The speed of gravity

The internet is full of cats and porn. No breaking news, here. There are a lot of other places with interesting information, though. One of them is the askscience of reddit. If you follow the link, you'll find this one too.

The question stated is: if gravity is transferred at $c$ (speed of light), and Sun is 8 minutes away at $c$, regarding the fact the Sun moves, does it mean Earth is attracted to the position the Sun had 8 minutes ago?

Video is from a guy named DjSadhu. Music is cool, if you ask me.

Spacetime as a consequence of something else: ER=EPR.

There's so much I don't know about GR that talking about interpretations and physics trends is a dangerous matter, specially if my words are intended to be, you know, taken seriously. That's the reason I try to focus in learning instead of trying to develop things on my own. And I don't always succeed anyway, so look at that.

Nevertheless sometimes comes the time when you find something interesting and you have to share it and... Well, hell, this is my blog, right?

I have found recently the ER=EPR conjecture and I have tried to learn a bit about it. Shall we talk about it a little? I'll go on with Schwarzschild metric inside the Earth a little bit later. :)

Maxima ctensor overview

I have installed Maxima (finally) and I have been playing with it a little. First part of the post is about a general explanation about what Maxima's ctensor can and can't do. Second and third part will try to explain functionality with a couple of easy examples. I have not tried neither itensor nor atensor; as I stated in the past post, their functionality is not what I need for now.
So far, and summarizing, I must admit Maxima falls short for my intentions. Truth is it's a good tool anyway and it should be easy to adapt to what I want when I had the time to go for it.