4 ms·
>A galactic year is only a few million earth years no. It is 250 million years. >so our orbit must have remained in the stable region for the first billion ye
by trhway 7y ago
>A galactic year is only a few million earth years
no. It is 250 million years.
>so our orbit must have remained in the stable region for the first billion years or so and we continue to be inside it.
not really. While moving on that spiral trajectory, we've made only 16 rotations since Sun's formation. When the life on our planet started our neighborhood looked very different, not the boonies we're at right now :)
- zaarn 7y ago>no. It is 250 million years. I don't see how that contradicts is being a few million years? >not really. While moving on that spiral trajectory, we've made only 16 rotations since Sun's formation. When the life on our planet started our neighborhood looked very different, not the boonies we're at right now :) Orbits don't really do spiral patterns in practice. Atleast not at this scale. The star would either be in a fairly stable orbit or on trajectory to leave the galaxy (minus elliptical orbits but those would carry the sun in and out of the dead zone quite often). Moving on a spiral trajectory does happen in orbital mechanics but only in one direction; inwards. Outwards spiraling would require quite a few quirks in the galactic gravity field. The spiral pattern itself isn't the result of a firework wheel, it's quite a quirk in the distribution of stars, though there are various models that explain them, they all involve very stable orbits for most stars.