SpaceFollow

One of the first things my professor did in my astronomy class this year was to impress upon us a sense of scale. Which ends up being pretty difficult, since the human mind has trouble wrapping itself around just how big the universe really is.

Here's an example. This is the Hubble Ultra Deep Field image. Warning, big picture is big.

To take it, they basically pointed the Hubble Space Telescope at a tiny patch of sky. 3 arc minutes across. That's roughly 1 tenth of the diameter of the moon when viewed from here on Earth. They left the shutter open for 114 days.

There are roughly 10,000 galaxies in that one image, in that one tiny patch of sky.

Some of those galaxies, or rather the images of them, are from 13 billion light years away - meaning that some of them likely formed between 500 and 700 million years after the Big Bang. There are likely some of the first galaxies in this image.

Now, let's do some math. Imagine that each of those galaxies has 300 billion stars. That's actually probably a low number. It's roughly the amount of stars the Milky Way has, and the Milky Way is only "meh" when it comes to numbers of stars, and the universe was actually much more active in terms of star formation earlier on in its lifetime. Still, 300 billion is a nice baseline number.

So, assuming that each galaxy has ~300 billion stars, and there are 10,000 galaxies in that picture, we're looking at 3 quadrillion stars. 3 x 10^15. 3,000,000,000,000,000. 3 million, billion stars in that tiny patch of sky one tenth the width of the moon. Now think for a second about how big the sky is when you look at it. Think for a second about how many of those 1/10th of the moon pieces you could cover the dome of the sky with. 10,000 galaxies in each one. 3 quadrillion stars in every little arc minute. 30 quadrillion stars, blocked by the moon alone.



The Universe. Is. Huge.



Now, here's where it gets fun. Current estimates put the average percent of stars with planets at between 20% and 50%. Let's average that and say 35% of all stars have planets circling them. Now let's look at our three quadrillion stars and say that of those, there are 1.05x10^15 with planets. SpoilerIn reality, planets wouldn't have formed for another few billion years, but shut up, I'm having fun with this image. That's 1,050,000,000,000,000 stars with planets around them.

Say that only .1% of extrasolar planets actually end up with a planet that can support life.

Say that only .01% of those planets actually develop life.

Say that only .001% of those planets develop sentient life with any meaningful civilization.

In that one picture we're looking at? 1,050 different civilizations.

@#%^ yeah, space is awesome.

Spoiler

Edited, May 5th 2012 1:46am by IDrownFish

Dibs on the first Asari.

Lol, fine by me. But if given the chance, I may have to switch up the chirality of some proteins. If you know what I mean.

Space is awsome! Someday we'll get there in force. Someday.

I'm watching "The Right Stuff" again.

It doesn't need that. You're trying to make the equation to do something it does not. All it does is generate a number of advanced civilizations from a set of probabilities within your specific parameters (galaxy, local cluster, universe). Well, the initial equation was just for our galaxy, but it is easily spread.

That's all it does. It doesn't say anything about whether or not we'll find them, though it could be useful as a factor in another equation trying to answer that question (though it would need to be MUCH more advanced, considering the probability of communicating within our galaxy is far more likely than with another).

It's like saying that the formula to calculate the area of a circle is lacking because it needs something else to calculate the volume of a sphere. Your asking for different outputs, and each equation is built around those.

If you are interested in a formula that uses the Drake Equation as an input to calculate the number of potentially communicable civilizations, I'm sure it exists. It would be much less useful though. The Drake Equation is cool because it shows how little it takes to believe in the existence of alien life. It's not meant to give a reliable number of possible civilizations, because we can't actually reliably calculate most of those probabilities.

[EDIT]

Actually, I looked it up. I learned a version of the Drake equation that differs from the widely used one (being the original). I'm guessing my professor was just trying to prove a point by leaving out the last two variables of the equation, that being that the chance for life was huge.

That said, there still doesn't need to be an adjustment for the distance because the version of the equation I was unfamiliar with has it built in. The chances for detection increase linearly with the amount of time they are broadcasting. It may not be perfect, but it's good enough. Since the equation is returning an average number of potentially communicable civilizations, it shouldn't be an issue--you're going to assume they are relatively homogenous across distances, for the purposes of the equation.

It's really just a thought experiment. And the constraints are left to you. Their distance from me doesn't matter at all if I'm not limiting form of communications to light, for instance.

Edited, May 8th 2012 12:42am by idiggory

And now I'm wasting my whole morning watching shuttle pieces crash to earth.

Also I thought if we ever met other civilizations all our little microbes would assume we killed each other off or something. Let the aliens be aliens elsewhere if that's the case.

Less viral, more bacterial or fungal or something. Like would any of the billions of little critters we carry with us find them tasty? I mean there's no guarantee they could eat 'em at all or anything, but still!

Yeah, human language is built around genetic preconceptions. The concept of "I" for instance--a lack of personal identity would already be a massive hurdle. And that's on top of so many others.

That takes "talking out your ***" to a new level.

Smell you later?

This conversation stinks.

Yeah, we kind of crapped the bed on this one.