2 ms·
I don't know where we stand now, but there are two arms and a galactic year is ~250 million terrestrial years, so I'd say a priori on average ~250/2/2 = ~60 mil
by blauditore 9y ago
I don't know where we stand now, but there are two arms and a galactic year is ~250 million terrestrial years, so I'd say a priori on average ~250/2/2 = ~60 million years from now.
- fastball 9y agoProbably better to take the average of the last known extinction events and extrapolate from there. Average time between events: 96 Myr. Time since last event: 33 Myr. Time to next event: 63 Myr. Wow, surprisingly close to your method. Pack up your bags boys, we're gonna get extincted in 60 million years.
- vorg 9y agoThere are two thick arms, and two thin ones in the picture, as well as a spur (the Orion Spur in which our Sun presently dwells). The article postulates the existence of a second spur on the far side of the galaxy where we can't see, based on the history of extinction events in the past 250 million years and the observed symmetry of many other spiral galaxies.