Dell Axim X5 400Mhz PPC pocket stars 5.12 7x35/10x50/15x70 Bino's
"Scientists aren't perfect, just peer reviewed.""Eye of Sauron Observatory", featuring "Sauron's Other Eye", 16" dob, conical Royce mirror.
Quote:If we take a characteristic orbit period of material about a galaxy as 250 million years, then galaxies 'settled down' to near their final configuration in some 10 orbit periods. That does seem pretty quick.
Guy “The first gulp from the glass of natural sciences will turn you into an atheist, but at the bottom of the glass God is waiting for you.” ― Werner Heisenberg
12" LX200 GPS
10" LX200 GPS
4" Unitron 150
4" Bosma refractor
Denk Binotron 27, D14's and D21's
Galaxy Note 8 running SkySafari Pro via Bluetooth
Wireless Autostar II
Quote:Dave,The 'preservation' of structure after mergers is hardly the norm. Look at the mess resulting after two spirals collide. Especially if their axes of symmetry are far from parallel, the result soon becomes more an elliptical, perhaps with a disk of gas settling down (like the Sombrero and the Hamburger, perhaps?). The expected variation in the sense of rotation among galaxies in a cluster suggests that mergers should more often result in a mixing of stellar orbits, and so a more elliptical configuration when tidal structures settle down.Depending on the velocity, directions of rotation, and other impact parameters for two impacting spirals, the gas can be largely stripped from each as they pass through each other. The gas clouds will slam together and effectively come to a screeching halt, the stellar systems continuing on, albeit strongly disturbed by tidal forces. The shocks induced in the gas will initiate ferocious star birth, perhaps making a new irregular galaxy.
Quote:I don't think anyone has said that the Big Bang's background was homogeneous.
Quote:In its early days, the universe was extremely smooth and homogenous... but not quite perfectly so. The Cosmic Microwave Background