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seen Jun 14 at 20:15

Jun
14
reviewed Close Why one cannot escape from a black hole
Jun
14
reviewed Reject suggested edit on Do stars have exactly sphere shape?
May
15
comment Does matter accumulate just outside the event horizon of a black hole?
@StanLiou Great, thanks!
May
15
answered Which is the most early type star with a planet discovered by radial velocity method?
May
15
comment Does matter accumulate just outside the event horizon of a black hole?
@Jonathan One way of thinking may be, that the information of the matter is stored at the event horizon, some fluid-simulations indicate a fractal structure of the event horizon due to infalling matter; this might be a way to overcome the information paradox. That's neither the Schwarzschild nor the Kerr solution.
May
15
comment Does matter accumulate just outside the event horizon of a black hole?
@StanLiou How can the finite life-time of the Black hole due to Hawking radiation be made consistant with the infinite amount of time (future) needed for the expansion of the event horizon (in the outer time-frame)?
May
15
comment Does matter accumulate just outside the event horizon of a black hole?
@Jonathan If you assume e.g. the Schwarzschild solution, the simplest form of a black hole, from an outside observer you need to distinguish three zones: the space-like, the light-like, and the time-like zone. The light-like zone corresponds to the event horizon. If you transform properties of matter between these zones they change their physical properties so much, that the term "the matter is" doesn't make much sense, neither "matter" nor "is". One space dimension changes roles with time.
May
15
answered Does matter accumulate just outside the event horizon of a black hole?
May
15
comment How many earths fit in the observable universe?
@RobertCartaino That's why I just provided two valid digits; so the numbers should be valid more or less next week, too. ;) Btw. sorry for pressing Earth into a cube, next time I'll be more careful.
May
15
comment Does matter accumulate just outside the event horizon of a black hole?
My personal opinion: That's the reason (together with Hawking radiation making the BH vanishing over finite time, as seen from outside), why an event horizon never can form. But that's not (yet?) the main-stream opinion.
May
14
answered How many black holes exist?
May
14
answered Does Earth revolves around Milky Way?
May
14
comment Can Mercury hit Earth or Mars in the next 5 billion years?
@BlackbodyBlacklight There are quite a number of possible 1:1 resonances, including horse-shoe orbits, pseudo-orbits, and trojans, but also inclined or elliptical orbits around the Sun. But that's certainly only a possible, although yet unbased, temporary outcome, not a cause, as you say.
May
14
comment When will all eight planets in our solar system align?
$x\equiv \theta_i (\mod l_i)$ works the same in comments. I think, your approach is the best you can do without excessive simulations. All you need to do, is to insert the actual data; that has been the part, which made me hesitate to provide an answer.
May
13
comment Can Mercury hit Earth or Mars in the next 5 billion years?
@BlackbodyBlacklight After a change to an outer orbit e.g. due to a close encounter with Venus as a consequence of orbital instability of Mercury, an 1:1 orbital resonance with Jupiter isn't necessarily impossible, but rather unlikely, and references to an according simulation are missing.
May
13
answered How many earths fit in the observable universe?
May
10
comment Can we find out whether early Venus was Earth-like or not?
... plus higher escape velocity needs high impact energy making appropriate impacts rare, and asteroids of Venus impacts more than 3 billion years ago should be rarified in the meanwhile, or left the inner solar system.
May
9
comment Can Mercury hit Earth or Mars in the next 5 billion years?
... fixed Wikipedia link.
May
9
comment Can Mercury hit Earth or Mars in the next 5 billion years?
Same here (newscientist.com/article/…), where the broken link in Wikipedia should point to.
May
9
comment Can Mercury hit Earth or Mars in the next 5 billion years?
@KeithThompson The headline of the paragraph says "Mercury–Jupiter 1:1 resonance". That's stricter than the phrase in the body of the paragraph: "the two may fall into sync". It's a little unclear, what the author really intended to say. Might be "fall into sync" is meant as a precursor of possible 1:1-resonance, or it's just an unlucky headline. In the only available reference (adsabs.harvard.edu/abs/1994A&A...287L...9L) I couldn't find statements about resonance or "sync", just about the long-term chaos in the solar system.