It's not clear whether Mars had a thick atmosphere to lose. If it did, though, there's only two things that could have happened to the heavy molecules (e.g. CO2) that it contained: they could have been sequestered in reservoirs such as carbonates (not much of which have been yet found), or they could have been lost to space through non-thermal processes. In the last 3.5 billion years on so, the major non-thermal loss process is sputtering by the solar wind, as you say.
Whether a terraformed planet is usably terraformed is a matter of time scales. Models suggests that between 0.1 and 3 bar CO2 could have been lost through sputtering over a period of about 3.5 billion years. Taking the maximum rate, this is an annual loss of less than 1 part per billion per year, or 0.1 bar in 100 million years. Thus no significant loss due to sputtering would occur on the time scale of human civilization.
I vaguely recall seeing calculations for the duration of an atmosphere on a terraformed Moon. IIRC, even such an atmosphere might last for useful time scales; a 1 bar Earth-like atmosphere might last for several thousand years before being lost due to thermal escape and sputtering.
Well... CO2(liquid) is not stable on the Martian surface, but it should be stable in the Martian subsurface; "cryoclastic" flows might therefore explain some of the flood structures. (See Hoffman, 2000). I don't buy it as an explanation for all the features (e.g. the apparent rivers and sedimentary basins), but it's an interesting theory.
The paper by Shelby et al. is here, but I belive full access requires a subscription. (Most universities have this.) Wiltshire has a less technical Perspective in the same issue.
Bob
Different opinion from you != Crooks
on
Fighting UCITA
·
· Score: 2
I don't particularly like UCITA myself. I'm not strongly opposed to the Maryland version, in the same way that I am to the original version. I think the primary reason Maryland decided to implement UCITA this year was because the General Assembly Leadership felt it was necessary to attract software companies as well as No. VA; I tend to doubt it will have this effect.
Nevertheless, it is not a valid conclusion that anybody who supports UCITA is either a self-serving megacorp, a moron or a crook. I don't like all the leadership in Annapolis, but I know a fair number of General Assembly members myself, and all the members I know honestly want to do what's best for the constituencies.
You aren't going to get anywhere in trying to win legislators on to your side if you assume that the only reason they disagree with you is because they've been bought out.
Before anybody else automatically condemns the State of Maryland for approving a bill with the words "Uniform Commercial Transaction Act" in its title, perhaps they ought to read the actual text of the bill the General Assembly passed. (What, Slashdotters read primary sources? God forbid!) The Maryland General Assembly has a page with the text of the bill; amendments are also available seperately if you just want to see what the subcommittees that worked diligently on the bill for two months changed.
A brief discussion occured on the bill after its Maryland passage at TECHNOCRAT.NET. People might also be interested on what Del. Kumar Barve, chair of the House subcommitee that examined the bill, had to say:
As I am sure you know, the House of Delegates approved a heavily amended UCITA bill. There seems to be a great deal of confusion regarding this amended version.
The House Subcommittee on Science and Technology held ten open public work session attended by both opponents and proponents of the bill. Many suggestions which came from these work sessions were incorporated into our final version.
Currently, there is no current federal or state statue that applies to computer software licensing. However, twelve court cases have upheld shrinkwrap licenses and there have been no court cases to the contrary since 1993. By passing UCITA, consumers will now be allowed to get their money back if the product does not work as advertised or was purchased in error even after having loaded on their computer. Our amended version of UCITA also makes it clear that Maryland consumer laws apply to consumer computer transactions. Specifically, the Maryland version of UCITA prohibits software licensors from modifying or disclaiming implied warranties of merchantability.
Current law allows a company to disable software in home or business computers. Under UCITA, this practice is outlawed on home computers by our consumer protection laws and is heavily restricted in the commercial market.
Many of those concerned about the bill believe it gives software vendors control over your files and data. Under our version of UCITA, your data is your property.
The provisions do not change the law with respect to copyrighting and reverse engineering. UCITA explicitly states that all aspects of federal copyright law govern computer information transactions. The legislation also makes it clear that state trade secret laws and unfair competition laws are in full force and not overridden by UCITA.
Kumar Barve Chairman, Subcommittee on Science and Technology
I'm not saying that the Maryland law is perfect, just that you ought to know what your talking about before you express an opinion.
Although it is true we are detecting an awful lot of planetary systems that different from our own -- in particular, ones with gas giants in small, eccentric orbits -- we don't yet have the capacity to detect planetary systems like our own.
There are two boundary conditions on what we can detect: the size of the planets and the distance of their orbit from the star. This is because we can detect planets by noting how much their presence causes their parent star to move. At present, we can detect Saturn-class planets with periods of a couple of years or less. With ground based technology, we may eventually be able to detect Neptune-class planets and planets in Jupiter-like orbits. To detect terrestrial planets, we'll need orbital or lunar telescopes designed for planet searching.
Sending astronauts to Europa wouldn't be a good idea, anyways. Europa (along with Io) are well within Jupiter's radiation belts. Any humans travelling there without a lot of protection would die very quickly.
A trip to Ganeymede would significantly increases one's risk of cancer, but would not be immediately fatal. Callisto, of all the Galilean moons, is the only one with human-safe levels of radiation.
In addition, any life on Europa would probably be in Europa's ocean, which is probably buried underneath approximately 100 km of ice.
Based on what I know, the proposal that a lot of states are considering is that devised by the National Conference of State Legislatures' Internet Taxation Task Force. You can read a copy of their "'Zero Burden' Sales Tax Proposal".
The main aspects of this plan are:
Making sales taxes more similiar across the states
Simplifying state tax laws
Fostering the development of private third parties responsible for collecting and transmitting taxes
The Maryland General Assembly is considerably more liberal than their counterparts in Virginia. What does this mean? Well, it can mean a lot of things; in this case, it means the opinion of the American Library Association (a member of 4cite) probably carries more weight in Maryland.
I don't know much about the Senate bill, but the sponsors of House Bill 19 are the members of the House leadership. Few of them know much about the bill yet. There are a few exceptions: Delegate Sandy Rosenberg and Delegate Nancy Kopp are both members of the House leadership who did not sign on to the bill -- they apparently have some vague idea of some disconcerting going on.
If we disregard any potential life forms not based on carbon and water -- a reasonable thing to do, scientifically, since we have no data points with regards to them -- life on these planets, like life on Jupiter or in Jupiter's atmosphere -- is quite unlikely.
But if these planets are in their stars' habitable zones, then so are the moons of these planets. And one of these moons might, perhaps, be a world with plentiful water that supports macroscopic life.
(Europa, a moon of Jupiter, is widely regarded as the best candidate for extraterrestrial life in our solar system. Although it is outside the traditional 'habitable zone' of the sun, it does have an immense ice covering. Its ocean of ice is believe to extend to around 50km in depth. Beneath this ice, there may be liquid water -- and perhaps organisms living off the geothermal energy generated by Europa's gravitational interaction with Jupiter.)
Slashdot Mirror
Whether a terraformed planet is usably terraformed is a matter of time scales. Models suggests that between 0.1 and 3 bar CO2 could have been lost through sputtering over a period of about 3.5 billion years. Taking the maximum rate, this is an annual loss of less than 1 part per billion per year, or 0.1 bar in 100 million years. Thus no significant loss due to sputtering would occur on the time scale of human civilization.
I vaguely recall seeing calculations for the duration of an atmosphere on a terraformed Moon. IIRC, even such an atmosphere might last for useful time scales; a 1 bar Earth-like atmosphere might last for several thousand years before being lost due to thermal escape and sputtering.
Bob
The paper by Shelby et al. is here, but I belive full access requires a subscription. (Most universities have this.) Wiltshire has a less technical Perspective in the same issue.
Bob
I don't particularly like UCITA myself. I'm not strongly opposed to the Maryland version, in the same way that I am to the original version. I think the primary reason Maryland decided to implement UCITA this year was because the General Assembly Leadership felt it was necessary to attract software companies as well as No. VA; I tend to doubt it will have this effect.
Nevertheless, it is not a valid conclusion that anybody who supports UCITA is either a self-serving megacorp, a moron or a crook. I don't like all the leadership in Annapolis, but I know a fair number of General Assembly members myself, and all the members I know honestly want to do what's best for the constituencies.
You aren't going to get anywhere in trying to win legislators on to your side if you assume that the only reason they disagree with you is because they've been bought out.
Bob Kopp
A brief discussion occured on the bill after its Maryland passage at TECHNOCRAT.NET. People might also be interested on what Del. Kumar Barve, chair of the House subcommitee that examined the bill, had to say:
I'm not saying that the Maryland law is perfect, just that you ought to know what your talking about before you express an opinion.
Bob Kopp
See also Getaway to Club Mir, posted January 15.
Although it is true we are detecting an awful lot of planetary systems that different from our own -- in particular, ones with gas giants in small, eccentric orbits -- we don't yet have the capacity to detect planetary systems like our own.
There are two boundary conditions on what we can detect: the size of the planets and the distance of their orbit from the star. This is because we can detect planets by noting how much their presence causes their parent star to move. At present, we can detect Saturn-class planets with periods of a couple of years or less. With ground based technology, we may eventually be able to detect Neptune-class planets and planets in Jupiter-like orbits. To detect terrestrial planets, we'll need orbital or lunar telescopes designed for planet searching.
Bob Kopp
Sending astronauts to Europa wouldn't be a good idea, anyways. Europa (along with Io) are well within Jupiter's radiation belts. Any humans travelling there without a lot of protection would die very quickly.
A trip to Ganeymede would significantly increases one's risk of cancer, but would not be immediately fatal. Callisto, of all the Galilean moons, is the only one with human-safe levels of radiation.
In addition, any life on Europa would probably be in Europa's ocean, which is probably buried underneath approximately 100 km of ice.
Bob Kopp
Based on what I know, the proposal that a lot of states are considering is that devised by the National Conference of State Legislatures' Internet Taxation Task Force. You can read a copy of their "'Zero Burden' Sales Tax Proposal".
The main aspects of this plan are:
Bob Kopp
I don't know much about the Senate bill, but the sponsors of House Bill 19 are the members of the House leadership. Few of them know much about the bill yet. There are a few exceptions: Delegate Sandy Rosenberg and Delegate Nancy Kopp are both members of the House leadership who did not sign on to the bill -- they apparently have some vague idea of some disconcerting going on.
Bob Kopp
(Yes, I am related to one of the above.)
If we disregard any potential life forms not based on carbon and water -- a reasonable thing to do, scientifically, since we have no data points with regards to them -- life on these planets, like life on Jupiter or in Jupiter's atmosphere -- is quite unlikely.
But if these planets are in their stars' habitable zones, then so are the moons of these planets. And one of these moons might, perhaps, be a world with plentiful water that supports macroscopic life.
(Europa, a moon of Jupiter, is widely regarded as the best candidate for extraterrestrial life in our solar system. Although it is outside the traditional 'habitable zone' of the sun, it does have an immense ice covering. Its ocean of ice is believe to extend to around 50km in depth. Beneath this ice, there may be liquid water -- and perhaps organisms living off the geothermal energy generated by Europa's gravitational interaction with Jupiter.)
Bob Kopp