Recent content by Wattever

Sorry if this is a stupid question, I haven't studied mechanics in a while and suddenly I'm confused about this. A mass m is hanging at the end of a spring. Forces on the mass: mg downwards and F upwards. Forces on the spring: mg downwards and a force upwards exerted on the spring by the...

This is what I do, but I'm still having a lot of trouble finding things that are not visible to the naked eye. For example today I was trying to find M57 which was very close to Vega. I got Vega but I couldn't find M57 :( The only thing that I couldn't see with the naked eye but eventually...

I don't know :( I drive nearly 45 minutes from the city, and I stop at a kind of a tourist village where only the street lights are on at night. I'm still going to try anyway! Edit: Oh I forgot to ask, will any of these things mentioned here be visible or detectable in the guide (the tiny...

The one I have is 102 mm and Focal Length 800 mm, so I guess things will be fainter :( How dark? The faintest stars I see with the naked eye are around 3.5 magnitude. I'm not sure, but I think that's very bad :/ I drive about an hour out of the city but I still have to go to somewhere...

Can I see anything other than the planets with a 4" telescope? I saw Jupiter (and four of its moons), Neptune, Mars and Venus but they were all really tiny so I was wondering if the planets are so tiny does that mean I wouldn't be able to see any of the other objects, like galaxies and nebulae...

Yes, obviously I realize that-- I explicitly said "due to the rotation of the Earth about its axis" in the second paragraph, which was a reply to integral and negitron. The first paragraph was a reply to D H. Two different situations. Anyway, I got it. The problem was just that by "the sun...

What? Whether I can see it or cannot is completely irrelevant to this topic where I'm looking to understand why the motion happens, ergo your mentioning that it takes months to observe was off-point-- which was what I was trying to say. I was watching the skyguide in Starry Night, which showed...

It's not observation that I'm concerned with here, it doesn't really matter if I can't observe it (I'm not claiming it doesn't happen, I just can't understand it). How come? If at a certain month the sun appears straight in front of my window and behind it some constellation, at a different...

I've been saying that if I ignore the rotation of the sun and Earth about their axes the sun should disappear for half of the year, like http://www.math.nus.edu.sg/aslaksen/applets/earth_fixed/earth_fixed.html" ! OK, the constellation behind the sun changes, but then shouldn't it appear as if...

I still have the same problem with that. I don't know if by sun's perspective you mean the sun (or the person on the sun looking at the earth) is rotating so as to be facing the Earth as it moves or if the person is looking straight ahead and only the Earth is moving. If it's the latter, I...

I can't understand why the sun moves across the ecliptic :( I've been searching for hours and I've found nothing more than "because of the Earth's revolution around the sun", so I'm assuming this is extremely obvious - but I can't understand it. I understand why the declination angle of the...

Yes, I think we're finally talking about the same thing now! I did not know that. I didn't know about time dilation either, and the length contraction hasn't been explained yet; I'm guessing these come furthur in the book. Hopefully I'll understand this when I get to them. Thank you all for...

For the same reason the two flashes of lightning appear not to be simultaneous to an observer at M'. Yes, this is what's bothering me. The scenario I gave is to explain why this definition doesn't make sense to me. Sure. What I wanted to clarify is that there are two observers on the train...

I will not be using it during the day, did not mean to imply that.

You guys, you're not even reading! Yes, the observer on the train will see it struck at t', but I'm pretty sure I've said over and over that the observer cannot see it at all! The observer can see the lightning, but not the cat! It's a transparent cat, ok? I did mention that the observer...