PDA

View Full Version : Mutant Nuclear Bacteria From Another World!



Makgraf
2004-Nov-17, 08:04 AM
So the Wall Street Journal has a story about a bunch of bacteria that was found growing in nuclear waste (http://online.wsj.com/article_email/0,,SB110055694326574611-IBje4NmlaR3oZyranSHaquDm4,00.html). These bacteria, or extremophiles, can tolerate 15 times the normal amount of radiation and could be used to clean up nuclear waste. Some scientists think they must have originally come from outer space (but one in the article dismisses that as "mythology").

The original extremophile found was nicknamed "Conan the Barbarian" but now scientists at the DoE have genetically engineered a better version known as Super Conan:

It can handle nasty chemicals as well as radiation, but the researcher who developed it, Michael J. Daly, says the government is afraid to let it out.

"We're at a point where we could do some field trials," he says, adding that his sponsors at the Energy Department doubt the public is ready for the release of this laboratory-engineered bug into the environment. It might eat nuclear wastes, but they worry about what else might it do, he says.
:o

Morrolan
2004-Nov-17, 10:06 AM
as always one may first want to ask the question: "if there's no <insert any item to be removed> to eat, what will <insert species to be introduced> eat instead if we introduce it in <insert area, country, region>?"

had these things been done in the past, the cane toad, for instance, may never have been introduced in Australia to try and eradicate cane beetles. which didn't turn out to work, as the cane toad much prefererred all the other tasty creatures Australia had to offer... and Australia would not now have such a big problem on their hands. and i'm certain there are quite a few other examples to be found.

frogesque
2004-Nov-17, 10:11 AM
[straight face.]

Ok, at first I couldn't see how superbugs digesting radioactive waste would help a clean up operation. After all, they may be resistant to radiation but don't actually break down radioactive particles into something benign but I see from the article that they can combine the waste into insoluble forms (presumably oxides). Maybe they also have another role in concentrating low grade ores similar to bio leaching copper, silver and gold etc. Books reference for further light reading (http://www.min-eng.com/bookcontents.html). I don't think this is really anything new other than the fact the particular microbes have been 'engineered' rather than evolved in the wild.

The ability to clean up other toxic waste (toluene is mentioned) is useful especially if PCBs can be handled as well but I would want to see a lot more controlled and biologically contained experimentation before setting them loose on something like, say an ocean oilspill. Right now I'm having breakfast and I'm not sure I want any of these superbugs inside me.[/straight face.]

...

Makgraf wrote:


The original extremophile found was nicknamed "Conan the Barbarian" but now scientists at the DoE have genetically engineered a better version known as Super Conan:


ROFL. I love it! :lol:

aurora
2004-Nov-17, 06:46 PM
had these things been done in the past, the cane toad, for instance, may never have been introduced in Australia to try and eradicate cane beetles. which didn't turn out to work, as the cane toad much prefererred all the other tasty creatures Australia had to offer... and Australia would not now have such a big problem on their hands. and i'm certain there are quite a few other examples to be found.

A couple of others:

Mongooses (mongeese?) in Hawaii, to kill nocturnal rats (a mongoose is diurnal), ended up eating eggs of ground nesting birds instead.

Starlings in North America, originally released in New York City because someone wanted to have all the birds from Shakespeare's plays (IIRC).

Accidental releases can be just as bad or worse, zebra mussles in North America, tree snakes in Guam.

Avatar28
2004-Nov-17, 07:02 PM
Accidental releases can be just as bad or worse, zebra mussles in North America, tree snakes in Guam.

I lived in the Northern Marianas for two years. They were ALWAYS afraid of getting those things hitching a ride and getting loose. Guam has a MAJOR problem with those things. They frequently get power outages because a snake has crawled up over the power lines and fried itself trying to get warm (cause, you know, tropical islands aren't warm enough already). I don't know the exact numbers, but they're huge. On the order of thousands per square mile I believe.

frogesque
2004-Nov-17, 07:20 PM
It's a very small world now I'm afraid. To some extent the arrival in the UK of the New Zealand Flatworm (http://www.dgsgardening.btinternet.co.uk/flatworm.htm) is a bit of down under revenge for the idiocies of the British colonials. When I lived in Northern Ireland my compost heap became infested with them. Worms that is, not colonial types.

Note to the squeamish: they are disgusting and that link has pictures.

Evan
2004-Nov-17, 07:29 PM
I become very uneasy when they engineer life forms with greatly enhanced survival traits. I don't think it wise.

Morrolan
2004-Nov-18, 03:09 AM
I become very uneasy when they engineer life forms with greatly enhanced survival traits. I don't think it wise.

yeah, i wish they'd stick to glow-in-the-dark guppies... :wink:

MrObvious
2004-Nov-18, 03:36 AM
I become very uneasy when they engineer life forms with greatly enhanced survival traits. I don't think it wise.


I would have thought we'd know better, after all look at what happened to the Eath when the aliens put us here to get rid of the bananas :wink:

doltish
2004-Nov-19, 07:24 PM
Well I have a suggestion...

If the DOE is going to go ahead and use the Yucca Mountain site for storage (nicer word for dumping) of nuclear waste materials, what harm would it do it unleash Conan and his brethren there? Yucca Mountain is in the middle of a desert with no aquifer or mineable resources. Basically no reason for anybody to ever go near it, not to mention with nuclear waste there nobody will ever be able to go near it anyway.

My education on things like this is non-existent, so please feel free to poke holes :)

Evan
2004-Nov-19, 07:44 PM
Nothing to eat.

I was re-reading the story.


Because the microbes endure radiation at levels higher than any natural source, some scientists have argued that they must have ridden in on comets.

Utter nonsense. See here about natural reactors (http://www.alamut.com/proj/98/nuclearGarden/bookTexts/Lovelock_Oklo.html)


"Bacteria could not have debated the costs and benefits of nuclear power. The fact that the reactors ran so long and that there was more than one of them suggests that replenishment must have occured and that the radiation and nuclear waste from the reactor was not a deterrent to that ancient bacterial ecosystem.

beskeptical
2004-Nov-25, 09:29 AM
Myth one - The bacteria are not ETs.

If the bacteria came from a comet or other convenient transport object, we could immediately tell because the bugs would have novel DNA. Bacteria don't evolve in complete isolation and have matching genetic sequences. There are too many base pairs for that. Either you pass sequences on and therefore get matching patterns, or you don't have the matching patterns.

Myth two - Just because it is new, or you don't understand it, doesn't mean it is dangerous.

We have been engineering bacteria to digest hazardous wastes for years. They happen to be very good at it and a very promising technology. If you are raised on toxins, you don't eat people, you eat toxins.

Bacteria don't fly. If contaminants can be spread by bacteria, then the contaminants can be spread without the bacteria as well. They are both carried and/or spread around in the same ways.

There is some bioengineering of bugs that might pose very serious hazards. I don't think toxin eaters are in that category. I'm much more concerned about splicing a gene to produce insulin into a bacteria. If such a bug could infect a person, producing insulin could easily be fatal.

But I do not know if such bioengineering is hazardous and I refrain from making such claims until I review the science. Remember, when the science is beyond your expertise, you really have no way of judging a hazard, or the reliability of evidence, or the correctness of a theory. We are quick to point out the same fallacies others have about the science we do have expertise in. However, we often fail to recognize the same fallacies we ourselves hold about scientific fields we have no expertise in.

RGClark
2004-Nov-26, 03:39 PM
Myth one - The bacteria are not ETs.

If the bacteria came from a comet or other convenient transport object, we could immediately tell because the bugs would have novel DNA. Bacteria don't evolve in complete isolation and have matching genetic sequences. There are too many base pairs for that. Either you pass sequences on and therefore get matching patterns, or you don't have the matching patterns...

Not necessarily. One theory of panspermia argues Earth was seeded with life from comets. In that case we would expect Earth life and extraterrestrial life to be similar.
On the other hand, we would expect such life surviving in comets would have high resistance to radiation.



Bob Clark

Evan
2004-Nov-26, 03:56 PM
The panspermia hypothesis merely begs the question of the origin of life and serves no useful purpose. It still does not address the origin of life.

RGClark
2004-Nov-27, 12:18 AM
The panspermia hypothesis merely begs the question of the origin of life and serves no useful purpose. It still does not address the origin of life.

It does if the question is "Does life exist on other worlds?"

A very significant question!


Bob Clark

Evan
2004-Nov-27, 12:36 AM
The panspermia hypothesis doesn't answer any questions even if life is found on other worlds. Even if such life is found and even if it uses dna similar to ours it still doesn't validate panspermia. It is entirely possible that using dna is the most likely way for carbon based life to develop. There is no way to prove or even conclusively disprove panspermia. It is therefor irrelevant. Even if life is found on other worlds panspermia provides no answers.

Ilya
2004-Nov-27, 01:04 AM
"15 times the dose which would kill a human"? That is, 6000 rad? For bacteria, and for insects for that matter, this is entirely normal. Indeed, it is a rare microorganism which can be killed by so LITTLE radiation.

I think Wal Street Journal confused "15 times normal" with 15,000 grays (1.5 million rad), which is remarkable even for bacteria:

http://www.gdr.org/microbessurvives.htm

Maksutov
2004-Nov-27, 06:43 AM
had these things been done in the past, the cane toad, for instance, may never have been introduced in Australia to try and eradicate cane beetles. which didn't turn out to work, as the cane toad much prefererred all the other tasty creatures Australia had to offer... and Australia would not now have such a big problem on their hands. and i'm certain there are quite a few other examples to be found.

A couple of others:

Mongooses (mongeese?) in Hawaii, to kill nocturnal rats (a mongoose is diurnal), ended up eating eggs of ground nesting birds instead.

Starlings in North America, originally released in New York City because someone wanted to have all the birds from Shakespeare's plays (IIRC).

Accidental releases can be just as bad or worse, zebra mussles in North America, tree snakes in Guam.
Then there's kudzu, originally promoted as pasturage and an erosion control agent. (http://www.invasive.org/eastern/biocontrol/25Kudzu.html) Thank you, David Fairchild. Hah! :evil:

beskeptical
2004-Nov-27, 06:48 AM
Myth one - The bacteria are not ETs.

If the bacteria came from a comet or other convenient transport object, we could immediately tell because the bugs would have novel DNA. Bacteria don't evolve in complete isolation and have matching genetic sequences. There are too many base pairs for that. Either you pass sequences on and therefore get matching patterns, or you don't have the matching patterns...

Not necessarily. One theory of panspermia argues Earth was seeded with life from comets. In that case we would expect Earth life and extraterrestrial life to be similar.
On the other hand, we would expect such life surviving in comets would have high resistance to radiation.

Bob Clark Panspermia was an idea of an astronomer who didn't know much biology. It is not a valid theory. We've discussed it here before if you want more details on why it isn't valid. In a nutshell, there is fossil evidence of life forms back 3.5 billion years or so, shortly after the Earth reformed after the lunar precursor impact. From there the earliest bacteria can be followed until the present. The map from past to present has enough markers to show how life evolved. There is no evidence of introductions of novel organisms.

In addition, if you took twin organisms 3.5 billion years ago and let one develop on Earth and one develop on another planet or comet, you would know they diverged 3.5 billion years ago by the number of differences in their DNA. While the rate of mutation is not as exact nor as consistent as radioactive decay, mutations do progress like clockwork.

The bottom line, without doubt, we could tell ETs from Ts.

beskeptical
2004-Nov-27, 06:59 AM
The panspermia hypothesis doesn't answer any questions even if life is found on other worlds. Even if such life is found and even if it uses dna similar to ours it still doesn't validate panspermia. It is entirely possible that using dna is the most likely way for carbon based life to develop. There is no way to prove or even conclusively disprove panspermia. It is therefor irrelevant. Even if life is found on other worlds panspermia provides no answers.If you mean, there is no way to prove or disprove the first life form on Earth arrived as opposed to developed, that may be true. The evidence strongly suggests life evolved here on Earth. Organic chemicals have arrived since they have been found in meteorites, but whole organisms were not needed to explain the original change from chemical to life form. RNA replicates without additional cell structures. RNA molecules can form from 'organic soups'. RNA can reproduce DNA molecules and so on.

On the other hand, the panspermia theory I am referring to is the one in which persons have suggested life forms from space are raining down all the time.

Evan
2004-Nov-27, 07:16 AM
Yes, I am referring to panspermia as the original source of life on Earth. As I said before, invoking panspermia to explain the origin of life here only removes by one step the original question of how life originated. It doesn't answer anything. As to living bits raining down on a daily basis, I hadn't considered that. I don't hang out with that crowd.:D

beskeptical
2004-Nov-27, 07:24 AM
Correction to my above posts before I get attacked for another absolute statement. :wink:

From Wikipedia, the free encyclopedia. (http://en.wikipedia.org/wiki/Panspermia)
Panspermia is a theory (more directly described as a hypothesis, as there is no compelling evidence yet available to support or contradict it) that suggests that the seeds of life are prevalent throughout the Universe and life on Earth began by such seeds landing on Earth and propagating.

If one is only talking about the origin of life on Earth, Panspermia is less and less likely an explanation the more we learn about evolutionary processes. However, it hasn't been disproved.

There is overwhelming evidence against repeated encounters with ET bacteria, however, which is what I had in mind in my post above. The fact ET DNA would still differ enough to be recognized as foreign is still a valid statement.

Whether or not ET lifeforms are based on carbon and on DNA does not mean we can't tell the difference. There are billions of base pairs in any organism's DNA code. There are three branches off the original tree, archaea, bacteria and eukaryotes. Modern life forms have many of the same DNA patterns as earlier life forms. The fact our DNA originated from the same pool of molecules billions of years ago and formed by copy mutation copy mutation copy mutation etc., shows up when we map out the genomes.

Evan
2004-Nov-27, 07:38 AM
Yep, it doesn't sit well with some people to know we have some of the same codons as fruit flies...

BTW, I don't become worried about making absolute statements in regard to absolute nonsense.

beskeptical
2004-Nov-27, 07:46 AM
Yep, it doesn't sit well with some people to know we have some of the same codons as fruit flies...

BTW, I don't become worried about making absolute statements in regard to absolute nonsense.It was a reference to a statement I made a while back, which I still hold is correct, "evolution is a fact that is no longer in question". I was quite surprised by the response.

(PS, to whom it may concern, don't hijack the thread. If you want to talk evolution, search out the past threads first.)

Evan
2004-Nov-27, 08:48 AM
Although I agree with you it does still serve us well to remember and know the difference between belief and knowledge. This is a distinction lost on most.

RGClark
2004-Nov-27, 05:10 PM
The panspermia hypothesis doesn't answer any questions even if life is found on other worlds. Even if such life is found and even if it uses dna similar to ours it still doesn't validate panspermia. It is entirely possible that using dna is the most likely way for carbon based life to develop. There is no way to prove or even conclusively disprove panspermia. It is therefor irrelevant. Even if life is found on other worlds panspermia provides no answers.

Huh? Life being found on other worlds wouldn't answer the question "Does life exist on other worlds?"


Bob Clark

Evan
2004-Nov-27, 05:52 PM
Life being found on other worlds wouldn't answer the question "Does life exist on other worlds?"

What does that sentence mean?

RGClark
2004-Nov-27, 06:06 PM
Myth one - The bacteria are not ETs.

If the bacteria came from a comet or other convenient transport object, we could immediately tell because the bugs would have novel DNA. Bacteria don't evolve in complete isolation and have matching genetic sequences. There are too many base pairs for that. Either you pass sequences on and therefore get matching patterns, or you don't have the matching patterns...

Not necessarily. One theory of panspermia argues Earth was seeded with life from comets. In that case we would expect Earth life and extraterrestrial life to be similar.
On the other hand, we would expect such life surviving in comets would have high resistance to radiation.

Bob Clark Panspermia was an idea of an astronomer who didn't know much biology. It is not a valid theory. We've discussed it here before if you want more details on why it isn't valid. In a nutshell, there is fossil evidence of life forms back 3.5 billion years or so, shortly after the Earth reformed after the lunar precursor impact. From there the earliest bacteria can be followed until the present. The map from past to present has enough markers to show how life evolved. There is no evidence of introductions of novel organisms.

In addition, if you took twin organisms 3.5 billion years ago and let one develop on Earth and one develop on another planet or comet, you would know they diverged 3.5 billion years ago by the number of differences in their DNA. While the rate of mutation is not as exact nor as consistent as radioactive decay, mutations do progress like clockwork.

The bottom line, without doubt, we could tell ETs from Ts.

I don't agree that panspermia is not regarded as a serious theory for the origin of life on Earth. More and more scientists are considering it as a viable theory with published reports that microbes could survive long periods in comets and meteorites, perhaps extending even between star systems.
The DNA record does not go all the way back to the beginning of the Earth, 4.5 billion years ago. Actually one reason that proponents of panspermia argue life arrived from comets is that the earliest evidence for life goes back to the Late Heavy Bombardment period, 3.85 billion years ago. This is mentioned in that reference from Wikipedia on panspermia:

"Narrow time window for geogenesis
The Precambrian fossil record indicates that life appeared soon after the Earth was formed. Unless the Earth just happened to be the site of a large number of fortuitous coincidences (not so unlikely under the anthropic principle), this would imply that life appears in several hundred million years when conditions are favorable.
...
If life originated on Earth, it did so in at most a 700 million year window (4.55 Ga - 3.85 Ga). On some models of planet formation this is almost too soon for the Earth to have cooled sufficiently to allow liquid water and support life. If life originated elsewhere, the window expands to 9850 million years, more than a factor of 14."


There is a great divergence between ancient microbes known as archaea from the commonly known bacteria, probably back to the earliest origins of life. If we do find bacteria in comets the divergence we see could be at the same level as the archaea and it would be difficult to distinguish the difference on DNA alone.



Bob Clark

RGClark
2004-Nov-27, 06:13 PM
Life being found on other worlds wouldn't answer the question "Does life exist on other worlds?"

What does that sentence mean?

I said previously that finding life on other worlds would answer a very significant question: "Does life exist on other worlds?"
Your response seemed to say it wouldn't answer any significant question.
I assume you mean either the question itself isn't interesting or that finding life on other worlds wouldn't answer the question of life on other worlds.


Bob Clark

Evan
2004-Nov-27, 06:20 PM
The sentence 'Life being found on other worlds wouldn't answer the question "Does life exist on other worlds?"' is logically inconsistent with itself.

I said that finding life on other worlds will not validate the panspermia hypothesis, and it will not. You need to read my posts more carefully.


Your response seemed to say it wouldn't answer any significant question.

About the panspermia hypothesis. I made that perfectly clear.

RGClark
2004-Nov-27, 07:42 PM
The sentence 'Life being found on other worlds wouldn't answer the question "Does life exist on other worlds?"' is logically inconsistent with itself.

I said that finding life on other worlds will not validate the panspermia hypothesis, and it will not. You need to read my posts more carefully.


Your response seemed to say it wouldn't answer any significant question.

About the panspermia hypothesis. I made that perfectly clear.

OK. I read more into your statement than you meant.

However, one way we might validate the panspermia hypothesis is if we find cometary material in our solar system or other star systems containing fossilized microbes older than the Earth itself. Comets for example are believed to be very old, stemming from the origin of our solar system.
There are also interstellar grains that are older than the solar system itself:

Moving Stars and Shifting Sands of Presolar History
Written by Donald D. Clayton
Centennial Professor, Department of Physics and Astronomy
Clemson University, Clemson, SC
"Many surprising things have been revealed by the presolar grains that scientists extract from meteorites. They are small (micrometer sized) mineral grains that existed in space, as part of clouds of interstellar dust, prior to the formation of our Sun and Solar System. What an astonishing discovery! These castoffs from ancient stars have been preserved within some types of meteorites making them available for close scrutiny in our laboratories."
http://www.psrd.hawaii.edu/July97/Stardust.html

These grains seen are abiotic. But if we found such equally ancient interstellar particles that contained microbe fossils we could deduce life existed prior to the formation of the Earth and logically would have been deposited here during its entire history.


Bob Clark

Evan
2004-Nov-27, 10:27 PM
"However, one way we might validate the panspermia hypothesis is if we find cometary material in our solar system or other star systems containing fossilized microbes older than the Earth itself. Comets for example are believed to be very old, stemming from the origin of our solar system."

Were microbial fossils to be found on interstellar grains it would indeed be a miracle. Since those grains stem from supernova explosions it would certainly have to be a very durable form of life. The Cheela, maybe? Cometary material also derives from the same source.

RGClark
2004-Nov-27, 10:47 PM
Were microbial fossils to be found on interstellar grains it would indeed be a miracle. Since those grains stem from supernova explosions it would certainly have to be a very durable form of life. The Cheela, maybe? Cometary material also derives from the same source.

If these other star systems that underwent supernovae explosions have Oort clouds we might get the castoffs from such comets as the expanding gas cloud hit them.


Bob Clark

expirationdate
2004-Nov-27, 11:43 PM
well hopefully the scientist working with this "super conan" develope an antidote/vaccine to kill this thing before they let it out and about on our planet. Just incase of a big cotastraphy like say in our crops? also as well as water if it affects the species of life that we feed from aswell as ourselves. That would be the smart thing to do.

as always one may first want to ask the question: "if there's no <insert any item to be removed> to eat, what will <insert species to be introduced> eat instead if we introduce it in <insert area, country, region>?"

had these things been done in the past, the cane toad, for instance, may never have been introduced in Australia to try and eradicate cane beetles. which didn't turn out to work, as the cane toad much prefererred all the other tasty creatures Australia had to offer... and Australia would not now have such a big problem on their hands. and i'm certain there are quite a few other examples to be found.

expirationdate
2004-Nov-27, 11:49 PM
Clark bud .. if you look back you'll find that you first sugested that it "would'nt" answer the question.


[quote="Evan"][quote]Life being found on other worlds wouldn't answer the question "Does life exist on other worlds?"

expirationdate
2004-Nov-27, 11:51 PM
also with what they would develope to kill "super conan" hopefully it doesn't have an even more dramatic effect on us than "s.c." would. Therefor leading them to developing something to kill s.c's vaccine and another for that ect... and so on. if that makes any sense.


well hopefully the scientist working with this "super conan" develope an antidote/vaccine to kill this thing before they let it out and about on our planet. Just incase of a big cotastraphy like say in our crops? also as well as water if it affects the species of life that we feed from aswell as ourselves. That would be the smart thing to do.

as always one may first want to ask the question: "if there's no <insert any item to be removed> to eat, what will <insert species to be introduced> eat instead if we introduce it in <insert area, country, region>?"

had these things been done in the past, the cane toad, for instance, may never have been introduced in Australia to try and eradicate cane beetles. which didn't turn out to work, as the cane toad much prefererred all the other tasty creatures Australia had to offer... and Australia would not now have such a big problem on their hands. and i'm certain there are quite a few other examples to be found.

Evan
2004-Nov-28, 07:37 AM
If these other star systems that underwent supernovae explosions have Oort clouds we might get the castoffs from such comets as the expanding gas cloud hit them.



After a supernova there will be no trace of an Oort cloud around the former star that went supernova.

Evan
2004-Nov-28, 07:41 AM
expirationdate,

What are you trying to say?

RGClark
2004-Nov-28, 03:29 PM
Clark bud .. if you look back you'll find that you first sugested that it "would'nt" answer the question.


[quote=Evan][quote]Life being found on other worlds wouldn't answer the question "Does life exist on other worlds?"

That sentence was supposed to be a question. It came from a misunderstanding of what Evan was saying. He was talking simply about the origin of life in general. I was raising a separate question about the existence of life on other worlds.


Bob Clark

RGClark
2004-Nov-28, 03:32 PM
If these other star systems that underwent supernovae explosions have Oort clouds we might get the castoffs from such comets as the expanding gas cloud hit them.



After a supernova there will be no trace of an Oort cloud around the former star that went supernova.

The Oort cloud extends from 1 to 2 light-years away from the parent star. I would expect small remnants of the comets there to survive as meteorites.


Bob Clark

Evan
2004-Nov-28, 06:50 PM
The Oort cloud extends from 1 to 2 light-years away from the parent star. I would expect small remnants of the comets there to survive as meteorites.

Firstly, metorites are objects that survive the plunge though our atmosphere to this earth.

More importantly, when a supernova happens being a couple of light years away is no protection. A supernova outshines an entire galaxy for a while. Anything in the remote vicinity is toast. Burnt toast.

RGClark
2004-Nov-29, 07:16 AM
The Oort cloud extends from 1 to 2 light-years away from the parent star. I would expect small remnants of the comets there to survive as meteorites.

Firstly, metorites are objects that survive the plunge though our atmosphere to this earth.

More importantly, when a supernova happens being a couple of light years away is no protection. A supernova outshines an entire galaxy for a while. Anything in the remote vicinity is toast. Burnt toast.


One of the models for the origin of gamma ray bursts is that they arise from impact of comets with neutron stars. Such models show that comets at Oort cloud distances could survive the supernova explosion:

Title: Can comet clouds around neutron stars explain gamma-ray bursts?
Authors: Tremaine, S.; Zytkow, A. N.
Journal: Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 301, Feb. 1, 1986, p. 155-163.
Abstract
The proposal of Harwit and Salpeter (1973) that gamma-ray bursts are due to impacts of comets onto neutron stars is examined further. It is assumed that most stars are formed with comet clouds similar to the Oort comet cloud which surrounds the sun, and it is suggested that there are at least four mechanisms by wich neutron stars may be formed while retaining their comet clouds: a spherically symmetric supernova explosion in an isolated star, accretion-induced collapse of a white dwarf in a cataclysmic variable with a very low mass secondary, accretion-induced collapse of a white dwarf in a wide binary with a low-mass giant companion, and coalescence of a close binary composed of two white dwarfs. Estimates are given of the cometary impact rates for such systems. It is suggested that if the wide binary scenario is correct, optical bursts may arise from the impact of comets onto the white dwarf remnant of the giant companion.
http://adsabs.harvard.edu/cgi-bin/bib_query?1986ApJ...301..155T

Title: Possible models for the high-energy transient GB790107
Authors: Livio, Mario; Taam, Ronald E.
Journal: Nature (ISSN 0028-0836), vol. 327, June 4, 1987, p. 398-400.
Abstract
The properties of the high-energy transient GB790107 place severe constraints on the viability of models proposed for typical gamma-ray burst events as applied to this soft gamma-ray repeater. Here, the various models proposed for gamma-ray bursts are reviewed. It is shown that a model involving a comet cloud around a neutron star is consistent with the observational data.
http://adsabs.harvard.edu/cgi-bin/bib_query?1987Natur.327..398L

Title: Gamma-ray bursts from young supernova remnants
Authors: Pineault, Serge
Journal: Nature (ISSN 0028-0836), vol. 345, May 17, 1990, p. 233-235.
Abstract
It is noted here that a neutron star may well acquire a large velocity at birth, causing it to drift through the Oort Cloud. As it crosses the most densely populated regions, collisions with comets could cause frequent gamma-ray bursts. Young SNRs may therefore be the site of some of the observed bursts, particularly the less energetic, more rapidly recurring type known as soft gamma-ray repeaters. SN1987A may become the source of gamma-ray bursts in a matter of decades.
http://adsabs.harvard.edu/cgi-bin/bib_query?1990Natur.345..233P

Title: Nature and Nurture: a Model for Soft Gamma-Ray Repeaters
Authors: Zhang, Bing; Xu, R. X.; Qiao, G. J.
Journal: The Astrophysical Journal, Volume 545, Issue 2, pp. L127-L130.
Abstract
During supernova explosions, strange stars with almost bare quark surfaces may be formed. Under certain conditions, these stars could be rapidly spun down by the torque exerted by the fossil disks formed from the fallback materials. They may also receive large kicks and hence have large proper-motion velocities. When these strange stars pass through the spherical ``Oort'' comet cloud formed during the presupernova era, they will capture some small-scale comet clouds and collide with some comet-like objects occasionally. These impacts can account for the repeating bursts as observed from the soft gamma repeaters. According to this picture, it is expected that SGR 1900+14 will become active again during 2004-2005.
http://adsabs.harvard.edu/cgi-bin/bib_query?2000ApJ...545L.127Z



Bob Clark

Evan
2004-Nov-29, 06:55 PM
That is all guesswork. It isn't logical for the Oort cloud to be retained after a supernova event. Oort cloud objects are thought to be essentially "dirty snowballs". As well as serious heating from the explosion the star throws off most of it's mass. The shock wave will accelerate Oort objects which are no longer orbitally bound to the remains of the star. Objects in the Oort cloud are very loosely bound by gravity anyway and the sudden reduction in mass of the primary will release them completely.

RGClark
2004-Nov-30, 04:37 PM
That is all guesswork. It isn't logical for the Oort cloud to be retained after a supernova event. Oort cloud objects are thought to be essentially "dirty snowballs". As well as serious heating from the explosion the star throws off most of it's mass. The shock wave will accelerate Oort objects which are no longer orbitally bound to the remains of the star. Objects in the Oort cloud are very loosely bound by gravity anyway and the sudden reduction in mass of the primary will release them completely.

Actually, it's very logical. The supernova gas cloud, or remnant, extends up to 10 lightyears from the star. It's extent is limited merely by the pressure of the extremely tenuous interstellar gas.
The Sun's Oort cloud extends 1 to 2 light years away from the Sun. For a star that goes supernova with a mass 10 times the Sun's we would expect it's Oort cloud to extend 10 times further away, or 10 to 20 light-years.
The shock wave is extremely well attenuated at this point.


Bob Clark

Kaptain K
2004-Nov-30, 05:02 PM
That is all guesswork. It isn't logical for the Oort cloud to be retained after a supernova event. Oort cloud objects are thought to be essentially "dirty snowballs". As well as serious heating from the explosion the star throws off most of it's mass. The shock wave will accelerate Oort objects which are no longer orbitally bound to the remains of the star. Objects in the Oort cloud are very loosely bound by gravity anyway and the sudden reduction in mass of the primary will release them completely.

Actually, it's very logical. The supernova gas cloud, or remnant, extends up to 10 lightyears from the star. It's extent is limited merely by the pressure of the extremely tenuous interstellar gas.
The Sun's Oort cloud extends 1 to 2 light years away from the Sun. For a star that goes supernova with a mass 10 times the Sun's we would expect it's Oort cloud to extend 10 times further away, or 10 to 20 light-years.
The shock wave is extremely well attenuated at this point.


Bob Clark
My guess would be that the extent of the Oort cloud would be closer to an inverse square function of size. So, make that 3-6 LY. I would sincerely doubt that a LBV such as S Doradus or the Pistol star would have an Oort cloud 130-260 LY across! :o

Evan
2004-Nov-30, 05:07 PM
That still doesn't address the fact that the mass of the star is drastically reduced. The former orbits of the Oort objects will resemble tangents as they will suddenly have escape velocity.

RGClark
2004-Dec-01, 12:46 AM
That is all guesswork. It isn't logical for the Oort cloud to be retained after a supernova event. Oort cloud objects are thought to be essentially "dirty snowballs". As well as serious heating from the explosion the star throws off most of it's mass. The shock wave will accelerate Oort objects which are no longer orbitally bound to the remains of the star. Objects in the Oort cloud are very loosely bound by gravity anyway and the sudden reduction in mass of the primary will release them completely.

Actually, it's very logical. The supernova gas cloud, or remnant, extends up to 10 lightyears from the star. It's extent is limited merely by the pressure of the extremely tenuous interstellar gas.
The Sun's Oort cloud extends 1 to 2 light years away from the Sun. For a star that goes supernova with a mass 10 times the Sun's we would expect it's Oort cloud to extend 10 times further away, or 10 to 20 light-years.
The shock wave is extremely well attenuated at this point.


Bob Clark

My guess would be that the extent of the Oort cloud would be closer to an inverse square function of size. So, make that 3-6 LY. I would sincerely doubt that a LBV such as S Doradus or the Pistol star would have an Oort cloud 130-260 LY across! :o

You may be right. Actually, I need to make a correction. That 10 light-year figure is only for the initial shock wave, taken from this page:

Introduction to Supernova Remnants.
http://agile.gsfc.nasa.gov/docs/objects/snrs/snrstext.html

The remnant continues to grow after this.


Bob Clark

expirationdate
2004-Dec-01, 09:09 PM
Ok Clark maybe I missed something. Evan.. I think what I'm trying to say is "if" they release this organism "super-conan" to eat nuclear waste and it spread they should there for develope another organism to hunt down and eat "s.c." in the case that it does its job but continues on to finding new food like say something that could potentially endanger our species. Another is that "if" the scientist developing this crap is smart which I'm sure they are they will perform all the essential test to ensure our safety and the safety of our food and quite simply that I may have confused myself trying to explain what I cannot fully understand. and I think who I replied to may have been a little off topic so therefor my reply taking it even furthur from what really is to be discussed.



Clark bud .. if you look back you'll find that you first sugested that it "would'nt" answer the question.


[quote=Evan][quote]Life being found on other worlds wouldn't answer the question "Does life exist on other worlds?"

That sentence was supposed to be a question. It came from a misunderstanding of what Evan was saying. He was talking simply about the origin of life in general. I was raising a separate question about the existence of life on other worlds.


Bob Clark

Evan
2004-Dec-02, 12:55 AM
The general problem is that bacteria have a way of mutating in a hurry. They can also exchange genetic material with other bacteria. Creating another bacteria to try and control SC only makes matters worse. No matter how many tests they do they don't know what will happen when it is set loose in the environment. We have been performing this experiment for some time already and we are now faced with "super bugs". These are disease organisms that are highly resistant to every antibiotic known. All we need is a bug that can't be killed by heat, cold, radiation and antibiotics.

pghnative
2004-Dec-02, 02:18 PM
um...why exactly are we scared of this "mutant bacteria"?? I cannot read the article, but it appears that the unique property of the bacteria is that it can survive in regions contaminated by heavy metals, in this case radioactive heavy metals. Since neither heavy metals nor radioactive heavy metals are used to control bacteria (whether in food. or infected animals/humans), I don't see the health risk if this bug were to "be let out and about "on our planet" where it could cause a "big cotastraphy [sic] like say in our crops".

The notion that these bugs are dangerous and that there would be a need to engineer a super bug to control it seems to be scare-mongering to me. There's no reason to suspect that these bugs (let alone the proposed super bug to control them) would be immune to cooking, irradiation, penicillin or refrigeration.

Evan
2004-Dec-02, 02:40 PM
There's no reason to suspect that these bugs (let alone the proposed super bug to control them) would be immune to cooking, irradiation, penicillin or refrigeration.

Huh? That is exactly what they are highly resistant to (minus antibiotic). That is how they were discovered. We already know how easy it is to induce antibiotic resistance.

frogesque
2004-Dec-02, 02:44 PM
The very fact that these bugs can thrive during a radio-active cleanup suggests they are capable of hadling quite a bit of irradiation. It's logical to have some biologically controlled experimentation before letting them loose in the wild.

Sense of proportion and sensible precaution would seem to be the keywords in this debate.

pghnative
2004-Dec-02, 02:50 PM
The very fact that these bugs can thrive during a radio-active cleanup suggests they are capable of hadling quite a bit of irradiation. Are we sure we're talking about the same types of radiation? I presumed that most of the radiation in the cleanup areas is particle radiation, which is not the type used to irradiate foods.

frogesque
2004-Dec-02, 02:57 PM
My understanding is these bugs have multiple copies of critical sequences within their DNA and are capable of rebuilding after being zapped. It doesn't seem to matter what you bomb them with.

I'm open to correction on this if anyone has better info.

Evan
2004-Dec-02, 03:55 PM
Radiodurans was discovered during experiments irradiating foods. That is done with cobalt 60 sources in most cases which is a very strong gamma emmiter. They kept using higher and higher doses and still some spoiled. That was radiodurans.

It doesn't matter what type of radiation is used as long as it is penetrating and ionizing. Ionizing radiation starts at the ultraviolet portion of the spectrum. From there on up it is all ionizing radiation. As the energy increases the photons take on more particle like properties. A gamma ray is any electromagnetic radiation with greater than ~100kev energy. It acts the same as a particle for most purposes and can penetrate lead for a distance.

Cobalt 60 emits very hard gamma at 1173 kev and x-rays at 1332 kev. It takes minimum 1/2 inch of lead to stop them. To Deinococcus radiodurans this level of radiation is about like a nice day in the sun.

eburacum45
2004-Dec-02, 06:49 PM
One day modified humans may have altered genetic material which is designed to cope with high radiation environments like D.radiodurans;

in fact this would be a very desirable genetic tweak, as so much of the solar system is saturated in various types of radiation; make humans and theire food crops resistant to radiation and suddenly much more territory opens up.
Modifications for microgravity and ;low pressure tolerance would be nice too.

The potential of genetic engineering can only be glimpsed in these early days of the technology;
unfortunately the glimpses of its potential for use in biological warfare cause the most concern to me at the moment.

tjm220
2004-Dec-02, 08:19 PM
...Cobalt 60 emits very hard gamma at 1173 kev and x-rays at 1332 kev...

Source on this? I found Co-60 (http://www.princeton.edu/~chirata/cobalt.html)gamma emission at 1173 keV and 1332 keV along with a beta component maxing out at 315 keV, no x-rays.

Evan
2004-Dec-02, 08:44 PM
Yeah, I didn't recall X-rays either but that is what it seems to say on the MSDS (http://www.stuarthunt.com/Downloads/RMSDS/Co60.pdf)

Perhaps I am misreading it.

tjm220
2004-Dec-02, 08:48 PM
With the chart labelling it looks like X-rays are present. It must be an exercise to the reader to identify the proper band of EM radiation.

John Dlugosz
2004-Dec-02, 08:49 PM
So the Wall Street Journal has a story about a bunch of bacteria that was found growing in nuclear waste (http://online.wsj.com/article_email/0,,SB110055694326574611-IBje4NmlaR3oZyranSHaquDm4,00.html). These bacteria, or extremophiles, can tolerate 15 times the normal amount of radiation and could be used to clean up nuclear waste. Some scientists think they must have originally come from outer space (but one in the article dismisses that as "mythology").


A year or two ago was brainstorming with a couple friends over lunch about story ideas. I've forgotton more than I remember, but here are some interesting thoughts:

Start with microbes that not only tolerate radiation but use it as an energy source. How to get that trait into macrofauna? Some animals have symbiotic bacteria inside them. For example, some squids have special organs for hosting bacteria that provide light sources to help with camoflauge. They also regenerate lost limbs. So, picture a giant squid that carries an organ at the end of a long feeding arm, and when the radiation damages it too much, switches to using the other arm while the first regenerates. Naturally it would (1) evolve rapidly, and (2) have selection pressure to be even larger, to better keep a distance from the "food" source.

Now, once such things arise, I imagine the environmentalists will be against clean-up of radiation waste dumps, since it is now a habitat for unique species!

--John