Baby Astronaut

That seems wrong. Earth shouldn't have been at 3/4 c as if it were also speeding past you, because of a simple flaw in that logic: as far as the Milky Way and the universe are concerned, the Earth hadn't moved any faster. It's only you who are moving at 3/4 c. The laws governing things don't care if your eyes seemed to view it the other way around. If you were speeding past a mountain, it would seem that it approached you and quickly passed, but to someone on the other side of the mountain, or to someone on the moon observing the mountain, the mountain's speed never changed. But yours did. And while acceleration is a factor in time change, it doesn't matter if you had sped up on Earth or in a galaxy far, far away -- approaching c will make your time go slower than others everywhere who are in a less speedy frame of reference. I've encountered your type of claim before on some media that explained relativity weirdness or some such, and partly based on what I know now, just don't buy into that particular aspect.

I don't believe that will happen. No proof, but just observation of observations (and of hypothesis) If it's true the universe had slowed down previously, and if Einstein's claim that space can expand, shrink, etc is true, I don't see how its expansion couldn't reverse in the future. It would be more logical that scientists do not claim an ultimatum of ever increasing space, but rather, they make a projection of what'll happen if (and only if) current trends persist. Aside from that, if dark energy were accelerating space, then isn't it feasible that after some point there wouldn't be enough dark energy to keep increasing the expansion, unless more dark energy were somehow created -- because the dark energy might be thinned out in the immensely expanded universe?

And here I'd have thought the photon would snap in half. They're so tiny, it's incredible to imagine a photon stretched as long as the universe. So when a photon is stretched very long, in order to see it directly with a powerful enough scope, will you be unable to see it when the photon's beginning length enters your eye, instead having to wait for its end length to catch up in order to see it? In other words, can our vision process the as of yet incomplete, first section of an overstretched photon, before the rest of it catches up? In regards to my original question, I didn't ask how long a photon can be stretched, but what's the reddest it can become. Is there a limit, for example, will the photon keep stretching but stop becoming more red after a certain point?

Is there a limit to the amount of redshift that light can experience before it stops redshifting any further? I'm asking separately for redshift caused by space expansion, and redshift caused by normal star movement.

Here are two problems I find with the folded paper analogy. If you did fold space, it would seem you'd also fold a good portion of its surrounding material, such as if you grabbed a point on a blanket and dragged it to another point -- large portions of the blanket will follow along. Even then, if you were to drag one point to another, you just traveled the distance anyway, so what's the point of going back and cutting through the paper (or blanket)?

I'm beginning to understand. Thanks for drawing the pics, big314mp. You even put a figure of me on them About the balloon universe, now that I'm looking at it in better perspective, a few things strike me as very odd. A. If light really does follow the surface, how can we ever tell it's curved? We'd be fooled into thinking the photons arrived from straight on. B. How do we know the light that greets us is on its first voyage around the balloon? It could be on its third or fourth trip around (perhaps the universe expanded slower back during those few earlier voyages). C. Where on the balloon are the oldest galaxies/stars in relation to our cosmic neighborhood? D. The shortcut distance through the balloon is still immense. I'll assume the wormhole travel is supposed to be instantaneous. If so, why cut "through"? Wouldn't it be just as quick to have the wormhole cut across, following the universe's curvature, if wormhole travel is in fact instantaneous?

Wow thanks for the insight, Martin. I hadn't realized their articles submissions were of previously existing articles (but often commercialized for SciAm). I'm reading your link now. OK read the link. I think much confusion from terminology would be avoided with a name change. For example, the Big Puff would be more self explanatory than Big Bang. And redspan would mark itself as being different than redshift. A doppler effect would mean the light is redshifted by the source's movement away from the viewer, where a cosmological expansion would mean the light is redspanned, or stretched, along the way by the increasingly expanding space between the source and the viewer. Now I have some questions from reading the article. 1. How can light lose energy from being stretched by space expansion? It would seem the space is sucking up the energy somehow. 2a. If the universe were like a balloon, can't we just take a shortcut through the balloon to reach the other side? The diameter would be shorter distance than the circumference. 2b. Are there any galaxies/stars in between the the opposite sides of the "balloon" universe? I'd think so, if it were like a raisin muffin expanding. 3. If all of space is bathed in the radiation from the cool afterglow of creation, why hasn't that afterglow instantly dispersed long ago? If the universe is really self-contained, I'd imagine that the (microwave background) radiation simply can't escape. 4. If space is really self-contained, and you'll appear at your starting point if you traveled in a straight line, isn't this compatible with how the illusion of a ship rising on the ocean horizon is used to explain the Earth's curvature? If you could observe a spaceship far away on the universe's balloon shape, wouldn't you see the craft "rising" out of empty space? 5. When they say that distant galaxies are moving away from us at over the speed of light, and vice versa, don't they really mean half that speed? For example, the combined speeds of expansion between us and them add up to the speed faster than light. More precisely, the speed at which expansion moves us away, plus the speed at which expansion moves them away, equals the higher speed.

What if enough dark matter was concentrated in an area, becoming ever large, will it collapse into a black hole? And if so, wouldn't it just become a normal black hole that couldn't be traced back to its dark matter origins? Can dark matter from into bodies like stars/planets do? Such bodies might emit dark energy.

Here is how I understood FayeKane's post. Gravity isn't really a tug by objects themselves in space, but a tug caused by their movement through time away from us. Perhaps like a "time wind" created by the more dense objects that drags along less dense objects towards them as they move through time, rather than space. Except the objects aren't moving away from us, it's their past existence that is moving away. Thus an object's existence a nano second ago will tug on objects existing in this nanosecond. And the time landscape is comparable to space, where one can measure it in inches or centimeters, to approximate how near you are to an object in time distance (rather than space distance). Of course I might be totally off. Regardless, I like the basis of your idea, FayeKane. Did I get close?

What I don't understand is how space is *something* when it is nothingness? If you took away all the energy, and you were the only thing (on a ship) moving in that void, wouldn't you be able to travel anywhere in that nothingness? I know every point would be identical in comparison, but still, wouldn't you be moving through "space"? And because you would be moving, time would also exist.

What if my question is applied to relativistic mass?

*bump*

That's the intro key concepts from a Scientific American article titled The End of Cosmology? The article goes on to explain that most of the universe will disappear from view, and asks "what has the universe already erased?" Surely many here are familiar with this, but I'd like to hear your thoughts on it.

Let's continue to imagine (as per Aterna's suggestion), for the sake of getting the question answered. Imagine that the universe froze in motion, allowing you to reach your destination if you had infinite time and were immortal. Or even that only the universe's expansion stopped (with no dire or perceptible consequences). What of Aterna's question then?

Not really sure what you mean. If you can elaborate please (but keep it in layman terms)?

Thanks for the link Klaynos. So, there's a dispute of whether the theory works for rest mass or relativistic mass? Here's what I understood: rest mass is easier to determine because, unless I'm mistaken, the energy of relativistic mass adds the energy of the whole system it's in. But we exist in a subsystem of a subsystem of a subsystem, etc. If that's correct, don't we have part of the speed needed for reaching light speed already supplied to us by the speed of our cosmic surroundings? Which, if objects truly weigh more the faster they move, we'd probably be able to move easier if our surrounding cosms would just slow it down a bit OK, back to earth. Is it really a virtual mass gain, and if so, is it by density? Or does the mass remain with both its original density and size, and only increases its weight?

Does that mean it's only a virtual increase of mass, like saying in order to go faster, the object would need that much more energy as if it really had the extra mass?

That cleared it up quite a bit, Pete. Thanks. I'm amazed. Does going in a circle really prevent a doppler effect? It makes sense now thinking about it, but I didn't know that before. One last thing. If the person in the stationary frame were to speak, I'd guess that the person in the moving frame (the one going in a circle) would hear a very fast voice, because the stationary person would actually be speaking faster. Am I correct? I really like your explanation. P.S. I realize I messed up the physics in my "re-engineered" question. The fast/slow should've been in reverse order.

I feel the need to start over. I'm not even certain if swansont's reply addresses each person (ie, both conversers), or just the recipeint on Earth. Plus, aren't the red-shifted signals like a doppler type effect? If so, we've definitely veered off-course from what I seek to know. So, let's completely disregard what came before. I'm not interested in phone signals, distances, or travelling away/to. Below, I've re-engineered my original question from the ground up. It's how I should've asked it the first time around. That quote above is ultimately want I seek the answer to. And while it might seem its answer is obvious, I just like to double check.

No hostility provoked Kyrisch. Heck, you might've just been trying to deter the possible spread of a misperception. I probably should have elaborated on my reason for asking the original question. See, if time passes differently for person #1 on Earth than for Person #2 on the spacecraft, it'd be cool to perceive that difference in real time. I'm not sure if anyone understood the scenario I aimed for. That is, if both parties can detect, in real time, the slowing or quickening of time for the other party (time passage isn't equal because of their great difference in speed). So one person might sound like a vinyl record being slowed, while the other sounds like a sped-up vinyl record (due to experiencing time faster). P.S. If not in real time, some viable method then. Did you mean to say that?

When an object travels at nearly the speed of light, it gains mass. My question is, how does its mass gain look to an observer? Let's say the object is a spacecraft leaving the galaxy, and you're here on Earth. If you had observed the people inside the spacecraft (from its departure until it eventually attained the near-light speed), would you have witnessed each person growing in size? Would the travellers have noticed their own growth while it happened? And if they continued on the way to gaining near-infinite mass, does that mean you'd eventually see their physical bodies and spacecraft expanding into our solar system (from their other end which is still in a distant galaxy), due to the cosmic mass gain? Or does the mass gain cause an increase of density rather than size? Or does it cause both? Or would they transform into a star first and then a black hole after a certain point of mass gain?

OK, would anyone mind answering the question if re-edited without the offending "P.S."?

Would you say that to whoever made the following scenario? If an observer watches a person on a train going near the speed of light.... Using wormholes, string theory...it's a possibility. Yet I'm only asking the same level of "let's pretend" as the scenario above. The instantaneous phone exists only to avoid comments like "it's a moot point since the signal couldn't reach a spacecraft travelling near the speed of light". A more valid answer would be "I don't know"

Can you explain how please? The two conversers would experience time differently. Will that reveal itself as a difference of pace in their conversation? The phone signal isn't the point at all (the reason for my P.S.)

If you were on earth, making a phone call to someone on a spaceship that's travelling near the speed of light, how would the speed of each converser's voice sound? a. Quicker. b. Slow as molasses. This is assuming the phone conversation were transported instantly via wormholes to each other?