Inside of a nebula

I'm taking a break from AI in this short post, it's time for something more general about the universe [see the last post in this category "what if we had a warp drive"].

In our daily activities we may not notice how lucky we are - we can see the sky. I mean the deep sky, even far beyond our Galaxy. And by looking at those things, we can learn that the Universe is expanding, that there are quasars, active galaxies, large scale cosmic structures, galaxy clusters, cosmic background radiation and many other marvels. We treat all that as obvious.

But imagine the Sun along with the solar system was trapped inside one of the dense nebulas, which there are countless numbers of in our Galaxy. Say we were trapped somewhere deep inside the Orion nebula.  All we would see in the night sky would be the faint pink glow of hydrogen and maybe a few blurred stars shining through the fog.

And best of all, since the nebula is many, many light years across, we could do nothing to see beyond it. Absolutely nothing. Discovering anything about the outside universe would require sending a probe light years away. This is not feasible at our current stage of technical development (and likely for many more years, unless some well established theories in physics get a major overhaul) and even if it were, it would take many, many years before it would reach the open space and then many years for it to even transmit anything back.

 Figure 1. Nigh sky on Earth (top/left) and on a hypothetical planet hidden inside of a nebula (bottom/right).  

So we wouldn't know anything about the Milky Way Galaxy. We would not know about the Big Bang and the Hubble constant. We would not know about black holes and Hawking radiation. We wouldn't know about other planets rotating around distant stars. We wouldn't know about supernovae, and likely we wouldn't be able to reliably measure the distance to the nearest starts, hence we would have no idea about the scale of the Universe.

We'd be completely shafted... Astronomers and astrophysicists would be sitting depressed in bars.

Chances are that some intelligent civilization out there is in that exact situation . So next time you see a star or better yet the Andromeda galaxy on an evening walk, consider how lucky you are...

(particularly if you happen to be an astronomer!)

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