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That and more. Currently we think there are 2 trillion of those little dots in the observable universe. There have been some very interesting whole sky surveys
by dougmwne 4y ago
That and more. Currently we think there are 2 trillion of those little dots in the observable universe. There have been some very interesting whole sky surveys that have mapped many of them. The Sloan Digital Sky Survey has data on location, distance and spectroscopy on 50 million of the little buggers. They have some neat 3D maps, think milk being stirred into the black coffee of the vast.
- peter303 4y agoI read the count of "observed" galaxies is 170 billion, i.e. extrapolating the deep field count. Certain assumptions about faint and redshifted galaxies increases that number to about trillion. Early galaxies may not look as regular and spirally as recent galaxies. JWST will see more detail in the early universe to better quantify this.
- dougmwne 4y agoYes, if we were to take our best image ever, the Hubble eXtreme Deep Field and multiply it by the whole sky, we would likely see 176 billion galaxies using that same telescope and exposure. That could be considered a lower limit. But we also have models of mass and galaxy formation that suggest the number of galaxies within the observable universe is many times larger, maybe up to 2 trillion. Hubble cannot see everything at every wavelength, even if we have unobstructed line of sight to it.