Sisyphus

"Would you say it's raining outside?" "Yeah, it's really coming down hard." "YOU'RE CLOSEMINDED AND LACK COMMON SENSE. THERE'S NO RAIN IN THE UPPER ATMOSPHERE. IS THAT NOT 'OUTSIDE' TOO?!?!?!?" "Ok, Bishadi."

What do you mean by Big Bang inertia?

So, the point of this thread is to say that the sky looks different at night than it does during the day? Ok. Consider it said.

I should be more clear. In your next post, answer my first question, what it is that "you say otherwise." What leads you to say that the sky is not blue? Keep in mind that if your answer is "common sense" then I'm closing the thread.

What is the purpose of this thread?

The "Baghdad batteries" are only from the early centuries AD in Mesopotamia, millenia after Egyptian pyramids and not even in Egypt. Also, they are nearly identical to sacred scroll containers known to have been used during that period. Hence, it seems to me (and most archeologists) that resemblance to electrical batteries is just a tantalizing coincidence. Batteries of slightly modified design could have been used to electroplate, but there's actually no real evidence of this or any other use, nor have there been any artifacts from that period discovered that appear to have been electroplated.

I'm probably going to regret asking, but what do you say otherwise?

Just be wary, as every fearmongering demagogue seems to have become a "libertarian" in the last half year or so.

But "things getting farther apart" is what is meant by "space expanding." Still, though, "moving" is not an appropriate word.

No, there is no "void."

Because, It is an expansion of space, not objects moving apart within space. Look into the link Klaynos posted.

That's not true. It it isn't expanding into anything. The expansion is an increase of distances, but not a movement into new areas (or any other kind of movement).

He said "it's always now" is a meaningless thing to say, and it is. It is not, however, a "shared now." In one reference frame two events might be simultaneous, while in another they are not. There is no "independent of their perspective."

At 20.5 ly, it would be quite a bit less than one-way.

If it was limitlessly stretchy, the pressure outside and inside would always be equal, and that same quantity of gas would expand into a larger and larger volume the higher up (and the lower pressure) you go. It isn't limitlessly stretchy, so the there's a minimum pressure the same inside gas can have. So, at lower atmospheric pressures, you need less gas to maintain the full volume, which will decrease the total weight, so venting some at high altitude will give you slightly more buoyancy. There is no thrust, it's just buoyancy. Buoyancy is going to be proportional to the difference in mass between the object and an equivalent volume of the fluid surrounding it, in this case, air. Not the ratio between the masses. Regular air is about 14 times as dense as hydrogen gas. So, an enclosed unit volume of hydrogen gas has 14-1=13 buoyancy in air, and an enclosed unit volume of vacuum of has 14-0=14 buoyancy in air. So, not a big difference. And the added structure to contain a volume of vacuum has to weigh less than the difference to be worth it. You're welcome. About time I get some actual respect around here.

You can't "use up the gravity," if that's what you're asking. When two massive objects fall together due to gravity, gravitational potential energy is "used up" in the sense that it's turned into kinetic energy. And it can be converted back again.

Just a note, "crystalline" is an adjective, not a noun, and it just means a repeating pattern of molecules. Diamonds are crystals. So is water ice, and countless other solids of all degrees of hardness. (Also, as has been noted, hardness is not a good criterion for quality of armor. Glass is about as hard as steel.) Merged post follows: Consecutive posts merged True, nobody uses "battleships" anymore. They've been obsoleted by aircraft carriers since WW2 (though it took a while longer for everybody to realize it). But in a thread about one person of no extraordinary means planning to build a battleship the likes of which the world has never seen, I think we can sidestep the larger questions of practicality.

What purpose does the protein "crystal" serve? Why use that rather than something else? Does anything like what you're looking for currently exist? If not, why do you expect that it could?

Sunlight is more than just slightly stronger on the moon. The Earth's atmosphere absorbs about 25% of sunlight before it reaches the surface. The Apollo 11 was also pretty close to the Moon's equator, so the sunlight would have been quite a bit brighter than it ever is anywhere on Earth.

Really? I know lots of animals can survive on just one food source, I just thought humans weren't one of them. Can we really digest all that? Wouldn't there be problems with trying to go pure carnivore?

We're clocks too. Just not nearly as precise as artificial ones.

I don't imagine there's any single natural food that would satisfy every nutritional need a human being has. You could survive a few months on any number of things (vitamin deficiency isn't going to kill you for a long time), and indefinitely on a moderately diverse diet. Once upon a time this was how everyone lived, and some still do. And keep in mind that domesticated plants and animals (i.e., pretty much everything you eat) are just wild plants and animals that humans deliberately raised for their own use, and usually bred to make more useful.

eric, what you're demanding, an "exact formula," is not reasonable. There is no secret formula for life. A living thing is just any arrangement of matter and energy that carries out the functions of life, specifically metabolism, growth, reproduction, homeostasis, response to stimuli, etc. There is no precise and universal definition, but that's basically it. If you want an example of how atoms might be arranged to create a living thing, then just look at any living thing. There's no point demanding anyone here give you an exact formula, though, since even the very simplest living things are far more complicated than can be described in a simple formula. It's not a matter of "3 cups of carbon, 2 cups of oxygen, cook on 350 for 45 minutes...." Similar to how there is no formula for what makes, say, a computer. If someone was angrily asking you over and over what makes a computer, and how can a computer be made of atoms if atoms can't compute anything, etc., how would you respond?

A way to rephrase this question is, do you want to support the balloon against outside pressure with hydrogen gas, or with solid structures? The upper atmosphere is going to be orders of magnitude less dense than any solid, but it can't be less dense than hydrogen gas which is allowed to expand. Infinity. Vacuum, by definition, has zero mass. (Although true vacuum isn't going to be attainable.) However, what matters is the total mass of the balloon. Yes, but it's the same question as above. I can't answer for certain without doing a lot of engineering calculations, but it's almost certainly better with just gas. Density = mass/volume All of your mass that's heavier than the outside atmosphere is going to be on the surface, the solid balloon itself. Therefore, by increasing the ratio of total volume to surface area, you are decreasing the ratio of mass to volume. Surface area increases with by the square of the length. Volume, however, increases with the cube of the length. Therefore, when increasing the overall size of your balloon, the volume increases faster than the surface area, and the density decreases. All of this, of course, is disregarding any additional structure or thickness you might need to hold together a larger balloon.

A cannon powered by explosives isn't going to work, because muzzle velocity has an upper limit based on the rate of expansion. A railgun has no such limit.