Am 07.03.2011 14:26, schrieb Invisible:

>> Take any mass and collapse it down small enough and it'll become a black
>> hole. Once it reaches a critical ration of mass/volume, then you'll have
>> a black hole. It may not last too long, or it may; and if it does, it
>> would be rather irresponsible to create one so close to our own planet.
>
> But if you have a small mass, why would it be crushed to a small size?

Non-gravitational external force. Smash two particles into each other 
hard enough, and you /might/ get them close enough together that they 
can't escape each other's gravitational well anymore.

>>> If the speed of light is constant, how the hell does light undergo
>>> Doppler shift?
>>
>> Same way sound Doppler shifts.
>
> But the speed of sound is /not/ constant. It changes depending on the
> motion of the source and the receiver. Light, on the other hand, has the
> seemingly impossible property that the relative motion of source and
> receiver somehow makes no difference to the apparent velocity of the
> light... but somehow *does* affect its wavelength? WTF?

That's one of the fun things about Einstein's theory of relativity 
(don't know if this one falls into the domain of special or general 
relativity).

You can put it like this: In your frame of reference, things buzzing 
towards you simply have a faster-ticking clock than things buzzing away 
from you (presuming that you define "now" based on when light from 
"somewhere" reaches you, rather than "when" it was emitted).

>>> Do spiders have a sense of smell?

Insects do, so I guess spiders do as well - though if they follow the 
insect way, then their "noses" are on their legs.

> A "root" is generally a part of a plant. Whereas a "route", as in, "this
> is how you get to this square number", would logically make more sense.

Even more generally, a "root" is something from which something bigger 
grows, so it does make sense. Also note that if it was "route", it would 
be "route to", rather than "root of".

> Probably means the original mathematician who worked all this out was
> French or something... :-P

Maybe, but he spoke (or at least) wrote Latin. The original word was 
"radix" (latin for - guess what - "root"). In German it's "Wurzel", 
which also means "root".

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