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cosmology question

  • Thread starter jack
  • Start date
I have been watching the history channel today and the programs where about the cosmos and there is a concept I don’t understand and maybe someone here can help. After the ‘big bang’ the universe is expanding and all the galaxies are moving away from us and away from each other, I get that. Another episode discussed galaxies and explained that many collided with each other including our own. So, may question is if the universe is expanding and galaxies moving away from each other how can some of them also collide? Has dark mass caused some of their paths to move out of a straight line? Just something I was wondering with no one I could ask personally. Thanks, Jack???
 
could some objects in a "Big Bang" be propelled faster than others?
 
Using nothing more than my logic, I'd guess it's like any explosion- there's only so much space at the initial explosion- a much smaller...radius for ample matter to go, versus now that it's expanded. Not to mention, as stuff moves and expands outward, collision as it moves is inevitable, unless everything moves perfectly parallel to each other, but that's not the way it happens. I'm sure there has to be a law of randomness or something.

As for dark matter, I dunno about that, but again, where does it say that in an explosion, every piece of debris moves separately and parallel to other objects? There's that, and the fact that every object has it's own and unequal gravitational pull- the variation in this would also create a flux. Something has to give.
 
Even though they're moving outward from the center the mass of the various galaxies are going to have an impact on surrounding objects and could cause galaxies to drift towards and collide with one another.

There was enough energy to blow everything apart and break the pull of gravity that was holding everything together. But all of these galaxies are still attracted to, and pulling on one another, and changing their course through space, making collisions bound to happen.

I think an argument for dark matter comes in because they're seeing greater acceleration, like in the arms of galaxies and their rotation, than there should be with the mass that's present.
 
There are other forces at work in the galaxy - including magnetism, electron forces and gravity. Objects tend to be attracted to each other for various reasons. Think of it as a bottle rocket that has many other rockets inside of it. The main explosion propels objects into the void and away from each other but when the smaller bombs go off, the objects they propel will go off away from the center of their own explosion and their vectors will often crisscross each other.
 
pretty much what they say......things dont move away from each other and never touch.....talking bout huge masses with major gravitational pulls, they will be attracted to each other.......
 
The distribution of matter/energy isn't symmetric in the universe (e.g. http://www.google.com/images?oe=utf...tle&resnum=5&ved=0CDwQsAQwBA&biw=1131&bih=575), therefore even things as small as a hydrogen atom will be more attracted to one object than another and will cause large scale clumping after millions of years. The gravity troughs created from that attraction of matter will inevitably suck in closer objects, either trapping them (like our planets orbiting the sun) or just make them fly by (comets etc.) and go interact with other gravitationally attracted objects in the universe too.

Theoretically of course, nobody was around during the supposed big bang to say for sure :p Like what caused the fluctuations in the background radiation? Perhaps you could go study physics and discover it and tell us in 10 years ...
 
Ever seen those big "Chrysanthemum" type fireworks? A big explosion propels parts of the mortar outwards, and then the pieces also glitter and explode, making a sort of starburst pattern in the sky.
nomura.jpeg

Think of each little spark in the starburst as a galaxy. Sometimes, external forces like wind will push two sparks together. (And for superheavy objects like galaxies, gravity often makes near-misses quite unlikely.)
Other times, a spark will collide with another due to the way it burns. To make another fireworks analogy, different celestial bodies do different things. Some just explode, like a firecracker, and stay more or less in the same place. Some travel in straight lines, like a bottle rocket, or the sparks flying from the spokes in the pic above. There are some, however, that take less predictable paths than sitting still or moving in a smooth line, like the spiraling ones below:
<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/VO92r9duN8U?fs=1&hl=en_US"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/VO92r9duN8U?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>
~Joe
 
also gotta figure there wasnt one explosion.....supposedly there was one big explosion but since that one individual stars have exploded(supernovas) and sent stuff off on different tangents aswell.....
 
  • #10
This really isn't worth debating seeing as the good lord made it all in seven days.

*cricket, cricket*
 
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