2,865 reputation
1119
bio website vyznev.net
location Helsinki, Finland
age
visits member for 2 years, 9 months
seen 17 hours ago

I like programming in Perl and C. I know Java and PHP too (I'm a MediaWiki developer), but I can't really say I like them. I keep meaning to learn Python some day, but never seem to get around to it.

I'm working on a Ph.D. in biomathematics. I also like programming puzzles and cryptography.

Please consider any (original) code I post to Stack Overflow (and other Stack Exchange sites) to be released under CC-Zero unless stated otherwise. You may do whatever you want with it and don't have to credit me in any way, although of course that would be nice.


Apr
16
comment Does the mass of a star change as it collapses into a black hole?
@trysis: On the surface. And no, it doesn't account for the presence of the atmosphere, so it's not actually sufficient to escape the Earth's gravity if you're starting from the surface. (In fact, an object moving at 11.2 km/s or faster near the Earth's surface would most likely shortly turn into a ball of incandescent gas due to aerodynamic heating. To actually get into space from the Earth's surface, you need to start relatively slowly until you've cleared most of the atmosphere.)
Mar
29
comment Where does a string tighten when you pull it?
The behavior you describe is fairly typical if the string is lying on the ground, so that there's significant static friction resisting its movement. If the string is in free-fall, or, say, floating on/in water, things can be very different.
Mar
10
reviewed Approve suggested edit on How to derive Schrödinger equation?
Mar
10
reviewed Approve suggested edit on Why do some sunsets have a green flash?
Mar
10
reviewed Reject suggested edit on How does isotropy of free space imply $L(v^2)$ for a free particle?
Mar
9
comment If I take a bottle of air into space, and open it, where does it go?
@XièJìléi: That just means you need a stronger balloon.
Mar
7
awarded  Guru
Mar
7
comment How does a half-life work?
Dammit, accepted. And just when I was this close to getting a Populist badge... ;-)
Mar
6
awarded  Good Answer
Mar
6
awarded  Nice Answer
Mar
6
awarded  Quorum
Mar
6
answered How does a half-life work?
Feb
18
comment Does space curvature automatically imply extra dimensions?
@SantiBailors: Maybe this math.SE thread might help a little.
Feb
12
comment Is there a delay in the effect of gravitational force?
Just blow up the large object into two pieces, with enough energy to send them off (orthogonally to the line between the original objects) at a good fraction of $c$. (I believe the technical term is "rapid change in the quadrupole moment," but for popular science, "blowing up" will do.) It's not quite magic teleportation, but it's a pretty fair approximation.
Feb
8
comment What justifies dimensional analysis?
+1 for "consider the units to be variables."
Jan
28
awarded  Custodian
Jan
28
reviewed Approve suggested edit on Can I excite an already unstable element for accelerated decay?
Jan
25
revised Why do chimneys have these spiral “wings”?
use protocol-relative links to avoid mixed content warnings when using https
Jan
19
comment Very strange shadow phenomenon
I don't think this is the full answer. The thing is, convolution (including blurring) and multiplication don't commute, so you'll get different results if you merge the layers before you blur them (which is closer to the real situation, assuming the book and elbow are at approximately the same distance from the wall). And indeed, doing it "correctly" should generally make the "bridge" region between the shapes darker than in your example.
Jan
18
answered Why does tossing a coin in a train and on a train differ?