The 1980 television series "Cosmos" – which featured Voyager mission scientist Carl Sagan – took viewers on a factual tour of the known universe and sparked the imaginations of many present-day scientists and engineers. The next generation may be inspired by the 2014 movie "Interstellar" – where a fictional team of astronauts searches for a habitable planet around a black hole in a distant galaxy. Clarke’s "2001: A Space Odyssey" in which a fictional astronaut is transported across the cosmos through a mysterious portal. The original show followed the crew of the starship Enterprise on a five-year mission to explore our galaxy.Īnother inspiration – science fiction author Arthur C. Many scientists say they were inspired by the science fiction television series "Star Trek" – which first aired on television in 1966 and has been reinvented numerous times on both small and big screens in the decades since. The mysteries of our universe have long captivated science fiction authors and filmmakers. For them too, this surface is situated in front of their horizon surface."Star Trek" inspired many scientists and engineers. For people far beyond the horizon, there is the same spherical surface from which the CMBR originated. Stars can of course be present behind the horizon. Well, not the same in the sense that they receive the same photons, but the form of the CMBR is the same, i.e., if you assume the CMBR to be the same throughout the whole universe. Observers far beyond the horizon will see the same CMBR. The CMBR originated throughout the universe. All visible stars lie in front of that horizon too. Then why isn't the wavelength of the CMBR stretched to infinity, like the wavelength of the radiation coming from stars on the horizon? Because the CMBR originated on a spherical surface, wrt to us, that lies in front of the horizon surface. The CMBR that we see today came into being before the birth of the most distant stars we are able to see. That is, all the stars that not lie behind the horizon of the visible universe. You can in fact, see all the stars that came into being after the "creation" of the CMBR. At that future time, the CMB will still be coming from regions that are further away than where we see the stars. We will be able to observe them in the future. However, there will be stars beyond those. When we look far away to regions that are approaching the current 45 billion light year distance of the CMB, we get the chance to witness the birth of those very old Galactic stars, but in another place. As we look into the distant universe we see other examples of those stars in distant galaxies, as they were in the past. The oldest stars we can see are in our own Galaxy, and are about 13 billion years old. Stars were born after the CMB was formed and we think that happened homogeneously across the entire universe. The CMB we saw yesterday came from regions that were nearer than the CMB we will see tomorrow. The CMB we see today has travelled from regions that are currently 45 billion light years away (thanks to the universal expansion). The salient facts are that the CMB was emitted almost isotropically from everywhere in the universe.
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