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<0> So I was browsing through astronomy articles on wikipedia and I got to wondering. The moon orbits the earth due to earths gravitational field, and the earth orbits the sun due to the suns gravitational field. Does the suns gravitational field effect the orbit that the moon has around the earth? Or does the suns gravity not exist as far as the moon is concerned?
<1> maybe it as an effect on precession ?
<1> http://en.wikipedia.org/wiki/Precession
<1> The gravitational tidal forces of the Moon and Sun apply torque as they attempt to pull the equatorial bulge into the plane of the ecliptic. The portion of the precession due to the combined action of the Sun and the Moon is called lunisolar precession.
<2> there's 1000mm in 1m right?
<2> i'm going crazy :/
<1> haha.
<1> right.
<2> so if I have a diffraction grating with lines spaced 5m apart, that means there are 200lines per mm ?
<3> SnakeChomp, Of course the moon is effected by the sun's gravitational field, however earth's gravitational field is simply more influential to it
<4> Hey all - I've got a question on the accuracy of blackpowder cannons. I know it's not pure physics, but this was my first thought on where to go. Anyone here know how accurate a light field gun is at about 300m?
<0> I imagine google would =P
<5> that would be up to the specific design. google for specific examples
<4> Oh, I googled :P
<4> Didn't find any real reports of a cannon's accuracy; just a bunch of chitchat about their use historically
<4> I'm not in #civilwar somewhere for a reason, this is hypothetical stuff.
<6> sure you're not in isreal at the moment? ;)
<4> Nope, nor Iraq, nor Afghanistan. I'm just a game developer who actually cares about real physics.
<4> if I was, I wouldn't terribly care how accurate they were, I'd just be firing canister :P
<4> heck, stuff a cannon full of primed hand grenades, if you're one of those nutters :P
<6> i'd recommend searching too though, i doubt anyone here would know that kind of thing off hand
<4> yeah, I'm still searching
<4> This isn't Day 1 of this :P
<4> I've even fired off some emails to re-enactment groups who have fired cannons, but no replies there
<6> maybe they need more time to find out :)
<4> Okay, I now know the accuracy of a 44lb naval gun firing a golf ball. The answer, of course, is zero, and that doesn't help much. :P
<7> Kuprin: would this help? http://www.myarmoury.com/talk/viewtopic.php?t=7369
<4> that looks familiar, I think I've been there and found both sides completely out to lunch, but I'll reread
<8> i don't understand 'horizontal problem' with the big bang
<9> Kuprin: your a game devoper you say??...well here is some advice....I had the most fun playing games that had some fairly broken physics engines.......work on game play and storyline first!!! **** the physics
<4> Oh, don't worry about that. I know that. Right now, however, I'm dealing with a physics issue. :)
<9> brings me back to the days of quake bunny hopping...
<9> man you really could fly...
<8> i guess the problem is that microwave background radiation is the same everywhere, even for points so distant from each other that there could have been no communication between them
<8> however, i don't see why you can't chalk it up to the same mechanism being in effect in two different places
<8> since the universe started as a point, aren't all points in it now 'causally related'
<8> couldn't they all feel the effects of some past event
<4> theoretically, yes
<8> what non-theoretical consideration makes the horizon problem actually a problem
<4> Yeah, I sorta thought of that right after I said it :P
<4> I'm sure we'll come up with one, though :P
<8> i feel like i'm missing something big
<8> ok the universe is 13.7 billion years old.
<8> we somehow know that we see unifrom cosmic microwave background from 15 billion light yrs away
<8> and that it originated when the universe was 300,000 yrs old
<4> there are a few ways to explain that and none of them can be proven. >_>
<8> and so it seems that at 300,000 yrs, multiple very separate points of the universe all emitted very similar CMB radiation.
<4> but why do we perceive it as so far away?
<4> even presuming the universe is expanding at the speed of light, that's outside of our little bubble...unless I'm missing something
<4> Okay, got my cannon question; it's not a question of the gun, I realized after reading about how accurate they were against static targets, but the fact that a cannon doesn't just go "bang" when you tell it to
<4> therefore, hitting any kind of moving target, unless especially large, with a cannon would be nigh-impossible at any range.
<4> (note that for all intents and purposes, a ship is a static target)
<8> Kuprin: the universe expands faster than the speed of light
<8> Kuprin: space itself stretches
<4> ah, I see. I wasn't up on that.
<4> how can we measure the age of the universe if that's true, then?
<8> estimates range from 11 to 20 billion years
<8> the main pieces of evidence i think are the speeds with which other stars are moving away from us and the temperature of radiant heat left over from the big bang
<4> Yeah, so the usual suspects, and "faster than light" is mostly a guess :P
<4> I just wish I could live long enough to see some people MEASURE some of this stuff, just to see what we actually get
<8> from wiki:universe, nasa's wilkinson microwave anisotropy probe measured radiant heat to calculate 13.7 billion years
<8> The goal of WMAP is to map out minute differences in the Cosmic Microwave Background (CMB) radiation in order to help test theories of the nature of the universe.
<9> "[18:46:53] <8> Kuprin: the universe expands faster than the speed of light" ....been out there with your measuring stick have we?
<9> All clowns are the manifisation of god
<9> there....now we can all say crazy things....
<8> JabberWalkie: that wouldn't help; the stick would expand
<9> umm...sure...
<9> wild speculation..much?
<8> from what i read, i thought this was pretty widely believed among cosmologists
<8> http://en.wikipedia.org/wiki/Redshift#Expansion_of_space
<9> yea i dont really think so.......
<9> the universe is no doubt expanding....but any explanation is sketchy at best
<8> the usual explanation is that it's expanding away from the big bang
<8> there are others but the big bang is supported by a few pieces of evidence
<8> i heard that the ratio of helium/hydrogen observed in the universe has been important
<9> yes....but expanding faster than the speed of light?...nonsence
<8> wikipedia says it like this: 'space is expanding according to the Friedmann-Lematre model of general relativity' and 'Most cosmologists agree that the observable universe is well approximated by an almost FLRW model'
<8> here's a good page: http://curious.astro.cornell.edu/question.php?number=575
<8> 'some of the galaxies we can see right now are currently moving away from us faster than the speed of light'
<8> it's pretty certain that space itself is expanding if you believe the red shift and that things cannot 'actually' travel faster than the speed of light.
<9> dancor: seems that there deffinition of distance is somone flawed.....they say the distance between two objects "right now".........well this would indicate some kind of simulatanity...which is impossable
<9> you can use relitivity for one then then shirk it off for the next....because it will give you answers that will get your more funding...
<10> mmmm, funding...
<10> which makes it hard to say what they are "currently" doing
<8> i guess funding is important. but i do believe that space is expanding, i think it's one of the more established things in cosmology. and i think cosmology is important. i don't think anyone is using it as a cash cow. of course it could turn out that space is not expanding.
<8> or rather, it could come to seem more scientifically likely that it isn't
<8> even if the language on the sites i could find seems bad, i do think there are well-defined, simple and elegant ideas under the words in this theory.
<11> hello there DanF_DrC
<5> hi
<12> Hello... I was wondering. I know that when a plane flys in a straight line, the gravity acts as a "string" and prevents it from continuing into space, but instead it travels in a circle around the earth...
<12> Does the same thing happen to air?
<12> Considering that gravity is a field I would ***ume it does.
<13> energy is finally being conserved, mostly, in my 2d pool ball simulation
<13> [ATL]Person: yes, gravity is what holds the air down too
<14> hi
<15> !Bonjour
<2> caa va?
<2> ca va?
<16> ca va bien, merci...
<2> ;)
<2> je suis fatigue
<2> or something
<2> mais tres bien
<15> moi aussi ;)
<15> je voudrais une c0ff3
<2> lol
<2> du c0ff3, non ?
<17> der kaffee schmeckt vehement nach kohlenw***er
<18> yo, i speak french too.
<18> je mapelle shray
<18> je voudrais un coca
<18> c'est magnifique
<18> j'ai tres fatigue
<18> etc
<18> lol
<18> French 1 in high school, holler!
<19> tres bien, vous aiment un biscuit?
<18> oui
<18> c'est delicieux
<19> :)
<18> i barely know any verbs
<19> nor do I
<16> je ne comprend pas
<18> lol
<19> been nearly 10 years since my french cl***
<18> yeah its been ~2 months since french 2
<18> llol
<16> heh, i quit french in 97
<18> i just dislike languages in general
<19> aw
<18> not computer science languages, though
<16> english ****s
<18> yeah essays ruined my life.
<18> can't wait to take Composition I in college.
<18> lol
<18> this should be fun :|
<18> let the hilarity ensue, of my particularly ****ty essays
<18> lol
<19> post them on the web, comments and all, and share the jollity
<15> amindenit.. mindenki franciazik? :)
<20> Theories come and go, data is forever.
<21> What about bing bang splash boom... big bangs & friends, I mean.
<20> what you say!? Someone set us up the singularity.
<22> hey all
<22> what about these them blackholes?
<20> and the recent finding that they may not exist?
<22> something about things comparable to wormholes in blackholes?
<22> well, no
<21> Let's hope they do process information instead of void it.
<22> over at http://antwrp.gsfc.nasa.gov/htmltest/gifcity/bh_pub_faq.html#universe
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