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Comment: Re:Cool: mouse-display recursion! (Score 1) 156

by AstroWeenie (#34964558) Attached to: Apple Files Patent For Display Mouse

They should put a little USB port on this display mouse, where you can plug in another mouse, to control a little pointer on host mouse's display, as an alternative to using it as a touch screen.

Great idea! But I want to plug in a little USB keyboard instead and use the mouse display for a command line interface.

Comment: No Plato users here? (Score 4, Interesting) 162

by AstroWeenie (#32344042) Attached to: Where Were You When PLATO Was Born?

Jeez, I can't believe I'm the first actual Plato user to post. I played lots of games on Plato in the middle of the night while I was writing my thesis in 1977-1978. It was amazing at the time -- an online system where you could play real-time networked games with people across the country built around a plasma bit-mapped "high resolution" display (probably 512x512 pixels). There was even a quasi-three-dimensional game called dnd where you explored dungeons with a party of other players. ("Quasi 3-D" because all it could do was draw the lines indicating the corners of walls, ceilings, floors.)

Anyway, I think it was way ahead of its time. I don't know how successful it was as an educational system, but it ought to be legendary as a network gaming system.

Comment: Re:Who still breathes CITY air? (Score 2) 164

by AstroWeenie (#27960541) Attached to: Study Shows Cocaine And Other Drugs In Spanish Air

Anything but DerriAir.

This reminds me of the proposed new state motto for Wisconsin: "Come Smell Our Fresh Dairy Air". But the popular winner in the statewide vote was "Eat Cheese or Die!"

Unfortunately the state declined both of these suggestions and decided to stick with the old slogan, "America's Dairyland".

Comment: Re:Many possibilities. (Score 1) 358

by AstroWeenie (#27353177) Attached to: Huge Supernova Baffles Scientists

Oh, and if I recall correctly, the largest known exoplanet is 16 solar masses

Ah, that would be 16 *Jupiter* masses. Since Jupiter is about 1/1000 the mass of the sun, 16 Jupiter masses is only 1.6% of a solar mass. You would get a nice little bang if that fell into a 50 solar mass star, but it wouldn't have much long term effect.

The dividing line between planets and brown dwarfs is about 15 Jupiter masses. Above that mass what you have is a star (because it has nuclear reactions involving deuterium that generate energy in the center).

Comment: Re:Many possibilities. (Score 5, Informative) 358

by AstroWeenie (#27351669) Attached to: Huge Supernova Baffles Scientists

Sorry, but most of your ideas are far off base.

One is that this was a binary system, that a second star was behind the first at the time of the "pre-supernova" photo, and that they collided. Remember, they have very few photographs, are not using any data from space telescopes like SWIFT, and are therefore filling in the blanks.

Not correct -- they used both historical Hubble data to detect the star before it exploded and followup Hubble observations to confirm that the star has now disappeared. And they have data from the Keck Observatory with observations of the supernova. That's about as good as it gets for data.

We can assume that star evolution is moderately well-understood (though not completely), so if what they think is the input is inconsistent with what they know is the output, the chances are really good that the input is wrong, especially with such little data.

Star evolution is well understood for the bulk of the lifetimes of stars like the Sun, but there are still many questions about this sort of massive star. Such stars lose most of their mass during their lifetimes through stellar winds, which are themselves very complicated and not that well understood theoretically. And then the stars go through this luminous blue variable stage (which is what this star was before it blew up), and that is very poorly understood and is the subject of a lot of current work.

So it is in fact much more likely that this has uncovered a part of late stellar evolution of massive, luminous stars that is not correctly described by current models. We don't need any really bizarre explanation like iron planets falling into the middle of the stars. (And that wouldn't work anyway -- the planet would have to have a mass bigger than the Sun to have a big effect.)

Comment: Re:Calling this "liquid wood" (Score 1) 226

by AstroWeenie (#26864341) Attached to: "Liquid Wood" a Contender To Replace Plastic

This plan would not put a pressure on landfills because it would require a specialized location anyway. To get around the methane problem, this area would have to be far deeper than an above ground landfill. In fact, it may be easier to turn the trees into woodchips and fill up abandoned mines with them. Or perhaps produce a wood-pulp slurry and inject it back into former oil-fields.

I think you underestimate the volume that would be required to store all this wood. According to Wikipedia, the world's annual CO2 emission is 2.7e10 metric tons, which corresponds to 7.4e9 metric tons of carbon. If you store this at a density of 1 g/cm**3, it would take a cube about 2 km on a side per year. Putting that in an abandoned mine with a shaft cross-section of (say) 10x10 meters would require using about 400 km of mine shaft each year. Since wood is not 100% carbon by weight, the required volume of wood chips would be considerably larger.

I don't know what the total volume of abandoned mineshafts is, but I doubt they would last long if filled up at this rate.

Comment: Re:Colliding black holes (Score 1) 201

by AstroWeenie (#25532477) Attached to: Black Holes May Not Grow Beyond Certain Limit

I'm sure I'm basing this on some bad sci fi movie or other, but can't two of these maxed out black holes merge together (in theory at least) to form a larger one?

Actually this is a very good question and was the first thought I had too. (And I am an astrophysicist.)

It looks like the answer that the paper offers is that to have two extremely massive black holes in the same galaxy would require that galaxy to be more massive than any we have found. There's a close correlation between the mass of the central black hole and the mass of the galaxy.

I consider this a slightly weaker explanation though, compared with the argument that the black hole can't continue to grow because gas can't accrete to it.

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