Spacetime geodesics (I).

Math, again, people!

A couple of posts ago I introduced myself to geodesics as free fall trajectories in curved spacetime. The problem with this description -one of them- is it's saying not enough. What I've learned since then about geodesics it's still not enough, but it's a step forward, so better than nothing.

This post was intended to solve geodesic equation for an easy case and show that spacetime nature depends on 4 coordinates -3 in space and 1 in time. The problem is the answer is not as straightforward as I expected. Let's see it anyway.

A geodesic is a curve. And like any curve, it can be described mathematically. General, index form is:

Leonard Susskind's GR lectures at Stanford.

I discovered Leonard Susskind because of the book "The black hole war". It was interesting and funny and the fact I was not able to grasp the last part of it -that holographic metaphore is disturbing-, didn't make me dislike it at all. I started to look at physicists more like human beings thanks to it. And that's saying a lot.

Before that, my only contact with physicists were close related hate-filled-relationships due to the fact engineering physics in Spain -the time I studied it, at least- were intended more to make an IQ selection than teaching actual interesting physics. I can blame no one for that. It's a consequence -one of the bad ones- of having a public university model. Good ones outnumbered bad ones, by the way. In the future, who knows.

 

Leonard Susskind a couple of years ago. From Stanford web.

What is happening at JSC?

Sorry for abandoning Math so soon. It is temporary, I promise. For the moment, I have to discuss another -possible- dead end. Which maybe it is not. I don't know yet. Media hype? Likely.

JSC stands for Johnson Space Center, which is one out of the 17 centers NASA has in the States.

I have heard some noise in the internet since September in sites like Gizmodo and Space.com about a JSC's scientist who claim feasibility of warping spacetime under certain specifications. Reliable science news, unfortunately, doesn't come from news sources, so I decided to wait a little before start looking for info.

Aerial view of JSC in 1989 -a long time ago, I know-. (Source: wikipedia)