The infinite vastness of space.

Musical accompaniment:

[video=youtube;XGK84Poeynk]http://www.youtube.com/watch?v=XGK84Poeynk&annotation_id=annotation_656108&feature=iv[/video]

When you really sit down and think about space and what it actually is, it starts to hurt your brain. Most of us just consider space to be our own solar system, maybe or own galaxy, but very few know space at a universal level. Infinite is so hard to visualize or ponder in your brain.

Discuss.

Well, I just read something about Voyager I recently. The thing has been going in a straight line for 30 years with basically nothing slowing it down, and it still hasn't gotten out of the solar system (which is apparently when the Sun stops acting on the probe with cosmic wind or some such thing). It's finally getting close to the edge - only 4-10 more years to go!

Also, it is (theoretically) possible to see light from the remnants of the Big Bang. It took billions of years for that light to reach earth, emitted long before anything approaching life lived on earth, and probably before the earth and Sun existed. Light travels at several million meters per second; a light-year is 10 trillion kilometers. It STILL took billions of years to get from the far side to here. And moreover, the universe is continually expanding; the distance is even longer now than it was then.

And almost all of it is completely empty. It's not called space for nothing.

Finiteness and infinity kind of don't mesh well. If it is truly boundless out there, however much one travels should not matter.
In our perception, getting from Earth to Mars was a success, and we were proud of it. But going from Zeno's paradoxes, we really haven't gotten anywhere.

 refresher

Consider: In order to travel x distance, one has to cover x/2 distance first. It branches into two here:

1/ In order to travel that x/2 distance, one has to cover x/4 distance first, so on and so forth. The conclusion is that one never actually starts moving at all.

2/ Supposing one somehow does manage to cover the x/2 distance, he then has to move from x/2 to x (the distance of which is x/2) and, again, cover half the distance before even thinking about reaching his goal. The conclusion is that one should never reach a destination.

While those paradoxes seem silly if you consider the "factual" observations (you can actually start moving and actually GET to some point in space), plug in the role of infinity and things start to look similar.
From Earth to Mars may be a big distance for us, but somewhere out there, it's tiny. How tiny? Tiny tiny. So the distance from us to that somewhere out there must be big? Yes, for now. Once we've conceptualized the distance, it, in turn, becomes arbitrarily small compared to some "infinity" out there.

Infinity is however big you can imagine plus 1. To conquer infinity with a finite method seems even more silly than Zeno himself. But of course, we can't just sit here and do nothing so people always try to get out there, but are we actually getting anywhere? We think we're walking, are we? We think we're looking far out into space, what with the Hubble and all those observatories, but are we?

Man, only reason I would wish for immortality is to be able to be present when humanity's perception of what space is changes. Just like back when people thought the Earth was flat, I'm pretty sure there are lots of surprises awaiting out there. But that's still so far away.

In a way, it's depressing. ;_;

One way of visualizing space as infinite is to imagine that it's curved in such a way that if you keep traveling along a trajectory, you'll end up in the same location after a certain distance. Kinda like being able to walk around the earth infinite times. A never ending journey.

This makes me think of this again.

 Spoiler

If we are supposedly an extremely rare occurrence of space then we could think there is a big possibility that we are alone, however grasping the concept that the universe is endless then the possibilities are endless as well, rendering infinite civilizations possible as well.

I wonder if humanity will ever achieve traveling to another planet and establishing a colony there.

One way of visualizing space as infinite is to imagine that it's curved in such a way that if you keep traveling along a trajectory, you'll end up in the same location after a certain distance. Kinda like being able to walk around the earth infinite times. A never ending journey.

Wouldn't that only work in a closed universe?

Wouldn't that only work in a closed universe?

I think that's what he's proposing. That it's not by definition limitless, just quirkily so.

Man, only reason I would wish for immortality is to be able to be present when humanity's perception of what space is changes. Just like back when people thought the Earth was flat, I'm pretty sure there are lots of surprises awaiting out there. But that's still so far away.

In a way, it's depressing. ;_;

It sure is depressing, but you can make a difference by helping future humans get to that point. I just hope that humans don't destroy themselves before they can travel the cosmos.

One way of visualizing space as infinite is to imagine that it's curved in such a way that if you keep traveling along a trajectory, you'll end up in the same location after a certain distance. Kinda like being able to walk around the earth infinite times. A never ending journey.

That could work by wrapping our three dimensional space around a fourth dimension, no?

< Doesn't know pomegranate about physics.

infinity is a concept. not necessarily a truth.

That could work by wrapping our three dimensional space around a fourth dimension, no?

No...

Wouldn't that only work in a closed universe?

It's somewhat paradoxical, but I really don't think that the universe has infinite matter. The only reason that the universe can be considered infinitely vast is that its true size is not truly known. However, even though the true size is unknown, people can still define an infinite volume to contain the universe. The infinite volume is what I'm going at.

It's like how radial coordinates wrap around origin infinitely many times, even though people often choose to stop drawing graphs at 2π.

But the term "infinite," used to define the universe, isn't talking about matter, it's talking about the empty space in which matter does not make up.

But the term "infinite," used to define the universe, isn't talking about matter, it's talking about the empty space in which matter does not make up.

theoretically it is both.