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Perhaps you could quantify the number of bullets "spraying?" You do know that migration from Mexico into the US is now negative?
The drug nonsense is in the gradual process of resolution as the Mexican quit helping us with our insanity, and even Americans gradually give up; there are 18 states and DC which have legal medical marijuana, and now two that have just plain legal marijuana: Colorado and Washington. That trend will grow, expand and eventually prevail.
As for Venezuela, I'm not aware that Venezuela has ever invaded another country since its independence in the early 19th century. I'm not aware of any significant military conflict that it's had with any other country since independence. Chavez may be dying of cancer, and his death or incapacity may produce some problems over succession, but a history of nearly two hundred years of peace with its neighbors means something.
Chavez doesn't like the US and does what he can to inconvenience us, which does not make him an idiot, a popinjay or irrational.
GW wrote, “I don't see much possibility for stability in Mexico or Venezuela, not for a long, long time.”
I don’t believe this statement has any relation to reality, at least with respect to Mexico, a country that has existed as a stable, peaceful, reasonably democratic state since 1921, excepting only the relatively minor clerical conflicts (the “Cristeros War”) that ended in 1929. The current drug conflicts do not affect the stability of the government and will be resolved with new policies withdrawing support for the US’s absurd drug war.
The Economist’s political instability index for 2009-10 has Mexico at 6.1. There are 78 countries in the world with higher instability indexes including Turkey, Russia and Greece. The US is 5.3 and ranks number 110.
Venezuela’s index is 7.3 and ranks number 29.
2012 Toyota Prius Plug-In Hybrid Performance and Specs
Specs
1.8-Liter 4-Cylinder ECVT Hybrid
Prius Plug-in Hybrid Advanced
1.8-Liter 4-Cylinder ECVT Hybrid
MPG and other
Mileage estimates - mpge Hybrid Mode mpg 95/50
Maximum EV Mode 11 mi.
Charging Time - 120V 240V ~3 hrs/~1.5 hrs
The Prius Plug-in was at participating dealers starting March 2012 in 15 launch states: Arizona, California, Connecticut, Hawaii, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Oregon, Rhode Island, Vermont, Virginia and Washington. Availability will open up to all other states in 2013.
So, we have not only the plug-in Volt, but also the plug-in Prius.
Most insurance losses are organized in what’s called a log-normal distribution, a very skewed probability distribution. Things that behave like insurance losses are hugely diverse, extraordinary and astonishing:
signal losses of WiFi networks
concentration of elements in the Earth’s crust
time from infection to first symptoms of infectious diseases
size of clouds and rainfall
survival time after cancer diagnosis
size of crystals in ice cream
length of spoken words in phone conversations
farm size
And, the distances that people drive.
According to the 2001 National Household Travel Survey, there were about 760 billion miles of long distance vehicle trips--defined as trips of 50 miles or more from home to the farthest destination. There were about 2298 billion vehicle miles of “daily trips” including commuting, shopping, school, restaurants, entertainment and health care. Trips of under 50 miles account for 75% of all travel in personal vehicles.
To break it down a little further, here’s a chart of how far people commute (according to the American Housing Survey of the Census Bureau):
Distance From Percent Cumulative
Home to Work of Trips Percent
Less than 1 mile 4% 4%
1 to 4 miles 21% 25%
5 to 9 miles 22% 47%
10 to 19 miles 29% 76%
20 to 29 miles 13% 89%
30 to 49 miles 9% 98%
50 miles or more 2% 100%
Other “daily trips” (for shopping, school, restaurants, entertainment, health care, etc.) follow the same kind of pattern with the difference that the average trip is shorter, and the percentage of trips over 9 miles is considerably less than the 53% for commuting to work.
Statistics like this make the completely unrealistic assumption that people do not do multiple things (like stopping at the store on the way home from work). Which means we can only use such numbers to get a rough idea of what’s going on.
But a rough idea is better than none at all, and the data suggest that, even if the range of plugin hybrids were only 9 miles, 47% of the people would get to work using no gas, and a higher percentage would use no gas for shopping, school, restaurants, entertainment and health care trips. With a 9 mile hybrid electric range and widely available plug ins, gasoline usage for “daily trips” would be reduced by more than 69%, because 47% of commuting trips are less than 9 miles (a higher percentage for other trips), and, for longer daily trips, applying a deductible of 9 miles before gas usage starts would eliminate more than 22% (15+4+2) of the gas usage for these commuting trips and even more for other trips.
Gasoline consumption for 75% of the total personal vehicle miles driven would be reduced by more than 69%. The other 25% of personal vehicle miles driven involve trips of more than 50 miles, but even these would be subject to the “deductible” of the first 9 miles of battery-electric operation. Overall gas consumption would decrease by more than half (.69*.75). Toyotas assertion that the MPGE is 95 miles supports this calculation, and is perhaps derived from a similar assumptions.
But these vehicles in gasoline mode, running as standard hybrids, already get more than double the distance per unit of fuel as the average US automobile. Fuel use would be reduced by half and then by half again, or about 75%.
The Chevy Volt has a claimed range of from 25 to 50 miles on a charge. If the actual range were, say, 30 miles, the reduction in gasoline usage would approach 90%.
This seems pretty dramatic to me.
GW, I think your concerns about OPEC, importing oil, and the urgency of finding a replacement for oil are all misplaced.
Start with OPEC; they have around a 40% share of the crude oil market. You cannot set prices with a 40% market share, but even then, there are three other issues:
1. OPEC is not monolithic. Getting twelve countries to agree, and more importantly abide by, any strategy on a long term basis must be an unenviable, if not impossible, challenge. Especially involving countries with such diverse and competing interests as Iran and Qatar or Algeria and Kuwait or the UAE and Venezuela. By the way, looking over OPEC roster of membership, I see twelve countries; Mexico is not included.
2. There are substitutes for crude oil that are currently in widespread use and whose use can be, and is being, broadly expanded: natural gas, bio-fuels and electricity generated from coal, nuclear, natural gas and numerous other non-oil sources. The 1986 to 2011 seven point decrease (from 40% to 33%) in oil’s worldwide share of energy use is a demonstration of those substitutions in the last 25 years.
3. The elasticity of demand for oil and its substitutes is not zero. Increases and decreases in efficiency and conservation are all affected by price, which also means that price is affected by these factors. The possibilities of these factors are illustrated in the US by the 50% increase in distance traveled per unit of fuel in 29 years - from 1980 to 2009 – with technologies in place to increase that distance by a factor of three in the next 20 years.
Then there’s the issue of oil imports. I’m always amused at the earnestness and urgency with which producing more oil domestically is advocated – the “drain America first” strategy. Look at Japan; they have virtually no oil, but they do have the largest economy in the world after the US and China, which have populations and land areas an order or magnitude larger. Still, US oil imports have been steadily DECLINING for years:
US oil imports in millions of barrels
2004 3,821
2005 3,755
2006 3,734
2007 3,691
2008 3,591
2009 3,315
2010 3,377
2011 3,322
Down 13% in 7 years, now at their lowest level since 1999, even with a 12% increase in population. And more than half the oil imports are from the Western Hemisphere.
Lastly, the urgency of replacing oil. There are three reasons to reduce the use of oil.
1. Most important is the effect on the climate. Unfortunately this applies to all fossil fuels and the problem is much broader than just oil. Natural gas produces about half the CO2 and other pollutants compared to oil, and can play a very significant role in reducing the effects of fossil fuels. Nuclear produces essentially no pollutants and its role really can and must be greatly expanded. All of the wind, solar, geothermal, tides, waves, bio-fuels, etc. will not make much more than a minor contribution over the next 50 years or so; efficiency improvements and conservation will play much more significant roles.
2. A large amount of oil is located in politically unstable regions. The oil makes these areas more significant and provides the resources for trouble makers to make trouble.
3. The unstable locations of a lot of oil, rising demand for energy and stable, or, perhaps, declining production of oil may make for large price increases and instabilities. A large violent conflict in the Middle East, for instance, could result in devastating economic problems. Shielding strategies against these possibilities are important and necessary, and will generally rely on replacing oil with something less volatile, and, hopefully, cheaper and more environmentally friendly. The strategic petroleum reserve is another shielding strategy.
The world is clearly moving in the direction of less reliance on oil; perhaps slower than one would like, but definitely moving. The technologies to greatly reduce the use of oil are widely used and expandable fairly easily, and there are many new possibilities on the horizon.
Faster might be better. On the other hand, we can expect technologies to continue to improve, which means that making these changes slowly will ultimately result in better technologies being deployed.
We're making progress, so don't sweat it so much.
And, besides all that, our species has increasing amounts of food available per person, and that increase has occurred mostly in the developing countries, indicating a more equal distribution of food amongst humans. Life expectancies world wide are rising and civil liberties are improving. These are all amazing accomplishments.
Better nutrition, better brains, longer lives, more opportunities and potential for billions of humans. And we're working on this oil problem.
THREE CHEERS FOR US! WE'RE DOING GREAT!
From 1975 to 2010 visits to the National Parks grew by 22%. The European-White population under the age of 80 and over the age of 4 grew 17% from 157 million to 183 million. For many reasons, known and unknown, Blacks, Latinos (tens of millions of whom were, and in many cases still are, undocumented, a condition which does not encourage extensive travel), Native Americans, Asians, people under the age of 5 or over the age of 80 are considerably less likely to visit National Parks.
These facts may explain the relatively slow growth of National Park use. There may be other sociological explanations which may be related to the general decline in participation in voluntary organizations such as archaeological societies and travel clubs.
In any case population growth does not explain the huge jump in passenger miles traveled in the US; 122 % increase from 1975 to 2008 while total population grew by only 41%.
Sorry that I did not understand that “western civilization was ‘designed’ by the dead hand of Adam Smith to run on cheap fuel” did not refer to Adam Smith. His phrase, by the way was “invisible hand.” Maybe “dead hand” has some cleverness not discernible by someone as unschooled as myself.
The numbers I posted for oil prices are, in fact, inflation adjusted, a fact that I thought was clear and quite apparent from casual inspection. The nominal price for a barrel of crude in 1958 was $3, a difference of almost an order of magnitude. I suspect that fuel prices are closely related to crude oil prices.
I did ask the National Park Service about their attendance figures; here are the number of visits by year in millions.
2010 281
2009 286
2008 275
2007 276
2006 273
2005 274
2000 286
1995 270
1990 259
1975 239
These figures do not appear to support an assertion that “Almost nobody drives all over the country for vacations anymore.” Also, there is total miles driven (in billions):
2008 2,974
2007 3,032
2006 3,014
2005 2,989
2000 2,747
1995 2,423
1900 2,144
1975 1,328
These figures do not appear to support an assertion that “there is not a lot of ‘by-choice’ driving going on out there in the US anymore.”
In addition, it is relatively easy for most US families to greatly decrease their usage of gasoline. From 1980 to 2009 the distance per unit of fuel in the US increased by about 50%, Small hybrid vehicles, such as the Toyota Prius, more than double this distance per unit of fuel as of 2009. Plug-in hybrids have the potential to more than triple distance traveled per unit of fuel – reducing fuel consumption per unit of distance by about 90%. All electric, natural gas and bio-fuel vehicles will also decrease the consumption of oil.
About 60% of all vehicles are scrapped every ten years in the US; virtually the entire fleet is replaced every 20 years. The speed of that replacement could be increased with modest expense and very little inconvenience.
Soo – twenty years to reduce the use of oil for transportation by 90%+ with no pain, no fuss. This does not seem like a big crisis, but, rather, a minor technical challenger.
GW wrote about something called, “long-constant supply-and-demand value in a market not limited by supply.” What on Earth, or space, is that? I assume “value” means market price, and market price in a perfectly competitive market is the price at which marginal revenue equals marginal cost. A monopolist will increase price by restricting supply to the point where the difference between total revenue and total cost is maximized. Marginal revenue will be higher than marginal cost. That price, of course, depends on the elasticity of demand. An oligopoly will restrict supply so that it is less than under a perfectly competitive market, but more than what a monopolist would enforce. The price will also fall somewhere in between.
All markets are always limited by supply at a price.
As for the effects of oil prices on economic activity, here are the unemployment rates in the US and world oil prices for various years.
Oil
Year Unemp Price
1958 7.5% $23.89
1961 7.1 21.91
1970 4.9 20.08
1971 5.9 20.43
1972 5.6 19.79
1973 4.9 24.39
1974 5.6 43.51
1975 8.5 52.11
1976 7.7 52.92
1977 7.1 54.58
1978 6.1 52.7
1979 5.8 78.73
1980 7.1 104.49
1981 7.6 90.49
1982 9.7 75.86
1983 9.5 67.12
1984 7.5 63.62
1985 7.2 57.51
1986 7.0 30.26
1987 6.2 35.9
1988 5.5 28.94
1989 5.3 33.97
1990 5.6 40.67
1991 6.8 34.09
1992 7.5 31.53
1993 6.9 26.66
1994 6.1 24.27
1995 5.6 25.26
1996 5.4 29.96
1997 4.9 26.69
1998 4.5 16.8
1999 4.2 22.79
2000 4.0 36.54
2001 4.7 29.86
2002 5.8 29.12
2003 6.0 34.6
2004 5.5 45.78
2005 5.1 58.83
2006 4.6 66.45
2007 4.6 71.03
2008 5.8 97.33
2009 9.3 57.18
2010 9.6 75.05
2011 9.0 88.93
Any pattern is difficult to discern and subject to differing interpretations. For instance, could it be that cause and effect is confused, i.e., unemployment drives oil prices, not oil prices drive unemployment.
Another resurrection. Nearly 4-1/2 year from Stormrage’s last post, and all of a sudden it’s BAAACK.
I think GW is being a bit alarmist about oil, OPEC and the destiny of everything.
According to BP in 2011 oil accounted for 33% of world energy supply, down from about 40% in 1986 – 25 years earlier. http://www.bp.com/assets/bp_internet/gl … t_2012.pdf
That’s certainly an encouraging trend, and we know many ways to continue and accelerate that trend by using more coal, natural gas and nuclear; and there might even be some small production from wind and solar. We also know how to increase the ratio of economic activity to energy use through many different technologies such as time-of-day metering, LED and florescent lighting, plug-in hybrid technologies, more efficient vehicles, buildings and other machines and facilities, and probably a hunk of things I don't know about.
As for OPEC, a monopolist will maximize profit by restricting supply, which will result in higher prices and marginal revenue higher than marginal cost. A monopolist will also attempt to be a secure and reliable supplier, in part by stabilizing prices. This will discourage any searches for alternative suppliers or technologies. Of course, OPEC is not a monopolist, much as they might like to be, but only an oligopoly. Acting rationally, which OPEC mostly does, they will reduce the use of oil while maintaining a stable supply and price. This hardly seems evil.
Where in “The Wealth of Nations” is there any design by Adam Smith concerning cheap fuel? In the 18th century the principle fuels were wood and coal, both of which are cheaper today than in the 18th century and neither of which are we in danger of exhausting.
Thanks for the input Frank. I went and joined Marsdrive just because of it. Another thing that I think would help is to do away with the silly user names. Real names and a little biography, especially from the people who run the site, would lead to more confidence, and more and more responsible posting.
I am disappointed that the site does not get more support, input and direction from the Mars Society. Another element of disclosure would be to discuss the relationship, if any, between the Mars Society and this site. Why is there not a link on the Mars Society site to this forum?
On this site, there is little about the Mars Society conventions, no links to the videos of the various speeches, no information about buying videos or other items, and no information about the 2013 convention, nor when to expect it.
Talk about raising the dead. The last post was 4-1/2 years ago. The last two posters haven't been around since May of 2008. Falkor, you're writing to the dead and gone.
I certainly have a lot less interest in posting here after the great crash. And way, way back there had been another great crash the result of which was the name "New Mars Forums."
It's tough to get too involved knowing that everything you and everyone else wrote over a period of weeks, months and years, may go into the bit bucket anytime. With Facebook you know stuff won't be relevant for more than a few days, but with a forum like this, one hopes for many years of continuity - the Mars Society is 15 years old. This forum should have a similar ambition. Two breaks lasting many, many months with limited recovery makes recovering trust and recovering willingness to invest time and effort, problematic.
Then the relative paucity of activity feeds the cycle.
One thing that I think would help regain that trust is disclosure. Who's running the site? How does it get paid for? How are people and data backed up? Who do we contact for information if the site is down? And how? What about fail safes? e.g., another website to go for information and commiseration if New Mars is down. Maybe with some duplicated discussions.
In the meantime, I'm just hoping the site stays up. Some assurance (which requires some openness) on that score would be very helpful.
Also, nonsense like "Apollo 20 mystery" does not encourage serious people to participate on this forum.
For the past several years, a group of optical scientists and engineers working at the UA Steward Observatory Mirror Laboratory underneath the UA’s football stadium have been polishing an 8.4-meter diameter mirror with an unusual, highly asymmetric shape. The mirror has an unconventional shape because it is part of what ultimately will be a single 25-meter optical surface composed of seven circular segments, each 8.4 meters in diameter. The board for the Giant Magellan Telescope Organization officially accepted the mirror in Washington, D.C.
Work on the second mirror began in January of this year, and a third is expected to be cast next September. At the Carnegie Institution for Science’s Las Campanas Observatory in northern Chile, earthmovers are completing the removal of 4 million cubic feet of rock to produce a flat platform for the telescope and its supporting buildings.
The telescope, slated to begin operations late in the decade, will address critical questions in cosmology, astrophysics and planetary science, including getting a clearer picture of planets that orbit nearby stars.
The Giant Magellan Telescope partner institutions are the Australian National University, Astronomy Australia Limited, the Carnegie Institution for Science, Harvard University, the Korea Astronomy and Space Science Institute, The Smithsonian Institution, Texas A&M University, the University of Arizona, the University of Chicago and the University of Texas at Austin. Members are providing and raising the funding toward the $700 million project, with about 40 to 45 percent of the funding secured.
Cosmic radiation is not a health risk for a 6-month flight; the dosage is known. The International Space Station has half the sky covered by the Earth and thus gets half the cosmic ray dosage of a spacecraft in interplanetary space. Astronauts and cosmonauts have been stationed in Earth orbit for more than a year and have received a cosmic ray dosage equivalent to a 6-month flight to Mars. Once on the Martian surface, Mars provides the same shielding against cosmic rays as the Earth does in low orbit; i.e., half the normal dose is protected against because it can only come from above, not below. To shield you from above you need 3 or 4 meters or so of dirt. Three meters of water would probably be better.
This is just not accurate. The Earth's magnetic field deflects some of the cosmic rays (virtually all of which are charged particles), especially the more common lower energy ones. This protection is very effectively provided to the International Space Station since the orbit is near the equator. The Sun's magnetic field also deflects cosmic rays, but that effect may be reduced the further one is from the Sun. Cosmic rays in interplanetary space are more intense than in low Earth orbit by more than a factor of 2. Does anyone know by how large a factor?
It's possible that local naturally occurring magnetic fields on Mars may have a similar local effect to Earth's magnetic field, greatly reducing the need for radiation shielding from both cosmic rays and solar particle radiation. Three or four meters of water or regolith is an awful lot of stuff. A 100 square meter living space would require 300,000 liters of water.
The issue of outsourcing old people is quite widespread. As Dev Patel put it, “There are many other countries where they don't like old people.”
Josh seems to suggest that an excess of accidents and radiation induced cancers on Mars may increase mortality rates across all age cohorts thus reducing the number of older people. The idea is that if people die young, they obviously won’t live to be old people thus reducing the necessity of outsourcing them to places like The Best Exotic Marigold Hotel.
I might observe that lower life expectancy is not likely to be a big selling point for Mars colonization. I can see the advertising brochure now, “More egalitarian death rates; on Mars you don’t have to be old to die.”
Fortunately, I think there are a few problems with Josh’s ideas.
In the United States about 7.4% of deaths are due to injuries of which about 1,4% are due to suicide, and 2.2% from vehicular accidents, homicides, police killings, executions, and operations of war. This leaves 3.8% of deaths due to other kinds of accidents. All of these causes of death occur disproportionately in younger age cohorts.
Injuries account for a lower percentage of deaths in most other developed countries, e.g., Canada 6%, Australia 5.7%, Israel 5.6%, Denmark 4.9%, Greece 3.4%, England and Wales 2.8%.
But, using the US as our base, it is, in my opinion, unlikely that 2.2% of deaths on Mars will be due to vehicular accidents, homicides, police killings, executions, and operations of war. It could, however, well be that 1.4% of deaths will be due to suicide, perhaps far higher. But maybe not, presumably there will be an attempt to weed out colonists with mental health issues that predispose them to suicide. In any case, excess suicides are not likely to be a great selling point for Mars colonization: “Increase your chances of dying at your own hand!”
Such mental health screening will likely also decrease the percentage of long term settlers with other mental health issues that affect mortality rates at younger ages, such as alcoholism. other addictions and a propensity to violence.
So, how much can one expect the non-vehicular accident rate to increase on Mars over the already high US rate? Double, from 3.8% to 7.6%? With the reduction in deaths in young age cohorts due to less alcoholism, vehicular accidents, homicides, police killings, executions, and operations of war, such an increase would average out to not much more than the current US rate of deaths from injuries. All with a rapidly increasing population of old people needing to be outsourced.
Triple to 11.4%, a net increase in the death rate of about 4 to 5% (11.8 - 3.8 – most of the 2.2% and something for less alcoholism and other mental health related health issues). Say it’s an increase of total deaths of about 61% (around 4.5/7.4) occurring in age cohorts in proportion to the incidence of deaths by injury in the various age cohorts. Here are deaths from injuries as a percentage of total deaths by various age groupings for the US:
Under 1 year 6%
1 to 4 years 44%
5-14 years 48%
15-24 years 77%
25-34 years 60%
35-44 years 34%
45-54 years 17%
55-64 years 6%
65-74 years 3%
75-84 years 2%
Applying a 61% increase to these percentages and applying those increases to the number of deaths in each age cohort in a period life table, making some adjustment for injury death rate differences between the sexes, beginning at, say, age 35 (the average age at which colonists will arrive on Mars), allows one to predict the effects on life expectancy of this increase in accident rate. You can find the Social Security Area Period Life Table for 2007 here: http://www.socialsecurity.gov/OACT/STATS/table4c6.html
The effect is remarkably small, reducing overall life expectancy at age 35 by about six months from 79.1 years to 78.6 years.
Mars will still have the old people to outsource.
Josh does raise the issue of increased rates of cancer due to radiation exposure. I think the Mars colony will not be saved from its old people by these cancers because of the precautions that will be taken about radiation exposure, the increasing ability to successfully treat cancer (especially knowing just what kinds to look for), and the long incubation periods of most cancers.
Colonies will have to be able to deal with all of their age cohorts: infants, children, adults and even old people. No Best Exotic Marigold Hotel for the Mars colony.
Returning to Earth people who have lived on Mars for 30 years is very problematic. What problems will come at this relatively old age from nearly tripling the gravity, changing the pressure and content of the air, a whole new pathogen and potential allergen environment, an utterly different social milieu, and what other issues? Even the ambient light and day/night cycle will be different.
It’s a whole different ball game making these adaptations in your 30s as opposed to your 60s, and many of these are one way, e.g., it’s a lot easier to adjust to 38% gravity than 263% gravity. It’s a lot less dangerous to reduce pathogens and potential allergens in a controlled fashion, than to increase them in an uncontrolled fashion.
Their physical and mental health problems will really escalate upon arrival at Earth.
My favorite quote from Erwin Schrödinger with respect to quantum theory: "I don't like it, and I'm sorry I had anything to do with it."
There is no dust storm risk factor for plants. Most plants would survive any recorded Martian dust storm, continuing to produce oxygen, food and other products and absorb CO2 with a possible hiatus of a day or two. Heat would be an issue at night during dust storms, but one fairly easily surmounted.
It is possible to grow plants in multiple levels using soil and natural light with mirrors, but it would make more sense to have the plants use the space rather than trays, i.e., grow bigger plants. It would not make sense to build a greenhouse much higher than about 2-1/2 meters. But plants can easily use 2-1/2 meters of height and a lot more.
The height of greenhouse plants can be controlled by a number of chemical and non-chemical methods. Rye, barley, wheat, rice, and sweet potato vines have been grown to heights of 1-1/2 meters, asparagus over 2-1/2 meters. Blueberry and huckleberry shrubs and cassava to nearly 4 meters, corn, tomatoes and grape vines to 6 meters. Obviously 38% gravity would permit much greater heights than would be necessary to utilize the highest reasonable greenhouse, and would increase crop yields commensurately.
No trays necessary with all their plumbing, wiring and maintenance.
Converting natural light to electricity, storing some electricity as methane and sometimes re-converting the methane to electricity, and then converting the electricity to artificial light seems extraordinary complex and unnecessary. And it would involve a loss of energy of from 90 to 97%. All of which seem especially unwise considering that solar electricity generation shuts down during the worst of the dust storms; but plants don't, except, possibly for a day or two at the most.
The biggest complication of using natural light is the fairly simple one of producing low quality mirrors and positioning them.
But Mars is better for eternal records storage since the planet will certainly survive the red giant phase of our Sun.
bobunf wrote:PV requires direct sunlight
No. PV can work with diffuse light.
There is no adverse effect on photosynthesis from the loss of direct sunlight, which is most definitely not the case with PV. Photosynthesis may actually increase. One study (http://www.jstor.org/discover/10.2307/1 … 1280469297) reports a 37% increase in carbon gain on cloudy days.
Also, plants survive long periods of time without light. Annual plants might survive up to 10 days with no light at all. Perennials can last for weeks and even months without light.
But, when a cloud blocks the sun, how much does electricity generation decline? About half if the cloud is thin and shadows are still cast on Earth. About 80% if the cloud is thick and no shadow is cast. About 99% for thick dark clouds covering the sky.
Obviating the need for artificial light means no need for PV panels, wiring, transformers, inverters, circuit breakers, light fixtures and bulbs; all of which requires a huge amount of on-going imports from Earth or a huge industrial base.
Dust storms are not an insurmountable issue with plants, which like defuse light - just what dust storms produce. Spirit and Opportunity continued to produce electricity during dust storms. The attenuation of TOTAL light at the surface is what matters for plants.
PV requires direct sunlight; plants don't, and can take advantage of all four sources of light: sunlight transmitted directly to the surface, sunlight reflected from the dust haze alone, sunlight scattered to the surface and reflected to the greenhouse, and sunlight reflected off the surface in all other directions, but which is subsequently scattered toward the greenhouse. We are talking about a haze and not a blackout.
Viking, Spirit and Opportunity images taken during dust storms show a significant amount of light, although a few days do seem to be quite dark, but not black. Plants are used to cloudy days on Earth
With or without dust storms, appropriately placed mirrors could increase the amount of light entering the greenhouse to simulate something approaching conditions on Earth.
Heat may be an issue at night, but nighttime insulation and heating water within the greenhouse during the day could provide a considerable, perhaps sufficient, buffer. This may be an additional problem during dust storms, but producing heat is a less demanding problem than producing light.
Hydroponics just seems too complicated biologically and mechanically. Greenhouse with soil nourished by human and, possibly later, animal waste. Use natural light, and we have a technologically simple system with 10,000 years of experience. It will produce food and air with very little need for energy, wiring, pumps, etc.
Dust storms are not an issue with plants, which like defuse light, just what dust storms produce. If the Rutherford studies point the way to near radiation free areas of Mars, that issue will also be solved.
Billionaires are generally not stupid. If there were huge jackpots to be made on Mars, the Moon or NEOs, they could figure that out without a Mars group approaching them - with or without a "professional and believable 'case for Mars.'"
Bob wrote, "Isn't 227,940,000 divided by 51,000 = 4.47?" I must have been falling asleep. Sorry.
I think the whole point of the Rutherford research to that it may be possible to find areas on Mars that would require little or no radiation protection; areas that are about as benign as Earth. That would be a huge simplification of any long term stays on Mars.
But it's an empirical question, which will only be determined by actual measurements on the Martian ground.
Isn't 227,940,000 divided by 51,000 = 4.47? That would give closer to 5% of the neutrons arriving at Mars.
Do not the fusion neutrons get slowed by the Sun's gravity? The escape velocity from the Sun is 618 kps, but that's from the surface. The impact of gravity from the core would be significantly higher, maybe about 800 kps?
Of course that decrease in velocity would take place over the whole 227 million kilometer journey to Mars, the effect of gravity decreasing with the inverse square of the distance, i.e., the bigger effect is felt earlier in the journey so that the average velocity would be less than 51,000-800/2.
Is there an effect from friction as the neutron travels through the 700,000 radius of the Sun?
Would the neutrons at Mars be a problem? It didn't seem to be an issue with astronauts at the ISS or going to and from the Moon. The quantity of neutrons from the Sun per square meter at Mars would be less than half the quantity at Earth because of the increasing area of the surface the neutrons are reaching. In other words the exposure would be about 2% of that at Earth.
Sounds to me like neutrons aren't much of an issue by the time one gets all the way to Mars.
If the velocity of neutrons from the sun were 1,000 kps, it would take about 1000 minutes for them to reach the orbit of mercury. That would be about 70 to 100 half lives. Even at 70 half lives, the residual number of neutrons would be about 1/10^21 of the original number.
I think one can pretty well say that there isn’t any neutron radiation coming from the Sun at the orbit of Mars.