Reviews for Earth Imaging Satellites

The average rating for Earth Imaging Satellites based on 2 reviews is 3.5 stars.

Review # 1 was written on 2013-08-20 00:00:00 Luanne Holden-boushey Great photos and explanations (for the most part). Hard to beat cosmology for giving us a different perspective. My favorite is a photo of the Ring Nebula - on the front cover and page 32. Old stars, the author writes, "dramatically blow off their outer layers, creating spectacular celestial fireworks...expelling their dying breaths" as "planetary nebulae." The Ring Nebula photo is of "a barrel-shaped puff of ejected gas energized by the white-hot ember at the nebula's center...once the star's nuclear furnace. No longer able to burn on its own, it is doomed to become increasingly cooler and dimmer. In a few thousand years the bright surrounding gases will fade and dissipate, leaving only the waning ember - a nondescript white dot in the cosmos." I believe this is our sun's future. Looking at a particular galaxy (M87) the Hubble's photo documents evidence of a black hole at the galaxy core, "a swirling disk of gas...rotating at...1.2 million miles per hour around an invisible object weighing two to three billion times more than the sun. The only thing known to be so heavy and so dark is a massive black hole." Mass-energy packed together in unimaginable density. The Hubble can see "light that began its journey long before the Earth existed," and "back to 90% of the beginning of time when "galaxies are quite young, but the light from them is ancient." Given the speed of light (186,000/second).... On the last page, Voit writes about "our ultimate fate": "In principle, if the universe contained enough matter, the gravitational pull of each part of the universe on every other part could stop the expansion and reverse it, pulling everything back together in a Big Crunch. From what we now know about the masses of clusters, this outcome seems unlikely. Odds are that the universe's galaxies will continue drifting apart indefinitely into an every darker, ever more dispersed future." It's said that dark energy is the likely culprit, but is the Big Bang propulsion escaping gravity's reach? Or, per Einstein's General Theory of Relativity, is something out there, beyond, pulling space-time? In any event, where are these expanding-outward galaxies going?

Review # 2 was written on 2015-10-12 00:00:00 Ethan Quillen Amazing photos, some with hundreds of galaxies in a single frame.