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1d
comment Roche Limit for Earth-like body around Earth-like body
Nice answer. Consider our own moon's effect on the oceans.
1d
comment moonless night and lunar phase
@questionhang: Correct. The Moon is in the direction of "up" during the night when it is full. So far as the Moon never appearing during the whole night, there may be up to about an hour of a very small sliver of moon slightly after sunset or slightly before sunrise. Any more than that and I wouldn't call it a 'moonless night'.
1d
comment moonless night and lunar phase
@Jeremy: By "once per month" I mean "once per lunar phase cycle the Moon passes close by the Sun".
2d
comment What should I look for in an astronomy tripod?
I need to take that picture for you!
Nov
3
comment I'd like to become an astronomer. What experience do I need?
I think that closing the question rather than asking for clarification is plain wrong. You could simply point the OP to Swinburne Astronomy Online or even Galaxy Zoo and answer their question. In fact, almost every single "star tour" that I give people ask "How can I become an astronomer". The field is so broad, and there is so much work for amateurs to do, that you are doing the OP and the community a disservice by closing this common, valid question.
Nov
3
comment How would Special relativity explain past-present-future if thinking about 13-billion-light-years distanced objects
Considering your example of the gravitational lensing, I'm removing my former comment. When I get some time I'll research the issue and get back to you. It won't be this week, though! Thank you.
Oct
19
comment Might Oort cloud comets be exchanged between solar systems?
Thank you for this terrific analysis.
Oct
19
comment Do all stars have an oort cloud or is it a rare occurance?
Concerning the assertion that passing stars may disturb Oort cloud objects, this question is in need of elucidation!
Oct
19
comment Might Oort cloud comets be exchanged between solar systems?
Note that this answer supports the assertion that passing stars can influence Oort cloud objects.
Oct
16
comment Time period in which a planet rotates
@DavidHammen: Thank you. What would be the case for objects whose vernal equinox precesses at an exaggerated pace?
Oct
14
comment Time period in which a planet rotates
Thank you Stan. I've been castrated more than once on English.SE for suggesting that a word's meaning could be inferred by its etymology. Apparently some people think that that term "living language" means "words mean whatever I want them to mean".
Oct
13
comment Can we see individual stars in other galaxies?
An event that occurs to a star.
Oct
13
comment Can we see individual stars in other galaxies?
In what way is a SN not a star? You could argue that a SN is a short-lived phase of a star, and I would agree with that. But for purpose of this discussion, in which the asker is interested in seeing spheres of fusing elements in other galaxies, a SN fits the description.
Sep
16
comment How many astronomers are there in the world today?
Would you consider me an astronomer? I'm a software developer by trade, with no formal astronomy education besides university physics. I'll tell you the names, distances, masses, and other information of most celestial objects with an absolute magnitude 3 or higher. I'll teach you quite a bit about theories including orbital mechanics, astrophysics, gravitation, and also about practicalities such as historical and current spacecraft and missions. If you consider me as an astronomer despite no formal training, then any estimate of amount of astronomers goes way up, there are many more like me.
Sep
4
comment How is space-time bent by black holes?
Exactly. For spherical objects the gravity felt depends on only the mass of the object and the distance from it's center (squared). Black holes are assumed to be spherical.
Sep
4
comment How is space-time bent by black holes?
Actually, you can get nearer to the geometric center of the mass, which accounts for the higher local gravity field (and tidal forces). Note that at the same distance from the (center) of the black hole and the (center) of the star, the black hole's gravity will be lower.
Jul
28
comment Escaping a black hole
Mitchell, you might want to accept the answer as given. It answers your question very well.
Jun
10
comment How does the evolution of a solar system not break the second law of thermodynamics?
The statement "the radiated photons are out there somewhere" really does make it clear.
Jun
10
comment How does the evolution of a solar system not break the second law of thermodynamics?
So where was the corresponding increase in entropy to offset the creation of the solar system? Heat loss?
May
5
comment What would happen if an ice cube is left in space?
This is a terrific answer.