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Hello,


Aug
31
comment Can you tell just from its gravity whether the Moon is above or below you?
The presentation seems to have disappeared from the website, but a copy is available from the Wayback Machine at web.archive.org/web/20130430131234/http://earth.eo.esa.int/…
Aug
31
revised Can you tell just from its gravity whether the Moon is above or below you?
typo
Aug
31
accepted What is the largest possible mass for a stable planet made of iron?
Jul
28
comment What is the largest possible mass for a stable planet made of iron?
@WetSavanna: no, I'm not asking for the most stable form, but instead about the phase that's only one step more stable than an iron planet. There are likely multiple steps between an iron planet and a black hole.
Jul
28
comment What is the largest possible mass for a stable planet made of iron?
@Floris: The huge pressure would somehow force some parts of the mass to gain so much velocity that is stronger than the gravity, and so is ejected. It doesn't sound very likely, but I can't exclude it, so I wanted to mention it for completeness.
Jul
28
awarded  Editor
Jul
28
comment What is the largest possible mass for a stable planet made of iron?
@HDE226868: it probably couldn't form from any realistic astronomical process, because there's not enough iron anywhere, so this is hypothetical. But maybe it could form from the core of a star after the rest of the star leaks away.
Jul
28
revised What is the largest possible mass for a stable planet made of iron?
added 136 characters in body
Jul
28
asked What is the largest possible mass for a stable planet made of iron?
Jun
8
comment How does this capillary-action setup not become a perpetual motion machine?
physics.stackexchange.com/q/89223/8851 "How is the water meniscus at the edge of a capillary tube", physics.stackexchange.com/q/88544/8851 "Capillary tube of insufficient length" may be more relevant. It deals not with the case of a hole on the tube, but with a shorter tube, but that's close enough.
Apr
27
comment Is the second defined arbitrarily?
"So practically the second was historically defined so that 60•60•24•365.25 adds up to a year." - I don't think that part is right.
Jan
14
awarded  Autobiographer
Jan
7
comment Feynman diagrams in effective theories
Slightly related to that pion exchange is physics.stackexchange.com/q/9663/8851 Is it pions or gluons that mediate the strong force between nucleons?
Dec
29
comment Why toroid has no magnetic pole?
I think you mixed up the equation.
Dec
24
awarded  Popular Question
Dec
19
comment Gravity waves detectors; are they all similar?
I think you have a typo in the name of that project you linked to.
Nov
10
comment Effects of travel greater than speed of light
See also the recent question physics.stackexchange.com/q/143615/8851
Oct
29
comment Why are we not able to move at the speed of light again?
See also the Usenet Physics FAQ, question "Is Faster-Than-Light Travel or Communication Possible?" at math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/FTL.html
Sep
30
comment How can we minimize the coefficient of static/kinetic friction?
Are you trying to reinvent the wheel?
Sep
30
comment Why can we cycle faster than we can run?
A typical biker rests on downhills, but I don't think a Tour de France biker ever does.