Having just come home from Netroots Nation Sunday, you’d think I’d be writing my annual “What I Learned at NN” diary, but following brillig’s diary yesterday, it might be too much too soon, plus it would require more time than I have right now to read over my notes so that I can remember what I learned. I could also have posted another entry in my California Road Trip series, but the next installment involves recounting some interesting events in the history of California, requiring me to devote some time to fact-checking, time that I don’t have right now. So instead, the subject of tonight’s diary is pretty lightweight: the fate of the universe. Please proceed below the fold to learn the future we all face….
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This youtube goes a long way in explaining what’s going to happen. For those who don’t have the time, or whose internet connection doesn’t allow for watching videos, a brief explanation lies below the video.
The video addresses the fate of the universe in the context of the question of whether there are limits to out travel in the universe. The answer is, yes, there are, in fact, severe limits to where we can travel (assuming relativity holds and no faster-than-light propulsion systems are developed). It is imaginable that we can travel to any place within our own galaxy, the Milky Way, or to our nearest neighbor galaxy, the Andromeda galaxy, and to other dwarf galaxies and globular clusters in a region called the Local Group in a region with a diameter of about 10 million light years. However, it is impossible to travel to any other galaxy or group of galaxies beyond the local group. Why? Because dark energy is causing acceleration of the expansion of the universe at such a fast rate that those other galaxies recede from us faster than we can approach them, even if we travel at 99 % of the speed of light.
All those science-fiction dreams of rocketing off to some different galaxy or other (besides Andromeda) have now officially crumbled to dust. (I will admit to having such dreams, fueled by a heavy dose of science fiction novels in my youth.) Of course, it’s not like there isn’t a huge quantity of space and stars and other exotic objects in our local group to explore, but we’ll never get to observe phenomena outside the local group close-up.
But that’s not all. As all those other galaxies race away from us at ever increasing speeds, they will fade from sight, both because of the increased distance, and also because the light is red-shifted to longer wavelength by the Doppler effect, removing the light from the visible part of the spectrum. No galaxies outside the local group will be visible anymore. After enough time has passed, it will no longer be possible even to observe the cosmic background radiation, the so-called echo of the Big Bang, the birth of the universe. This means that evidence of the origin of the universe will no longer be observable. Intelligent beings will have no evidence whatsoever of the history of the universe; it will appear to be entirely static to such observers.
During all this time, the galaxies in our local group, the Milky Way and Andromeda, will be drawn together by their mutual gravitational attraction to form a singly giant galaxy called… Milkdromeda. This, I think, is the most distressing part of the story. Milkdromeda? Seriously? You couldn’t think of something more imaginative? The name “Milky Way” is certainly descriptive of how we observe the course of stars in our own galaxy, though other peoples used other names for it. (Carl Sagan, in his original Cosmos book/series, noted that some Africans called it the Backbone of the Night.) I think the common name is okay but nothing special. Andromeda, on the other hand, I think is a beautiful name, just about the loveliest name of anything in the night sky. And then you want to destroy both these names by calling the combined galaxy “Milkdromeda”? Yech! Tell you what: why don’t we just drop any claim to “Milky Way” and call the combined galaxy “Andromeda,” so as to preserve that lovely name?
Of course, this could easily be a moot point if the human species does not survive. Now present on the Earth only 100-200 thousand years, we would have to survive for billions of years, something that no species (except possible some of the very simplest) has done. I don’t want to be Debbie Downer, but the odds are against us. On the other hand, if a complex, sentient species is capable of surviving that long, we’re the only candidate. No pressure or anything.
Let me end with a youtube that shows a simulation of the collision of the Milky Way with the Andromeda galaxy:
And now, what you’ve all been waiting for… the comments!
Top Comments (July 20, 2016):
From belinda ridgewood :
When Thinking Fella started waxing metaphorical (till it was good and shiny!), angry marmot had a stellar reply. From the marmot's own CUA diary.
Highlighted by ord ave guy:
In response to Bailey’s comment on Meatloaf’s health, labradog makes a funny comparison. From FaithGardner’s recommended post Third Eye Blind plays event near RNC, uses it as an opportunity to epically troll Republicans.
Highlighted by smoothnmellow:
This comment by Calvino Partigiani in Brainwrap’s recommended post.
Also, this comment from Pam LaPier, from the same post.
Top Mojo (July 19, 2016):
Top Mojo is courtesy of mik! Click here for more on how Top Mojo works.
Top Photos (July 19, 2016):
Tonight’s picture quilt is courtesy of jotter!