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vikiradTG2007

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How does a galaxy move through the cosmos? I mean are they rotating around or they are just moving around randomly like a tornado?
I suspect it seems rather random, but at least what I think is happening is that it's a combination of summed-up gravitational attractive forces from nearby galaxies plus left-over momentum from the Big Bang... after all, in a vacuum, except for collisions, there's nothing which dampens motion.
 

Hibbleton

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How does a galaxy move through the cosmos? I mean are they rotating around or they are just moving around randomly like a tornado?

This might not answer your question but might help you get a better understanding. There is only one person who can explain it the best...

Carl Sagan
R.I.P
1934-1996
 

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How does a galaxy move through the cosmos? I mean are they rotating around or they are just moving around randomly like a tornado?
Tidal interactions with neighboring galaxies and momentum from the ever-expanding universe (aka dark energy), however local groups of galaxies "defeat" the expansion with the sum of gravities of all the galaxies within that region. This is why you have net-like clusters and superclusters of galaxies. Usually you see galaxies with tons of neighbors, and there are few isolated galaxies. I think the general consensus is that the isolated ones have collided and reformed in shape, but that takes quite a bit of time.
 

mpicco

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Interesting, because I've always had the theory that everyone had a little bit of synaesthesia in them. For example, I always associate the number 3 with green. The brain works by association, so it would make logical sense that synaesthesics are perhaps more sensitive to these associations than others.

Sorry if I'm stating the obvious, I'm not an expert in anything. I do however have a passing interest in science and sciency stuff like this.
2 pages too late but related, when I was a kid, I think as many here, I used to play video games. And sometimes mom would bring tea while we were playing. There is this one game that... if I play it, or even remember it, brings back the taste of a certain pie I haven't had for years and years.
Letters, numbers etc however don't remind me of colors or sounds... except perhaps the I (in spanish it's read as "ee"), reminds me of sharp things.

As far as science, I'm very interested in many areas, did 2 years as a major in Biochemistry in the University but I had to drop out for personal reasons... I love astronomy, too which brings me to the subject of gravity (sorry I read the whole thread today).
We're all familiar that gravity according to Einstein and supported by many is a distortion of space... And they always give that example of the bowling ball being the sun and the orange is the earth, then place them in a deformable surface to simulate "space". Then they show how pushing the orange, it circles around the sun. That's all fine but sooner or later it'd spiral down and crash against the sun... How many pages does it take to explain why this doesn't happen?
 

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We're all familiar that gravity according to Einstein and supported by many is a distortion of space... And they always give that example of the bowling ball being the sun and the orange is the earth, then place them in a deformable surface to simulate "space". Then they show how pushing the orange, it circles around the sun. That's all fine but sooner or later it'd spiral down and crash against the sun... How many pages does it take to explain why this doesn't happen?
The cloth (EG, if you try this with a blanket) decelerates the orange. Not so in space.

I like to keep perspective when i think about physics in space by remembering that, if I were floating in space with no gravity acting on me, I could accelerate to the speed of light just by holding a running garden hose. It would take billions of years, but if I had enough water I'd get there.
 
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The planets orbits degrade over time away from the sun since the sun is constantly losing mass and that shifts the barycenter (center of mass) of the solar system outward.
 

mpicco

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The cloth (EG, if you try this with a blanket) decelerates the orange. Not so in space.

I like to keep perspective when i think about physics in space by remembering that, if I were floating in space with no gravity acting on me, I could accelerate to the speed of light just by holding a running garden hose. It would take billions of years, but if I had enough water I'd get there.
What about by peeing? xD
Just joking.

The planets orbits degrade over time away from the sun since the sun is constantly losing mass and that shifts the barycenter (center of mass) of the solar system outward.
So what will happen first... sun explodes into giant red or Neptune spears off into the unknown?
 

mpicco

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Our sun wont explode, and the former is the answer to your question.
This:

It'll grow into a red giant and consume everything inside of the asteroid belt
From the limited info on wiki

Earth's fate is precarious. As a red giant, the Sun will have a maximum radius beyond the Earth's current orbit, 1 AU (1.5?1011 m), 250 times the present radius of the Sun.[91] However, by the time it is an asymptotic giant branch star, the Sun will have lost roughly 30% of its present mass due to a stellar wind, so the orbits of the planets will move outward. If it were only for this, Earth would probably be spared, but new research suggests that Earth will be swallowed by the Sun owing to tidal interactions.[91] Even if Earth would escape incineration in the Sun, still all its water will be boiled away and most of its atmosphere would escape into space. Even during its current life in the main sequence, the Sun is gradually becoming more luminous (about 10% every 1 billion years), and its surface temperature is slowly rising. The Sun used to be fainter in the past, which is possibly the reason life on Earth has only existed for about 1 billion years on land. The increase in solar temperatures is such that already in about a billion years, the surface of the Earth will become too hot for liquid water to exist, ending all terrestrial life.
 

vikiradTG2007

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It's not an explosion per se, it's just an expansion. Two different things. The "death" of the red giant though, that will be more akin to an explosion, since it will eject a large part of its mass into the surrounding space and leave a dwarf star in the center of a nebula.
 

mpicco

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Yeah I know main sequence stars dont supernova, that doesnt mean they dont explode at the end. The "expel their gases" with great violence, that to me is an explosion :D
But anyway, back to the main question, will the planets orbits decay enough to escape sun's gravity before it becomes a white dwarf?
 

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Yeah I know main sequence stars dont supernova, that doesnt mean they dont explode at the end. The "expel their gases" with great violence, that to me is an explosion :D
But anyway, back to the main question, will the planets orbits decay enough to escape sun's gravity before it becomes a white dwarf?
Nope, the red giant phase would have gulped us all up, while the main giant planets would be much further away by the time it evolves into a white dwarf.

So enjoy your time here while you can.

Funny.. I just read that while the orbits of the planets are decaying and the planets are slowly moving away from the sun, when it becomes a giant, the complex tidal interactions are going to pull the Earth back down into a lower orbit, causing us to be engulfed by the expanding gas layers.

So basically... we're fucked...in 5 billion years. No matter what. But I guess by then we will have made thrusters large enough to push the Earth out of harms way/Colonized another planet/Fought Zerg on Char etc.
 

mpicco

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Well it said somewhere that the sun is burning hotter and hotter and as "soon" as 1 billion years it'd reach temperatures that would boil all the water on Earth... and that's kaboom for life here.
But perhaps it starts melting Mars' water and it has it's own period of 2 billion years of life like Earth did...

Some things make me wanna live forever just to see them happen xD
 

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Interesting, all of this. My brain hurts a bit in this thread, though, I must admit. -_-
 

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Interesting, all of this. My brain hurts a bit in this thread, though, I must admit. -_-
Here's a fun one.


And here's the real kicker - it doesn't matter how long the path of the idler photon is. It could be ten light years, it could hit the which-path detectors 10 years after the signal photon strikes the pattern detector. The interference pattern will or will not appear regardless of distance or the state of the entangled idler photon. The photon knows it's fate.
 
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SirEdward

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That's very funny. I can already see people working to delay the idler photon path so that we can actually record the signal photon before the idler gets to the splitter...
 
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