Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Comment: Re:Overdramatic (Score 3, Insightful) 42

by TMB (#49697337) Attached to: Galaxies Die By Slow "Strangulation"

The authors of this work didn't invent the word -- that's been one of the standard descriptions of this process for decades, and I'm not sure who first came up with it. I think it evolved from "suffocation", which does make more sense (it runs out of gas).

This is in contrast to other dramatic ways of making a galaxy "red and dead" like "harassment", "tidal strippping", and "cannibalism", during which the galaxy undergoes "violent relaxation" (the single best technical term in all of astrophysics).


Comment: Re:Most people answered too low. (Score 1) 158

by TMB (#49646105) Attached to: Devices I have with a GPS reciever built in:

You might be right, but you might also be the distant outlier. I'm pretty sure I have 2 -- one in my tablet and one in my satnav (not a built in one). My car is 8 years old, I have a very dumb phone that doesn't have one, I don't have a digital camera, my laptop doesn't have one, and I don't have a desktop. I'm not particularly atypical (okay, the fact that I don't have a smartphone is atypical, but if I did have a smartphone I wouldn't have a tablet, so that would balance out).

Comment: Depends on the requirements (Score 2) 298

by TMB (#49359909) Attached to: Ask Slashdot: What Makes Some Code Particularly Good?

The best piece of code I ever wrote in my life was nearly 100x faster than the next best algorithm ever written to do that problem. That took the expected run time down from a few days to an hour.

It was not a particularly well-commented piece of code. If it were, it would have been even better.

It was not a particularly obvious algorithm for solving the problem. If it were more obvious why one would choose to do it this way, it would have been even better.

If the primary concern is runtime (because it normally takes days to run), and you literally make it orders of magnitude faster, that's good code. It could be better if it were also better commented and easier to maintain, but those aren't *always* the primary concern (yes, sometimes they are. That's the point -- criteria differ!)


Comment: Re:Same as zero point energy? (Score 1) 236

by TMB (#49359879) Attached to: Dark Matter Is Even More of a Mystery Than Expected

That was what was first assumed. There's only one minor problem.

The amount of zero point energy is *120 orders of magnitude* larger than the measured magnitude of dark energy. And dark energy has about 3x the energy density of dark matter.

So, despite the fact that it looks like zero point energy, there's something else going on.


Comment: Re:WIMPs (Score 3, Informative) 236

by TMB (#49358417) Attached to: Dark Matter Is Even More of a Mystery Than Expected


There are actually many proposed extensions to the standard model that predict dark matter particles that would be classified as WIMPs, and there are some others where the interaction is not through the weak force but through a "hidden sector" force. Some of the possible parameter space of some those hidden sector models predict a cross-section that they would have been able to detect in this experiment. So this is indeed a useful result -- it does rule out some possibilities. But they're not necessarily the possibilities that most people would be betting on anyway, so the headline is overhyped.


Comment: Analogy (Score 5, Insightful) 196

by TMB (#49156721) Attached to: One Astronomer's Quest To Reinstate Pluto As a Planet

Here's an analogy I gave my students last week...

Imagine you're an alien and you land on Earth in front of a pet store. You go inside and you start meeting dogs. Some are big with a loud deep "WOOF", some are small with a quieter higher "ruff" and there's one little one that goes "meow". Some of them have big floppy ears, some of them have little floppy ears, and that little one has sharp pointed ears with tufts on the end. You think "That little meowing dog with the pointed tufted ears is an unusual dog!"

Then you go onto the rest of the pet store and find a whole bunch more small meowing things with pointed tufted ears, and you say "Oh... I see. That wasn't a funny dog, that was just the first cat I met!"

Pluto was the first Trans-Neptunian Object we met, and so we originally called it by our existing language ("planet"). But once we had a much better lay of the land, it became clear that it was just the first example of a quite different type of object.


Comment: Re:TV = video (Score 1) 244

by TMB (#48985897) Attached to: Over the past 10 years, my TV-watching has..

There's a huge range of ambiguity these days.

How often do I watch a TV set that has a signal coming from an antenna, cable, or satellite receiver? Absolutely never.

How about if I stream an old TV show on Amazon instant video on my computer? How about if it's the latest (but not live) episode from the current season of a show? How about if I stream a live Canucks game on my computer? How about if I stream any of those onto a TV set via a Chromecast? I can't see a reasonable argument that sitting in front of a TV set watching a live sports event isn't "watching TV" --- but you can come up with plenty of industry definitions where it doesn't qualify.

If all else fails, lower your standards.