Here is a case where a word used simplifies the explanation or description to the point of being misleading. The collision between the Milky Way Galaxy and Andromeda will not be a collision or crash in the sense that we experience such events on Earth. The space between the stars in each of these two galaxies is so enormous that there will almost certainly be no physical contact between any stars in the two galaxies. What will happen is a reshaping of the two galaxies as a result of the gravitational forces that will come into play as they pass through each other. Use of the word crash to describe what is going to happen is thus misleading. The mighty gravitational forces that will result from this event will likely send some stars careening into intergalactic space and reshape both galaxies into elliptical galaxies.
Both are presently spiral galaxies.
A similar problem exists with the Big Bang Theory name. My students often think that this event from which the universe we inhabit came into existence was some sort of explosion, as is implied by the term Big Bang. It is often described in the literature as an explosion. The problem is that explosions as we humans know them are (1) destructive events in which (2) material is thrown outward from a center point at roughly the same speed in all directions. Also, (3) the pieces from this explosion are flying outward through pre-existing space. Furthermore, (4) these ejected bits
from the explosion gradually slow down and eventually come to rest. However, the Big Bang was (1) a creative event and (2) nothing was flung from a center point. Observations, which have been repeatedly confirmed show that galaxies beyond our local group are all receding from us at velocities proportional to their distance from us. The farther they are from us the faster their rate of recession. This same observational evidence establishes that what we observe from our galaxy is what we would also observe from any other galaxy anywhere in the universe. Thus there is no center point to this expansion; there is no single central point from which every galaxy is receding. Also, (3) the galaxies that are receding from each other are not doing so because they are moving through space. Rather space itself between the galaxies is expanding. Finally, (4) observational data analyzed in 1998 established that rather than slowing down, the rate of
expansion of the universe is accelerating. Not something you would expect from something that was an explosion in the conventional sense of the word. Here is a link that might help in visualizing this: http://www.exploratorium.edu/hubble/tools/center.html
From: Tim Campbell
To: [address removed]
Sent: Saturday, January 12, 2013 11:42 AM
Subject: Re: [humanism-174] Galaxy crash sparks large spiral
Planet will be around, but scale is so enormous, anyone alive on Earth
would never notice the crash as being a crash!
In a message dated 1/12/2013 10:32:08 A.M. Eastern Standard Time,
[address removed] writes:
I'm not sure if the following numbers are right- our Milky Way is supposed
to crash with the Andromeda galaxy M31 in about 2 billion years, but our Sun
has about 4 to 5 billion years left before it swells up to a Red Giant
(possibly engulfing the Earth) and then collapses to a White Dwarf? So
although our oceans will have boiled away long before (in 0.5 billion yrs),
our planet will still be around to experience the galactic crash?
On Jan 11, 2013 3:19 PM, "sheri presloid" <[address removed]> wrote:
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