Archive for May, 2012

Not Coming Soon to a Spaceship Near You

Mustafa’s Space Drive: An Egyptian Student’s Quantum Physics Invention

Mustafa invented a way of tapping this quantum effect via what’s known as the dynamic Casimir effect. This uses a “moving mirror” cavity, where two very reflective very flat plates are held close together, and then moved slightly to interact with the quantum particle sea. It’s horribly technical, but the end result is that Mustafa’s use of shaped silicon plates similar to those used in solar power cells results in a net force being delivered. A force, of course, means a push or a pull and in space this equates to a drive or engine.

In terms of space propulsion, this is amazing. Most forms of spacecraft rely on the rocket principle to work: Some fuel is made energetic and then thrust out of an engine, pushing the rocket forward.

First of all: clever. The dynamic Casimir force was observed last year or thereabouts (thenabouts?), and it breaks down like this: the vacuum isn’t empty, it has a bunch of virtual photons and other virtual particle/antiparticle pairs in it. In the static Casimir effect you can get a force by excluding some of the EM modes, which gives an imbalance in the energy, which manifests itself as a force. In the dynamic Casimir effect, you move a mirror really fast and create real photons from the virtual photons (basically you are adding energy to them to allow them to become real). So as far as I can tell, this drive is photons. The generation of the photons is a new process, but at the end of the day, it’s photons. From a dynamics standpoint, this is going to be the same as shining an LED out of your rocket and feeling the thrust, because photons have momentum. This is the rocket principle, despite the implication of the article.

Which means this all boils down to how efficiently you can make your photons, from an energy and thrust/weight standpoint. I suspect that energy-wise, this is an inefficient way of making photons; LEDs are in the vicinity of 50% in converting input power to photons. All of that presupposes that photons are a good solution to the space propulsion problem, but photons are very inefficient in terms of how much momentum you get for the energy you use.

For a photon, the momentum is simply E/c. 1 eV of photons (be is a single photon or a bunch of lower-energy ones, it doesn’t matter) gives you a momentum of about 5 x 10^-28 kg-m/s of momentum. (Non-relativistic) Massive particles, though, have a momentum of sqrt(2mE). Give that same energy to a hydrogen atom and you get almost 50,000 times as much momentum; this scales with the square root of the mass, so Xenon, with an atomic mass ~130 times larger, boosts your momentum by another factor of 11 or so. That’s what you get with ion drives, and those still have limited use.

And Mustafa’s invention can, rudimentarily, be compared to a solar sail…because it doesn’t need “fuel” as such, and exerts just the tiniest push compared to the thundery flames of SpaceX’s rockets. It’s potential is enormous–because of its mechanical simplicity and reliability it could make satellite propulsion lighter, cheaper, and thus indirectly lower the cost of space missions of all sorts.

It’s actually half as efficient as a solar sail, because a reflection gives you twice the change in momentum (since the photon changes direction) and while, like an LED, no fuel is needed, you still need the energy source to run the thing. So it remains to be seen if this is viable and better than existing systems, but there’s a reason why we don’t use photons already (other than by accident, as with the mentioned Pioneer anomaly — which was a ten billionth of a g, i.e. a tiny effect) and this isn’t going to get you into orbit in the first place.

An Interview with Stella Bridger

Ken Doyle, Safecracker

Q: How often do people get locked in vaults?
A: More often than you’d think and bank PR departments would like.

Usually the victims are children or seniors. Grandpa is busy examining the contents of his safe deposit box at closing time when a bank employee only performs part of the vault-closing procedure. Some vaults are L-shaped or there may be alcoves or obstructions inside, so it can happen if the closer doesn’t “walk the vault” as well as call out to possible occupants.

Q: Do you ever look inside?
A: I NEVER look. It’s none of my business. Involving yourself in people’s private affairs can lead to being subpoenaed in a lawsuit or criminal trial. Besides, I’d prefer not knowing about a client’s drug stash, personal porn, or belly button lint collection.

When I’m done I gather my tools and walk to the truck to write my invoice. Sometimes I’m out of the room before they open it. I don’t want to be nearby if there is a booby trap.

And people do put booby traps in safes.

Taken From Us Too Soon

The Graveyard Of Shelved Ice Cream Flavors

Like most cemeteries, the Flavor Graveyard attracts its share of mourners and other visitors.

“It’s not uncommon,” Greenwood says. “You walk up to the graveyard here, and there’ll be fans that are up here putting flowers next to a headstone, or down on one knee, kind of paying their respects.”

I’ve never seen that kind of dedication in a droid before.

It's Not You. It's Me.

Taster’s Choice: Why I Hate Raw Tomatoes and You Don’t

All my life, I’ve been vaguely ashamed of my dislike, probably because it was such a profound disappointment to my mother, and naturally I craved her approval.

But no more! I just discovered that I am not alone in the blogosphere when it comes to hating raw tomatoes. Kylee Baumie of Living Green just came out of the closet as a “mater hater.” So did Steve Bender, a.k.a., the Grumpy Gardener, and Chris Tidrick, who blogs at From the Soil. They recently discovered their mutual dislike while at a Garden2Blog event in Arkansas. Like Chris, I, too, carefully remove all bits of tomato from food and leave it on the side of the plate. Solidarity!

We mater-haters have to stick together. As Grumpy notes, “Telling people you hate fresh tomatoes is like saying you hate giggling babies or that you loathe the prospect of world peace.”

Count me in this group. We should have t-shirts made.

I’m also sensitive to the bitterness in the foods Jennifer mentions, so it may be that I have that gene, too.

They Are No Longer Unwritten

The Unwritten Rules of Journalism

I don’t blame science reporters for flubbing facts on occasion. Science is difficult to understand, and scientists famously lack communication skills.

But the problem extends beyond simply misunderstanding the science. In fact, science writers appear to obey a collection of unwritten rules when trying to convey science to a mainstream audience.

Cynical, even by my standards. But cynical ≠ wrong.

et al, Brute?

Top Wrangler

When I was in the navy, we (well, me, mostly) used to joke about doing a movie about Nuclear Power School in the format of Top Gun. (Top Chalk?). Similarly, there’s a reason they never do movies like that. (Not having call signs was but one of many fatal shortcomings)

A Rose at Any Other f-stop …

Liquid splashes that look like flowers.

Vessels and Blooms

I created the liquid Vase in the autumn of 2011. I worked on creating the floral forms and leaves through the winter and put it all together Spring 2012. All of my images, unless otherwise noted are single capture events. I do not use photoshop to create composited images. What you see is what occurred in that single exposure.

This Week, Next Week … in Space

A week in space: Dragon docks, dark matter doesn’t not exist (maybe), and the many ways you could have seen the eclipse

Plus the upcoming transit of Venus.

Is Secrecy Worth It?

A tale of openness and secrecy: The Philadelphia Story

The former Manhattan Project scientists who founded what would eventually become the Federation of American Scientists were adamantly opposed to keeping nuclear technology a closed field. From early on they argued that there was, as they put it, “no secret to be kept.” Attempting to control the spread of nuclear weapons by controlling scientific information would be fruitless: Soviet scientists were just as capable as US scientists when it came to discovering the truths of the physical world. The best that secrecy could hope to do would be to slightly impede the work of another nuclear power. Whatever time was bought by such impediment, they argued, would come at a steep price in US scientific productivity, because science required open lines of communication to flourish.

At the University of Pennsylvania were nine scientists sympathetic to that message. All had been involved with wartime work, but in the area of radar, not the bomb. Because they had not been part of the Manhattan Project in any way, they were under no legal obligation to maintain secrecy; they were simply informed private citizens. In the fall of 1945, they tried to figure out the technical details behind the bomb.

This basic problem hasn’t gone away. The conflict between the desire for secrecy and progress’s need for communication is still there.

Which Way is Up?

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I wrote about the KOH etch of Silicon some time ago. Lots of things are made of Silicon.

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