Sun hit Earth's magnetic field, these particles all follow the "magnetic field lines" to Earth's North and South magnetic poles which leads to a concentration effect and the charged particles get thick enough to interact visibly with the atmosphere ("see") when they follow the field lines right into the atmosphere towards the poles. How's THAT for a run-on sentence?
Well, that's a real interesting question. We know next to nothing about radiation and a Mars mission, in fact the one instrument that got knocked out on the latest Mars orbiter was the radiation meter that was supposed to give a baseline reality check for a manned mission. Better luck next time getting that data, I guess. Solving the radiation problem is the hidden agenda for manned 21st century spaceflight that people don't even realize is a problem. The Apollo capsule had enough "shielding" to make a single back-and-forth trip thru the Van Allen belts because it was designed with sturdy walls to be a re-entry capsule. Even so, during Apollo they had to keep the sun under continuous observation and they were prepared to abort a launch if there had been a big solar flare, which is what causes short-wave radio communications and bright auroras on Earth every so often and would KILL an Apollo crew deader than a doornail if they were running a mission at the time. There was actually a contingency plan - I kid you not - that if a solar flare started after a moon landing, the guys on the moon could cover the LEM with dirt for shielding and wait the flare out before coming home - too bad, the guy orbiting the moon had no chance at all. Check this out...it includes the following quote: "...as an example the August 1972 flare, which it says could have subjected an unshielded astronaut to 20,000 REM in 14 hours....The 1972 flare took place between the Apollo 16 and Apollo 17 lunar expeditions. Had it occurred during an Apollo expedition the astronauts would have been incapacitated immediately and dead within hours or days...."
20,000 REM in 14 hours? 500 REM kills half the people exposed and leaves the survivors sick as dogs, 1000 REM kills everybody. How the hell do you shield against something like this? Very good question. You just about can't protect "the whole ship" because the shielding mass is just too great to lug around. Most concepts for Mars missions include something called a "storm shelter" concept which usually winds up being a coffin-sized hideaway in the middle of the mission water tanks. The closer you look the worse the problem becomes. THere's a lot of talk also about using superconducting magnets to set up a mini-magnetic field around the spacecraft (just like Earth's) but no hard engineering on just what it would take to get the job done....
The difference between StarTrek and reality is profound. Routine spaceflight to the moon is likely to always be a mad dash to/from the shelter of Earth's magnetic field to a shelter covered with moondirt. Guess wrong, get fried. All of these orbiting hotel concepts haven't done their homework. Space is a BRUTAL environment. It's worth going there anyway.
What's necessary would be to move ISS from 17,000 MPH (it's current Earth orbital speed) to 25,000 MPH (Earth to moon escape speed). This sounds like only a 50% increase in current speed but energy goes as the square of the speed so we would have to DOUBLE the current kinectic energy of the space station to send it to the moon. This is probably do-able using ion drive thrusters if there was some REALLY REALLY COMPELLING reason to do so - it wouldn't be easy.
However, the PROBLEM comes in that if we did this, the station would be making once-per-week trips thru the Van Allen radiation belts and exposed to raw solar wind / flares during the moon-half of the voyage, none of which it was designed to withstand and which would fry the crew and electronics pretty damn quick. People don't realize just how much protection from space radiation the Earth's magnetic field gives at an orbit of 200 miles or so, and how bad things get above that altitude. In a hurry.
Another problem is the logistics of carting the fuel up to allow back-and-forth transitions from 17,000 MPH to 25,000 MPH to allow crew and supply transfers. If you do the math, it ain't pretty and we sure can't afford to do it routinely at the $10,000 per pound the Shuttle costs.
PLUS when we included the Russians in the ISS program we put it in this weird (57 degree inclined) orbit that the Russians can get to with their far-north launch sites and it is the worst possible orbit (just about, a polar orbit is the dead worst) to suddenly make a break for the moon....
Nice idea, tho. I think we should be doing lunar exploration too.
This is a 1040. US citizens fill one out every year and send it in to the Internal Revenue Service (our friendly government tax people) on April 15. Check here for the complete list of fun-to-fill-out IRS forms. US law says the IRS doesn't actually have to have your 1040 in their grubby little hands on April 15, just that when they DO get it, it had better be in an envelope postmarked April 15. This rule leads to all kinds of crazy stuff happening on April 15, with postal people dressing up in monkey suits and standing by specially designated drop points until midnight....
Hey! A Chtorr reference! Which of these 42 worlds do ya think is the Chtorr homeworld? When's the next novel coming out? The last one I read was about the airship expedition over the Amazon, ending with Jim and Liz getting medi-vaced out of the rain forest...to be continued....
Even MORE interesting is THIS image from the press kit that shows not only lots of water at the south pole but a significant concentration around the north pole and best of all - three or four EQUATORIAL (read warm) spots that seem fairly wet. Oaises, anyone? We just found our landing sites...
Re:Compare To Photos of Martian South Pole Reveals
on
Lots of Ice On Mars
·
· Score: 2
Even MORE interesting is THIS image from the press kit that shows not only lots of water at the south pole but a significant concentration around the north pole and best of all - three or four EQUATORIAL (read warm) spots that seem fairly wet. Oaises, anyone? We just found our landing sites...
Compare To Photos of Martian South Pole Reveals..
on
Lots of Ice On Mars
·
· Score: 2
What's really interesting is to compare the neutron maps with photo maps of the Martian ice cap on the south pole here. You've got to be careful about the scale and orientation of these two images, since they are totally different (90 degrees is at three-o-clock on the neutron map, nine-o-clock on the photo map) but what's really facinating is that the visible ice pack is not circular-symmetrical around the pole and the neutron data IS.
A couple of comments. First, this is an old idea - cyclers have been proposed for over 20 years and Aldrin's seminal addition to the concept was made in 1985 - see here for details. My question is, why is this meme back in the public consciousness NOW? It can't be because Aldrin thinks Bush will support the concept now that he's Prez; the new Bush NASA is going exactly the opposite route than cyclers with their sudden support of nuclear propulsion. Second question, where did the sudden push for NASA nukes come from? Especially at the expense of previously planned missions to Pluto and Europa? And my third question, why is space so passe to Slashdotters and by extension tech oriented fans in general? All the space articles on Slashdot get one-tenth to one-quarter the postings of just about any other topic; if even the geeks don't care about space that much any more, how can we ever hope to have a stable space program instead of this outer plane probes / no wait, nuke rockets / no wait, cyclers mass confusion?
Here's more than you ever want to know about spina bifida / hydrocephalus and how it generally affects those who have it - one of whom talks about it here. One study on IQ follow-up is here but it only says the expected problems result. My wife is a labor / delivery nurse and sees this pretty frequently, it's not pretty and just about always causes neurological damage....
The key to consciousness is in the ORGANIZATION of the neurons in the "proportionally sized" area of interest. When they show us micrographs that indicate the wiring is identical between men and other apes, then maybe I'll change my mind, but not before. You have some people (hulking linebackers) with big heads and brains (literally) and others (petite cheerleaders) with small heads and brains - but they both are equally intelligent humans (sort of...)
Now THIS is a great analogy. I'll bet you did pretty well on the SAT...
Guys in Glass Houses....
on
Tandys Never Die
·
· Score: 3, Informative
...shouldn't throw rocks. There was really no such thing as a uber-TRS-80. It was a code designation for a number of computers made by Tandy Radio Shack using the Z-80 microprocessor. The Model 100 portable was as much of an "official" TRS-80 as the original Model I or business-oriented Model II or FCC-approved Model III etc etc etc....
If you want to buy one, go to EBay. Notice the TRS-80 moniker located upper right in the photo...
This poster is trying to get the basic facts and these are the basic facts. Getting into how neutron bombardment of a lithium wall will produce far more tritium that needed for the reactor, and how this surplus tritum will almost certainly end up in the US nuclear weapons program (which I don't necessarily think is a bad thing) is really irrelevant to the level of basic understanding this poster is trying to achieve for him(her?)self...
We looked at GPS and yeah, they're cheap, and yeah, they're accurate, and nope, they won't pick up a satellite signal inside the basement where all the emergency EMA computers are, and it's easier to just put in a clock card than it is to put the GPS where it can pick up the signal and then run a serial port line from the GPS to the computer.
Now, if Garmin came out with a cheap GPS that plugged directly into ethernet instead of a serial port, then we'd have something....
A pound of lithium or sodium will absorb a LOT more heat than a pound of solder, so by using reactive alkali metals you have a lot less stuff to pump around than if you used something else as a coolant. Pumping a lot less stuff means a simpler system, and that's always good.
Also, the key reason (which isn't even mentioned in the ABC article) for using lithium is that when lithium is hit by the fusion reactor's neutrons, it will change into radioactive tritium gas, which is a rare fuel the fusion reactor needs to keep going. So you start the reactor with a little bit of tritium you got someplace else, then use the reactor's own neutrons to convert common metal (lithium) into the rare fuel you need to keep it going. No other metal - sodium, lead or tin included - will do this, only lithium.
You are the smartest person in this whole thread, pal - instead of showing your ingnorance by stubbornly defending a particular position with facts (me included), you openly admit the things you don't know and ask intelligent questions to make yourself more knowledgable. Do not ever lose this open mind you have - it is much more rare than tritium gas.
Time Shifts Can Be A Matter Of Life Or Death
on
Weird PC Clock Behavior?
·
· Score: 4, Informative
I know where you are coming from! This time shift has been a major headache for me at work. My group installs computer systems at emergency management agencies (EMAs) that selectively trigger radios by a precoded geographical zone or serial number. We have a security feature in our broadcast that is basically a time stamp - the radio rejects a broadcast if the timestamp is more than 5 minutes off its internal clock. This prevents somebody from taping a monthly test message and rebroadcasting it at three in the morning to falsely trigger the radios. Well, at the EMAs they just want to sit down at the PC during an emergency and click on a button - so the PC is ignored until it's really needed and then they don't want to waste time checking to see if the clock has jumped. If it has, oops, the broadcast timestamp doesn't match and the radios don't trigger!!!
We have never figured out how to stop the computer time from jumping and if anyone else has, please let me know! The workaround solution we've come up with is to either install a network time update program running in the background if the computer is on the web (for examples, search for "time sync" hereor for the more common rural EMAs that have no Internet connection, we install clock boards. We have found three sources for clock boards: Beagle Software, OutSource and ICS Advent. The Beagle product is ISA only, the OutSource product only works with Win 2000/NT (not Win 95/98) and the ICS product is far and away the most expensive. If anybody knows of others besides these three, please let me know!
Slashdot Mirror
While I realize you are making a whimsical statement that I can agree with (I've never seen an aurora either), in case somebody out there doesn't know the real reason auroras show up at high latitudes (Canada etc) is that when the charged particles from the Sun hit Earth's magnetic field, these particles all follow the "magnetic field lines" to Earth's North and South magnetic poles which leads to a concentration effect and the charged particles get thick enough to interact visibly with the atmosphere ("see") when they follow the field lines right into the atmosphere towards the poles. How's THAT for a run-on sentence?
Well, that's a real interesting question. We know next to nothing about radiation and a Mars mission, in fact the one instrument that got knocked out on the latest Mars orbiter was the radiation meter that was supposed to give a baseline reality check for a manned mission. Better luck next time getting that data, I guess. Solving the radiation problem is the hidden agenda for manned 21st century spaceflight that people don't even realize is a problem. The Apollo capsule had enough "shielding" to make a single back-and-forth trip thru the Van Allen belts because it was designed with sturdy walls to be a re-entry capsule. Even so, during Apollo they had to keep the sun under continuous observation and they were prepared to abort a launch if there had been a big solar flare, which is what causes short-wave radio communications and bright auroras on Earth every so often and would KILL an Apollo crew deader than a doornail if they were running a mission at the time. There was actually a contingency plan - I kid you not - that if a solar flare started after a moon landing, the guys on the moon could cover the LEM with dirt for shielding and wait the flare out before coming home - too bad, the guy orbiting the moon had no chance at all. Check this out...it includes the following quote: "...as an example the August 1972 flare, which it says could have subjected an unshielded astronaut to 20,000 REM in 14 hours....The 1972 flare took place between the Apollo 16 and Apollo 17 lunar expeditions. Had it occurred during an Apollo expedition the astronauts would have been incapacitated immediately and dead within hours or days...."
/from the shelter of Earth's magnetic field to a shelter covered with moondirt. Guess wrong, get fried. All of these orbiting hotel concepts haven't done their homework. Space is a BRUTAL environment. It's worth going there anyway.
20,000 REM in 14 hours? 500 REM kills half the people exposed and leaves the survivors sick as dogs, 1000 REM kills everybody. How the hell do you shield against something like this? Very good question. You just about can't protect "the whole ship" because the shielding mass is just too great to lug around. Most concepts for Mars missions include something called a "storm shelter" concept which usually winds up being a coffin-sized hideaway in the middle of the mission water tanks. The closer you look the worse the problem becomes. THere's a lot of talk also about using superconducting magnets to set up a mini-magnetic field around the spacecraft (just like Earth's) but no hard engineering on just what it would take to get the job done....
The difference between StarTrek and reality is profound. Routine spaceflight to the moon is likely to always be a mad dash to
What's necessary would be to move ISS from 17,000 MPH (it's current Earth orbital speed) to 25,000 MPH (Earth to moon escape speed). This sounds like only a 50% increase in current speed but energy goes as the square of the speed so we would have to DOUBLE the current kinectic energy of the space station to send it to the moon. This is probably do-able using ion drive thrusters if there was some REALLY REALLY COMPELLING reason to do so - it wouldn't be easy.
However, the PROBLEM comes in that if we did this, the station would be making once-per-week trips thru the Van Allen radiation belts and exposed to raw solar wind / flares during the moon-half of the voyage, none of which it was designed to withstand and which would fry the crew and electronics pretty damn quick. People don't realize just how much protection from space radiation the Earth's magnetic field gives at an orbit of 200 miles or so, and how bad things get above that altitude. In a hurry.
Another problem is the logistics of carting the fuel up to allow back-and-forth transitions from 17,000 MPH to 25,000 MPH to allow crew and supply transfers. If you do the math, it ain't pretty and we sure can't afford to do it routinely at the $10,000 per pound the Shuttle costs.
PLUS when we included the Russians in the ISS program we put it in this weird (57 degree inclined) orbit that the Russians can get to with their far-north launch sites and it is the worst possible orbit (just about, a polar orbit is the dead worst) to suddenly make a break for the moon....
Nice idea, tho. I think we should be doing lunar exploration too.
For example, like this...
Boy, oh, boy, moving money from science to ISS may be illegal, but I guaran-damn-tee you it has happened by the billions....
This is a 1040. US citizens fill one out every year and send it in to the Internal Revenue Service (our friendly government tax people) on April 15. Check here for the complete list of fun-to-fill-out IRS forms. US law says the IRS doesn't actually have to have your 1040 in their grubby little hands on April 15, just that when they DO get it, it had better be in an envelope postmarked April 15. This rule leads to all kinds of crazy stuff happening on April 15, with postal people dressing up in monkey suits and standing by specially designated drop points until midnight....
Hey! A Chtorr reference! Which of these 42 worlds do ya think is the Chtorr homeworld? When's the next novel coming out? The last one I read was about the airship expedition over the Amazon, ending with Jim and Liz getting medi-vaced out of the rain forest...to be continued....
Even MORE interesting is THIS image from the press kit that shows not only lots of water at the south pole but a significant concentration around the north pole and best of all - three or four EQUATORIAL (read warm) spots that seem fairly wet. Oaises, anyone? We just found our landing sites...
Even MORE interesting is THIS image from the press kit that shows not only lots of water at the south pole but a significant concentration around the north pole and best of all - three or four EQUATORIAL (read warm) spots that seem fairly wet. Oaises, anyone? We just found our landing sites...
What's really interesting is to compare the neutron maps with photo maps of the Martian ice cap on the south pole here. You've got to be careful about the scale and orientation of these two images, since they are totally different (90 degrees is at three-o-clock on the neutron map, nine-o-clock on the photo map) but what's really facinating is that the visible ice pack is not circular-symmetrical around the pole and the neutron data IS.
Do it with an old 486 motherboard like this or this or this or this or this or this or this or.....
Cost-free Internet-based images of Earth are available at Terraserver...
A couple of comments. First, this is an old idea - cyclers have been proposed for over 20 years and Aldrin's seminal addition to the concept was made in 1985 - see here for details. My question is, why is this meme back in the public consciousness NOW? It can't be because Aldrin thinks Bush will support the concept now that he's Prez; the new Bush NASA is going exactly the opposite route than cyclers with their sudden support of nuclear propulsion. Second question, where did the sudden push for NASA nukes come from? Especially at the expense of previously planned missions to Pluto and Europa? And my third question, why is space so passe to Slashdotters and by extension tech oriented fans in general? All the space articles on Slashdot get one-tenth to one-quarter the postings of just about any other topic; if even the geeks don't care about space that much any more, how can we ever hope to have a stable space program instead of this outer plane probes / no wait, nuke rockets / no wait, cyclers mass confusion?
Here's more than you ever want to know about spina bifida / hydrocephalus and how it generally affects those who have it - one of whom talks about it here. One study on IQ follow-up is here but it only says the expected problems result. My wife is a labor / delivery nurse and sees this pretty frequently, it's not pretty and just about always causes neurological damage....
The key to consciousness is in the ORGANIZATION of the neurons in the "proportionally sized" area of interest. When they show us micrographs that indicate the wiring is identical between men and other apes, then maybe I'll change my mind, but not before. You have some people (hulking linebackers) with big heads and brains (literally) and others (petite cheerleaders) with small heads and brains - but they both are equally intelligent humans (sort of...)
Hey, I got modded down!!! That wasn't sarcasm, I was SERIOUS!
Now THIS is a great analogy. I'll bet you did pretty well on the SAT...
...shouldn't throw rocks. There was really no such thing as a uber-TRS-80. It was a code designation for a number of computers made by Tandy Radio Shack using the Z-80 microprocessor. The Model 100 portable was as much of an "official" TRS-80 as the original Model I or business-oriented Model II or FCC-approved Model III etc etc etc....
If you want to buy one, go to EBay. Notice the TRS-80 moniker located upper right in the photo...
The problem with being a gunslinger is that there's always somebody that's faster on the draw...
Hmmmm.. I meant to say, I had just read Tau Zero, a GREAT sci-fi novel...
I got started on an IBM 1170 in the early 1970s. I was in high school and I had just read - a GREAT sci-fi novel that is all but forgotten today and has been out of print for a while. Anyway, my first punchcard program was a FORTRAN program to calculate time dilation factors for relativistic space flights like the ill-fated Leonora Christine. We were landing on the moon and even kids like me from rural Tennessee were getting on real computers and figuring out the jump to light speed. Heady times. The punch card decks even smelled good.
And BTW, to the AC that's been modded down to -1, I'm hardcore enough to have a 5 digit slashdot ID...
This poster is trying to get the basic facts and these are the basic facts. Getting into how neutron bombardment of a lithium wall will produce far more tritium that needed for the reactor, and how this surplus tritum will almost certainly end up in the US nuclear weapons program (which I don't necessarily think is a bad thing) is really irrelevant to the level of basic understanding this poster is trying to achieve for him(her?)self...
We looked at GPS and yeah, they're cheap, and yeah, they're accurate, and nope, they won't pick up a satellite signal inside the basement where all the emergency EMA computers are, and it's easier to just put in a clock card than it is to put the GPS where it can pick up the signal and then run a serial port line from the GPS to the computer.
Now, if Garmin came out with a cheap GPS that plugged directly into ethernet instead of a serial port, then we'd have something....
A pound of lithium or sodium will absorb a LOT more heat than a pound of solder, so by using reactive alkali metals you have a lot less stuff to pump around than if you used something else as a coolant. Pumping a lot less stuff means a simpler system, and that's always good.
Also, the key reason (which isn't even mentioned in the ABC article) for using lithium is that when lithium is hit by the fusion reactor's neutrons, it will change into radioactive tritium gas, which is a rare fuel the fusion reactor needs to keep going. So you start the reactor with a little bit of tritium you got someplace else, then use the reactor's own neutrons to convert common metal (lithium) into the rare fuel you need to keep it going. No other metal - sodium, lead or tin included - will do this, only lithium.
You are the smartest person in this whole thread, pal - instead of showing your ingnorance by stubbornly defending a particular position with facts (me included), you openly admit the things you don't know and ask intelligent questions to make yourself more knowledgable. Do not ever lose this open mind you have - it is much more rare than tritium gas.
I know where you are coming from! This time shift has been a major headache for me at work. My group installs computer systems at emergency management agencies (EMAs) that selectively trigger radios by a precoded geographical zone or serial number. We have a security feature in our broadcast that is basically a time stamp - the radio rejects a broadcast if the timestamp is more than 5 minutes off its internal clock. This prevents somebody from taping a monthly test message and rebroadcasting it at three in the morning to falsely trigger the radios. Well, at the EMAs they just want to sit down at the PC during an emergency and click on a button - so the PC is ignored until it's really needed and then they don't want to waste time checking to see if the clock has jumped. If it has, oops, the broadcast timestamp doesn't match and the radios don't trigger!!!
We have never figured out how to stop the computer time from jumping and if anyone else has, please let me know! The workaround solution we've come up with is to either install a network time update program running in the background if the computer is on the web (for examples, search for "time sync" hereor for the more common rural EMAs that have no Internet connection, we install clock boards. We have found three sources for clock boards: Beagle Software, OutSource and ICS Advent. The Beagle product is ISA only, the OutSource product only works with Win 2000/NT (not Win 95/98) and the ICS product is far and away the most expensive. If anybody knows of others besides these three, please let me know!