On a somewhat related note I'm wondering what the expansion of the universe means for our bodies and matter in general? I think, like the accepted answer suggests, the forces on the atomic level make it so that larger structures get back to a certain equilibrium even if constantly streched equaly in all directions. But I have a hard time imagining what the universe expanding really means on a human/solar system scale…
How would a passing gravitational wave look or feel? (2017)
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Re: How would a passing gravitational wave look or feel? (2017)
#12Obviously as "a disturbance in the force".
Re: How would a passing gravitational wave look or feel? (2017)
#13[dead]
Re: How would a passing gravitational wave look or feel? (2017)
#14On a somewhat related note I'm wondering what the expansion of the universe means for our bodies and matter in general? I think, like the accepted answer suggests, the forces on the atomic level make it so that larger structures get back to a certain equilibrium even if constantly streched equaly in all directions. But I have a hard time imagining what the universe expanding really means on a human/solar system scale…
Matter isn't pinned to the space it's in (source: try walking around). As space expands, the other forces which are orders of magnitude stronger than the expansion of space slide matter along so that distances don't change. You can only detect the expansion of space by measuring the distance between things that are so spread apart that the other forces between them are essentially zero.
Re: How would a passing gravitational wave look or feel? (2017)
#15Re: How would a passing gravitational wave look or feel? (2017)
#16On a somewhat related note I'm wondering what the expansion of the universe means for our bodies and matter in general? I think, like the accepted answer suggests, the forces on the atomic level make it so that larger structures get back to a certain equilibrium even if constantly streched equaly in all directions. But I have a hard time imagining what the universe expanding really means on a human/solar system scale…
https://m.youtube.com/watch?v=5U1-OmAICpU
"Brooklyn is not expanding"
Re: How would a passing gravitational wave look or feel? (2017)
#17On a somewhat related note I'm wondering what the expansion of the universe means for our bodies and matter in general? I think, like the accepted answer suggests, the forces on the atomic level make it so that larger structures get back to a certain equilibrium even if constantly streched equaly in all directions. But I have a hard time imagining what the universe expanding really means on a human/solar system scale…
The whole "expanding Universe" model is repeatedly dealt blows in the past few years, so I'd accept it as a plausible, but not sufficiently demonstrated hypothesis and not waste time bothering about the impact on our bodies. But if you will, think about it like that. All life adapts to its environment. All life. All the time. Everywhere. And the expansion is not that fast that a single generation of anything from a o…
Almost agreed, but I feel compelled to correct one thing, because it's a common and annoying misconception "nature lovers" harbor:
> One of millions of variables we constantly adapt to. If it's slow enough, no problem. But if it's hitting us fast(...), that... we may have problems with. That's when you see unrest, violence, crime. Wars. Famine. Suffering.
No. Famine, starvation, disease, suffering, mass deaths - and even wars - are exactly the process through which life adapts to slow changes. That's what it means for ecosystems to thrive, for nature to be in balance - that balance is held dynamically, by constant cycles of excessive slaughter followed by mass starvation.
We brought a lot of new problems on the table, both for ourselves and all other life, the latter of which can't even keep pace. But senseless suffering and comically painful death - that one came from nature, and we're actually successfully reducing it.
Re: How would a passing gravitational wave look or feel? (2017)
#18[deleted]
Re: How would a passing gravitational wave look or feel? (2017)
#19On a somewhat related note I'm wondering what the expansion of the universe means for our bodies and matter in general? I think, like the accepted answer suggests, the forces on the atomic level make it so that larger structures get back to a certain equilibrium even if constantly streched equaly in all directions. But I have a hard time imagining what the universe expanding really means on a human/solar system scale…
Personally I like the raisins in a baking muffin analogy better as it's 3 dimensional
The inflatable balloon analogy has the advantage that, two-dimensionally, there's no "edge" beyond which you could travel.
Re: How would a passing gravitational wave look or feel? (2017)
#20On a somewhat related note I'm wondering what the expansion of the universe means for our bodies and matter in general? I think, like the accepted answer suggests, the forces on the atomic level make it so that larger structures get back to a certain equilibrium even if constantly streched equaly in all directions. But I have a hard time imagining what the universe expanding really means on a human/solar system scale…
Expansion happens only in the Lemaitre-Friedmann-Robertson-Walker walker metric, which is a solution to the Einstein equations in a homogeneous universe. That's a fine approximation to our universe at the largest scales, but not on the scale of a solar system. Spacetime locally around the earth looks much more like a Schwarzschild solution. So we're not experiencing expansion. If you are asking hypothetically, if a h…
A translation would be appreciated, OP was asking for an explanation for the general public. Even highly technical people will struggle to understand this if you use such insider jargon without clarification.
Surely expansion is happening at every scale but locally other factors dominate right? To what degree? Is it mainly gravity? Electromagnetic attraction between atoms and/or molecules?
The naive mental model that I have is of two balls tied with a rubber band, each on a treadmill going in opposite directions. Since the rubber band attraction dominates, they slip on the surface of the treadmill and their distance is barely affected even if the surface underneath “expands” outwards quite quickly. Is this a reasonable analogy or is it too simplistic?
Of course the rubber band force is proportional to the distance, while the attraction forces we are talking about are inversely proportional. And I have no idea if the expansion of the universe can be reasonably modeled as an outwards “drag force” on matter. How “sticky” is matter with respect to space?