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Dr Strangelove
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quote:
Originally posted by chegitz guevara
Venus' atmosphere is 90 times thicker than Earth's, and it's closer to the Sun, so it's more likely to get blown away. Venus is also slightly smaller than Earth. Definately the mass of a planet has a lot of say in how much of an atmosphere a planet has, but it's clear that gravity alone isn't the whole o the equation. |
Venus' atmosphere is composed of heavier gases, like sulfer compounds, many of which wouldn't be gasified if the surface and atmospheric temperatures weren't so high. I believe that its closer proximity to the sun allowed the heavier compounds to be formed and gasified, trapping heat, which led to even heavier compounds being liberated into the atmosphere, and so on until an equilibrium was reached. The thickness of the atmosphere then would be a factor of the planet's size and its surface and atmospheric temperatures. I don't see how closeness to the sun would cause atmospheric gas to be blown away. It might cause lighter gases to literally diffuse away?
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Lord Merciless
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Magnetic field has no effect on gamma rays.
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South killer
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quote:
And how do we know that the knowledge we gain by moving out into space might not present a solution to some of the problems we face here at home? I already mentioned Helium-3 and it's possibility for use in fusion reactors. If we figure out how to make fusion work, and how to get the fuel required, it could provide us with an abundant and clean source of energy.
Statements like yours are just like the ones made when people used to say that man will never fly, so why bother trying. We just might learn something we never even concieved of before that will transform our society forever, and for the benefit of all humanity. |
The solution to this is very simple: igualitarian distribution of the goods for all.
Sorry but i think it's dumb (or sellfish) for mankind to spend millions and millions of dollars in space programs while a third of the people on earth are starving.
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Willem
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Canada
Dec 2001
time: 00:27
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quote:
Originally posted by South killer
The solution to this is very simple: igualitarian distribution of the goods for all.
Sorry but i think it's dumb (or sellfish) for mankind to spend millions and millions of dollars in space programs while a third of the people on earth are starving. |
If it wasn't for the space program, you probably wouldn't be communicating with people from around the world today. It's played a major role in the development of computer technology and will transform our world in ways we can't even imagine yet today.
How much will the Internet help people in remote and impoverished areas when they'll be able to access information on health care, birth control, crop management, animal husbandry etc, etc, simply by logging on to a computer somewhere. And it's only been around for ten years now!
Just imagine how things will change in 20, 30, 40 years when people all over the world start gaining access to the huge store of information that the Internet provides. And that's just one thing that the space program has helped us develop, there's all sorts of other things as well. Another is fuel cell technology, a potentially clean way of operating our cars and trucks.
Any money we spend on space research will come back to us ten-fold in the future.
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Proteus_MST
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Difficult to say, if it should be terraformed.
As a Biologist I would like it to first be fully explored for fossils of lifeforms (for example bacteriae).
Due to the close proximity of the habitability zones of mars to earth and the former presence of water on the planet, it could be interesting to conduct extensive surveys.
There is also the mysterie of those possible Bacteria fossils in ALH 94001 where it AFAIK up to date couldn´t be definitely proven or disproven if the residues are remnants from Mars-microbae.
So I would chose to first conduct extensive biological research on Mars before making a decision wehter terraform Mars or not (I fearexisting fossils could be destroyed if as a result of terraforming the climate gets more humid and the atmospheric pressure rises).
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Main_Brain
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Economic World Center
Jul 2002
time: 06:27
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Mars=Chinese territory
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yavoon
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sava's US is population is barely growing if u discount immigration. I don't see any reason for us to chase down europe's population density.
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Ned
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of Aptos, CA
Oct 1999
time: 21:27
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The loss of Mars magnetic field caused it to lose its atmoshere. But that was eons before all life was killed by solar radiation. I will try to find a link to the effects of radiation on humans without the protection of a magnetic field. However, it looks like Earth will very soon lose its own magnetic field. See below.
Ouch!
Sun's rays to roast Earth as poles flip
Robin McKie, science editor
Sunday November 10, 2002
The Observer
Earth's magnetic field - the force that protects us from deadly radiation bursts from outer space - is weakening dramatically.
Scientists have discovered that its strength has dropped precipitously over the past two centuries and could disappear over the next 1,000 years.
The effects could be catastrophic. Powerful radiation bursts, which normally never touch the atmosphere, would heat up its upper layers, triggering climatic disruption. Navigation and communication satellites, Earth's eyes and ears, would be destroyed and migrating animals left unable to navigate.
'Earth's magnetic field has disappeared many times before - as a prelude to our magnetic poles flipping over, when north becomes south and vice versa,' said Dr Alan Thomson of the British Geological Survey in Edinburgh.
'Reversals happen every 250,000 years or so, and as there has not been one for almost a million years, we are due one soon.'
For more than 100 years, scientists have noted the strength of Earth's magnetic field has been declining, but have disagreed about interpretations. Some said its drop was a precursor to reversal, others argued it merely indicated some temporary variation in field strength has been occurring.
But now Gauthier Hulot of the Paris Geophysical Institute has discovered Earth's magnetic field seems to be disappearing most alarmingly near the poles, a clear sign that a flip may soon take place.
Using satellite measurements of field variations over the past 20 years, Hulot plotted the currents of molten iron that generate Earth's magnetism deep underground and spotted huge whorls near the poles.
Hulot believes these vortices rotate in a direction that reinforces a reverse magnetic field, and as they grow and proliferate these eddies will weaken the dominant field: the first steps toward a new polarity, he says.
And as Scientific American reports this week, this interpretation has now been backed up by computer simulation studies.
How long a reversal might last is a matter of scientific controversy, however. Records of past events, embedded in iron minerals in ancient lava beds, show some can last for thousands of years - during which time the planet will have been exposed to batterings from solar radiation. On the other hand, other researchers say some flips may have lasted only a few weeks.
Exactly what will happen when Earth's magnetic field disappears prior to its re-emergence in a reversed orientation is also difficult to assess. Compasses would point to the wrong pole - a minor inconvenience. More importantly, low-orbiting satellites would be exposed to electromagnetic batterings, wrecking them.
In addition, many species of migrating animals and birds - from swallows to wildebeests - rely on innate abilities to track Earth's magnetic field. Their fates are impossible to gauge.
As to humans, our greatest risk would come from intense solar radiation bursts. Normally these are contained by the planet's magnetic field in space. However, if it disappears, particle storms will start to batter the atmosphere.
'These solar particles can have profound effects,' said Dr Paul Murdin, of the Institute of Astronomy, Cambridge. 'On Mars, when its magnetic field failed permanently billions of years ago, it led to its atmosphere being boiled off. On Earth, it will heat up the upper atmosphere and send ripples round the world with enormous, unpredictable effects on the climate.'
It is unlikely that humans could do much. Burrowing thousands of miles into solid rock to set things right would stretch the technological prowess of our descendants to bursting point, though such limitations do not worry film scriptwriters. Paramount's latest sci-fi thriller, The Core - directed by Englishman Jon Amiel, and starring Hilary S**** and Aaron Eckhart - depicts a world beset by just such a polar reversal, with radiation sweeping the planet.
The solution, according to the film, to be released next year, involves scientists drilling into Earth's mantle to set off a nuclear blast that will halt the reversal.
Given that temperatures at such depths rival those of the Sun's surface, such a task would seem impossible - except, of course, in Hollywood.
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yavoon
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Ned does it make u the least bit suspicious that they say it happens every 250k years or so and then say it hasn't happened in a million? seems like they have some parts of the mechanism left to explain.
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Ned
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of Aptos, CA
Oct 1999
time: 21:27
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Here is a recent article that speculates that human visits of 1.5 years are tolerable.
http://www.marssociety.org/news/2003/0316.asp
AP Falsely Reports Mars Radiation Data
March 14, 2003
The Associated Press yesterday issued a wire article claiming that "the radiation on the surface of Mars is so intense that it could endanger astronauts sent to explore the Red Planet." The AP claimed that these were the findings of the MARIE instrument currently operating on the Mars Odyssey spacecraft, and ascribed the view that such radiation doses were too high to allow human explorers to Dr. Cary Zeitlin of the National Space Biomedical Institute in Houston. Dr. Zeitlin is the Principal Investigator for the MARIE radiation detection instrument.
In fact, however, the MARIE data, which is publicly available at the MARIE website at marie.jsc.nasa.gov/Results.html, show exactly the opposite. Currently posted data for January 2003 show radiation levels in low Mars orbit of 25 millirads/day, or 9 rads/year. While this level is slightly less than twice the regulatory dose for persons employed in the nuclear industry, it represents no significant threat. According the conservative "linear hypothesis" for dealing with low doses accepted in the radiation health physics community, a dose of 13 rads delivered over a 1.5 year Mars mission surface stay would represent a statistical increase in likelihood of cancer (at some point later in life) of about one quarter of one percent. In contrast, the average American smoker receives a 20 percent increase in cancer risk. The Mars radiation risk is thus only about 1/100th as dangerous as smoking.
The MARIE radiation measurements were taken in Mars orbit. Doses on the surface would be even lower.
Thus far from proving that radiation is a showstopper for human Mars missions, the MARIE data show that radiation is NOT a major obstacle to human exploration.
The AP misreportage of the MARIE results is particularly disturbing because it directly contradicts the points that Dr. Zeitlin made at the Mars Odyssey press conference. Subsequent to the publication of the AP article, Dr. Zeitlin sent the following email to Mars Society president Robert Zubrin to set the record straight:
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Bob,
Saw your quote in a version of the AP article that's making the rounds tonight about radiation risks on a Mars mission. Unfortunately your quote is set up as if it were in opposition to my statements, when in fact we are in agreement: the radiation is not a show-stopper. I said this quite explicitly in the press conference and in fact you can see in another (more soberly-written) article that I called the risk "manageable." I am not sure whether Mr. Bridges didn't understand what I was saying or chose to sensationalize it; I prefer to give him the benefit of the doubt and assume he misunderstood. However, not everyone did, as you can see in this article: www.space.com/missionlaunches/odyss...ion_030313.html
The AP misreportage of the MARIE results is a major disservice to the American public and space program. The Mars Society calls on the Associated Press to issue a retraction and correction of its erroneous article.
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Full and accurate discussion of the Mars Odyssey results will be presented at the Sixth International Mars Society convention, which will be held at the Hilton Hotel in Eugene Oregon, August 14-17, 2003. Registration is now open at www.marssociety.org.
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05-05-2003 08:50
UN puts it at 
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