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How long has the milky way been a spiral galaxy?
After answering another question, I realized that the center of our galaxy is much older than the spiral arms. Was the Milky way once an irregular galaxy? Perhaps a galactic collision led to the formation of the spiral arms. Or are the spiral arms simply a characteristic of a mature galaxy that rarely interacts with other galaxies?
*Hubble *probably
I know, it's the hubbe deep field. Hubble showed us images of primitive, young galaxies from the early universe, so I probabley should look into it to try to find out how young galaxies eventually turn into spiral galaxies like our own.
kozzm0:
We have 2 pretty reliable measurments, don't we?
1:the speed of light. The farther away things are, the older they are. Using speed of light is precise enough for most applications.
Consistant light sources at different differences allow scientists to measure red shifts.
But you do have a point, nothing is quite accurate enough.
The Milky Way is at least 10 billion years old so has existed for a large proportion of the age of the Universe. It will have begun, like all galaxies, as a vast agglomeration of gas and dust, and over huge periods of time, the influence of gravity, plus angular momentum have composed it into the form it now has. The exact way in which galaxies form is not precisely understood, and a lot of work is going on around the world to solve the conundrum.
