Dark Matter part2

PBS nova series

Category:

Education

Tags:

• nova
• pbs
• dark
• matter
• science
• physics
• star
• space
• mass
• light
• atom
• molicule
• astronomy

[Tripside007]

@cluebcke You can't acurately represent the real effect, even if the objects were represented in 2D, although I do see your point, but this way is just easier for us to picture it. In reality the warp is happening all around the object.

[Tripside007]

@cluebcke Actually what they're suggesting is that the gravitational pull is happening because of both simultaneously, since normal matter alone doesn't justify for all the gavitational pull generated, because it doesn't weight enough on it's own.

[cluebcke]

@gratefulDeadHead1234 The other issue with this common type of animation is that it implicitly includes some external force of gravity, pulling heavy things down--but in reality gravity, and the curvature it creates, is coming from the bodies themselves. I don't know how you avoid that with this type of visualization, but it's important to keep an eye on where this kinds of visual metaphors break down.

[cluebcke]

@gratefulDeadHead1234 So what we're doing when we show space as a grid is flattening 3-dimensional space (width+length+height) down to 2 dimensions (width+length), in order to show the curvature of 4-dimensional space-time in 3 dimensions (by warping the grid). But if we remove a dimension from our representation of space, we have to remove the same dimension from our depiction of things contained within space, like stars and planets. I hope that makes some kind of sense.

[gratefulDeadHead1234]

@cluebcke why?

[cluebcke]

Sigh. Same misguided animation of 3D suns and earths rolling around on a rubber grid. For that analogy to work, the sun and Earth need to be 2D circles on the surface of the grid that is distorted in three dimensions.