260 reputation
26
bio website
location Burnaby, Canada
age 39
visits member for 4 years, 9 months
seen Aug 24 at 21:52

I have spent the past 8 years working at a small ISP, where I manage E-mail, DNS, Web, and Voip servers for a couple thousand clients.


Aug
11
comment why is dark matter the best theory available to explain missing mass problems?
+1 for "People have been challenging this idea all along." The fact is that Dark Matter is a theory of last resort. Physicists are about the last people in the world to believe in anything so spooky.
Aug
10
comment Why isn't dark matter just matter?
That should read "hundreds of cold, stellar-mass objects surrounding us in all directions". Or millions of cold, Jupiter-mass objects surrounding us in all directions. Either way, that will have some rather extreme effects.
Aug
10
comment Why isn't dark matter just matter?
"assuming that such planetary systems are fairly rare", actually, since 95% of all matter is apparently undetectable to us, such planetary systems would have to be exceedingly abundant, and that too leaves a good many problems, like the fact that our own solar system appears to be unperturbed by the hundreds of massive objects surrounding it in every direction.
Aug
10
comment Why isn't dark matter just matter?
I think it's more to the effect that it would take an infinite amount of energy to cool matter to actual absolute zero. The best we've been able to do so far has been some very small fraction of 1 Kelvin. And yes, it would absorb heat from the rest of the universe, or the host galaxy, or the surrounding stars and baryonic matter. Unless dark matter just doesn't absorb heat at all, in which case, it's still some kind of matter that we've never seen before.
Mar
12
comment Why are stars white?
We perceive most of them as being white, because most of the visible stars are white to whitish-blue. There are tons and tons of red dwarfs out there that aren't visible because frankly, red dwarfs are really dim. But there are also lots of red giants out there, and they're more obvious. On a clear winter night, you should go out into the country and find Orion. You will see a fair variety of colours in that constellation alone. So the other reason that you perceive them as all white is you just haven't been doing enough observing.
Sep
24
awarded  Autobiographer
Jul
8
comment Classic home experiments for an 8-year-old child
Another way to do these experiments is with Hot Wheels track, allowing you to precisely control the exit speed and the angle of launch. You can use either the cars themselves or ball bearings and golf balls. The denser the projectile, the less air resistance will interfere with the experiment.
Jul
8
comment Classic home experiments for an 8-year-old child
Actually, I was thinking of an experiment just like this one. When I was in Physics 101, we used a metal ball loaded onto a spring with a quick-release to do this experiment. However, there are some easy analogues that are readily available in toy stores. Nerf guns, or other toy guns that use some kind of spring-loaded projectile. You can also look up the formulae for projectile motion and figure out the forces involved.
Apr
11
comment Why can light (photons) bends in a curve through space without mass?
@PoomrokcThe3years: Yes, this phenomenon has been observed, and is accurate to Einstein's equations. :)
Feb
18
awarded  Necromancer
Dec
26
awarded  Yearling
Dec
18
comment How do you respond to questions like “Have you ever observed a UFO?”
I'd respond to the conspiracy types that personally, I would be the first to let them know! Screw the Man!
Dec
13
comment How do you respond to questions like “Have you ever observed a UFO?”
Perhaps the response could start with "You know, as a scientist, explorer of the night sky, and science fiction fan (admit it! You are!), I would love to see visitors from another planet! However, every time we investigate any reports of such, they've all turned out to be completely mundane." Neil Degrasse Tyson says that he's ready to be abducted by aliens, and the moment that happens, he's swiping the first thing in reach of the examination table, providing actual physical evidence of his trip.
Dec
13
revised How is a star's parent galaxy recognized?
added 866 characters in body
Dec
13
answered How is a star's parent galaxy recognized?
Dec
13
comment How is a star's parent galaxy recognized?
Both galaxies and supernovae are redshifted. You just need to compare the redshift of the host galaxy to the supernova in question, and you can discern whether or not the supernova - or quasar - belongs to that galaxy or not.
Dec
13
comment Why can I never see any stars in the night sky?
I would posit that you don't need to stay in complete darkness for 20-30 minutes for this to work. One of my most memorable views of the night sky before I started pursuing astronomy seriously was on a road trip at night in the winter time. We got out of the car to check on someone who had landed themselves in a ditch, and lo, not only a plethora of stars and the milky way, but an obvious difference in the colour of some of the stars. It doesn't help to look up on a clear night, either. Not everyone is so blessed with that regularly. :)
Dec
13
answered How would the night sky appear at the edge of the galaxy?
Dec
12
awarded  Commentator
Dec
12
comment How is it possible for astronomers to see something 13B light years away?
And here, I thought that the reason we use redshifts is because it's far easier than searching for standard candles within galaxies and comparing for absolute magnitude. In more distant galaxies, it's next to impossible to find say, Wolf-Rayet variable stars. Then add to that the fact that finding absolute distance of an individual galaxy would require months of observation. Redshift on the other hand, can be measured instantaneously and works great as a reasonable estimate. Every once in a while, we'll catch a type 1b supernova and compare it to the redshift to re-calibrate our measurments.