• Technology

    Battling Over Aging Nuclear Warheads

    By Posted on 4.17.2009 28 Comments

    U.S. nuclear warheads might have been technological marvels a half-century ago, but today they're akin to a fleet of '57 Chevys — at least according to those who say the U.S. arsenal is begging to be traded in for a new model called reliable replacement warheads, or RRW.

    For the last half-century, the U.S. has maintained its 5,400-warhead arsenal by replacing degraded plastic and rubber parts. But the most important part of the warhead — its explosive radioactive core — naturally decays over time and has not been replaced.

    The warheads will remain dependable for at least 82 more years, or until the year 2091, according to a 2006 report by JASON, an independent scientific advisory group for the U.S. government. At that point, the warheads’ decayed cores could leave the U.S. with an impotent nuclear arsenal. "The concern is, can we keep the nuclear arsenal safe, reliable and effective for as long as we’ll need nuclear forces?" says John R. Harvey, a physicist in the U.S. Department of Energy’s National Nuclear Security Administration.

    4.16.2009 at 03:19pm - Comment by steveH

    wumhenry; You're right, Pu241 has a half-life of 14.4 years. And it doesn't matter, since Pu239, with a half-life of 24,110 years happens to be the isotope actually useful for weapon use. (Pu241 is a contaminant produced after increasing time as Uranium is "cooked" to produce Pu in production reactors.) There are two other isotopes useful for weapon, but they're U235 and U233. Tritium, with a half-life of 12.3 years (4500 +- 8 days), is used in weapon triggers, and has to be replaced periodically in stored weapons to maintain their functionality.

  • Technology

    Nuclear Moon Bases

    By Dawn Stover Posted on 11.21.2008 25 Comments

    When lunar astronauts flick on their televisions after a long day of prospecting, they’ll have a trashcan-size nuclear reactor to thank for their nightly dose of prime time. NASA, looking past the already daunting task of simply getting humans to the moon by 2020, recently started considering proposals for ways to power lunar habitats. Batteries and fuel cells provide only short-term solutions. Solar power would be limited where a single night lasts as long as 354 hours. So space-agency officials have started making plans to go nuclear.

    11.22.2008 at 12:37am - Comment by steveH

    "I see no reason we couldn't periodically send rocket capsules of nuclear waste to be incinerated in the sun" Because it takes more deltaV (change in orbital velocity, which means using fuel) to dump a package into the Sun than to accelerate that same package to solar escape velocity and send it out of the solar system. You can't cheat Sir Isaac; at least we can't cheat physics yet.

  • DIY

    Quantum Physics in a Glass

    By Posted on 7.25.2008 11 Comments

    Before the discovery in the 1920s of quantum mechanics—laws that explain the way the world works on the very small scale of atoms and electrons—the fact that bleach and peroxide glow when mixed would have seemed like just another chemical reaction that gives off light, like fire or fireflies. But it’s actually a glimpse into the impossible.

    8.1.2008 at 10:22pm - Comment by steveH

    gretle, You would be looking for Luciferin and Luciferase, the two chemicals that light up lightning bugs. One source on line offers luciferin for $69 for 100mg of the material. I suspect shipping is extra.

  • Science

    Prehistoric Explosions Wiped Out Ocean Life-- And Created Petroleum

    By Posted on 7.26.2008 38 Comments

    A new study by the University of Alberta suggests that a massive undersea volcano eruption 93 million years ago was the source of much of the world’s oil. Researchers Steven Turgeon and Robert Creaser were alerted to the prehistoric blast when they found specific levels of osmium isotopes (indicators of volcanic activity in sea water) in black shale rocks off the coast of South America and in the mountains of central Italy.

    7.29.2008 at 07:30pm - Comment by steveH

    "Fossil fuels are a danger to our earth, if you don't beileve it look at downtown LA, there is a looming smog that never seems to go away." This theory would be more interesting were it not for the fact that smog in L.A. preceded the arrival of the Spanish. Being a bowl surrounded on three sides by mountains, with a thermal inversion trapping smoke and dust much of the time, local indigenes helped things along by burning grassland to improve farming and hunting. About the only time it really clears up is when the Santa Ana winds come up to blow the muck out to sea. They also fan brushfires of the area's chaparral vegetation, which is very much like oil-soaked old wood. The worst years for smog in the L.A. Basin were during the late '60s, and air quality has improved pretty much continuously since that time. Smog/smoke/haze isn't going away from there unless someone takes out a big chunk of the surrounding mountains. Sorry.

  • The Environment

    Sunny News for Solar Power

    By Posted on 7.15.2008 10 Comments

    When I was eight years old, my uncle told me that I’d get a solar-powered car for my sixteenth birthday – and that it would be affordable. When I turned 16 in 2002, though, solar power was still inefficient and expensive, and I landed a bike instead. It's taken impossibly high fuel costs, global warming, and some serious engineering developments, but six years later, solar power is finally becoming a viable alternative to oil.

    7.16.2008 at 03:09pm - Comment by steveH

    "Get outta the way oil companies solar is coming through." This would be a more interesting comment were it not for the fact that the "oil companies" have been spending a *lot* over the past couple decades on developing solar and other non-fossil-fuel technologies. Arco and BP, for example, have been major players in photovoltaic and solar-dynamic power generation tech.

  • DIY

    How to Make Convincing Fake-Gold Bars

    By Posted on 3.14.2008 18 Comments

    On Wednesday, the BBC reported that millions of dollars in gold at the central bank of Ethiopia has turned out to be fake: What were supposed to be bars of solid gold turned out to be nothing more than gold-plated steel. They tried to sell the stuff to South Africa and it was sent back when the South Africans noticed this little problem.

    6.27.2008 at 10:04pm - Comment by steveH

    Tungsten metal won't stick to a magnet, at least not strongly enough that you'd notice; it's paramagnetic. You could measure the amount of paramagnetism with some specialized gear, but not by feeling a magnet stick to your fake gold bar. Some tungsten alloys are ferromagnetic, but you wouldn't want to use them for making your fake gold bars, they wouldn't be dense enough.



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