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Lucretius
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I know that the velocity of our galaxy towards Andromeda is approximately 300,000km/s, but how quickly does this velocity change? Or can we tell given our relatively short time observing the sky?
jcsd said:Acceleration requires a force, which force is acclerating the Milky Way towards Andromeda? The only force that could conceivably be signifcant is gravity.
A simple back of the envelope caluclation (pretty rough and ready, could easiy be an order of magnitude out), reveals the acceration due to the Andromeda galaxy's gravity of the Milky Way is approx. 3 x 10^-21 ms^-2.
vincentm said:I believe the velocity that the Andromeda galaxy is accelerating towards the Milky Way is 50 kilometers a second, i could be wrong though.
Lucretius said:I know that the velocity of our galaxy towards Andromeda is approximately 300,000km/s
the acceration due to the Andromeda galaxy's gravity of the Milky Way is approx. 3 x 10^-21 ms^-2.
SpaceTiger said:jcsd already noted this, but that's much too large. 300,000 km/s is the speed of light.
Are you just using Newton's law of gravity? If so, what numbers are you using? With 1012 solar masses for Andromeda and a megaparsec separation, I'm getting it to be about a factor of a billion less:
[tex]a \sim 10^{-13}~m/s^2[/tex]
My number is more like what I would expect, since accelerating at that rate for the age of the universe produces a velocity:
[tex]v \sim at_u \sim (10^{-13}~m/s^2)(10^{10}~years) \sim 100~km/s[/tex]
which is of the same order of magnitude as the current velocity between the galaxies.
Also, I think it's worth mentioning that the masses of the Milky Way and Andromeda galaxies are still very uncertain, so estimates of the acceleration would be as well.
BTW: The unit calculator in my signature makes these calculations a lot easier.
Kino said:In answer to the first post: the acceleration won't change, but the velocity will. This could be determined by the change in blue-shift (as it is approaching us).
The acceleration of our galaxy, the Milky Way, is approximately 0.000000000000000000000000000000000000024 meters per second squared. This acceleration is caused by the gravitational pull of other galaxies and dark matter.
Scientists use a variety of methods to measure the acceleration of our galaxy, including studying the motions of stars and galaxies, analyzing the cosmic microwave background radiation, and using computer simulations.
The acceleration of our galaxy is affected by the distribution of matter and energy within the universe, including the presence of dark matter and dark energy. It is also influenced by the gravitational pull of neighboring galaxies and cosmic structures.
No, the acceleration of our galaxy has changed over time. Scientists believe that the acceleration of the expansion of the universe has been increasing due to the influence of dark energy.
The acceleration of our galaxy may not directly affect our daily lives, but it is a fundamental aspect of our understanding of the universe and helps us to better understand the origin and evolution of the cosmos.