1,023 reputation
518
bio website github.com/spraff
location London, United Kingdom
age 95
visits member for 3 years, 3 months
seen yesterday


Aug
4
awarded  Popular Question
Jul
31
awarded  Notable Question
Jul
29
revised Has New Horizons' visit to Pluto taught us anything deeper than mere… facts?
added 162 characters in body
Jul
29
asked Has New Horizons' visit to Pluto taught us anything deeper than mere… facts?
Jul
24
awarded  Good Question
Jun
16
comment How is angular momentum conserved in this proton+water scenario?
Take our origin to be the topmost hydrogen atom, so $r$ and $p$ are colinear, $L$ is zero.
Jun
15
comment How is angular momentum conserved in this proton+water scenario?
Angular speed is initially zero, nothing is rotating. How can angular momentum be zero?
Jun
15
awarded  Popular Question
Jun
15
asked How is angular momentum conserved in this proton+water scenario?
Jun
12
asked Why does planetary spin affect the stability of orbits?
May
16
accepted Why does fusion stop at iron when nickel is most tightly bound?
May
7
awarded  Yearling
Apr
23
comment How does $p=fv$ hold when $v=0$ and an engine is working?
RE infinity -- the velocity increases so the power increases, although the energetic processes in the engine are happening at the same rate.
Apr
18
asked How does $p=fv$ hold when $v=0$ and an engine is working?
Mar
4
comment Why does fusion stop at iron when nickel is most tightly bound?
Any idea why Fe is so often quoted as being the stop point?
Mar
3
asked Why does fusion stop at iron when nickel is most tightly bound?
Jan
29
comment What is a reasonably accurate but simple model of the Milky Way's gravitational field?
I mean $\Phi(a,b)+\Phi(p,q)\neq\Phi(a+p,b+q)$, right? And because of this fact I can't simply transform $\nabla\Phi(r,z)$ into Euclidian coordinates to get the Euclidian vector which corresponds to $\nabla\Phi(x,y,z)$ can I?
Jan
28
comment What is a reasonably accurate but simple model of the Milky Way's gravitational field?
I'm having trouble with the concept of a non-Cartesian vector. Vectors are defined by linearity, aren't they?
Jan
26
awarded  Nice Question
Jan
26
comment What is a reasonably accurate but simple model of the Milky Way's gravitational field?
I can transform into cylindrical coordinates no problem, but when I apply $\nabla\Psi$ how do I interpret this equation? What do those hats mean? Is the result in cartesian coordinates? If not how do I interpret addition of terms?