Author Topic: Which is easier, building industry on planets, or in space?  (Read 20709 times)

Offline Jim

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Re: Which is easier, building industry on planets, or in space?
« Reply #100 on: 09/04/2011 01:37 PM »
Uh, no, since Mars has no magnetic field to deflect high energy particles and radiation from the sun, it won't matter how thick you make the atmosphere on Mars. Mars is constantly losing its atmosphere to solar wind as well. You can make the atmosphere as thick as you want on Mars, and it still won't protect unshielded organisms from radiation/high energy particles.

Your source please

Offline A_M_Swallow

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Re: Which is easier, building industry on planets, or in space?
« Reply #101 on: 09/04/2011 01:38 PM »
If you can't post a source other than wikipedia, we don't have anything further to discuss...

True.  He won.

Offline Hop_David

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Re: Which is easier, building industry on planets, or in space?
« Reply #102 on: 09/04/2011 10:41 PM »
If you can't post a source other than wikipedia, we don't have anything further to discuss...

The Wikipedia Stopping Power article Robotbeat pointed to cites these sources:


^ ICRU Report 73: Stopping of Ions heavier than Helium, Journal of the ICRU, 5 No. 1 (2005), Oxford Univ. Press ISBN 0198570120
^ P. Sigmund: Stopping of heavy ions. Springer Tracts in Modern Physics Vol. 204 (2004) ISBN 3540222731
^ Stopping Power for Light Ions
^ Paul, H (2006). "A comparison of recent stopping power tables for light and medium-heavy ions with experimental data, and applications to radiotherapy dosimetry". Nuclear Instruments and Methods in Physics Research Section B 247: 166. Bibcode 2006NIMPB.247..166P. doi:10.1016/j.nimb.2006.01.059.
^ a b ICRU Report 60: Fundamental Quantities and Units for Ionizing Radiation. International Commission on Radiation Units and Measurements, Bethesda, MD, USA (1998) ISBN 0913394599
^ a b c d J. F. Ziegler, J. P. Biersack, and U. Littmark. In The Stopping and Range of Ions in Matter, volume 1, New York, 1985. Pergamon. ISBN 0080220533
^ a b SRIM web site
^ W. E. Burcham. Elements of nuclear physics. Longman, London and New York, 1979 ISBN 0582460271
^ Nordlund, K; Runeberg, N; Sundholm, D (1997). "Repulsive interatomic potentials calculated using Hartree-Fock and density-functional theory methods". Nuclear Instruments and Methods in Physics Research Section B 132: 45. Bibcode 1997NIMPB.132...45N. doi:10.1016/S0168-583X(97)00447-3.
^ Robinson, Mark; Torrens, Ian (1974). "Computer simulation of atomic-displacement cascades in solids in the binary-collision approximation". Physical Review B 9: 5008. Bibcode 1974PhRvB...9.5008R. doi:10.1103/PhysRevB.9.5008.
^ Biersack, J; Haggmark, L (1980). "A Monte Carlo computer program for the transport of energetic ions in amorphous targets☆". Nuclear Instruments and Methods 174: 257. Bibcode 1980NucIM.174..257B. doi:10.1016/0029-554X(80)90440-1.
^ Robinson, M (1992). "Computer simulation studies of high-energy collision cascades1". Nuclear Instruments and Methods in Physics Research Section B 67: 396. Bibcode 1992NIMPB..67..396R. doi:10.1016/0168-583X(92)95839-J.
^ Nordlund, K (1995). "Molecular dynamics simulation of ion ranges in the 1–100 keV energy range". Computational Materials Science 3: 448. doi:10.1016/0927-0256(94)00085-Q.
^ Beardmore, Keith; Grønbech-Jensen, Niels (1998). "Efficient molecular dynamics scheme for the calculation of dopant profiles due to ion implantation". Physical Review E 57: 7278. arXiv:physics/9901054. Bibcode 1998PhRvE..57.7278B. doi:10.1103/PhysRevE.57.7278.

At the moment, I judge Robotbeat's argument persuasive.

Unless I've missed something, you've cited zero sources to support your notion that a magnetosphere is necessary for radiation protection.

Offline Tass

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Re: Which is easier, building industry on planets, or in space?
« Reply #103 on: 09/06/2011 08:19 AM »
Indeed. Someone with more brain wattage than I calculated that if you could raise Mars to 1 ata. It would take millions of years before the solar wind would strip it away to a non-life sustaining level. If you were somehow to raise the Earth's moon to 1 ata it would take thousands of years before the Moon would no longer have a breathable atmosphere.

As human recorded history is only 10000-6000 years(depending on who you question). Our entire civilization could grow thrive and die before a 1 ata Mars would become uninhabitable, by the process of solar wind degradation of the atmosphere. Other ways to make Mars uninhabitable might do the job better :D
Save your insults for someone else, I just want to see your sources of information that are suporting your claims. Thats all, nothing else.
I may be blind or something, but I am utterly incapable of finding even a single insult in the above post. 

Offline Rhyshaelkan

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Re: Which is easier, building industry on planets, or in space?
« Reply #104 on: 09/06/2011 08:51 AM »
Indeed. Someone with more brain wattage than I calculated that if you could raise Mars to 1 ata. It would take millions of years before the solar wind would strip it away to a non-life sustaining level. If you were somehow to raise the Earth's moon to 1 ata it would take thousands of years before the Moon would no longer have a breathable atmosphere.

As human recorded history is only 10000-6000 years(depending on who you question). Our entire civilization could grow thrive and die before a 1 ata Mars would become uninhabitable, by the process of solar wind degradation of the atmosphere. Other ways to make Mars uninhabitable might do the job better :D
Save your insults for someone else, I just want to see your sources of information that are suporting your claims. Thats all, nothing else.
I may be blind or something, but I am utterly incapable of finding even a single insult in the above post. 

I am sure the insult was misconstrued when I said "degradation." Some people cannot take a joke.
I am not a professional. Just a rational amateur dreaming of mankind exploiting the universe.

Offline JohnFornaro

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Re: Which is easier, building industry on planets, or in space?
« Reply #105 on: 09/06/2011 12:40 PM »
I may be blind or something, but I am utterly incapable of finding even a single insult in the above post. 

What?  Are you saying that blind people are the  problem with HSF? 

There.  That quick example of the faulty reasoning which characterizes some posters.  Such faulty reasoning is ensconced in the higher levels of our politics, bureacracies, and so forth.  And it plays out in many ways.  For example, "Mars is easier".  "Frankly, we've been to the Moon before".  "Four segments can't be made to work.  Only five segments."

The post in question was not insulting in the least.  In some ways, the sequence was childish.  "Show me your source".  "Oh yeah? Show me your source!"  The thinking being that an opinion or observation is a priori false without a link, no matter how spurious the link.  The lack of admitting contrary evidence, no matter what.  The insistance upon only accepting evidence that supports a claim.

Boring, but oh well.
Sometimes I just flat out don't get it.

Online Robotbeat

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Re: Which is easier, building industry on planets, or in space?
« Reply #106 on: 09/06/2011 09:42 PM »
If you can't post a source other than wikipedia, we don't have anything further to discuss...
As noted by others, the wikipedia article in question had a page of sources cited.

Even better, I showed you a video of the phenomenon in question (high energy charged particles interacting and losing energy to and having a limited range in the atmosphere--i.e. being stopped by air). The experiment is easily repeatable with household items and items available at a grocery store or drug store (smoke detector, black construction paper, felt, dry ice, rubbing alcohol, that sort of thing). Here's another example, using only household-type items:

What more do you want?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline LegendCJS

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Re: Which is easier, building industry on planets, or in space?
« Reply #107 on: 09/06/2011 10:07 PM »
You apparently don't understand the concept of stopping power. A charged particle has a finite distance that it can travel through air before being stopped because it leaves a trail of ions as it goes through the air (and ionizing the air takes energy... which slows the particle down to a stop after a certain distance).

This is so bloody obvious, and it is in the link I posted before (though the forum software ate it the first time I posted it) http://en.wikipedia.org/wiki/Stopping_power_(particle_radiation)

I've done the experiment myself during my Sophomore year in college. It's easy to see in any cloud chamber (in fact, cloud chambers wouldn't work if charged particles weren't affected by atmosphere):


All these by-products and ionized air particles created by the high energy particle's interaction with atmosphere that can do more damage to a human than if there had been no atmosphere in the first place.  However, if the original particle was charged then a magnetic field could stop it before interaction with the atmosphere.

I don't think you are saying this, but claiming that having a thick enough atmosphere is the only factor to consider in creating a safe radiation environment on Mars is wrong.  Magnetic field has to be considered as well.

Our radiation safe conditions on Earth are a result of both thick atmosphere and a magnetic field.  One without the other may not cut it on Mars, especially the likely situation of a thin (compared to earth) atmosphere and no magnetic field.
« Last Edit: 09/06/2011 10:10 PM by LegendCJS »
Remember: if we want this whole space thing to work out we have to optimize for cost!

Online Robotbeat

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Re: Which is easier, building industry on planets, or in space?
« Reply #108 on: 09/06/2011 10:17 PM »
Except you are wrong. If Mars had a thick, Earth-like atmosphere, the radiation dosage would be lower than the background radiation of some areas on Earth. An Earth-like magnetic field doesn't help deflect the highest energy cosmic rays, anyway, though it does help lower the radiation dosage somewhat in LEO. But the atmosphere is more important (since it shields against UV and X-rays, as well... something that magnetic fields have exactly zero influence on), and if thick enough can provide plenty of shielding for Mars inhabitants. A magnetic field is helpful, but is most certainly not absolutely required for effective shielding.

A thick enough atmosphere is good enough for completely safe levels of shielding even with ZERO magnetic field.

Heck, the cosmic ray radiation dosage in Hellas Basin, with just the current atmosphere of Mars, is already as low as the background radiation in parts of Ramsar, Iran (10 rem is basically equivalent to 100 mSv):
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA03480
Quote
The areas of Mars expected to have the lowest levels of cosmic radiation are where the elevation is lowest, because those areas have more atmosphere above them to block out some of the radiation. Earth's thick atmosphere shields us from most cosmic radiation, but Mars has a much thinner atmosphere than we have on Earth.

For reference, the natural background dose in parts of Ramsar, Iran, is about 132 mSv (~13rem/year) inside some residences, and people live and have lived long, healthy lives there for generations. http://www.angelfire.com/mo/radioadaptive/ramsar.html
« Last Edit: 09/06/2011 10:24 PM by Robotbeat »
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Offline LegendCJS

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Re: Which is easier, building industry on planets, or in space?
« Reply #109 on: 09/07/2011 12:22 AM »
Except you are wrong. If Mars had a thick, Earth-like atmosphere, the radiation dosage would be lower than the background radiation of some areas on Earth. An Earth-like magnetic field doesn't help deflect the highest energy cosmic rays, anyway, though it does help lower the radiation dosage somewhat in LEO. But the atmosphere is more important (since it shields against UV and X-rays, as well... something that magnetic fields have exactly zero influence on), and if thick enough can provide plenty of shielding for Mars inhabitants. A magnetic field is helpful, but is most certainly not absolutely required for effective shielding.

A thick enough atmosphere is good enough for completely safe levels of shielding even with ZERO magnetic field.

Heck, the cosmic ray radiation dosage in Hellas Basin, with just the current atmosphere of Mars, is already as low as the background radiation in parts of Ramsar, Iran (10 rem is basically equivalent to 100 mSv):
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA03480
Quote
The areas of Mars expected to have the lowest levels of cosmic radiation are where the elevation is lowest, because those areas have more atmosphere above them to block out some of the radiation. Earth's thick atmosphere shields us from most cosmic radiation, but Mars has a much thinner atmosphere than we have on Earth.

For reference, the natural background dose in parts of Ramsar, Iran, is about 132 mSv (~13rem/year) inside some residences, and people live and have lived long, healthy lives there for generations. http://www.angelfire.com/mo/radioadaptive/ramsar.html

About atmospheric shielding of UV: I present to you this reference: http://www.sciencedaily.com/releases/2001/08/010802080620.htm.

It states that solar wind generated charged particles destroy ozone through the mechanism of breaking nitrogen and water molecules apart and forming hydrogen and nitrogen oxides, which in turn destroy ozone.  Hydrogen oxides last for the duration of the solar storm event, while the nitrogen oxides last for months afterwards.  It was stated that for a particular event studied on order of 1% of atmospheric ozone was destroyed due to a solar flare/ coronal mass ejection that punched its way through Earth's magnetic field.

One percent per large solar storm event is not that much, but with no magnetic field on Mars, the assault would be continuous. Both kinds of oxides would be present in perpetuity, with nitrogen oxide building to significant levels.

It would stand to reason that with no magnetic field a planetary atmosphere could not maintain ozone levels in significant quantities to block UV radiation.

I buy the greater importance of atmospheric mass over magnetic field in blocking other kinds of radiation.

I suppose the discussion of having any ozone at all in a terraformed atmosphere is kind of an oxymoron given that most strategies for terra-forming Mars involve releasing large amounts of high GWP gasses like CFCs and the like, especially ones with lifetimes of O(10^4) years in the atmosphere.
« Last Edit: 09/07/2011 12:31 AM by LegendCJS »
Remember: if we want this whole space thing to work out we have to optimize for cost!

Online Robotbeat

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Re: Which is easier, building industry on planets, or in space?
« Reply #110 on: 09/07/2011 12:39 AM »
Right, a magnetic field is important for shielding the atmosphere from being stripped away (and other effects like you linked to) on a long timeline.

It's not unreasonable to imagine that if you had managed to terraform Mars, you could much more easily build a large superconducting ring around the Martian equator to create a magnetic dipole as great as the Earth's magnetic field (something like 9*10^22 Amps*m^2). The superconductor current density record is something like 27 MA/cm^2, so a cable around Mars's equator carrying enough current to create a dipole as great as the Earth's would have a cross section of 100 cm^2, or would be about five inches in diameter (plus cooling and insulation). That's really not that big. And we're likely to make significant advances in superconductors (as far as current density goes, at least) in the next million or so years! ;)
« Last Edit: 09/07/2011 12:40 AM by Robotbeat »
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Offline JohnFornaro

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Re: Which is easier, building industry on planets, or in space?
« Reply #111 on: 09/07/2011 05:15 PM »
The experiment is easily repeatable with household items ...

Didn't they give an actual demonstration of this technique in the documentary film "ET"?
Sometimes I just flat out don't get it.

Offline Rhyshaelkan

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Online Robotbeat

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Re: Which is easier, building industry on planets, or in space?
« Reply #114 on: 09/30/2011 11:58 PM »
http://science.nasa.gov/science-news/science-at-nasa/2008/21nov_plasmoids/


Over a timescale of hundreds of millions of years. Far longer than we've even been a species. Heck, longer than there's been mammals on Earth. While that's an interesting link (and thanks for posting it, it actually is pretty related to a class I'm taking right now), it doesn't have much to do with the topic at hand. Well, at least not much more than the fact that the Sun is going to enter its Red Giant phase, eventually. It's not impossible to produce an artificial field strong enough to keep the atmosphere from leaving over millions of years.
« Last Edit: 10/01/2011 12:01 AM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

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