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Why India's Mars Probe Was So Cheap

rlseaman Re:Way to compare apples to light bulbs (200 comments)

It is not true that "there have been many, many, many more attempts at Mars than missions that actually got there", see:

http://en.wikipedia.org/wiki/L...

Mars exploration splits into two eras, the cold war competition between the U.S. and Soviets - which the U.S. won hands-down, Yay Mariner! Yay Viking! - and the past couple of decades with the U.S. and other countries collaborating in various combinations.

During the cold war the U.S. had a track record of 8 successful missions versus 2 launch failures. During the recent couple of decades we've had 9 successes versus 3 diverse spacecraft failures. And many of those successes have been far beyond mission profiles. So the NASA Mars team is about 17 wins against 5 losses. This would be regarded as stunningly successful in any sport.

The Soviets in the early days had many launch failures that can't really be charged to the Mars missions themselves - and were about the reverse of the U.S. cold war ratio for those that did get to Mars. It was still a remarkable achievement for them to place any one of those missions in orbit.

There have also been about a half dozen non-NASA Mars missions during the past two decades. Two Russian missions unfortunately continued the trend of never leaving LEO. And now India is one-for-one. May they keep it up! Europe is one-for-two and Japan is zero-for-one. Talk about small number statistics, but that's 2 wins / 2 losses. Quite respectable. One hopes other nations join the fun.

In the aggregate this is a remarkable tally of successful missions considering Mars is never closer than 50 million kilometers or so. Anybody know the corresponding statistics for missions in LEO?

about 2 months ago
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J.J. Abrams To Direct Star Wars VII

rlseaman Galaxy Quest reboot ? (735 comments)

Just as long as he doesn't get his hands on Galaxy Quest. Some things are sacred!

It would be all like "Give up! Surrender!"

about 2 years ago
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Political Science Prof Asks: Is Algebra Necessary?

rlseaman The world is not flat (1010 comments)

"Political Scientist" is a colossal oxymoron.

Whatever this guy and Thomas Friedmann (and alas! Terry Pratchett) say, the world is not flat. Algebraic equations of degree higher than linear (and even - gasp - other than polynomials entirely) are needed to describe how it works. Algebra is the bare minimum to comprehend how functions work. It is telling that TFA doesn't even mention differential equations - the real basecode of the universe. A grounding in algebra provides the most basic of tools to understand graphical representations of a dynamic multivariate world, even without calculus.

That a political scientist would emphasize "lies, damn lies, and statistics" as the pinnacle of mathematics is unsurprising.

more than 2 years ago
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Leap Second Bug Causes Crashes

rlseaman Re:All of my servers were fine (230 comments)

NASA Goddard is near Baltimore. They lost power in the storm and are operating under "Code Red": http://www.nasa.gov/centers/goddard/

Quite likely other misbehavior blamed on the leap second is actually the result of the storm (or like Pirate Bay, some unrelated crash).

more than 2 years ago
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Ask Slashdot: How To Introduce Someone To Star Trek?

rlseaman Start with Galaxy Quest (634 comments)

How is it possible that 300 messages into the thread nobody has suggested starting (and ending) with Galaxy Quest?

more than 2 years ago
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In America, 46% of People Hold a Creationist View of Human Origins

rlseaman Re:I'm Good Enough, I'm Smart Enough! (1359 comments)

It depends on the figure of merit and on the measure of central tendency being applied to it. "Average" can mean different things. If the distribution is skewed, the arithmetic mean will always lie to one side or the other of the median.

Stuart Smalley seems the poster child for Dunning-Kruger and related effects.

more than 2 years ago
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In America, 46% of People Hold a Creationist View of Human Origins

rlseaman I'm Good Enough, I'm Smart Enough! (1359 comments)

In related news, 46% of Americans believe themselves "above average".

more than 2 years ago
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World's Largest Digital Camera Project Passes Critical Milestone

rlseaman Re:Not that much storage (73 comments)

Astronomical data are background limited. The noise is as interesting as the signal, and many sources lie beneath the noise and are only visible through coadding. The gain and read-noise of LSST's detectors will be tuned similarly to other astronomical cameras because these parameters are governed by the experimental design.

Lossless Rice compression should be around R of 2-2.5 (http://arxiv.org/pdf/0903.2140.pdf) with lossy compression of reduced data products falling between R of 3 to 5 depending on the quantization selected (http://arxiv.org/pdf/1007.1179.pdf).

There will be no delta frame advantage since the compression is governed entirely by the noise (i.e., entropy) due to the sparse signal in astronomical data and the noise is a combination of gaussian and poisson (shot noise) sources that varies from exposure to exposure.

In fact, a key goal of the project is precisely to look for differences between each frame and a baseline static sky so the differences must be preserved in great detail.

more than 2 years ago
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Ask Slashdot: Advice For Budding Scientist?

rlseaman Science is a calling (279 comments)

A career in the sciences is far less likely to be touched by fraud than more commercial endeavors. "Follow the money" as they say. Each discipline is its own community, however, and the level of political infighting, the need to struggle for funding, the publication pressures, etc, vary greatly. External pressures are different, too, but condensed matter physics is about as far from the front lines of the culture war as one can get :-) I do wonder what mythical past the recent critics of science (and of academia in general) are comparing us with. Government funding has always been in the mix. Corporate funding has always come with strings attached. Read Neal Stephenson's Baroque Cycle to get a sense for the underlying drama of research as a creative exercise. A good bit of luck is needed to follow the narrow path to tenure. (I stepped off long ago.) A good bit of luck is needed to bubble to the "top" of any organization of any type. The difference with the sciences is that there are innumerable interesting detours and niches along the way. Having a graduate degree in a STEM field is an advantage for pursuing many future options. And the journey has been a hell of a lot of fun! Ultimately the question becomes "compared to what?" How will you put food on the table if you forgo grad school? And is a seat at a smaller table enough for you?

more than 2 years ago
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Physicists Discover Evolutionary Laws of Language

rlseaman "Culturomics" is not destined for long life... (287 comments)

Blame the WSJ for the tropes here about physicists and "culturomics". The lead author of the linked paper is an economist. The WSJ article also mingles information from other publications. On the other hand, Steven Pinker has (rather persuasively) argued for a physical model underlying the structure of language (and not just in English): http://stevenpinker.com/publications/stuff-thought

more than 2 years ago
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Scientists Say People Aren't Smart Enough For Democracy To Flourish

rlseaman Original citation says nothing of the sort (1276 comments)

I read through the 4-pointers and didn't see a citation to the original paper. This appears to be it: http://maxwellsci.com/print/crjss/v2-255-261.pdf It has precious little to do with any of the grandiose claims being attributed to it. TFA and the scores of echoed "See? I told you democracy was a scam!" articles are aggressively misconstruing the meaning of this. The paper is a couple of years old and the author appears to have no special expertise in this field.

more than 2 years ago
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Scientists Say People Aren't Smart Enough For Democracy To Flourish

rlseaman The article is garbage (1276 comments)

It's a tradition on slashdot to not read the article, but has anybody of any political persuasion here actually clicked the link? It's a piece of crap designed to be echoed around the internet. So far I've been unable to locate the cited research from either this article or in any of its echoes or by searching directly. The word "smart" is something added to create heat, the phrase used is "leadership skills", and there is no indication how such skills are gauged in either the simulated voters or the simulated candidates. Nor any mention that the voters only get to choose between two starkly different candidates - this is a rather binary decision to simulate. It is insipid to blame the voters for the candidates produced by the major parties.

more than 2 years ago
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Astronomers Estimate Milky Way May Have 100 Billion Alien Worlds

rlseaman Re:Like Pluto? (294 comments)

Pluto (the dog) was named after Pluto (the planet), not the other way around.

more than 2 years ago
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First Complete Lizard Genome Sequenced

rlseaman A picture may help (105 comments)

See (for instance):
http://www.amnh.org/exhibitions/hall_tour/spectrum/non_flash_index.html

This isn't about an imposed classification, it is about a family tree. Crocodiles are more closely related to birds than either are to snakes. Snakes are more closely related to birds than either are to turtles.

That is, these guys:
http://www.wolaver.org/animals/crocodile-plover.jpg

share a *much* more recent common ancestor than these two:
http://berkeley.edu/news/media/releases/2009/02/images/salamander-pgoebeil.jpg
and:
http://images3.wikia.nocookie.net/__cb20090630160120/uncyclopedia/images/2/2f/Geico-gecko.jpg

You are more closely related to a goldfish than the goldfish is to a shark:
http://rlv.zcache.com/goldfish_bowl_tshirt-p23514656184174989535jn_400.jpg

http://bit.ly/nknQ00

more than 3 years ago
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Developing Nuclear Power Plant Tech For the Moon and Mars

rlseaman Re:different design points (273 comments)

If you're going to do this, run it in the opposite direction as a geothermal (well, selenothermal) heat pump. Yes, yes - still need to establish a cold sink. But the value of all these ideas depends on the detailed engineering, not on slashdot opinion mongering.

more than 3 years ago
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'The Code Has Already Been Written'

rlseaman In a robot world it helps to have an exoskeleton (253 comments)

It's naive to consider either class of software as being sufficient, or either kind of programming to be superior. Like most problems there is a strong management component to assigning resources to each in appropriate scales.

A computer scientist/software engineer delivered a well-phrased summation of half of this discussion during a 5-minute talk at a recent lightning software session at a science meeting. (Note that there are rarely science sessions at software meetings.) A domain scientist/software engineer then delivered a well-phrased summation of the other half of this discussion. Both were right and both were wrong.

My five minutes? Pointing out that the real issue was that management rarely supplies sufficient resources to coherently accomplish software projects of any type. Typically projects are underscoped by a factor of three or more, whether the particular project is to build a robot or an exoskeleton. This is true whatever software process is followed, but in terms of the Mythical Man Month, it's like omitting the nurses and anesthesiologist from the surgical team.

more than 3 years ago

Submissions

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The Future of Time: UTC and the Leap Second

rlseaman rlseaman writes  |  more than 3 years ago

rlseaman writes "UTC ("Coordinated Universal Time") is very close to being redefined to no longer track Earth rotation. Clocks everywhere — on your wall, wrist, phone or computer — would stop keeping Solar time. See the article in the July-August 2011 "American Scientist" magazine: "Before atomic timekeeping, clocks were set to the skies. But starting in 1972, radio signals began broadcasting atomic seconds and leap seconds have occasionally been added to that stream of atomic seconds to keep the signals synchronized with the actual rotation of Earth. Such adjustments were considered necessary because Earth's rotation is less regular than atomic timekeeping. In January 2012, a United Nations-affiliated organization could permanently break this link by redefining Coordinated Universal Time."
(Preprint at http://arxiv.org/abs/1106.3141)"

Link to Original Source
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Military to restrict information on space debris

rlseaman rlseaman writes  |  more than 5 years ago

rlseaman (1420667) writes "A Slashdot-ready question of the week in NASA Tech Briefs:

'Should the military restrict space debris information gathered by its classified satellites?'

'This week's question concerns the U.S. military's right to restrict information gathered by its classified satellites. Until recently, data collected by U.S. classified satellites on asteroids and meteoroids that enter the Earth's atmosphere was routinely made available to the scientific community. A new U.S. military policy, however, now regards all data collected by classified satellites, including information on space debris entering our atmosphere, to be secret and, therefore, not for public distribution. Scientists studying the risks posed by space debris claim that such information is vital and that restricting access to it makes no sense whatsoever. What do you think? Should the military restrict space debris information gathered by its classified satellites?'

Also see Military Hush-Up: Incoming Space Rocks Now Classified by Leonard David at Space.com."

Link to Original Source
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Spacecraft totaled over Siberia

rlseaman rlseaman writes  |  more than 5 years ago

rlseaman writes "'The AP reports (via Salon): "Two big communications satellites collided in the first-ever crash of two intact spacecraft in orbit, shooting out a pair of massive debris clouds and posing a slight risk to the international space station. NASA said it will take weeks to determine the full magnitude of the crash, which occurred nearly 500 miles over Siberia on Tuesday.'"
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Nanomaterials may double life of concrete

rlseaman rlseaman writes  |  more than 5 years ago

rlseaman writes "NIST Tech Beat describes a new method, VERDICT (Viscosity Enhancers to Reduce Diffusion In Concrete Technology), to increase the service life of concrete. Nanomaterials slow penetration of salt and sulfur ions that damage the concrete. In the millennia since the Romans, previous research to improve service life has focused on reducing porosity, but denser concrete itself leads to cracking. The engineers were inspired by food processing additives like xanthum gum: '"Swimming through a pool of honey takes longer than making it through a pool of water," engineer Dale Bentz says.' But viscosity isn't enough — the key is high concentrations of small molecules."
Link to Original Source

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