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The AMS is interesting. It is CERN-like detector in space. Its the most expensive experiment on the ISS. It required a special act of Congress to extend the

The AMS is interesting. It is CERN-like detector in space. Its the most expensive experiment on the ISS. It required a special act of Congress to extend the shuttle program one extra mission past its termination. Early results show more anti-matter positrons in space than predicted. One interpretation attributes this to dark matter. AMS continues to collect data to refine results.

pavel_lishin 11y ago
Are there any plausible theories for how dark matter would generate positrons?
jessriedel 11y ago
Worth point out that (apparently) the only reason that the AMS was attached to the ISS rather than launched as an independent satellite is that it would have been hard to power it. So it leaches off the ISS solar panels. https://en.wikipedia.org/wiki/Alpha_Magnetic_Spectrometer https://en.wikipedia.org/wiki/Alpha_Magnetic_Spectrometer Obviously, this can't be counted as more than a tiny fringe benefit of the ISS, since one could always have built a bigger, independent version of AMS with more solar panels (for a lot less than $150B).
- deleted 11y ago
  [deleted]
- azernik 11y ago
  Not sure that's a fair cost comparison - the ISS is reusable infrastructure whose power, propulsion (station-keeping), and structural investments are reused for multiple payloads. We just happen to be using the vast majority of it for life-support...
  - jessriedel 11y ago
    I just mean that if AMS is near the top of the list of reasons to have built the ISS, then either you have a bad list or the ISS probably didn't justify its enormous expense. Sure, it's possible that true value of the ISS was the in providing power and station-keeping for thousands of little experiments, but that seems highly unlikely. Better to just launch an unmanned station every couple years with a hundred experiments on board than to pay the fantastical expense of live astronauts.
    - AYBABTME 11y ago
      Learning how to keep humans in space is a quite worth the expense in my opinion. One day or another, we'll have to figure it out.
      - brownbat 11y ago
        This is an interesting point that has worried me in the past. The clock is ticking on this planet, and this solar system. But the more I've thought about it, the less convinced I am that this really justifies manned exploration at its current costs. It will take some big changes to make space more habitable than Earth. If we can make a survivable enclosure in space, odds are that we can make a survivable enclosure on Earth and save the fuel costs, keeping us closer to some nifty raw materials. Massive impacts might make that unsafe,[0] but mostly we're looking at being engulfed by the sun in 5 billion years as a hard stop. It's hard to really comprehend how much time that is. It's ten times longer than primates have been around. It's almost 1.5 times as long as all life has been around. Humanity as we know it will no longer exist at that point. If we have living descendents, they could be as unrecognizable to us as apes are to amoebas. At that point we're just planning for "life in general" to survive, which we could accomplish by just sending probes with some spores or dormant bacteria on long voyages to distant habitable planets. I wouldn't generally recommend procrastination, but this is probably a problem we can kick down the road a few generations. If we hit snooze for just 1/5000th of the remaining time we have, that'd give us a solid million years to up our technological game before tackling interstellar travel. At that point, the problem will probably have become either trivial or hopeless. So ultimately, I'm not yet convinced that human survivability experiments are 1000 times as urgent as telescopes, probes, and rovers. That's what I'd be looking for to justify manned's absurd cost premium. I was actually hoping this article would convince me otherwise, but if put up next to the top things we've learned from unmanned space experiments, I don't think it would compare very favorably. Definitely not 1000 times favorably. I think we all yearn for the stars, and know this is the sort of thing we want to conquer, we want it to be among the great triumphs of humanity. But if we really want it, we should be smart about it. There's so much low hanging fruit we can get from unmanned. It could aid technological progress and deep understanding of the universe, leading to breakthroughs that ultimately leapfrog us past some challenges we'd meet if we just tried to bang our head against colonization today. [0] Note that mammals have survived some crazy impacts before, probably by living underground. If we can make a survivable enclosure underground or under the ocean, that will be easier than making one and then launching it into space. Also, near earth object detection and mitigation programs are probably the best way to improve humanity's survivability given current technological capacities (ie, we can't build megastructures in space yet), and those programs compete for NASA money against humans in space too! Gradual climate change is unlikely to make Earth less habitable than Venus or Mars or space. Even if we lost most of our atmosphere and temperatures began to fluctuate by +/- 50 degrees, there'd still be advantages to building controlled structures on Earth rather than building such structures and launching them into inhospitable space. There are degrees of inhospitably, and Earth would have to become nightmarish (eg, probably engulfed by the sun) before we left.
- kens 11y ago
  I looked at the ISS research in detail a few years ago, and there are several experiments counted as ISS research because they were on a space shuttle flight that went to the ISS. My point is that as you mention with the AMS, the benefits of the ISS are exaggerated in this way. Overall, the research results of the ISS struck me nothing you'd put into even the top 100 discoveries of the year, and nothing worth the cost. To see just how costly the ISS is compared to other research projects, see: http://www.scientificamerican.com/sciam/assets/Image/sad1015Flet4p_updatelarge.jpg http://www.scientificamerican.com/sciam/assets/Image/sad1015...

pavel_lishin 11y ago

Are there any plausible theories for how dark matter would generate positrons?

jessriedel 11y ago

Worth point out that (apparently) the only reason that the AMS was attached to the ISS rather than launched as an independent satellite is that it would have been hard to power it. So it leaches off the ISS solar panels. https://en.wikipedia.org/wiki/Alpha_Magnetic_Spectrometer https://en.wikipedia.org/wiki/Alpha_Magnetic_Spectrometer Obviously, this can't be counted as more than a tiny fringe benefit of the ISS, since one could always have built a bigger, independent version of AMS with more solar panels (for a lot less than $150B).

deleted 11y ago
[deleted]
azernik 11y ago
Not sure that's a fair cost comparison - the ISS is reusable infrastructure whose power, propulsion (station-keeping), and structural investments are reused for multiple payloads. We just happen to be using the vast majority of it for life-support...
- jessriedel 11y ago
  I just mean that if AMS is near the top of the list of reasons to have built the ISS, then either you have a bad list or the ISS probably didn't justify its enormous expense. Sure, it's possible that true value of the ISS was the in providing power and station-keeping for thousands of little experiments, but that seems highly unlikely. Better to just launch an unmanned station every couple years with a hundred experiments on board than to pay the fantastical expense of live astronauts.
  - AYBABTME 11y ago
    Learning how to keep humans in space is a quite worth the expense in my opinion. One day or another, we'll have to figure it out.
    - brownbat 11y ago
      This is an interesting point that has worried me in the past. The clock is ticking on this planet, and this solar system. But the more I've thought about it, the less convinced I am that this really justifies manned exploration at its current costs. It will take some big changes to make space more habitable than Earth. If we can make a survivable enclosure in space, odds are that we can make a survivable enclosure on Earth and save the fuel costs, keeping us closer to some nifty raw materials. Massive impacts might make that unsafe,[0] but mostly we're looking at being engulfed by the sun in 5 billion years as a hard stop. It's hard to really comprehend how much time that is. It's ten times longer than primates have been around. It's almost 1.5 times as long as all life has been around. Humanity as we know it will no longer exist at that point. If we have living descendents, they could be as unrecognizable to us as apes are to amoebas. At that point we're just planning for "life in general" to survive, which we could accomplish by just sending probes with some spores or dormant bacteria on long voyages to distant habitable planets. I wouldn't generally recommend procrastination, but this is probably a problem we can kick down the road a few generations. If we hit snooze for just 1/5000th of the remaining time we have, that'd give us a solid million years to up our technological game before tackling interstellar travel. At that point, the problem will probably have become either trivial or hopeless. So ultimately, I'm not yet convinced that human survivability experiments are 1000 times as urgent as telescopes, probes, and rovers. That's what I'd be looking for to justify manned's absurd cost premium. I was actually hoping this article would convince me otherwise, but if put up next to the top things we've learned from unmanned space experiments, I don't think it would compare very favorably. Definitely not 1000 times favorably. I think we all yearn for the stars, and know this is the sort of thing we want to conquer, we want it to be among the great triumphs of humanity. But if we really want it, we should be smart about it. There's so much low hanging fruit we can get from unmanned. It could aid technological progress and deep understanding of the universe, leading to breakthroughs that ultimately leapfrog us past some challenges we'd meet if we just tried to bang our head against colonization today. [0] Note that mammals have survived some crazy impacts before, probably by living underground. If we can make a survivable enclosure underground or under the ocean, that will be easier than making one and then launching it into space. Also, near earth object detection and mitigation programs are probably the best way to improve humanity's survivability given current technological capacities (ie, we can't build megastructures in space yet), and those programs compete for NASA money against humans in space too! Gradual climate change is unlikely to make Earth less habitable than Venus or Mars or space. Even if we lost most of our atmosphere and temperatures began to fluctuate by +/- 50 degrees, there'd still be advantages to building controlled structures on Earth rather than building such structures and launching them into inhospitable space. There are degrees of inhospitably, and Earth would have to become nightmarish (eg, probably engulfed by the sun) before we left.
kens 11y ago
I looked at the ISS research in detail a few years ago, and there are several experiments counted as ISS research because they were on a space shuttle flight that went to the ISS. My point is that as you mention with the AMS, the benefits of the ISS are exaggerated in this way. Overall, the research results of the ISS struck me nothing you'd put into even the top 100 discoveries of the year, and nothing worth the cost. To see just how costly the ISS is compared to other research projects, see: http://www.scientificamerican.com/sciam/assets/Image/sad1015Flet4p_updatelarge.jpg http://www.scientificamerican.com/sciam/assets/Image/sad1015...