The LIGO experiment may have detected gravitational waves- more information Thursday!
65 replies, posted
[QUOTE=Zenreon117;49715630]I did some hand waving, sue me. Artistotle held that things wish to tend towards their natural resting state which, for most things, was generally down. He had other concepts which are irrelevant to what I am saying. Downwards can have a meaning insofar as it is that which describes the change in this model.[/QUOTE]
Aristotle advanced human knowledge in many ways; physics was not one of them.
[QUOTE=JohnnyMo1;49713147]Pretty much just confirming an important prediction of general relativity. Direct detection of gravitational waves is extremely difficult because they're normally extremely weak and your experiment needs to be very tightly controlled. Actually we already had indirect confirmation of gravitational waves which was awarded a Nobel Prize. Google "Hulse-Taylor binary." I bet there will be a Nobel for this as well.
There would be big trouble if gravitational wave were never detected. They're predicted by general relativity, and afaik theories with gravitons would have serious trouble without gravitational waves.[/QUOTE]
I thank the facepunch lords for your domain specific knowledge.
[QUOTE=JohnnyMo1;49715698]Not really though. In fact, an awful lot of physicists (myself included) hate the "rubber sheet" demonstration/analogy because, while it provides a decent visual, it causes way too many conceptual issues. What is the space curving into? So gravity pulls things "down" everywhere in some extra dimension because space is curved downward in that direction? No, it's just a poor demonstration that breaks horribly when you try to push the analogy too far.[/QUOTE]
Ok fine it's a 3 dimensional tablecloth.
You know, the kind you'd use for a 4 dimensional table.
I just wanted to make a shit joke and the tablecloth is the only model to visualize gravitational waves that I know of. Most people that would have the capacity to understand the physics are probably able to understand what the demonstration is attempting show.
[QUOTE=spiritlol;49716077]Ok fine it's a 3 dimensional tablecloth.
You know, the kind you'd use for a 4 dimensional table.
I just wanted to make a shit joke and the tablecloth is the only model to visualize gravitational waves that I know of. Most people that would have the capacity to understand the physics are probably able to understand what the demonstration is attempting show.[/QUOTE]
I wasn't trying to criticize you for posting it, just point out to Zenreon that you can't push the model too far. It's far from a perfect analogy.
Ya I know I didn't meant to come off as aggressive. I just can't honestly think of any other way I've ever seen them portrayed. Even if it's not a sheet then its a plane with a displacement, which is essentially the same visualization.
Which makes it more irritating. It's like the common visual models of atoms. It works on a tiny surface level for the most rudimentary understanding of concepts, but it falls apart quickly. It'd be best to ditch it and just go with the correct model.
[QUOTE=spiritlol;49716077]Ok fine it's a 3 dimensional tablecloth.
You know, the kind you'd use for a 4 dimensional table.
[/QUOTE]
I hate those things, they're impossible to fold
[IMG]https://dl.dropboxusercontent.com/u/12024286/3d%20tablecloth.png[/IMG]
[sp]Yes I realize I fucked up the legs but by the time I noticed I had already merged layers and it was too late[/sp]
Just announced, they detected gravitational waves!
Livestream:
[url]https://www.youtube.com/watch?v=c7293kAiPZw#t=1156.348[/url]
I wish they'd play the unshifted sound, especially since it's actually in range of human hearing.
[editline]12th February 2016[/editline]
CERN is doing a more technical webcast as well, for the more scientifically-inclined:
[url]https://webcast.web.cern.ch/webcast/embed.php?event=496299[/url]
Biggest discovery in a hundred years? Secret of the universe? Science history happening right now? No idea how to feel about this, just sat in front of the TV dumbfounded
edit: Science-illiterate pageking
[highlight](User was banned for this post (""pageking" shitpost" - Orkel))[/highlight]
[QUOTE=JohnnyMo1;49715698]Not really though. In fact, an awful lot of physicists (myself included) hate the "rubber sheet" demonstration/analogy because, while it provides a decent visual, it causes way too many conceptual issues. What is the space curving into? So gravity pulls things "down" everywhere in some extra dimension because space is curved downward in that direction? No, it's just a poor demonstration that breaks horribly when you try to push the analogy too far.[/QUOTE]
don't think of it as literally downwards, rather think of "down" as representative of inwards
[QUOTE=Ninja Gnome;49721488]don't think of it as literally downwards, rather think of "down" as representative of inwards[/QUOTE]
So then you're thinking of vectors pointing toward a mass in flat space and you're back to Newtonian gravity, having shed basically the only useful feature of the demonstration.
So i missed the livestreams, any new info?
[QUOTE=JohnnyMo1;49721753]So then you're thinking of vectors pointing toward a mass in flat space and you're back to Newtonian gravity, having shed basically the only useful feature of the demonstration.[/QUOTE]
This pretty much always pissed me off with the curving spacetime/pushing down spacetime metaphor.
You're explaining gravity, by saying heavy objects deform some kind of 'sheet', and then things move towards it based on gravity.
So you explained gravity using gravity as your metaphor, which makes no fucking sense
[QUOTE=The Rizzler;49720433]Biggest discovery in a hundred years? Secret of the universe? Science history happening right now? No idea how to feel about this, just sat in front of the TV dumbfounded
edit: Science-illiterate pageking
[highlight](User was banned for this post (""pageking" shitpost" - Orkel))[/highlight][/QUOTE]
There are many big discoveries that have happened within 100 years. Especially nuclear weaponry and power, that's a big discovery.
[QUOTE=Empty_Shadow;49724640]This pretty much always pissed me off with the curving spacetime/pushing down spacetime metaphor.
You're explaining gravity, by saying heavy objects deform some kind of 'sheet', and then things move towards it based on gravity.
So you explained gravity using gravity as your metaphor, which makes no fucking sense[/QUOTE]
Setting aside the 'how' of the metaphor for a moment, and not worrying too much about how it 'results' in gravity the analogy does give a good idea about how to think about some of the features of curved space. For example...
In the rubber sheet analogy we'd travel 'across' the sheet if we were to move through space, and if you somehow took a trundle wheel or some equivalent measuring device and measured the distance through space to the centre of the sun from the Earth (i.e. you measured what you'd naturally consider to be the 'radius' of the Earth's orbit) and multipied it by 2 pi you'd find... the answer [B]wouldn't[/B] be the circumference of the Earth's orbit. The circle you'd calculate from the radius you measured would have a circumference [I]larger[/I] than the Earth's orbit, but... wait, what?
This is because the spacetime is 'curved' in the radial direction. That is to say the 'radius' which you measured with your trundle wheel, or whatever device you used, i.e. the path [I]across[/I] the rubber sheet to the centre is obviously longer than the length you'd measure if you stuck a tall post vertically into the centre of the depressed, rubber sheet and then measured the distance between the edge of the sheet and the post (or if you simply laid a measuring stick over the sheet from edge to edge and halved the value for the radius).
Of course, in the rubber sheet analogy it is implicit that we're some kind of 2-dimensional being travelling across this two dimensional sheet; a flatlander as it were. We'd have no intuitive, natural concept of the extra, third dimension that the fabric was bending 'into' if this were actually the case, though, so we wouldn't be able to just merely tack a 3-dimensional post (such structures would be meaningless in our universe) into the sheet and measure the distance between it and the edge. But being that we DO live in a 3-dimensional universe we can picture such things (at least for an equivalent 2-dimensional scenario) and we can use this to get some more understanding for what's happening.
The case we find ourselves with is merely an extra dimension higher; a four dimensional being would have no problem understanding the 'rubber volume' analogy as they'd be able to see a 3-dimensional volume being warped into a fourth dimension which is inaccessible to the beings within the volume.
[QUOTE=JohnnyMo1;49713147]Pretty much just confirming an important prediction of general relativity. Direct detection of gravitational waves is extremely difficult because they're normally extremely weak and your experiment needs to be very tightly controlled. Actually we already had indirect confirmation of gravitational waves which was awarded a Nobel Prize. Google "Hulse-Taylor binary." I bet there will be a Nobel for this as well.
There would be big trouble if gravitational wave were never detected. They're predicted by general relativity, and afaik theories with gravitons would have serious trouble without gravitational waves.[/QUOTE]
Quick question, do you actually get a notification when someone posts that thing?
[QUOTE=viperfan7;49724842]Quick question, do you actually get a notification when someone posts that thing?[/QUOTE]
your username is highlighted if someone says it in the [URL="https://facepunch.com/fp_ticker.php"]ticker[/URL] and the emote code is his username
[QUOTE=Empty_Shadow;49724640]This pretty much always pissed me off with the curving spacetime/pushing down spacetime metaphor.
You're explaining gravity, by saying heavy objects deform some kind of 'sheet', and then things move towards it based on gravity.
So you explained gravity using gravity as your metaphor, which makes no fucking sense[/QUOTE]
i thought it wasn't meant to explain how gravity works, rather demonstrate gravity's effect on objects, like orbiting, greater mass having greater gravity, and how gravity diminishes with distance
[QUOTE=Ninja Gnome;49724915]i thought it wasn't meant to explain how gravity works, rather demonstrate gravity's effect on objects, like orbiting, greater mass having greater gravity, and how gravity diminishes with distance[/QUOTE]
Typically it's used as a model of curved space and GR, but all those features are present in Newtonian gravity.
[QUOTE=viperfan7;49724842]Quick question, do you actually get a notification when someone posts that thing?[/QUOTE]
What this guy said:
[QUOTE=salty peanut v2;49724847]your username is highlighted if someone says it in the [URL="https://facepunch.com/fp_ticker.php"]ticker[/URL] and the emote code is his username[/QUOTE]
[QUOTE=Dwarden;49714552]inb4 'surfing on gravitation waves' ;)
[highlight](User was banned for this post ("Meme reply" - Craptasket))[/highlight][/QUOTE]
guess my post was too short and someone failed to understand it' not meme
but factual short hint on propulsion method based off gravitation waves
(those days there such propulsion system is openly discussed as next to EM ones)
something to read on the subject
[URL]http://arxiv.org/ftp/physics/papers/0410/0410022.pdf[/URL]
[URL]http://www.gravwave.com/docs/DirectionsForGWPropGraWaV.pdf[/URL]
[URL]http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19800010907.pdf[/URL]
[URL]https://fas.org/irp/agency/dod/jason/gravwaves.pdf[/URL]
[URL]http://arc.aiaa.org/doi/abs/10.2514/6.2001-3913[/URL]
one can find even patents filled with GW propulsion [URL]http://www.google.com/patents/US20070001541[/URL]
(quite interesting part of the patent is section discussing prior art and examples who/when)
note: even popular warp (Alcubierre drive) space-time is manipulated in way that
a positive gravity well generates in front of a spacecraft, while a negative gravity pushing force is behind it.
The spacecraft rides such “gravity wave,” accordingly to the laws of Einstein’s General Theory of Relativity,
the spacecraft essentially stands still yet the universe moves around it, theoretically at speeds faster than the speed of light.
recent LIGO discovery thus confirms and push us toward chance that one (or all) of such concepts and theories may become reality
Not quite, for Alcubierre drives still break causality which is one of the core theories that has not shown signs of breaking. Not to mention energy requirements, and the whole "sterilize the fuck out of a system" - effect when you drop out of the bubble.
Alcubierre drives are a fun thought experiment at best.
[QUOTE=Dwarden;49725472]guess my post was too short and someone failed to understand it' not meme [/QUOTE]
"inb4" is a bannable meme.
[QUOTE=Headhumpy;49727059]"inb4" is a bannable meme.[/QUOTE]
guess I'm too old to know all the 'new meme' thing
cause ib4 was way to save typing in before on chat-intensive services in times of BBS, Telnet and IRC:)
[QUOTE=Falkok15;49724707]There are many big discoveries that have happened within 100 years. Especially nuclear weaponry and power, that's a big discovery.[/QUOTE]
Yeah, true. The media sure was hyping it up though, turning on the TV and you see "SECRET OF THE UNIVERSE" you're probably sticking around
I think the media's hyperbole compensates for how scientists often understate their discoveries, haha. "We found gravity waves." (moderate applause)
You do start thinking though. You live your life accepting certain laws, until one day your worldview gets adjusted ever so slightly (or validated further, rather). It might seem like we've found all the most important discoveries, but make no mistake we're still creeping forward. Maybe that's just me not being involved that much in the world of science though :v:
[QUOTE=Dwarden;49727430]guess I'm too old to know all the 'new meme' thing
cause ib4 was way to save typing in before on chat-intensive services in times of BBS, Telnet and IRC:)[/QUOTE]
'inb4' nowadays most commonly precedes a completely pointless predictive comment, it's as annoying to read as greentext imo (which also originated from old chat services), should just talk like normal people
I didn't know pageking was bannable though :( not contesting the ban at all, but it isn't mentioned in the rules. Maybe I just made a genuinely crap post haha
Do these waves follow the wave equation or are they governed by different equations?
[QUOTE=themooselord;49727931]Do these waves follow the wave equation or are they governed by different equations?[/QUOTE]
Yep, they're governed by a form of the wave equation. The "mathematics" section of the gravitational wave wiki article talks about this briefly.
Does this mean we're a tiny bit closer to understanding how the fuck gravity works?
[QUOTE=Buck.;49713794]I mean it took nearly 100 years to confirm the theory and finally detect them, gravitational waves sound hard to work with. It feels futile. Or is it now just a matter of observing and collecting enough data that we could start seeing patterns that lead to even further discoveries?[/QUOTE]
Ya its more of a case our instruments finally got big enough and flashy enough to detect this stuff over the noise, previous detectors (and iterations of this one) have just not been able to be precise enough for us to say for certain that we are looking at something. The proposed European mission in a few years planned to put up a detector thousands of kilometers appart through the use of satellite clusters, confirming this now will greatly improve the chances of that mission working
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