Welcome to City-Data.com Forum!
U.S. CitiesCity-Data Forum Index
Go Back   City-Data Forum > General Forums > Science and Technology > Space
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
Reply Start New Thread
 
Old 03-11-2017, 12:13 AM
 
17,877 posts, read 15,719,596 times
Reputation: 11649

Advertisements

Quote:
Originally Posted by Bitey View Post
If that bullet were the only object or matter or energy source in space besides the gun that fired it, then yes it would continue on its course and velocity in perpetuity, as would the gun in the opposite direction.
You mean it will continue accelerating, or just stay at muzzle velocity?
Reply With Quote Quick reply to this message

 
Old 03-11-2017, 01:03 AM
 
Location: Brackenwood
9,874 posts, read 5,535,674 times
Reputation: 21962
Even space isn't completely frictionless as there is debris, dust particles, gases, etc. that will slow it down, albeit negligibly so. Provided the bullet doesn't come close enough to a celestial body with enough mass and gravitational pull to alter the bullet's trajectory, it will travel through space on its present course in perpetuity, probably decelerating ever so slightly as it does. And if the gun is out in the middle of space well away from any celestial bodies, it won't reach any unless the bullet is traveling faster than the universe is expanding, which is unlikely.
Reply With Quote Quick reply to this message
 
Old 03-11-2017, 09:37 PM
 
17,877 posts, read 15,719,596 times
Reputation: 11649
Quote:
Originally Posted by Bitey View Post
Even space isn't completely frictionless as there is debris, dust particles, gases, etc. that will slow it down, albeit negligibly so. Provided the bullet doesn't come close enough to a celestial body with enough mass and gravitational pull to alter the bullet's trajectory, it will travel through space on its present course in perpetuity, probably decelerating ever so slightly as it does. And if the gun is out in the middle of space well away from any celestial bodies, it won't reach any unless the bullet is traveling faster than the universe is expanding, which is unlikely.
What exactly is moving away from each other? Is it just galaxies or galaxy cluster? Why not the celestial bodies within, like star system moving away from star system, or even within the star system, like planets moving away from each other?
Reply With Quote Quick reply to this message
 
Old 03-12-2017, 12:03 AM
 
23,510 posts, read 69,890,838 times
Reputation: 48854
Quote:
Originally Posted by NJ Brazen_3133 View Post
What exactly is moving away from each other? Is it just galaxies or galaxy cluster? Why not the celestial bodies within, like star system moving away from star system, or even within the star system, like planets moving away from each other?
That is one of the harder concepts to grasp. Imagine a sphere with the visible universe in it. Now increase the size of the sphere, but at the same time, keep the particles of universe in their same positions relative to each other and the exterior of the sphere. That is the basics of expansion.

Now... remove the sphere but imagine the same action.

Then... allow that the force of gravity in planetary systems and galaxies is enough greater than the force causing expansion that the distances between planets and the sun don't change, and the galaxies remain as galaxies.

That is a crude model, but shows the basics. A key that it is true is the red shift of light from stars. That red shift occurs equally in all directions, which can only happen if the stars are moving away at more or less equal speeds.
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply
Please update this thread with any new information or opinions. This open thread is still read by thousands of people, so we encourage all additional points of view.

Quick Reply
Message:

Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Science and Technology > Space

All times are GMT -6.

© 2005-2024, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Contact Us - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37 - Top