Uncommon Sense

May 30, 2017

If the Universe Is So Vast, Where Is Everybody?

Filed under: Science — Steve Ruis @ 10:29 am
Tags: , , ,

The question in the title is a variant of “Are we alone?” Are there other sentient life forms in our galaxy? Enquiring minds want to know.

This post is prompted by a review of a new book (ALIENS: The World’s Leading Scientists on the Search for Extraterrestrial Life, edited and with an introduction by Jim Al-Khalili).  I have not read the book and do not intend to. The reason? The discussion is premature.

One of the powers of human minds is to imagine (possibly the greatest of human powers) but it has a gigantic flaw: garbage in, garbage out. If our imagination has little to no data to work on we come up with quite fallacious outcomes. This is how we got demons and gods and unicorns and leprechauns.

So, what evidence do we have regarding the universe? We have optical and EMR evidence for the existence of billion upon billions of stars in our galaxy and billions upon billions of galaxies in our universe. But realize we have not known this for long. One hundred years ago, we knew that the Milky Way was a manifestation of other stars in our “neighborhood” but we though that that represented the totality our universe, too. We had observed fuzzy spots in those star fields but hadn’t acquired the evidence to recognize them as other galaxies. And while we had speculated that many of those stars would have planets about them, we had no direct evidence that was so until quite recently. The first actual planet circling another star was identified in … wait for it … 1992. So, we have been aware that there are other planets “out there” for all of 25 years. We have subsequently identified hundreds of others.

Do we have any evidence that life exists on those planets? No, but we do not have any evidence that life does not exist either. At this point, we are not yet ready to make those discoveries (although we are close).

The question in the title implies that since there are so many stars, there must also be unbelievably large numbers of planets, and if life is not an isolated accident, or divine bit of magic, occurring here and only here, then where are those other peoples? There is a mistake embedded in this question though, leading to flights of imagination fueled only by fairy dust. The universe is indeed vast, but the primary constituent of our universe is empty space, aka nothing. The next closest star to us is about four light years away from us. To go there to get direct evidence of what exists there, we would have to travel for four years at the speed of light. Since the fastest speed ever achieved by a man-made object is about 25 miles per second, and the speed of light is about 186,000 miles per second, at that speed (as an average), a trip to Alpha Centauri would take a bit under 35,000 years. If we could get their magically and then sent data back to Earth, it would take four years to get here and when it arrived the information would be four years old.

The universe is unimaginably vast, but this is also misleading because it is also vast in time. A civilization could have arisen around Alpha Centauri, to the point that it was capable of building spacecraft capable of very high speeds who could have made the trip in under 20 years, let’s say. But if this occurred 100,000 years ago, there wouldn’t have been anyone here to notice. (That doesn’t stop the imagination, of course, … Ancient Aliens!)

The universe is vast in time as well as space. In order to generate a signal that we could interpret as synthetic instead of natural, that civilization would have to exist within a small radius in space and time. If it is over 100 years out of phase with us now, we wouldn’t have a chance of detecting it. So, 100 years in time is our bubble. How many years has the universe been around? That number is 14,000,000,000 years, roughly. Our “time” as a species capable of detecting another sentient species in our vicinity is therefore about 0.0000025% of the time that has occurred to now. Considering that our spatial bubble is roughly 100 light years wide and the universe is roughly 28,000,000,000 light years wide, we have in out neighborhood, 0.0000012% of the universe’s space. Consequently, we have a combined fraction of the universe’s space and time of  3 x 10–14%. In other words, 99.99999 … 9999% of the universe is outside of our purview, either existing in the past or so far away as to be unattainable.

Something you need to know. Those extra-solar planet hunters … when they “find” evidence of yet another such planet, if that planet is, say, 540 light years away, when the light gets to us it is showing us what was going on 540 years ago. Even if there were a planet with a civilization what could produce radio waves or some such we could detect, that information is 540 years old. What is to say what will happen to us in the next 540 years? Right now our prospects of existing that long do not look good. At the rate we are shitting in our own food bowl, we might not have much of a civilization to be found by aliens.


  1. If we also consider that galaxy groups are moving away from each other, meaning… Oh dear


    Comment by john zande — May 30, 2017 @ 11:56 am | Reply

    • Pant, pant, … can’t catch up …

      On Tue, May 30, 2017 at 11:56 AM, Class Warfare Blog wrote:



      Comment by Steve Ruis — May 30, 2017 @ 12:15 pm | Reply

    • Neat video. But we cannot see the universe as it is “right now” as they claim, as the light we are seeing is from the distant past. A bigger quibble is that in a million years, we are all going to look like Ferengi, WTF?

      I do not know why we should feel at all odd about this as we will personally be around only a few decades, and humanity is unlikely to make another 100,000 years, then kaput. Interestingly, when I read SF stories about the far, far future, it being bleak, I felt a certain angst associated with that story. I wonder if that is rooted in our feeling of permanence that we associate with the earth, even though we change it on a daily basis, e.g. Easter Island.


      On Tue, May 30, 2017 at 11:56 AM, Class Warfare Blog wrote:


      Liked by 1 person

      Comment by Steve Ruis — May 30, 2017 @ 12:26 pm | Reply

      • I devour SF, although our chances of getting to any of it is highly, highly unlikely. Bugger.


        Comment by john zande — May 30, 2017 @ 12:46 pm | Reply

        • Although, Jules Verne could have impressed with some of the progress we have achieved.

          Liked by 1 person

          Comment by List of X — May 30, 2017 @ 12:54 pm | Reply

          • No doubt, the short term stuff can be quite predictive. Am reading Distress right now by Greg Egan (fantastic writter), and that is set more to the end of this century. Perfectly believable. But then Egan sets another a story millions of years ahead of now, and although I want it, I can’t see us surviving the biological realities of our stupidity.


            Comment by john zande — May 30, 2017 @ 12:57 pm | Reply

            • I tend to agree but find the current trend to apocalyptic or post-apocalyptic fiction a bit much. I am one of those cheerful, let’s see how far we can get kind of people. So, Alistair Reynolds, Sharon Lee and Steve Miller, C.J. Cherryh, even Terry Brooks … no matter how dark it gets there is hope and occasionally triumph.

              On Tue, May 30, 2017 at 12:57 PM, Class Warfare Blog wrote:



              Comment by Steve Ruis — May 30, 2017 @ 1:23 pm | Reply

              • Egan and Reed (my two absolute favourites) are pretty positive


                Comment by john zande — May 30, 2017 @ 1:53 pm | Reply

                • If you like a good romp, try Neil Asher.

                  On Tue, May 30, 2017 at 1:53 PM, Class Warfare Blog wrote:



                  Comment by Steve Ruis — May 30, 2017 @ 2:12 pm | Reply

    • But “God” loves us …

      Liked by 1 person

      Comment by Nan — May 30, 2017 @ 2:57 pm | Reply

      • … to death … and eternal punishment. Strange sort of love … I guess you get used to it.

        On Tue, May 30, 2017 at 2:57 PM, Class Warfare Blog wrote:



        Comment by Steve Ruis — May 30, 2017 @ 3:36 pm | Reply

        • Well, I was thinking more of the actual existence of a “god” (who, of course, loves us) when one considers the vastness of the universe. Somehow, to me, the two aren’t compatible.


          Comment by Nan — May 30, 2017 @ 3:39 pm | Reply

          • I have always been puzzled for the Creationists who claim we are “special” (Now isn’t that special!) and that all of this was created for us. So, why all of the rest of the universe? Totally unnecessary. If you want twinkly lights in the nights sky, but up some Christmas lighting, sheesh.

            On Tue, May 30, 2017 at 3:39 PM, Class Warfare Blog wrote:



            Comment by Steve Ruis — May 30, 2017 @ 10:08 pm | Reply

  2. Pretty impressive blog post …


    Comment by Nan — May 30, 2017 @ 2:23 pm | Reply

    • Yuge … the biggest ever! :o)

      On Tue, May 30, 2017 at 2:23 PM, Class Warfare Blog wrote:


      Liked by 1 person

      Comment by Steve Ruis — May 30, 2017 @ 2:43 pm | Reply

  3. One of the things I like to teach is “How to think like a scientist.” That is the Florida standard but I prefer to call it “think like it really happens”. All kids like UFO’s and Bigfoot, and the Loch Ness Monster. I use almost the exact same wording and arguments and evidence that you used here on “Do UFO’s Exist Day” Great minds think alike! So when they ask the inevitable question of “what do you believe?” I respond, “Well what do you think I believe after all we have discussed?” The smarter ones reply with “Yes there are other life forms out there, but they aren’t visiting us!” I simply smile. Great post!


    Comment by Holding The Line In Florida — May 31, 2017 @ 7:11 am | Reply

    • If you really want to know about real scientific facts of Aliens life form, then just read my blog. Subhodeep1987.wordpress.com


      Comment by subhodeep1987 — October 4, 2017 @ 9:58 am | Reply

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