This paper has uses so many assumptions to reach such an old and obvious answer as to render itself practically useless. I guess the bar is pretty low at the Journal of Cosmology and Astroparticle Physics. Then again Loeb is known for dressing up homework problems and publishing them as amazing revelations. Somehow the reviewers haven't caught on.
High energy particle interaction will make the water radioactive over time.
This is inaccurate. Solar wind and Galactic cosmic ray protons and the infrequent gamma-ray will not make the water radioactive. Neutrons are non-existent out there, and electrons and X-rays will get stopped by the hull.
Gamma rays can cause nuclear excitation, but that usually decays within minutes of the hit, and is proportional to the primary incident radiation anyway.
Radiation on the surface is simple. Just spend most of your time underground, especially during a solar flare. You'll probably want to do that anyway, for cost and safety of creating a pressurized habitat.
Astrophysicist here. I read his paper, and it strikes me as an engineer's approach rather than an astrophysicist's. He builds up a very complicated framework from many, many assumptions and gets a very complicated model with "more accurate" solutions.
An astrophysicist learns where to make simplifying assumptions that ease the calculation and make the relationships clearer without sacrificing too much accuracy. The less complicated the model, the less likely you are to be wrong (Occam's Razor).
Now I don't know in this specific instance if a simpler model is viable (I'm not an asteroid specialist), but the difference between his paper and all of the other hundreds of astrophysics papers I've read was stark. The sheer length of the paper suggests that it is highly improbable that there are no mistakes at all, even for someone of his intellectual capability.
Now, couple that to the lack of a public release of his analysis code, and you have a conclusion emerging...
That is exactly what I thought when I saw that. I thought it was a wartime recollection or something. Whoever wrote "Vietnam medic" apparently has missed some of the finer points of the English language.
Out of curiosity, what would you say if someone asks you whether nuclear fusion takes place in a neutron star?
I'd probably take the weasel answer and say, "Well it depends..." lol.
Whether material accreted onto the surface is part of The Neutron Star officially or not is debatable, but I think most people would agree that anything gravitationally bound is part of it. Would you say that the Earth's atmosphere isn't part of the Earth? Because the atmosphere is completely different from the surface, so... ?!?!
Also, when that accreted matter flashes, what do you think becomes of it? The neutrons and such are incorporated into the degenerate matter (IIRC). In which case, you have fusion going on.
I guess that's why we have PhDs, huh? Funny how education makes you see things as more complex, rather than simpler.
Well, that would be fusion *on* a neutron star, not *in* it. It's not just semantics; the process you are talking about does nothing to support the NS against gravity, since it's at the surface. The point is, a neutron star, by itself doesn't have any fusion.
OK, you saved your face with semantics, but what you said was very misleading.
I'm about to get my PhD in astrophysics, so hmmmmph.;-)
Are we out of names now. They names this little baby : OGLE-TR-122b.
What is the point of naming thousands of stars that you survey at the time of the survey? This is just a code that tells them which in a catalogue it is. Now if it becomes famous, they can give it a stupid name, like karvind. Will that make you happy?
The second reason is surface area. The Sun has a surface area of approximately 6 x 10^20 meters compared with Jupiter's 6.4 x 10^18 meters. This star is only slightly larger than Jupiter in terms of volume and so will have a comparable surface area. This means that the radiation of heat in the star will not be as efficient as in the sun and that means less fusion is required to keep the tempreture of the star constant.
No, sorry. The ratio of surface area to heat-generating volume is what you mean. This quantity goes like 1/r, so larger stars have less efficient cooling, neglecting radiative transfer effects. Sure the star has less surface area than the Sun, but it has an even smaller relative volume.
So basically you should say that the star is only generating a minute amount of fusion, *and* it is a more efficient radiator.
Correct. It's not possible to fuse atomic nuclei when the object is itself, one large nucleus.
*sigh* So many people on slashdot who think they know everything. Many neutron stars with massive companions have regular thermonuclear flashes of hydrogen on their surface that they accrete from the companion and then heat up. The intensive pressure at the surface plus the heat makes the H fuse.
Unfortunately, high-energy radiation (like the stuff in space) only cares about the density of atoms in its path, which translates into *mass* density, so this would be wholly inadequate. Same reason lead shields you better than concrete or air or clothes. Shielding something from heat is a whole different animal than stopping high-energy particles or photons, which is a mostly atomic effect.
It's amazing how many of you crawl out of the woodwork on a question like this pretending to know anything about this. Why doesn't someone just ask the Spirit mission scientists what they are doing?
In truth, there are probably a half dozen likely ways in which the image could turn out all red. None of you knows for sure, so stop acting so authoritative.
"That's why Mars has a butterscotch sky- very low density atmosphere made up almost entirely of CO2"
Not really. CO2 doesn't change the color of the sky. It Rayleigh scatters just about exactly like N2. If Mars has a sufficent quantity of dust suspended, the reflected light from the dust could add a reddish tinge to a blue sky, but the CO2 has nothing to do with it.
No kidding. Worst review screenshots ever. I wanted to see some new Panther screenshots, but instead all I saw was X11 crap. Is this guy on crack or what?
I think you're exactly right. I was assuming that a way could be found to make the organism fitter w/the addition of the data. I admit that would be extremely hard (if not impossible), but it's the only assumption we can work on, since even silent mutations can be eliminated by genetic drift (in small bacterial colonies anyway).
Your #2 was what I was implying. Bacteria have such highly optimized genomes that inserting a data storage sequence would most certainly change the evolutionary fitness of the organism. In that way, you can possibly escape mutation degradation. In eukaryotes its much trickier, but there are plenty of highly conserved locations in the genome. Take the histone proteins for example.
And if you consider RNA editing (where the wacking out or modification of nucleotides prior to translation), you gain a tremendous amount of flexibility in the smaller genomes of these bugs.
Are you sure about RNA editing in bacteria? The rate of ribosomal attachment to a free RNA strand is very high, and it is unlikely that you can preserve the free mRNA long enough (without a nucleus) to edit it. At least that's the dogma I was taught. If you know a way, then please tell...
My first impluse was that this is way off. I'm used to working with plasmids where frequently like 60% of the sequence is junk. They use E. Coli and D. radiodurans in the study mentioned in the article. A brief survey of E. Coli K12 (the parent of most common lab strains) sez that about 5-10% of it is non-coding. The old initial reference claims about 11% is non-coding, but a good chunk of that may be regulatory. The radiodurans genome is about 9% non-coding. The up shot is that there is actually a fair amount of 'junk-DNA' in (at least the Coli) bacterial genomes. Not a lot by human standards but enough to be able to squeeze in a chunk here or there if you're careful.
This is fascinating. Still, I wouldn't say that regulatory DNA is 'junk'. And the other small fraction whose purpose is not understood may well be functional, right? It would be an interesting experiment anyway.
Slashdot Mirror
This paper has uses so many assumptions to reach such an old and obvious answer as to render itself practically useless. I guess the bar is pretty low at the Journal of Cosmology and Astroparticle Physics. Then again Loeb is known for dressing up homework problems and publishing them as amazing revelations. Somehow the reviewers haven't caught on.
As a fellow unfiltered mouther, I'm glad that Clarkson's boot has had repercussions. The show was about cars, not politics and diplomacy.
Or do it under the ocean. What happened to the ocean floor habitats that 1950s promised us?
Neutrons will travel at the speed they are emitted, not the wind speed, because they are uncharged and don't interact with the plasma.
High energy particle interaction will make the water radioactive over time.
This is inaccurate. Solar wind and Galactic cosmic ray protons and the infrequent gamma-ray will not make the water radioactive. Neutrons are non-existent out there, and electrons and X-rays will get stopped by the hull.
Gamma rays can cause nuclear excitation, but that usually decays within minutes of the hit, and is proportional to the primary incident radiation anyway.
Radiation on the surface is simple. Just spend most of your time underground, especially during a solar flare. You'll probably want to do that anyway, for cost and safety of creating a pressurized habitat.
By the time the DHS was formed, COBOL was already obsolete. They should've never used it in the first place.
Astrophysicist here. I read his paper, and it strikes me as an engineer's approach rather than an astrophysicist's. He builds up a very complicated framework from many, many assumptions and gets a very complicated model with "more accurate" solutions.
An astrophysicist learns where to make simplifying assumptions that ease the calculation and make the relationships clearer without sacrificing too much accuracy. The less complicated the model, the less likely you are to be wrong (Occam's Razor).
Now I don't know in this specific instance if a simpler model is viable (I'm not an asteroid specialist), but the difference between his paper and all of the other hundreds of astrophysics papers I've read was stark. The sheer length of the paper suggests that it is highly improbable that there are no mistakes at all, even for someone of his intellectual capability.
Now, couple that to the lack of a public release of his analysis code, and you have a conclusion emerging ...
Do they mean Andrew Strominger at Harvard? I've never heard of Andrew Stromberg.
Agreed. It's just doublespeak.
If he really wanted to help, he would make MRI cheaper, because it is far more informative than ultrasound.
That is exactly what I thought when I saw that. I thought it was a wartime recollection or something.
Whoever wrote "Vietnam medic" apparently has missed some of the finer points of the English language.
Out of curiosity, what would you say if someone asks you whether nuclear fusion takes place in a neutron star?
..." lol.
... ?!?!
I'd probably take the weasel answer and say, "Well it depends
Whether material accreted onto the surface is part of The Neutron Star officially or not is debatable, but I think most people would agree that anything gravitationally bound is part of it. Would you say that the Earth's atmosphere isn't part of the Earth? Because the atmosphere is completely different from the surface, so
Also, when that accreted matter flashes, what do you think becomes of it? The neutrons and such are incorporated into the degenerate matter (IIRC). In which case, you have fusion going on.
I guess that's why we have PhDs, huh? Funny how education makes you see things as more complex, rather than simpler.
Well, that would be fusion *on* a neutron star, not *in* it. It's not just semantics; the process you are talking about does nothing to support the NS against gravity, since it's at the surface. The point is, a neutron star, by itself doesn't have any fusion.
;-)
OK, you saved your face with semantics, but what you said was very misleading.
I'm about to get my PhD in astrophysics, so hmmmmph.
Are we out of names now. They names this little baby : OGLE-TR-122b.
What is the point of naming thousands of stars that you survey at the time of the survey? This is just a code that tells them which in a catalogue it is. Now if it becomes famous, they can give it a stupid name, like karvind. Will that make you happy?
The second reason is surface area. The Sun has a surface area of approximately 6 x 10^20 meters compared with Jupiter's 6.4 x 10^18 meters. This star is only slightly larger than Jupiter in terms of volume and so will have a comparable surface area. This means that the radiation of heat in the star will not be as efficient as in the sun and that means less fusion is required to keep the tempreture of the star constant.
No, sorry. The ratio of surface area to heat-generating volume is what you mean. This quantity goes like 1/r, so larger stars have less efficient cooling, neglecting radiative transfer effects. Sure the star has less surface area than the Sun, but it has an even smaller relative volume.
So basically you should say that the star is only generating a minute amount of fusion, *and* it is a more efficient radiator.
Correct. It's not possible to fuse atomic nuclei when the object is itself, one large nucleus.
*sigh* So many people on slashdot who think they know everything. Many neutron stars with massive companions have regular thermonuclear flashes of hydrogen on their surface that they accrete from the companion and then heat up. The intensive pressure at the surface plus the heat makes the H fuse.
I think a $1000 racing wheel counts as a toy for the rich (comes with a real Momo wheel):
m l
http://www.thomas-superwheel.com/prods/01fml26.ht
(No, I don't work for them -- I just think they're cool.)
Unfortunately, high-energy radiation (like the stuff in space) only cares about the density of atoms in its path, which translates into *mass* density, so this would be wholly inadequate. Same reason lead shields you better than concrete or air or clothes. Shielding something from heat is a whole different animal than stopping high-energy particles or photons, which is a mostly atomic effect.
It's amazing how many of you crawl out of the woodwork on a question like this pretending to know anything about this. Why doesn't someone just ask the Spirit mission scientists what they are doing?
In truth, there are probably a half dozen likely ways in which the image could turn out all red. None of you knows for sure, so stop acting so authoritative.
"That's why Mars has a butterscotch sky- very low density atmosphere made up almost entirely of CO2"
Not really. CO2 doesn't change the color of the sky. It Rayleigh scatters just about exactly like N2. If Mars has a sufficent quantity of dust suspended, the reflected light from the dust could add a reddish tinge to a blue sky, but the CO2 has nothing to do with it.
No kidding. Worst review screenshots ever. I wanted to see some new Panther screenshots, but instead all I saw was X11 crap. Is this guy on crack or what?
America already has very difficult to counterfeit money with all these features, including DNA fingerprinting. Check out Liberty Dollars
BTW, they're inflation proof and just plain look cool.
I think you're exactly right. I was assuming that a way could be found to make the organism fitter w/the addition of the data. I admit that would be extremely hard (if not impossible), but it's the only assumption we can work on, since even silent mutations can be eliminated by genetic drift (in small bacterial colonies anyway).
Your #2 was what I was implying. Bacteria have such highly optimized genomes that inserting a data storage sequence would most certainly change the evolutionary fitness of the organism. In that way, you can possibly escape mutation degradation. In eukaryotes its much trickier, but there are plenty of highly conserved locations in the genome. Take the histone proteins for example.
And if you consider RNA editing (where the wacking out or modification of nucleotides prior to translation), you gain a tremendous amount of flexibility in the smaller genomes of these bugs.
...
Are you sure about RNA editing in bacteria? The rate of ribosomal attachment to a free RNA strand is very high, and it is unlikely that you can preserve the free mRNA long enough (without a nucleus) to edit it. At least that's the dogma I was taught. If you know a way, then please tell
My first impluse was that this is way off. I'm used to working with plasmids where frequently like 60% of the sequence is junk. They use E. Coli and D. radiodurans in the study mentioned in the article. A brief survey of E. Coli K12 (the parent of most common lab strains) sez that about 5-10% of it is non-coding. The old initial reference claims about 11% is non-coding, but a good chunk of that may be regulatory. The radiodurans genome is about 9% non-coding. The up shot is that there is actually a fair amount of 'junk-DNA' in (at least the Coli) bacterial genomes. Not a lot by human standards but enough to be able to squeeze in a chunk here or there if you're careful.
This is fascinating. Still, I wouldn't say that regulatory DNA is 'junk'. And the other small fraction whose purpose is not understood may well be functional, right? It would be an interesting experiment anyway.