Although this is probably the best way to use nukes, the problem is in the sentence "Anything that has mass". How much polyethelyne will be required? You're using an extremely powerful energy source but coupling that with a mechanism that needs you to deliver a lot of mass to the asteroid (which is very expensive) to make it effective. Otherwise, with just a little plastic the conversion of nuclear energy to kinetic energy just won't be efficient.
A more efficient use of the (nuclear) energy in the weapons would be to set a reactor down on the surface and use the electricity generated it to power an accelerator to fire bits of the asteroid away. It would, however, take a long time of course (as well as add a lot of complexity). Another idea would be to use the shaped nuclear charge as you previously described but with dug up asteroidal material (couple tons of rocks brought up from the surface by robots?) instead of mass brought from earth. Vaporized rock might not be as good as plastic at absorbing soft X-rays but you could use a lot more. (You'd need radiation hardened robots of course to do this more than once).
Of course you could always forgo the nukes and use my idea for converting the spin rotation of the asteroid into kinetic energy (see comment below).
In 1993 (+/- a year or so), I co-wrote the grant proposal for our NGOs (non governmental organizations) in Los Angeles to the NTIA (National Telecommunications Infrastructure Administration?) which I believe was one of the things Gore got funded. In it we provided 5 community organizations in Los Angeles with internet links (T1 lines), networks, computer classrooms and training to private citizens (kids mainly) from diverse ethnic communities.
We got $100K from the NTIA followed by $150K from PacBell and $100K from Pacific Gas & Electric (I may be a little off on some of these numbers). I think it lasted a couple years. Lots and lots of kids got on line back then. I did it on a volunteer basis but learned a lot.
If the asteroid has any appreciable spin it should be possible to convert it to into kinetic energy to move it off course.
Land a spacecraft at the asteroid's "equator". Extend a long tower/cable into space such that the end is considerably past the asteroid's "geo-sync" point. Securely attach the end of this tower/cable to the asteroid (may require just running a long cable around the entire equator). Get some robots to start collecting, digging up or mining asteroidal material.
The bigger the asteroid (and harder to move) the more rotational energy it will have to move it. Of course you need lots of time (like most methods). Now, just like the speculative "space elevators" proposed for earth, transport the material up the tower/cable. Carefully timing the release of it from the space will send the material in one direction and the asteroid in another. Not fast but could be quite cheap; this system may not even need solar power because some power could be generated by the material as it is slung off beyond the geo-sync point.
If you have the power (actually delta-v) to put it into orbit, why not put it at the L1 point between the Sun and the Earth. Then, send a solar powered rock grinding machine to gradually reduce it to a fine powder. Slowly spray the powder into space (very easy because of the asteroid's negligible gravity) and you'll directly block out the sun. If the powder is fine enough, a few thousand cubic meters of rock should be enough to create a dust cloud hundred's of kilometers square. That'll be enough to reduce incident solar radiation a few percent (enough to compensate for global warming).
Of course the cloud will gradually blow away after a few years of solar wind, so you'll need to keep the machine going. This is a safety feature, you don't want this to be permanent!
If this alien perspective is awesome, thought provoking (or at least makes one pause for reflection) consider what the view would've been like from "Triana".
That was the space probe proposed by Al Gore in 2000 that was an earth looking satellite to be placed at the earth-SUN (not moon!) L1 point. This would've allowed it to have a continual, full on view of the sunlit side of the earth; it would've been invaluable for climate studies, weather forecasting, solar studies (how much sunlight is ACTUALLY reaching us) etc.
Of course our anti-intellictual/anti-science president cancelled it. Anyway, I would imagine the lunar transits would be spectacular, in fact we would almost be getting two missions for the price of one (because the instruments would only need be slightly redirected to image the moon).
I don't know enough about astronomy to know how close the plane of the moon's orbit is to the plane of the earth's orbit but there should be occasional transits which, in addition to being pretty, would also give us information about atmospheric attenuation (when the earth passes in front of the moon).
Now the soap box- As an American it is so depressing when I see how the average person has come to think of intellectual as a dirty word. America is losing its greatness because it is embracing faith over reason, guts over brains, instinct over analysis. Already biotechnology is moving overseas; today you can get your dog cloned in Korea (why isn't that a slashdot story?) tomorrow maybe your heart or liver. The cancellation of this space probe was just the start of the country's fall over the last seven years.
And no, Al Gore isn't an Alien and yes he did have a hand at a critical phase of the Internet's development. (In 1993 I got a $100K grant from the NTIA which he set up).
By the way, this is the thinking behind the ten thousand "immortals" of Xerxes army. His hand picked crack troops were always kept at this number with replacements making up the dead/injured.
You can see one fictionalized representation of them in the movie "The 300". They were the warriors who went up against the greeks wearing the shiny silver masks. As befitting their awesome reputation, they were the first ones to draw greek blood (although they still got slaughtered).
Are you sure? My mistake then though I was almost certain that they had to use up a lot of extra fuel to carry the Huygens probe into Saturn orbit. It would have been better for them to have dropped it off on the inbound trajectory. Are you sure this wasn't a change to the revised plan?
Anyway, do you know how much fuel is left? Another poster indicated that there may (only) be as much as a year left (of thruster fuel) which means that it wouldn't even finish its extended mission. That is disheartening to say the least and I'm surprised that they wouldn't be saying things like "we'll get as much of this extended mission done before we run out of fuel". Still Cassini has been an extremely successful probe to date so I'm not complaining.
I've looked all over the Cassini web site and I can't seem to find out anything that says how much fuel is left. Not the plutonium in the RTGs (that should last another decade or so) but rather the (bi-propellant?) in the main fuel tanks or the (mono-propellant? hydrazine?) used in the thrusters.
Not only is the lack of thruster propellant typically what ends the life of otherwise useful satellites (Cassini is not spin stabilized so attitude correction is ultimately performed by the thrusters) but in addition to keeping Cassini pointed in the right direction, it REQUIRES a significant (compared to most space probes), delta-v capability. This is because it must be able to change its trajectory to take advantage of gravity assist from Titan, if it cannot precisely hit the "window" it is aiming for, it will be sent into a totally different (and unrecoverable) orbit. (Of course if it were not for the "space billiards" gravity assist maneuvers there is no way Cassini would have been able to achieve more than a tiny fraction of its current mission. This, to me is the most impressive and gratifying part of the entire mission).
These relatively large changes in delta-v are what Cassini needs its two main engines for (one's a backup). Unfortunately due to a mistake in design, Cassini had to unexpectedly use up about a third(?) of its propellant because it had to carry the Huygens probe into Saturn orbit with it (rather than releasing it on its inbound trajectory). This was because the engineers neglected to design the radio to handle the large doppler shift that would have occurred had Cassini whizzed by on its hyperbolic trajectory before the orbital insertion burn while Huygens slowly parachuted to Titan's surface. By decelerating Cassini into Saturn orbit, THEN releasing the probe they were able to receive MOST of the data transmitted (another goof lost one channel) so it saved that part of the mission but at the expense of fuel.
Now if the orbital planners have been very careful (are you reading this Sherman?;) they may have been able to use less fuel than planned by being very accurate with their burns. So the question is: What will run out first? The main propellant used for orbital changes or the hydrazine used for attitude adjustments? (Also remember that Cassini doesn't have a separate instrument platform so every instrument pointing activity requires turning the entire spacecraft, most of this is done with reaction wheels but there is friction and sometimes the wheels must be desaturated).
Or is something else going to run out first? (Kodak film, videotape, mailing envelopes, postage stamps;) Or am I completely wrong about this? (Perhaps they've figured out how to use Saturn's magnetic field to help stabilize the spacecraft).
I hope that after this mission extension (and the next) they'll do something really crazy like use up a ton of fuel for a really really risky low slow flyby THROUGH the rings. Imagine seeing thousands and thousands of boulder-to-mountain sized rocks in a vast plain far as the eye can see with Saturn looming in the background! Just like the paintings by Chesley Bonestell (and lots of science fiction shows like Voyager). Good science too.
I assume this is a joke but just in case it isn't please note that I emphasized the word MASS. That's because they are not using this object to define an object's weight (that would be in Newtons) but rather it's mass. To use it to compare against another object you could use any sort of device like springs or centrifuges. You would see if the same amount of force on the two objects produced the same amount of acceleration or if the same amount of acceleration required the same amount of force. (M=F/A).
Of course if you were really ambitious you could convert the objects totally to energy and measure that! (M=E/C^2).
Is this really the reason why it's a sphere? Crystals don't PRECISELY grow into a sphere do they? Won't they still need to shave or polish it to get it to the exact radius? And then they'll need to calculate the number of atoms using Pi, an irrational number!
Why don't they make it a cube and find a length that is close enough (cubed) to give them the approx. right number of atoms and then make THAT the standard? They'll then have an EXACT number of atoms making up each length. It should be easier to cut or shave off the requisite number of atoms to maintain it, a (perfectly) flat surface seems much easier to maintain than a 3D curved surface. In fact if they make it just a little too small they could probably even ADD to the cube in single atomic layers using vapor deposition!
Obviously brighter minds than mine have thought this through more thoroughly, so really, I'm curious: why is it a sphere?
By the way, maybe this is a good use for the ISS, to keep the 1kg reference MASS somewhere it won't be distorted by gravity, not kept at any particular country for measurement and you can keep it in a high quality vacuum for free! (A little expensive to get to though).
I understand that the Governor was a biology major at Brown University. Considering that Evolution is THE unifying theme for Biology I am very disappointed that he has repudiated his own training (however slight) for political expediency.
Or perhaps the Biology program at Brown is not as rigorous as it should be?
"Nothing in Biology makes any sense except in the light of Evolution" - Theodosius Dobzhansky (thanks Google!)
No, I don't mean by causing a nuclear winter through an impact. Instead how about putting it into a "halo" orbit where it circles (in a halo) between earth and sun. (As a previous poster indicated, it'll take something like like 1.37km/s delta-v, you'll need a mass driver/ion engine or something like that. Then, with a solar powered grinder, take the asteroid which may already be largely rubble and make it into a powder, spewing it slowly into space (with a 1.5cm/s escape velocity it'll be hard not to).
The (very fine) dust from 71K tons of asteroid might be able to cast quite a shadow. Of course, the solar wind will eventually blow it away (which is probably a good thing, we don't want a permanent solution). But it might buy us some time at the relatively cheap cost of single (big) space mission.
(this idea is a cheap variant of something I heard a space scientist propose, launching trillions of small actively controlled refracting lenses/films to block out the sun. His idea was expensive but permanent. Mine is cheap but temporary).
Bonus: Put a special nozzle on the dust ejector and you might be able to form patterns. Companies might pay to see their logo's silhouetted against the sun that everyone on earth could say every day. (How about Ray-Ban?).
(this comes from another Arthur C. Clarke story where someone causes the ionosphere to light up by shooting up a cloud of particles from the moon. Unbeknownst to the scientists performing the experiment a company had put a special nozzle on the ejector).
Does anyone who knows anything about solar physics know whether or not you could use a small body like this as a solar flare shelter? If you are in deep space or in a hard-to-change orbit around a large body (like the moon), if a solar flare happens you're out of luck. If you're on the surface of a body with little or no atmosphere I guess you're still out of luck. But with a small body like this could you just zip to the side in the shadow? Could this make long-term trips like this safer than say going to the moon?
The idea is reminiscent of an Arthur C. Clarke story about a trip to Icarus.
On a more sinister note, while the delta-V for CAPTURE of this body around earth might be prohibitive using todays technology, what about for IMPACT? Not the U.S. would want to do such an obvious war provoking act but wondering if it could be done with just chemical propellants. Of course it depends on how far in advance you have to alter the course, orbital parameters etc.
Now if we were really good at orbital mechanics we could possibly have it skim the atmosphere to lose some delta-v for capture. Don't think anyone's gonna try that though.
It is conceivable that soon technology/engineering will make it possible to have a multi billion pixel display.
An interesting application might be to assign a pixel to each person living. Then as they pass through the phases of life, their brightness could wax and wane. Also perhaps color could be used to identify race or geography.
Might be an interesting display in a world's fair/expo kind of context. Being able to walk right up to it and realizing that you are just one of the billions of little dots could be pretty awe inspiring.
Perhaps it would give new meaning to the comment "he seems kinda bright". (ba du bum;)
yeah, I figured that might be what it would sound like so I only asked for his address (his e-mail is publically available). I was very briefly thinking about asking him wiring details (bank name, account number) because I wire money all the time and it would get to him much quicker but I knew that it would sound way to much like the Nigerian scam. Pretty funny though and proves you can never be too careful on the internet.
Hello Slashdot community. So I've decided to support Prof. Myers, I sent him the following e-mail and fully intend to follow up on my promises.
Please do not think that I expect a substantial fraction of slashdotters (or anyone actually) to follow my initiative. I'm semi-retired, have a reasonable amount of resources at my disposal and basically don't have a life. I just mention it as a possible option.
By the way, does anyone know if there is any sort of organization that formally supports scientists under attack like this? Sort of an ACLU for the sciences?
Hi Prof. Myers
I read about your problems with Stuart Privar. To make a long story short, I understand he is a wealthy businessman and may/is suing you.
I am very tired about seeing science in America getting abused by (as Al Gore would put it) "attacks on reason". Should you begin to incur any significant amount of court costs, I would like to offer a modest amount of assistance (in the 3 to 4 figure range).
As I am not a scientist myself but have a deep abiding interest in and respect for those who are expanding mankind's knowledge I would like to help in some way however small. I realize that scientists are human too and I'm sure have their share of problems but in this case it seems like you are definitely being prosecuted out of malice or breath-taking ignorance.
So if you need my modest assistance please send me a return e-mail with an address to where I can send the check. It may take awhile (a few weeks?) because I am out of the country. As a matter of trust, you can find my ramblings on Slashdot, I go by the user name "wisebabo". Please do not give in if you can and admit guilt (with a slap on the wrist), someone needs to show these people that the majority(?) of Americans support scientific progress. But it is your choice and I/we are in no position to tell you what to do.
Please do not disclose my identity/e-mail address (except as required by law). Good luck-
Perhaps you should look at the "balloons" you're riding on (cars and motorcycles at least). Talk about an application where "the rubber meets the road"; it shows how you can engineer (and on a vast industrial scale) almost anything, even safety critical equipment. Also look at the skirts of military class hovercraft. In addition to taking the abuse of pounding surf and various shrubs and other land obstacles they might blow over, they have to take direct (light) enemy fire as well as the occasional land mine.
Skipping a step or two in the development of a space craft (or habitat) is not without precedent. After the Apollo 1 disaster, NASA stepped back for a year from its already horrific schedule to rethink safety. By the time they were ready to restart they were so far behind schedule that, had they stuck to the original plan, they would never have made it "before this decade is out" (John F. Kennedy).
Then some particularly enlightened (and ballsy) director made a brilliant decision. Instead of testing first the booster, then the booster plus the second stage, then the booster and the second stage plus the third stage, and then everything with the spacecraft "stack" and finally all of this with the command module having an (unmanned) re-entry at escape velocity speeds (the third stage would be used to propel the space craft DOWN) he had the following idea. (Actually I'm sure the idea was floating around, HE had the power to make it happen).
Since everything is ready (on the ground at least) why not test everything at once?
It worked. The unmanned Apollo 5(?) not to be confused with the launcher Saturn 5 (or in Roman numerals V) worked flawlessly and was a huge success. With it, NASA made up all of its lost time and then some and was able to land man on the moon in the summer of 1969.
The things the United States (and the world) is capable of, given the will and dedication of its people, is simply astounding. Gives me hope at the same time I despair as how it has been squandered by the present administration.
I can't believe that they really can begin to propose odds like that on life's origin. What if life didn't begin with clays acting as catalysts for chemical reactions but instead required a reducing atmosphere? (Current thinking is that life originally used hydrogen sulfide as an energy source, possibly from undersea "smokers"). Can the comets provide that kind of environment? What would happen when the few nascent life forms that survive the planetary bombardment that they are part of are dumped from their interplanetary cocoons into the tremendously different environment of the early earth? Don't you think that there is a good idea that the life forms that survived that environment were the ones that evolved there?
Add to that the fact that we really don't have a clue as to how life started here (or anywhere else for that matter) and you really begin to question the judgment of giving odds to this sort of thing.
I'm not saying they're wrong, I like panspermia theories as well. It's just for people to put some sort of numerical values on this kind of thing when we know so little is just well crazy. And what numerical values! Maybe after if we send out some cometary probes and find them teeming with primitive life could you claim such a thing. Even then do they use DNA or RNA? Any evidence of spectral emission lines of this from any of our flyby probes? (It would be even more earth-shaking if there was DIFFERENT life there!)
Still I enjoy reading ScienceDaily.com. (Daily in fact) It's a great site not like some pseudo New-Scien(tist) kind of site.
Despite the fact this is a blatently racist comment, I think it should be obvious to anyone familiar with research in the U.S. that a great percentage is done by Chinese graduate students/professors. Just look at recent citations in bio-tech/physics/semiconductors/chemistry/nano-tec hnology. The number of high-tech companies run by or with high level technology officers who are of Chinese descent is huge. Needless to say, if the Chinese are kept out/were kept out of this country, the industries that depend on talented individuals would collapse. Perhaps that is why Microsoft has built one of their largest (the largest?) research labs there: http://research.microsoft.com/aboutmsr/presskit/ba ckgrounders/asia_bg.aspx
Fortunately I think most slashdotters understand this so I won't bother to elaborate further. (I remember similar comments made about the Japanese and Koreans before they started kicking our butts in consumer electronics, semiconductors, automobiles, etc.). I'm even curious to know how many Chinese slashdotters there are out there. (I'm not one).
You're supporting just how bad things are if you must compare current CO2 levels with those of 65 MILLION years ago! (All of the studies you cite are of that period). You seem to be implying that the last time CO2 levels were this high was when the dinosaurs went extinct. Doesn't that seem to indicate just how extreme the changes we are bringing upon ourselves are? Don't you think that was pretty bad for the dinosaurs and all large animals? (even if they weren't responsible).
Sure we might only wipe out millions of species (instead of 10s of millions) and displace 100s of millions of people/destroy economies instead of causing our own extinction but don't you think that is bad enough? What will you tell your children when they realize it will require thousands of human lifetimes to restore the biodiversity we have today (and caused the needless suffering of billions)?
If an investment of $1 billion could "produce more than 100 gigawatts of electricity by 2050, equaling the combined output of all 104 nuclear power plants in the U.S." then we would all be getting our electricity (and probably all of our fuels would be made using electricity) from geothermal sources.
Since I have some faith in studies from M.I.T. it seems like the writers are off by a few orders of magnitude. Probably they meant $800 billion to $1 trillion?
A virus (DNA or RNA) when injected into a cell utilizes the existing cellular machinery to make mass copies of its own genetic code, encase them in proteins that its genetic code has transcribed and explodes the cell to allow the newly created viral particles out. In a few cases (retroviruses) the virus becomes reverse transcripted into the cell's DNA and can stay there hidden (like HIV) for a long time, sometimes even reproducing with the cell (a possible source of "junk" DNA or even some cancers). Notice that a virus has far less than the minimum number of genes to create the cellular mechanisms for life let alone reproduction.
Venter's group has taken a cell and replaced ALL of the original DNA with the newly introduced DNA. (I believe a virus replaces nothing, it merely adds its own genetic code). While the newly introduced DNA comes from another bacterium, there is no reason to think that the DNA from a completely "man-made" source couldn't be introduced instead. By introducing fewer and fewer genes, Venter (and others) hope to find the "minimum" number of genes needed to make a living creature.
Once this minimal life is created is new, possibly never before seen in nature, genes can be introduced one at a time. Because these genes are added to a "clean" slate, their functionality and efficiency can be controlled and optimized. Kinda like a much more powerful version of the transgenic mice they use in research where they selectively eliminate just ONE gene from the mouse strain to see what its effect is. I believe they have strains for all/almost all the thousands of genes in mice so they can evaluate them for various genetic ailments, disease resistance and whatnot. (Harvard was the first to get a patent on the genetic code of one of these mice: the first patented life. Go Harvard!)
Here instead of removing one gene from the entire set (to an admittedly MUCH more complex organism), Venter will be able to control ALL the genes in his bacteria. This will greatly reduce/eliminate unwanted interactions (because the "unneeded" genes have been eliminated) allowing R&D to go much more quickly. Thus the optimism on creating oil producing bacteria. (Please note that "unneeded" refers to our needs not the bacteria, we can make a bacteria that is alive but is utterly dependent on vital nutrients that "wild" bacteria make themselves. Since our bacteria is simpler, we will use it not the wild version.)
Slashdot Mirror
Although this is probably the best way to use nukes, the problem is in the sentence "Anything that has mass". How much polyethelyne will be required? You're using an extremely powerful energy source but coupling that with a mechanism that needs you to deliver a lot of mass to the asteroid (which is very expensive) to make it effective. Otherwise, with just a little plastic the conversion of nuclear energy to kinetic energy just won't be efficient.
A more efficient use of the (nuclear) energy in the weapons would be to set a reactor down on the surface and use the electricity generated it to power an accelerator to fire bits of the asteroid away. It would, however, take a long time of course (as well as add a lot of complexity). Another idea would be to use the shaped nuclear charge as you previously described but with dug up asteroidal material (couple tons of rocks brought up from the surface by robots?) instead of mass brought from earth. Vaporized rock might not be as good as plastic at absorbing soft X-rays but you could use a lot more. (You'd need radiation hardened robots of course to do this more than once).
Of course you could always forgo the nukes and use my idea for converting the spin rotation of the asteroid into kinetic energy (see comment below).
In 1993 (+/- a year or so), I co-wrote the grant proposal for our NGOs (non governmental organizations) in Los Angeles to the NTIA (National Telecommunications Infrastructure Administration?) which I believe was one of the things Gore got funded. In it we provided 5 community organizations in Los Angeles with internet links (T1 lines), networks, computer classrooms and training to private citizens (kids mainly) from diverse ethnic communities.
We got $100K from the NTIA followed by $150K from PacBell and $100K from Pacific Gas & Electric (I may be a little off on some of these numbers). I think it lasted a couple years. Lots and lots of kids got on line back then. I did it on a volunteer basis but learned a lot.
If the asteroid has any appreciable spin it should be possible to convert it to into kinetic energy to move it off course.
Land a spacecraft at the asteroid's "equator". Extend a long tower/cable into space such that the end is considerably past the asteroid's "geo-sync" point. Securely attach the end of this tower/cable to the asteroid (may require just running a long cable around the entire equator). Get some robots to start collecting, digging up or mining asteroidal material.
The bigger the asteroid (and harder to move) the more rotational energy it will have to move it. Of course you need lots of time (like most methods).
Now, just like the speculative "space elevators" proposed for earth, transport the material up the tower/cable. Carefully timing the release of it from the space will send the material in one direction and the asteroid in another. Not fast but could be quite cheap; this system may not even need solar power because some power could be generated by the material as it is slung off beyond the geo-sync point.
If you have the power (actually delta-v) to put it into orbit, why not put it at the L1 point between the Sun and the Earth. Then, send a solar powered rock grinding machine to gradually reduce it to a fine powder. Slowly spray the powder into space (very easy because of the asteroid's negligible gravity) and you'll directly block out the sun. If the powder is fine enough, a few thousand cubic meters of rock should be enough to create a dust cloud hundred's of kilometers square. That'll be enough to reduce incident solar radiation a few percent (enough to compensate for global warming).
Of course the cloud will gradually blow away after a few years of solar wind, so you'll need to keep the machine going. This is a safety feature, you don't want this to be permanent!
If this alien perspective is awesome, thought provoking (or at least makes one pause for reflection) consider what the view would've been like from "Triana".
That was the space probe proposed by Al Gore in 2000 that was an earth looking satellite to be placed at the earth-SUN (not moon!) L1 point. This would've allowed it to have a continual, full on view of the sunlit side of the earth; it would've been invaluable for climate studies, weather forecasting, solar studies (how much sunlight is ACTUALLY reaching us) etc.
Of course our anti-intellictual/anti-science president cancelled it. Anyway, I would imagine the lunar transits would be spectacular, in fact we would almost be getting two missions for the price of one (because the instruments would only need be slightly redirected to image the moon).
I don't know enough about astronomy to know how close the plane of the moon's orbit is to the plane of the earth's orbit but there should be occasional transits which, in addition to being pretty, would also give us information about atmospheric attenuation (when the earth passes in front of the moon).
Now the soap box-
As an American it is so depressing when I see how the average person has come to think of intellectual as a dirty word. America is losing its greatness because it is embracing faith over reason, guts over brains, instinct over analysis. Already biotechnology is moving overseas; today you can get your dog cloned in Korea (why isn't that a slashdot story?) tomorrow maybe your heart or liver. The cancellation of this space probe was just the start of the country's fall over the last seven years.
And no, Al Gore isn't an Alien and yes he did have a hand at a critical phase of the Internet's development. (In 1993 I got a $100K grant from the NTIA which he set up).
By the way, this is the thinking behind the ten thousand "immortals" of Xerxes army. His hand picked crack troops were always kept at this number with replacements making up the dead/injured.
You can see one fictionalized representation of them in the movie "The 300". They were the warriors who went up against the greeks wearing the shiny silver masks. As befitting their awesome reputation, they were the first ones to draw greek blood (although they still got slaughtered).
Are you sure? My mistake then though I was almost certain that they had to use up a lot of extra fuel to carry the Huygens probe into Saturn orbit. It would have been better for them to have dropped it off on the inbound trajectory. Are you sure this wasn't a change to the revised plan?
Anyway, do you know how much fuel is left? Another poster indicated that there may (only) be as much as a year left (of thruster fuel) which means that it wouldn't even finish its extended mission. That is disheartening to say the least and I'm surprised that they wouldn't be saying things like "we'll get as much of this extended mission done before we run out of fuel". Still Cassini has been an extremely successful probe to date so I'm not complaining.
Okay thanks, I guess then there may not be an extension after this one then. :( I hope the reaction wheels hold up!
I've looked all over the Cassini web site and I can't seem to find out anything that says how much fuel is left. Not the plutonium in the RTGs (that should last another decade or so) but rather the (bi-propellant?) in the main fuel tanks or the (mono-propellant? hydrazine?) used in the thrusters.
Not only is the lack of thruster propellant typically what ends the life of otherwise useful satellites (Cassini is not spin stabilized so attitude correction is ultimately performed by the thrusters) but in addition to keeping Cassini pointed in the right direction, it REQUIRES a significant (compared to most space probes), delta-v capability. This is because it must be able to change its trajectory to take advantage of gravity assist from Titan, if it cannot precisely hit the "window" it is aiming for, it will be sent into a totally different (and unrecoverable) orbit. (Of course if it were not for the "space billiards" gravity assist maneuvers there is no way Cassini would have been able to achieve more than a tiny fraction of its current mission. This, to me is the most impressive and gratifying part of the entire mission).
These relatively large changes in delta-v are what Cassini needs its two main engines for (one's a backup). Unfortunately due to a mistake in design, Cassini had to unexpectedly use up about a third(?) of its propellant because it had to carry the Huygens probe into Saturn orbit with it (rather than releasing it on its inbound trajectory). This was because the engineers neglected to design the radio to handle the large doppler shift that would have occurred had Cassini whizzed by on its hyperbolic trajectory before the orbital insertion burn while Huygens slowly parachuted to Titan's surface. By decelerating Cassini into Saturn orbit, THEN releasing the probe they were able to receive MOST of the data transmitted (another goof lost one channel) so it saved that part of the mission but at the expense of fuel.
Now if the orbital planners have been very careful (are you reading this Sherman? ;) they may have been able to use less fuel than planned by being very accurate with their burns. So the question is: What will run out first? The main propellant used for orbital changes or the hydrazine used for attitude adjustments? (Also remember that Cassini doesn't have a separate instrument platform so every instrument pointing activity requires turning the entire spacecraft, most of this is done with reaction wheels but there is friction and sometimes the wheels must be desaturated).
Or is something else going to run out first? (Kodak film, videotape, mailing envelopes, postage stamps ;) Or am I completely wrong about this? (Perhaps they've figured out how to use Saturn's magnetic field to help stabilize the spacecraft).
I hope that after this mission extension (and the next) they'll do something really crazy like use up a ton of fuel for a really really risky low slow flyby THROUGH the rings. Imagine seeing thousands and thousands of boulder-to-mountain sized rocks in a vast plain far as the eye can see with Saturn looming in the background! Just like the paintings by Chesley Bonestell (and lots of science fiction shows like Voyager). Good science too.
I assume this is a joke but just in case it isn't please note that I emphasized the word MASS. That's because they are not using this object to define an object's weight (that would be in Newtons) but rather it's mass. To use it to compare against another object you could use any sort of device like springs or centrifuges. You would see if the same amount of force on the two objects produced the same amount of acceleration or if the same amount of acceleration required the same amount of force. (M=F/A).
Of course if you were really ambitious you could convert the objects totally to energy and measure that! (M=E/C^2).
Is this really the reason why it's a sphere? Crystals don't PRECISELY grow into a sphere do they? Won't they still need to shave or polish it to get it to the exact radius? And then they'll need to calculate the number of atoms using Pi, an irrational number!
Why don't they make it a cube and find a length that is close enough (cubed) to give them the approx. right number of atoms and then make THAT the standard? They'll then have an EXACT number of atoms making up each length. It should be easier to cut or shave off the requisite number of atoms to maintain it, a (perfectly) flat surface seems much easier to maintain than a 3D curved surface. In fact if they make it just a little too small they could probably even ADD to the cube in single atomic layers using vapor deposition!
Obviously brighter minds than mine have thought this through more thoroughly, so really, I'm curious: why is it a sphere?
By the way, maybe this is a good use for the ISS, to keep the 1kg reference MASS somewhere it won't be distorted by gravity, not kept at any particular country for measurement and you can keep it in a high quality vacuum for free! (A little expensive to get to though).
how else would the scanner be able to read the eye?
I understand that the Governor was a biology major at Brown University. Considering that Evolution is THE unifying theme for Biology I am very disappointed that he has repudiated his own training (however slight) for political expediency.
Or perhaps the Biology program at Brown is not as rigorous as it should be?
"Nothing in Biology makes any sense except in the light of Evolution" - Theodosius Dobzhansky (thanks Google!)
No, I don't mean by causing a nuclear winter through an impact. Instead how about putting it into a "halo" orbit where it circles (in a halo) between earth and sun. (As a previous poster indicated, it'll take something like like 1.37km/s delta-v, you'll need a mass driver/ion engine or something like that. Then, with a solar powered grinder, take the asteroid which may already be largely rubble and make it into a powder, spewing it slowly into space (with a 1.5cm/s escape velocity it'll be hard not to).
The (very fine) dust from 71K tons of asteroid might be able to cast quite a shadow. Of course, the solar wind will eventually blow it away (which is probably a good thing, we don't want a permanent solution). But it might buy us some time at the relatively cheap cost of single (big) space mission.
(this idea is a cheap variant of something I heard a space scientist propose, launching trillions of small actively controlled refracting lenses/films to block out the sun. His idea was expensive but permanent. Mine is cheap but temporary).
Bonus: Put a special nozzle on the dust ejector and you might be able to form patterns. Companies might pay to see their logo's silhouetted against the sun that everyone on earth could say every day. (How about Ray-Ban?).
(this comes from another Arthur C. Clarke story where someone causes the ionosphere to light up by shooting up a cloud of particles from the moon. Unbeknownst to the scientists performing the experiment a company had put a special nozzle on the ejector).
Does anyone who knows anything about solar physics know whether or not you could use a small body like this as a solar flare shelter? If you are in deep space or in a hard-to-change orbit around a large body (like the moon), if a solar flare happens you're out of luck. If you're on the surface of a body with little or no atmosphere I guess you're still out of luck. But with a small body like this could you just zip to the side in the shadow? Could this make long-term trips like this safer than say going to the moon?
The idea is reminiscent of an Arthur C. Clarke story about a trip to Icarus.
On a more sinister note, while the delta-V for CAPTURE of this body around earth might be prohibitive using todays technology, what about for IMPACT? Not the U.S. would want to do such an obvious war provoking act but wondering if it could be done with just chemical propellants. Of course it depends on how far in advance you have to alter the course, orbital parameters etc.
Now if we were really good at orbital mechanics we could possibly have it skim the atmosphere to lose some delta-v for capture. Don't think anyone's gonna try that though.
It is conceivable that soon technology/engineering will make it possible to have a multi billion pixel display.
;)
An interesting application might be to assign a pixel to each person living. Then as they pass through the phases of life, their brightness could wax and wane. Also perhaps color could be used to identify race or geography.
Might be an interesting display in a world's fair/expo kind of context. Being able to walk right up to it and realizing that you are just one of the billions of little dots could be pretty awe inspiring.
Perhaps it would give new meaning to the comment "he seems kinda bright". (ba du bum
yeah, I figured that might be what it would sound like so I only asked for his address (his e-mail is publically available). I was very briefly thinking about asking him wiring details (bank name, account number) because I wire money all the time and it would get to him much quicker but I knew that it would sound way to much like the Nigerian scam. Pretty funny though and proves you can never be too careful on the internet.
;)
Thanks for reading
Hello Slashdot community. So I've decided to support Prof. Myers, I sent him the following e-mail and fully intend to follow up on my promises.
Please do not think that I expect a substantial fraction of slashdotters (or anyone actually) to follow my initiative. I'm semi-retired, have a reasonable amount of resources at my disposal and basically don't have a life. I just mention it as a possible option.
By the way, does anyone know if there is any sort of organization that formally supports scientists under attack like this? Sort of an ACLU for the sciences?
Hi Prof. Myers
I read about your problems with Stuart Privar. To make a long story
short, I understand he is a wealthy businessman and may/is suing you.
I am very tired about seeing science in America getting abused by (as
Al Gore would put it) "attacks on reason". Should you begin to incur
any significant amount of court costs, I would like to offer a modest
amount of assistance (in the 3 to 4 figure range).
As I am not a scientist myself but have a deep abiding interest in
and respect for those who are expanding mankind's knowledge I would
like to help in some way however small. I realize that scientists
are human too and I'm sure have their share of problems but in this
case it seems like you are definitely being prosecuted out of malice
or breath-taking ignorance.
So if you need my modest assistance please send me a return e-mail
with an address to where I can send the check. It may take awhile (a
few weeks?) because I am out of the country. As a matter of trust,
you can find my ramblings on Slashdot, I go by the user name
"wisebabo". Please do not give in if you can and admit guilt (with a
slap on the wrist), someone needs to show these people that the
majority(?) of Americans support scientific progress. But it is your
choice and I/we are in no position to tell you what to do.
Please do not disclose my identity/e-mail address (except as required
by law). Good luck-
Perhaps you should look at the "balloons" you're riding on (cars and motorcycles at least). Talk about an application where "the rubber meets the road"; it shows how you can engineer (and on a vast industrial scale) almost anything, even safety critical equipment. Also look at the skirts of military class hovercraft. In addition to taking the abuse of pounding surf and various shrubs and other land obstacles they might blow over, they have to take direct (light) enemy fire as well as the occasional land mine.
Skipping a step or two in the development of a space craft (or habitat) is not without precedent. After the Apollo 1 disaster, NASA stepped back for a year from its already horrific schedule to rethink safety. By the time they were ready to restart they were so far behind schedule that, had they stuck to the original plan, they would never have made it "before this decade is out" (John F. Kennedy).
Then some particularly enlightened (and ballsy) director made a brilliant decision. Instead of testing first the booster, then the booster plus the second stage, then the booster and the second stage plus the third stage, and then everything with the spacecraft "stack" and finally all of this with the command module having an (unmanned) re-entry at escape velocity speeds (the third stage would be used to propel the space craft DOWN) he had the following idea. (Actually I'm sure the idea was floating around, HE had the power to make it happen).
Since everything is ready (on the ground at least) why not test everything at once?
It worked. The unmanned Apollo 5(?) not to be confused with the launcher Saturn 5 (or in Roman numerals V) worked flawlessly and was a huge success. With it, NASA made up all of its lost time and then some and was able to land man on the moon in the summer of 1969.
The things the United States (and the world) is capable of, given the will and dedication of its people, is simply astounding. Gives me hope at the same time I despair as how it has been squandered by the present administration.
I can't believe that they really can begin to propose odds like that on life's origin. What if life didn't begin with clays acting as catalysts for chemical reactions but instead required a reducing atmosphere? (Current thinking is that life originally used hydrogen sulfide as an energy source, possibly from undersea "smokers"). Can the comets provide that kind of environment? What would happen when the few nascent life forms that survive the planetary bombardment that they are part of are dumped from their interplanetary cocoons into the tremendously different environment of the early earth? Don't you think that there is a good idea that the life forms that survived that environment were the ones that evolved there?
Add to that the fact that we really don't have a clue as to how life started here (or anywhere else for that matter) and you really begin to question the judgment of giving odds to this sort of thing.
I'm not saying they're wrong, I like panspermia theories as well. It's just for people to put some sort of numerical values on this kind of thing when we know so little is just well crazy. And what numerical values! Maybe after if we send out some cometary probes and find them teeming with primitive life could you claim such a thing. Even then do they use DNA or RNA? Any evidence of spectral emission lines of this from any of our flyby probes? (It would be even more earth-shaking if there was DIFFERENT life there!)
Still I enjoy reading ScienceDaily.com. (Daily in fact) It's a great site not like some pseudo New-Scien(tist) kind of site.
"Basically they have little natural talent"
c hnology. The number of high-tech companies run by or with high level technology officers who are of Chinese descent is huge. Needless to say, if the Chinese are kept out/were kept out of this country, the industries that depend on talented individuals would collapse. Perhaps that is why Microsoft has built one of their largest (the largest?) research labs there: http://research.microsoft.com/aboutmsr/presskit/ba ckgrounders/asia_bg.aspx
Despite the fact this is a blatently racist comment, I think it should be obvious to anyone familiar with research in the U.S. that a great percentage is done by Chinese graduate students/professors. Just look at recent citations in bio-tech/physics/semiconductors/chemistry/nano-te
Fortunately I think most slashdotters understand this so I won't bother to elaborate further. (I remember similar comments made about the Japanese and Koreans before they started kicking our butts in consumer electronics, semiconductors, automobiles, etc.). I'm even curious to know how many Chinese slashdotters there are out there. (I'm not one).
You're supporting just how bad things are if you must compare current CO2 levels with those of 65 MILLION years ago! (All of the studies you cite are of that period). You seem to be implying that the last time CO2 levels were this high was when the dinosaurs went extinct. Doesn't that seem to indicate just how extreme the changes we are bringing upon ourselves are? Don't you think that was pretty bad for the dinosaurs and all large animals? (even if they weren't responsible).
Sure we might only wipe out millions of species (instead of 10s of millions) and displace 100s of millions of people/destroy economies instead of causing our own extinction but don't you think that is bad enough? What will you tell your children when they realize it will require thousands of human lifetimes to restore the biodiversity we have today (and caused the needless suffering of billions)?
If an investment of $1 billion could "produce more than 100 gigawatts of electricity by 2050, equaling the combined output of all 104 nuclear power plants in the U.S." then we would all be getting our electricity (and probably all of our fuels would be made using electricity) from geothermal sources.
Since I have some faith in studies from M.I.T. it seems like the writers are off by a few orders of magnitude. Probably they meant $800 billion to $1 trillion?
A virus (DNA or RNA) when injected into a cell utilizes the existing cellular machinery to make mass copies of its own genetic code, encase them in proteins that its genetic code has transcribed and explodes the cell to allow the newly created viral particles out. In a few cases (retroviruses) the virus becomes reverse transcripted into the cell's DNA and can stay there hidden (like HIV) for a long time, sometimes even reproducing with the cell (a possible source of "junk" DNA or even some cancers). Notice that a virus has far less than the minimum number of genes to create the cellular mechanisms for life let alone reproduction.
Venter's group has taken a cell and replaced ALL of the original DNA with the newly introduced DNA. (I believe a virus replaces nothing, it merely adds its own genetic code). While the newly introduced DNA comes from another bacterium, there is no reason to think that the DNA from a completely "man-made" source couldn't be introduced instead. By introducing fewer and fewer genes, Venter (and others) hope to find the "minimum" number of genes needed to make a living creature.
Once this minimal life is created is new, possibly never before seen in nature, genes can be introduced one at a time. Because these genes are added to a "clean" slate, their functionality and efficiency can be controlled and optimized. Kinda like a much more powerful version of the transgenic mice they use in research where they selectively eliminate just ONE gene from the mouse strain to see what its effect is. I believe they have strains for all/almost all the thousands of genes in mice so they can evaluate them for various genetic ailments, disease resistance and whatnot. (Harvard was the first to get a patent on the genetic code of one of these mice: the first patented life. Go Harvard!)
Here instead of removing one gene from the entire set (to an admittedly MUCH more complex organism), Venter will be able to control ALL the genes in his bacteria. This will greatly reduce/eliminate unwanted interactions (because the "unneeded" genes have been eliminated) allowing R&D to go much more quickly. Thus the optimism on creating oil producing bacteria. (Please note that "unneeded" refers to our needs not the bacteria, we can make a bacteria that is alive but is utterly dependent on vital nutrients that "wild" bacteria make themselves. Since our bacteria is simpler, we will use it not the wild version.)