Baby Astronaut

It's said that the universe is expanding at such an increasing rate that its outermost areas will pass a cosmological "event horizon" that is beyond our reach. Afterwards, evidence of that part of the universe will vanish forever. Not true. I may have no evidence to present, but all you really need to do is extrapolate on a basic theory to know it might become possible to see any part of the universe beyond that supposed event horizon. Wormholes are the key -- if they exist. If they don't, other ways are sure to pop up. Such means of travel don't care if a spot in universe is not reachable by conventional means. Unless, of course, I'm wrong. Thus my reason for posting: your counter-remarks or agreements.

Does your clock example work like shown in the image? The light moving forward would make the "tick" sound, and the light moving away at their back would make the "tock" sound. "A" is holding the clock sideways. Is that what your example was meant to show? If so, it the relativity of space just seems like a way to ease a math problem, rather than actual differences as with time being relative. I mean, when two people travel at far different speeds, they are really experiencing the difference, and not even perceiving it. Thus "relativity" with space doesn't seem to be the same concept as relativity of time. Because in your example, the people are aware of the differences, but those seem virtual, not real.

Same conclusion. North of it is the stars, galaxies, etc

When answering questions of how can space never end, a typical answer-in-question-form is "what is above the North Pole?" or "if the universe were a room, what is beyond the walls?" and then in self answer "-nothing". I see a flaw in those analogies. Obviously, above the North Pole is atmosphere, space, planets, dust, stars. And beyond the room's walls are other rooms with more walls or the great outdoors. Doesn't it seem like when a caveman might say nothing exists beyond the horizon? No offense to anyone, just what it comes across as. Anyone else feel that way?

Can you explain this a bit more clear? The idea of relative space is totally foreign to me, never heard of it. Also, I'm not familiar with many physics terms. I understand different speed frames measuring different time rates. Isn't there a simple equivalent for teaching relative space? For example, I don't know what Cartesian means in that sense, nor what you mean by "Length isn't an absolute".

Can someone explain how space is relative in the same visual manner as the explanation above for how time is relative? I don't understand "Length contraction at relativistic speeds."

Really? How is space relative?

Does this mean that potential energy is dependent on gravity? Because with a higher gravity, the rock would crash harder into the ground below. And with a lower gravity, less impact = less energy.

Here is an image showing Mt Everest and a Venus mountain compared to Olympus Mons on Mars. However, I've always thought that if Mars once had water, then a great part of Olympus Mons would've been underwater. So it's kind of "cheating" to declare it the tallest mountain among our sun's planets. Here is an image of Earth's Mauna Kea, in case you think the seafloor part of a mountain is used in the measurements. If that were the case, then Mauna Kea would be higher than Mt Everest. So my question is, does anyone know the deal with Olympus Mons? When they measured it, was a pre-existing Martian ocean given consideration? Or does that matter after the ocean is dry? For example, if Earth dried up, would scientists declare as the new tallest land mountain?

I see what you're saying, MrGamma. A few of the small jagged points look alike (especially the right-most arrow on each image), and the layouts are highly similar to one another, like when people first noticed the Americas would fit neatly at Europe and western Africa. If all you're saying is that yes, water has eroded the surface rock, but the widening has been mostly the work of tectonic activity (giving credit to both) -- then I believe you're onto something.

Thank you Bignose, great explanation! I finally understand (and realize that for the most part I did understand this before, just didn't know it's the definition for conservation of energy).

Might I pipe in to ask if someone can explain in layman terms what does conservation of energy mean? (like if you were to explain it to a non-scientific average person, for example ) Thanks.

I think I'm seeing the problem here. 1. The scientists considered the eyeballed test as proof, which goes against the standards of rigid testing. 2. Even if the objects measured as reaching the ground at the same time, how do we know the same would hold true in a finer measurement than currently possible? For example, if the best equipment can only measure at x3 resolution, then what if the objects indeed would hit differently at x10, but we just don't know it yet? I can even add, what counts as hitting at the same time? The bottom-most atom of each object? Or maybe its bottom-most electron (or quantum particle)? Let's begin with #1. No problem here. Scientists had already made the calculations, and the eyeball test was just a simple display for lots of non-scientists to see. However, no real scientist would accept a test done without precise measurements as fact, regardless of how convincing it looked. The eyeball test was likely just eye candy for enthusiasts. As for #2, it goes back to what Mr Skeptic mentioned about uncountably infinite possibilities. Science needs to be centered around things which have a basis in existing science, and avoid chasing every infinite possibility, unless there is strong indication within an unproven area that further examination of it might hit gold. The rules for science exist for good reasons. There are plenty of scientists that might have a genius idea but are unable to find data that supports their intuition. They probably feel bummed about not being able to convince others to explore the idea, but might dedicate a portion of their lives seeking a calculation or math formula indicating they're "getting warmer" and hopefully get the attention of more scientists. Yet their idea can lost in the shuffle, even if it would've led to a scientific breakthrough, if only they had stumbled upon a good formula to describe it. At first glance it might seem a loss for science, its potential to lose discoveries of great significance that don't get accepted for reasons of insufficient data at the time. But we have philosophy for that, and it might cover your needs of being heard and given credibility. Science doesn't offer that, and science isn't here to babysit unproven assumptions just in case they might really be true. Scientists can and will listen to your ideas, but in respect to science discipline, they'll likely not accept the idea as science if it diverts heavily from the known without proof. Unless of course they work in the cabinet of the prez. I'm sure they'll accept your idea for a bit of $$ I can't speak for anyone here, or for scientists in general, as those are just my ideas of how the science disciplines work. But I don't think I'm too far off.

I'm still trying to digest your answer. But in the meantime, here's another curious thought. Your images are the type used to illustrate the gravity well by the coin rolling in the funnel you dropped a coin into. They claim gravity works similarly. However, the coin would have to approach the funnel just right in order to avoid simply dropping right in immediately. And the coin doesn't remain at the same level each revolution -- it draws closer and closer. So this presents some issues. 1. The dimple in space would have to be subtly widespread at the top, and over an enormous distance. That way, no matter how the coin approached, it would get a chance to slightly adjust its course to the slight decline leading to the center far away. Sometimes the coin approaches dead-on, and thus crashes into the hole much as space debris hits earth instead of being caught in its orbit. 2. The slingshot effect makes less sense, because a spacecraft would enter the dip, catch some acceleration, but then should lose that acceleration because in order to leave the dip, it would have to climb the same level of dip. 3. The dip means that whatever object caused it has displaced an amount of space. Maybe the space around the dip is now more compact, squeezed together. It's only logical since it has to go someplace. I'm not certain if that's what is referred to as "warping" of space, but if so, it would not be too far-fetched to imagine that space's properties would be affected somehow. For example, water being squeezed under pressure has a different freezing temperature. So maybe warped space has its differences too.

As a curious thought, if gravity is really caused by an object causing a dimple in space, then wouldn't the act of lesser mass objects falling into that dimple be in itself gravity in action? Do you see what I mean? Object falls in a hole = gravity. Smaller object falls into dimple around larger object = gravity. So basically, aren't we using gravity to explain gravity?

Actually, it's more like asking what if a 50-story wide volcanic fireball fell into a drop of water?

What about the moon? It's moving away slowly. The sun couldn't turn to rock because fusion prevents it due to its mass. Actually, the math already exists. There is gravity' pull, the approximate force exerted by the wind, the leaf's weight and the strength of its connection to the tree. The math tells you the leaf stands a minor chance to be ripped from the tree, and if that happens, the leaf will almost definitely be tossed around violently. But asking for math to determine the leaf's path of motion would be like someone asking you for math that determines precisely when the sun will spit out its next blob/planet. So hopefully you see it's not the same thing. We only ask to show us the mechanisms that allows what you claim. If you are unable, then it's a good idea to inform us that what you claim is just that -- an idea -- not a dismissal of current scientific measurements, tests, and consensus. You can state a belief that your hypothesis will eventually break new ground and prove other things wrong, but let others know it's a hunch rather than a claim of real science. And I don't mean "real science" in a patronizing way. Science is about real calculations of observable mechanics, and includes projections based on what the math suggests. Even when projections are based on observation alone, scientists run it through existing math and calculations to see how it fits with known models, and even if it does fit, they publish it so that other scientists can attempt to find holes in it, and even if they draw enough credibility, they still test it in labs, and even if the tests look good, they publish the entire testing procedure and publish their findings so that other scientists can reproduce the experiments and double-check the tests. In my view, that's what real science is. To claim things like in a Star Trek movie or throw predictions/observations around is not science, it's merely speculation -- which in itself isn't bad, it's just a different thing altogether.

(Mmmm, kebabs) Thank you much Gilded, that practically answers everything but one little detail. The article claims that a return stroke causes the flash we see. Yet if the lightning branches don't reach the ground, I assume that return strokes couldn't have reached the branches, so how do they light up?

Based off what I've learned here, I'm going to say no. I'm not sure if my last post (above yours) is correct in principle, but that's my opinion of how light maintains a constant speed in all frames of reference. In other words, between different frames the math problem readjusts so that light speed always measures c. For example, let's say c were 20, and your speed through both space and time is 10. If you increased your space speed to 15, then your speed through time would adjust to 5. If you increased your space speed to 17, then your speed through time accordingly drops to 3.* In any case, light emitted by you is still c -- you might've increased your space speed, but it takes you that much longer to catch up to the light, whose experience of time doesn't change, while for us it does. I could be wrong on that aspect, but won't know for sure until someone knowledgeable responds to that post. *Math is oversimplified and possibly not accurate.

http://www.space.com/scienceastronomy/lightning_backgrounder.html I have some questions from the article linked above. 1. If lightning seeks an easy path to the ground, why does it branch, rather than stay as one thicker bolt? 2. If lightning is seeking a path to strike ground, does that mean the positive charge higher in the cloud has been depleted? 3. If lightning sends out a stepped leader, then how does a multi-branching occur? 4. The article mentions one return stroke from the ground, but how is that possible on a multi-branched lightning? Wouldn't that be several return strokes occur from various locations at once? 5. If lightning heats the air to 54,000 degrees Fahrenheit (five times hotter than the sun), how is it that any lightning strike victim can survive heat heat of that magnitude?

It's really not that bizarre at all. Very simple in fact. Since time has slowed down for you, but not for light, then when you are moving at the speed of light, time is at a standstill for you, but not for light which therefore still hits the mirror at c speed. If you were going at half the speed of light, just your time would slow down to half, thus light reaches the mirror at c speed. Is that correct?

Arguing back on this is like defending science by attending an intelligent design meeting. Such fun I think I'll pipe in OK traveler, if the sun truly spit out blobs of itself, then how did it manage to spew the larger planets further, and the smaller planets closer? Gravity-wise it doesn't make sense. And what of the Oort Cloud? Does the sun once in a while sneeze, creating a mess load of tiny blobs? That could explain the asteroid belt. In defense of traveler, gravity might not prevent the spitting of blobs, as gravity doesn't prevent solar flares reaching out far. But I think Edtharan pretty much debunked traveler's hypothesis.

I appreciate how the math is portable between the traveler and the stationary object, but isn't that a virtual effect rather than a real world case? One example to support this is the difference of how much work it takes to move your body towards a mountain, compared to how much work it takes to move the mountain towards you.

Thanks, I get it now. So, what JED3 said isn't really like what I had seen described before. In that explanation, I think they said when you move towards something, you aren't really moving your own body, but instead you're moving everything towards you. Is that even a real scientific view?

I'm not sure if we're talking about the same thing. Do you mean that a clock on the mountain will also move slower because the traveler moved past it at a higher speed? Basically, the mountain is going at teh same higher speed in relation the quick traveler, thus no time change for either because their clocks are equally slowed? My response was based on what I thought JED3's post implied, that time wouldn't move slower for the faster object if both were in the same "time frame" (whatever that means), because the stationary object would actually be moving at the traveler's speed in comparison to the traveler. I fail to see how that's possible. First, atomic clocks which are both on Earth have shown different times when one is stationary and the other has moved quickly. Second, can the determine the boundary of a time frame even be determined? Certainly true.* *Except for the Prez's gut, it's 100% accurate so scientific validation of its assumptions is totally unnecessary.