Current best estimates are that the universe as we know it started 10 - 20 billion years ago . 15 billion is the number I hear most often. While 15 billion is a big number it’s one I can sort of wrap my mind around. I’m 50 years old (rounded down). 15 billion is only 300 million times older than I am or 3.0E+8. (It’s been a long time since I’ve worked with scientific notation, so I hope I’m getting this right.) OK, that seems reasonable.
On the other hand I weigh about 100 kilograms. The mass of the earth is about 6.0 X 10(24) kg. And that’s just the earth. The sun is 2.0E+30 kg. It looks like the universe weighs in at about 1.6E+60 kg, but I’m not sure if that’s counting the 95% that’s unaccounted for. Anyway that’s 1.6E+58 times greater than I weigh.
We can do the same thing with distances, but frankly I’m tired of Googeling.
So what’s going on here? I realize I’m comparing apples and oranges, still the cosmological time component seems tiny compared to the mass and distance components.
I suppose this could be the stuff GD, but I suspect that a B-average, non-mensa, unexceptional programmer is not the first to notice this, and that there is some physicist has already come up with an explanation…
While it is possible for a human to “rationalize” a number that large, I think it is difficult for the human mind to really “appreciate” or comprehend how long even 1,000,000 is, let alone 1,000,000,000 or 15,000,000,000.
Sure, you can put it in perspective, but I don’t think you can appreciate it.
I agree with bnorton, that it doesn’t seem long enough. I also think that I have no problem appreciating these numbers, but I can’t speak for anyone else. If I had never heard the number, just from my “feel” of how old the Universe should be, I would have put it 10 or 15 orders of magnitude higher. It blows my mind that people used to think that Universe was mere thousands or millions of years old.
I don’t think that there’s a good physical reason for this to be so. I’ve just accepted that there’s no reason that reality should match up with what I feel.
Incidentally, I usually hear around 13 Gigayears, which is even worse than 15.
If you counted out loud “1 … 2 … 3 … 4 …” at one number per second, it would take you over 475 years to count to 15,000,000,000. That means if you finished up today, you would have started a hundred years before the Pilgrims landed at Plymouth Rock.
(Assuming you can even say numbers like “eleven billion, seven hundred sixty seven million, three hudred eighty eight thousand, nine hundred twenty one” in one second, of course. :))
You’re comparing two things more dissimilar than apples and oranges, more like comparing rocks and blue. A blue whale’s mass and age may have a closer ratio to the age and mass of the universe but it’s just as arbitrary and meaningless to compare them. Consider too that you were only born 50 years ago, the particles in your body mass have been around much, much longer. That puts your age/mass ratio much further out of whack when compared to the universe as a whole. I like pondering vast things like the nature of the universe too but see no reason to compare numbers that have little or no context to each other.
To put it another way, if you were given one dollar for every year that the universe has existed, you’d have fifteen billion dollars. Hey… wait a second. Bill Gates could still buy and sell you!
[KentBrockman]If they were all put in the Grand Canyon, it would fill it two feet deep. That may not sound like much, but keep in mind, it’s a very big canyon.[/KentBrockman]
Don’t forget that time is a dimension. It extends both forward as well as backward! The total time of the Universe will continue on into the future for many many many more years. It is hard to figure out the exact amount of time the universe has, but I think if you did, it may be an amount that you would feel is long enough.
Although it really doesn’t matter. Who says that the Universe had to exist a long time before you came into existance to wonder why it hasn’t been longer? The same goes for the size and mass of the Universe. It just happens to be a whole lot.
I used to think this too, but then I decided, what difference does it really make? Once things get started all you need is a rate of change to end up where we are, and why should one rate be better than another? What makes 10 billion years better than five minutes? The thing I have a hard time comprehending is that there was a ‘time’ before the universe. (Yes I know, time begins when the universe begins, so it is meaningless to talk about time before… and now my eyes are crossed)
I agree with the OP, though I hadn’t thought of it before. It’s just not a number that’s so large, it boggles the mind, like most other things in the universe. Two years for every person on the planet.
Then if you think about all the stuff that’s happened in that time - the condensation of particles to atoms, to suns which baked then exploded, creating the heavier elements, a cloud of which eventually condensed to form the solar system. Then primitive proteins arose, happened to arrange in self-replicating clusters, which led to DNA, then the long process of trial and error evolution. That’s just a lot of events in a time span that I can almost get an intuitive handle on.
Enola Straight has a very good point, and that’s that, when dealing with measurements, it’s important not to place to much significance on the number.
For example, did you notice that the univerese is only 1 (one!) eon old (here I’m defining eon to be about 15 billion years). One! That’s a number I can easily wrap my head around!
Did you know the entire universe weighs only three shitloads? Only three shitloads!! It blows my mind that the entire universe could be so small! (I’m defining a shitload to be about 5 x 10[sup]59[/sup] kg.)
It’s kind of like the old joke, “No, please cut the pizza into 8 slices; I don’t think I could eat 12.”
The universe really isn’t that old. It’s only 3 times older than the earth. There are still stars which formed when the universe was so young it there was virtually no metal around.
Also remember that the universe existed before time as we know it existed according to the BBT. What we assume happened in the 1st second might have taken trillions of years.
scr4 I have to ask you what you mean when you say the universe isn’t that old. It is the definition of old, in fact there isn’t anything older around, and you can’t speak of anything that is older than the universe. If the universe is x years old then it is meaningless to speak of something that is x+1 years old. It can’t exsist.