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Comment: Re:E=mc^2 (Score 1) 255

by AJWM (#43597703) Attached to: Does Antimatter Fall Up?

Right, we know it has positive inertial mass. We haven't yet properly observed their gravitational mass. We assume the two are equivalent; they may not be.

Actually, physicists have antimatter all wrong. A positron actually does have a negative charge but also has negative inertial mass, so it will react to an electromagnetic field the opposite way an electron does. We just observe that as reversed charge.

(Yes, I did just make that up, tongue firmly in cheek.)

Comment: Re:Most important question... (Score 1) 255

by AJWM (#43597681) Attached to: Does Antimatter Fall Up?

Much (most?) of the energy from an ordinary nuclear bomb comes off as gamma rays. Because the atmosphere happens to be relatively opaque to gamma, it absorbs them and superheats. That's what generates the fireball.

So, expect the same thing to happen with antimatter.

And actually pure gamma emission is what happens when electrons and positrons collide. Proton-antiproton collisions tend to produce gamma plus some secondary particles (pions (pi-mesons), if I remember right, but I may not).

Comment: Re:Huh? (Score 1) 272

by AJWM (#43585993) Attached to: Stolen Laptop Owner Outwits Mugger, Police, and the Media

From Wikipedia: "The Internet protocol suite resulted from research and development conducted by the Defense Advanced Research Projects Agency (DARPA) in the early 1970s. After initiating the pioneering ARPANET in 1969, DARPA started work on a number of other data transmission technologies. [...] From 1973 to 1974, Cerf's networking research group at Stanford worked out details of the idea, resulting in the first TCP specification."

And then it took about 8 years to be blessed as a standard, which is about average.

I laugh, ha!, at your check mate.

Comment: Re:Antares: an outsourced rocket (Score 1) 85

by AJWM (#43513359) Attached to: Privately Built Antares Test Flight Successfully Launched From Virginia

Orbital has a history of using hardware from other sources. The main stage of their Taurus is based on the Peacekeeper missile, for example.

Nothing really wrong with that, except it means they don't have the same kind of cost control that SpaceX does, who design and build all their own systems.

Comment: Re:Well done to all involved (Score 2) 85

by AJWM (#43513331) Attached to: Privately Built Antares Test Flight Successfully Launched From Virginia

Rockets are very complicated machines, and we have much still to learn.

They're complicated when the design criteria includes maximizing performance regardless of cost, which was the general design rule in the 1950s and 60s. (In the 70s and 80s, that morphed to maximizing NASA jobs and the number of congressional districts the work is done in, almost regardless of cost.)

As an above poster mentioned, the Saturn F1 (for example) has been redesigned as the F1-B with different design goals, reducing the parts count (hence complexity, at the same time simplifying manufacturability) by two orders of magnitude and increasing thrust (at a very slight drop in Isp -- performance).

So I'd say we're learning.

Comment: Re:Huh? (Score 4, Interesting) 272

by AJWM (#43513263) Attached to: Stolen Laptop Owner Outwits Mugger, Police, and the Media

Given that the internet (okay, ARPANET) was actually invented in 1969, Dick's book wasn't that much ahead of its time. TCP came a few years later.

(1969 was a surprisingly watershed year: first (and second) manned moon landing, the beginning of the internet, and the development of UNIX.)

Q: What do you call a principal female opera singer whose high C is lower than those of other principal female opera singers? A: A deep C diva.

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