# Trying to track down one of the popular physics books

I've been trying to track down one of the popular physics books, a title I read years ago and can't recall. The author referred to a hypothetical astronaut, travelling at or close to lightspeed. Looking out of his ship's rear window he observes the stars behind him gradually reddening and dimming and eventually disappearing altogether as wavelength becomes infinite. In the forward direction the universe is foreshortened to a point as all light is completely blue-shifted. The author suggested that the astronaut is effectively dragging along his own personal black hole behind him, as this would logically account for his inability to see any stars astern of him. I eventually saw in these observations the answer to something which had been puzzling my poor brain for years (ever since reading "Einsteins Universe" even earlier !!) I'm darned if I can remember the title or author of the book that I found this in. I've tried all the ones I can remember, not that there have been very many, I'm not much of a scientist and less of a mathematician. I havent looked around the site yet (newbie) and for all I know this is Mother's Milk to the regulars.

EnumaElish
Homework Helper
A book

I am not a physicist by training and have no formal education in cosmology beyond what is accessible through "popular culture" and "sci-fi." Having said that, a sci-fi novel centered around the theory of relativity is tau zero by Poul Anderson $$\copyright$$ 1970 (page numbers below refer to Gollancz edition 2000, isbn 0-57507-099-4) and has passages almost exactly like your description. (I have copied Amazon's link at the end of this post.) I started it last week and couldn't put it down; I think I achieved a new personal record in reading.

p. 45: "More and more, the stars thinned out behind the ship and crowded before her. Doppler effect operated simultaneously. Because she was fleeing the light waves that overtook her from astern, to her their length was increased and their frequency lowered. In like manner, the waves into which her bow plunged were shortened and quickened. Thus, the sums [suns?] aft looked ever redder, those forward bluer."

p. 112: "The farther stars were coalescing into two globes, fiery blue ahead, deep crimson aft. But gradually those globes contracted toward points and dimmed; because well-nigh the whole of their radiation had been shifted out of the visible spectrum, toward gamma rays and radio waves."

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Thanks for that. I think I might read it myself !! Never read any Poul Anderson. Shame I couldn't E-Mail him and jog his memory.