Piqued #2: A Crash Course In Spacetime
What the hell is spacetime?
It's everywhere
I started to write about the theoretical methods which might bring your great great great grandkids to the stars , when I realized I was getting ahead of myself. Before you can really understand what a worm hole is, or what a contracting/expanding bubble of space-time is, we needed to have a conversation about spacetime.
We all exist in Spacetime. You can't see spacetime directly, but it surrounds you, like The Force sort of, and it physically affects you every second.
This guy came up with the idea.
Edit: Not exactly. The fact is there were several scientists whose work all culminated in the current conception of spacetime. Einstein's special relativity was centrally important. But it was based in part on the prior work of Lorentz and Poincare. The spacial, geometric explanation of spacetime was actually formulated in 1908, building upon special relativity, by Hermann Minkowski. And, indeed, spacetime as we are referring to it here is known as "Minkowski Spacetime."
(Thank you @lemouth for pointing out the innacuracy! For real - if you see something wrong, or even near wrong, in my posts, let me know!)
Before this scientists considered the universe in two parts - one part was the 3 dimensional, physical part called Space. The other part was this thing that drags us all kicking and screaming to the grave, called Time.
After doing a lot of math I will never understand, a radical conclusion emerged:
Space and Time were not distinct but one cohesive four dimensional system called Spacetime
What does that mean?
Consider this slightly clearer picture.
The simplest way to conceptualize spacetime, for those of us who are not mathematically inclined, is as a flat mesh everything sits on top of. We don't really sit on it - we are actually immersed in it and constantly interact with it - but the "sitting" image is much easier to digest.
So, we're all sitting on this mesh called spacetime. Like the planet in the above picture, we all make dents in the mesh. The more mass something has - the heavier a thing is - the larger the dent.
So you or I make tiny tiny dents. But something big, like the Earth, makes a big dent, and the sun makes an even bigger dent.
This is also a simple way of visualizing gravity. Why do you and I not fly off the earth into space? Because we are so small that we have rolled into the big dent the earth makes in spacetime.
It also explains why the earth continues to circle the sun - the earth is rolling around the even larger dent the sun has made in space time.
For a much more in depth and really great explanation, you should watch this awesome video produced by PBS
Needless to say my explanation is all totally, bordering on deceptively, simplified. Spacetime is a mathematically profound concept which results in lots of strange effects - effects like time dilation, and the potential to warp or fold spacetime without breaking the laws of physics. But, for our purposes, broad strokes, this is the take away.
TLDR Spacetime is like a big mesh or sheet that everything in the universe sits on. The heavier the object, the more it dents or sinks into the mesh. These dents are a simple way to visualize gravity.
Now that we have that super basic understanding in place, we can talk about how humanity could theoretically use the nature of spacetime to move across the stars faster than the laws of physics would otherwise allow.
Next time on Piqued - Worm Holes and Warp Speed.
Image sources 1, 2, 3
Other source 4
I have a comment this time :)
It is slightly misleading to link the notion of spacetime to Einstein only. The work of others of that era, including Minkowski, Lorentz and Poincare to cite three of them, is as important. After all, we are talking about Minkowski's spacetime, Lorentz transformations and Poincare transformations.
To emphasize a little bit, spacetime itself is different from the theory of special relativity, and the latter is Einstein's. Special relativity says that there is a maximal speed and that the laws of physics are identical in inertial reference frames. No spacetime in there :)
The reason why we are calling spacetime Minkowski's spacetime (and not Einstein's spacetime) is that it is Minkowski who presented special relativity in a geometrical manner (thus within spacetime).
Note that I am not saying that what you wrote was wrong, but it is IMO slightly misleading and confused. :)
You are absolutely correct - and I am going to edit it to better clarify.
And please continue to comment on future mistakes, errors and misinterpretations. Part of my aim is to oversimplify for the sake of a broader understanding - but the truth is my own knowledge can be too shallow. It's one thing to simplify something complicated and another entirely to misrepresent due to ignorance. To the extent i approach or accidentally engage in the latter I apologize now and in the future, but will always try to avoid it and fix it when it does.
You don't have to apologize! We are all humans after all. Your positive reaction to my comment is making me happy :)
I am a firm believer that ignorance is an acceptable flaw if you have a willingness to admit your wrong and rectify your ignorance! I've corrected the article to include Lorentz and specifically Minkowskis post special relativity work. Thank you again!
As well as Poincare - this is what happens when you are editing from inside a bar :))
:)
@lemouth - I have a new post which continues this discussion. I wanted to jump to warp engines an wormholes - but as I wrote that I realized I needed to talk about the speed limit first. I would love your opinion given your expertise! https://steemit.com/science/@dber/piqued-3-a-crash-course-towards-the-speed-of-light
Thanks for the pointer to your post! I will try to find some time today or tomorrow and let you know!
Thank you! Regardless of whethrr you upvote it your opinion really does matter to me - no point in my being entertaining if I'm not right!
Amazing article. I hope to learn some more from you. I EXPECT to hear more. Keep it up @dber
Thank you nicnas! I intend on writing a lot more.