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Comment: Re:Long-lived isotopes won't work (Score 1) 139

by Ruie (#41063155) Attached to: Rover Fuel Came From Russian Nuke Factory, But Supplies Running Low

As part of the pseudo-environmentalist lead scare campaign against nuclear power you always hear about things that will supposedly be radioactive for ONE MILLION years (thank you Dr. Evil).

Well, those ONE MILLION year radioactive elements won't power an RTG because they decay so slowly that the rate of heat production would hardly be measurable even with sensitive test equipment. You could use a lump of that stuff as a paper weight and as long as you didn't eat/drink/breath it then you would never have any negative health effects from it.

The real issue with radioactive material is from materials like cesium and strontium that are pretty radioactive and have mid-range half-lives of ~30 years or so. Not a real issue for long-term storage since they will be pretty much gone in 1000 years, but not something you want spread around the environment ala Chernobyl, which, BTW, is coming up on its first half-life anniversary for the nastier elements.

This not quite right. A half life of 1 million years is only ~10000 times longer than Pu-238, which glows red hot in air. So to measure heat production you could simply use a large quantity of long lived isotope, (say 100x as much) and insulate it better, such as by enclosing in Dewar flask.

Of course, for a space mission you'd want to minimize the weight.

Comment: Re:And NASA has made mistakes with this before... (Score 2) 228

by Ruie (#40947435) Attached to: Upgrading Software From 350 Million Miles Away

I think it is safe to assume that they purposely bricked the rover (or test rover) before the mission. And made sure it played out as the GP stated. And that they did this many different ways.

Ideally - yes. In practice, they have limited funds and lots of deadlines.

If they had lots of time to debug it, there would be no need to upload new software.

Comment: Re:Not necessarily (Score 1) 397

by Ruie (#40888539) Attached to: Mathematician Predicts Wave of Violence In 2020

Calling Stalin's government "Jewish" is a bit weird. I have really no idea as to what the ethnic background of the Soviet leaders, but they definitely weren't religiously Jewish. AFAIK, they were from a mixture of backgrounds, though I doubt that there were many Ukrainians among them.

In fact, Stalin was strongly antisemitic..

Comment: Re:Regulation caused the Great Depression (Score 1) 397

by Ruie (#40888487) Attached to: Mathematician Predicts Wave of Violence In 2020

Here's the basic story of the Great Depression, which is very similar to the story of the more recent financial crisis. 1. Times were good in the 1920's on Wall St. People could and did make good money trading stocks. [..] 5. End result: Crash. And when one business crashes, their stock, which was considered good, is now worthless, so businesses holding their stock also crash, so it cascades through the system leaving things worse than if the Crimson Permanent Assurance had hit them.

Replace "stocks" with "mortgage backed securities", fast forward 70 years or so, and the same thing happened. It happens any time that a con man can successfully make worthless pieces of paper look like representations of valuable property. And yes, it could conceivably happen that the pieces of paper that say "One Dollar" on them will also become worthless - if it does, you want to have land and a team of people who will help you defend it.

It happens more frequently ! dot.com bubble of 2000, LTCM collapse, 1980s collapse, etc. Roughly every 5-7 years, with some collapses being larger than others.

This is really just our economy's analog of Chinese ghost cities.

Comment: Re:React positively? (Score 1) 154

by Ruie (#40861839) Attached to: NASA's Bolden Speaks On Future Mars Mission, Chinese Moon Landing

Well we could, yeah... but what for? Other than bragging rights and planting the flag?

Mining for Helium-3 for the also underfunded, and therefor non-existent, fusion projects.

A smaller gravity well launchpad for said robotic probes.

The technological breakthroughs that would come with trying to sustain life long term in a harsh unforgiving environment.

I recently heard a very interesting presentation by a scientist working on fusion where he had shown the historical investment in fusion research and made a very good point that instead of saying "fusion is 25 years away" one should really be saying "fusion is $80 billion away".

Apparently this number has consistently come up in reviews of fusion programs, but the funding was being whittled away year after year.

Comment: Re:Fake (Score 2) 206

by Ruie (#40824369) Attached to: Images Show Apollo Moon Flags Still Standing
You want your mirror large in order to resolve small angles and small objects. The smallest angle you can resolve is lambda/D where lambda is the wavelength of light you are using (400nm for near-UV blue) and D is the diameter of your mirror or lens.

So suppose you have satellite in 100km orbit around the moon with a 2.4meter aperture (like Hubble) using 400nm light. Then the smallest angle you can resolve is 0.034 arcseconds and you cannot resolve features smaller than 16mm. If you use red light (600nm) then you cannot resolve features smaller than an inch.

Comment: Re:But...but... (Score 3, Insightful) 206

by Ruie (#40822843) Attached to: Images Show Apollo Moon Flags Still Standing
You are oversimplifying things. Yes, slow moving charged particles (such as electrons or Helium nuclei) can be easily shielded. However, fast moving particles are much harder to shield against as they create showers of new particles (of lower energy) upon collision.

The spectrum of these particles extends way up - scientists are busily observing particles with energies on EeV scale (roughly what a moving golfball has), though these are quite rare.

Neutral particles, like gamma rays, can only be shielded by a bulk material - the penetration depth depends on density.

Lastly, we have we have direct visual observation of cosmic rays by astronauts on Apollo missions and ISS.

In summary - being in space is kinda like being on a battlefield - if your general did not screw up the chance of being hit by an artillery shell is quite small. But this does not mean it cannot happen.

Comment: Re:The problem is Ballmer (Score 1) 407

by Ruie (#40803671) Attached to: Microsoft's Lost Decade
I am glad you liked it.

One other way to look at this is that if you try to maximize some function describing performance this decreases the uncertainty in function value (as the first derivative is 0) at the cost of increasing uncertainty in function parameters (i.e. everything else).

And unlike share price risk is good deal harder to quantify..

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