Log in

Bandman's Journal of DOOM [entries|archive|friends|userinfo]

[ website | Standalone Sysadmin ]
[ userinfo | livejournal userinfo ]
[ archive | journal archive ]

[Links:| The Circus My Official Home Page Vito's Random Pictures My Linkbar MOVLUG ]

The odds of extraterrestrial life existing... [Feb. 7th, 2011|02:20 pm]
[Tags|, , , ]
[mood |contemplativecontemplative]

There's a famous equation that is supposed to determine how likely it is that intelligent life that can communicate with us exists in the galaxy. It's called the "Drake Equation", and here's how it's defined:

All of those variables are outlined on the wiki page, but basically, you take the total number of stars in the galaxy, multiply it by the number of planets around those stars, multiply THAT by the fraction of planets that can potentially support life, then by the fraction of planets which actually do develop life, then by the fraction of planets with life that evolve into intelligent life, then by the number of planets who actively try to communicate, then by the amount of time the civilization exists for.

Basically, we're pulling numbers out of our collective scientific butts.

However, it occurred to me today that there's a much more important question that may go into the Drake equation...you can see that it calls for "planets which can potentially support life". What that means is, are planets in the "habitable" zone, also known as the "Goldilocks" zone, because it's not too close to the sun to burn up the atmosphere, nor too far away such that it receives too little heat.

It gets complex, though, because the habitable zone of stars is variable, based on the size of the star and its output (huge stars like Betelgeuse have amazingly huge habitable zones, but don't last very long, and probably not long enough to develop life, let alone intelligent life).

So basically, we live near an "average" star, Sol. If we assume that its habitable zone is average, too, then we know that it stretches from just inside the orbit of Venus to just inside the orbit of Mars (or maybe outside the orbit of Mars, depending on who you ask). We're smack dab in the middle.

So say we get three "good" orbital "spots" for planets. Does that mean you could say we can plug in that number to the Drake equation? Well, sure, you /could/, but it might be disingenuous...check this out.

There are 8 planets in our star system. There are, however, 130+ known moons. Now granted, lots of these moons are nothing more than glorified asteroids, but a great many are quite large (Ganymede, a moon of Jupiter, is twice as massive as our moon, and larger than the planet Mercury).

A great many of the exoplanets we've been finding have been gas giants, probably because for a long time, we've used gravitational shifting to determine the existence of these planets, but our techniques are getting better. The smallest exoplanet we've found so far is a "superearth" (in other words, most likely made of rock and metal, like our planet) twice the mass of Earth. Everyone gets really excited when it comes to finding superearths, especially if they're in the habitable zone, because it's believed that they're most likely to harbor life.

While that's exciting to me, it's more exciting when I hear of a super-massive gas giant in the habitable zone. While a star like ours gives the ability to have a few good candidate planets, one gas giant the size of Jupiter gives the ability to have several candidate moons, and a planet 10 times the size of Jupiter? How many rocky moons could that support? Dozens, probably.

The idea of a single planet providing dozens of spots for life is exciting. The issue then, is, is the average rocky moon as capable of supporting life as the average rocky planet?

That's definitely not established. We have exactly one data point on life being established on a rocky planet (that's us, by the way). We have absolutely no data on life existing on rocky moons.

The biggest difference between most moons (that we've seen) and most planets (again, that we've seen) is that the majority of moons are tidally locked. What that means is that because of the gravitational stresses on the moon from the planet (and vice-versa), moons tend to always have the same side of the moon facing the planet. That's the way our moon is (The side of the moon facing us is always the same). That's also the way most other moons in the Solar system are, too.

The popular idea that the moon has a "dark side" is wrong. The "back" of the moon is lit half the time, and is dark half the time, and the day / night cycle (which we see as the phases of the moon) is around 28 days. That means that where-ever you are on the moon, it's day for around 14 days and night for around 14 days. As far as we can tell, that's not ideal circumstances for life to develop (but again, only one data point).

In any tidally locked moon, the length of the day is equivalent to the orbital period (assuming there's only one sun in the star system). For a moon like ours, as we said, that's 28 days. Ganymede flies around Jupiter in 7 days, though, so it's not a given that extreme periods for the day/night cycle are necessary.

The question that, in my opinion, the Drake Equation hinges on is whether or not life can evolve on a tidally locked moon. If so, the opportunities for life are vastly improved.
link11 comments|post comment

(no subject) [May. 19th, 2010|03:41 pm]
This is the kind of thing that the federal government was designed to prevent. The US government functions, among other things, as a federation between the states, and needs to be the arbiter of disputes such as this. In my opinion, of course.
link1 comment|post comment

Some thoughts on the environmental movement... [Apr. 19th, 2010|02:46 pm]
I wrote this in response to a Slashdot comment, and it was too good (actually, just too long) not to share somewhere...


>RE: Food - by mcgrew (92797) *
>Why should CO2 from any animal; food, wild, human, whatever, count?
>What's the difference between cow farts and elephant farts?
>This CO2 is natural, CO2 from burning jurassic plants is not.

You can't just compare like that. You've got to look at volume.

For instance, you say cow farts are "natural" sources. Natural how? As in, because they're produced by animals? How would you explain the unnatural population of animals that we've bred into being, solely for consumption? All of those extra animals contribute, too, but can't be considered "natural", at least in the way you were meaning it.

The truth is that there is not, never was, and can't be, a single canonical "right" amount of CO2 in the atmosphere. We're living in a world that changes drastically over the course of 10,000 years. Millions of years ago, insects were the size of us, just because of a _slight_ change in the O2 percentage in the atmosphere. Was that wrong? Or was that right? How about a few millions of years before that, when CO2 was king, and plants evolved because it was the most plentiful, and they exuded a caustic gas, O2?

This biosphere adapts. The animals (including us) come and go, and change and adapt to the circumstances of thousands and millions of years, but there's no "wrong" or "right", there's only "right now".

Now, you could argue from the point of view that since we're the dominant form of life, most intelligent, and technologically advanced, we have a sort of noblesse oblige to "fix" things. Especially since there's evidence that we "broke" them.

There's a sort of universal guilt among the ecologically-friendly people that attempts to repent for their lifestyle. "Carbon credits", for one. Buying organic food, for another. People feel guilty for their "footprint" and try to buy the new age equivalent of indulgences. "I fly a lot, so I buy carbon credits". Great. I mean, not as good as not flying, but at least you feel better about yourself. "I buy organic because pesticides hurt the environment". Awesome. Unfortunately, you had to work nearly twice as much to pay for those organic foods, not to mention that it's unbelievably inefficient, and much more susceptible to disease than the cheaper, prettier, just-as-healthy food 20 feet down the row at the grocery store.

We need to get past the guilt for breaking our planet, because we haven't. It isn't broken. We might have changed our planet, but it's not broken. As soon as we change the terminology, we can stop focusing on the guilt, and start focusing on what's really happening. We want to change the planet again, but in the other direction. We want to change it, because it's going to be more comfortable for us like that. It's what we're used to. It's how we like it, and we (might) have the technology to do it. So stop concentrating on guilt, and start concentrating on the real goal. We're being selfish, by trying to adjust the planet for our own gain, and there's nothing wrong with that. We've been doing it ever since we killed the first snakes that lived under the rocks we moved when we built the first house. It's only a matter of scale.
link1 comment|post comment

This is so funny I have to share [Aug. 26th, 2009|12:23 pm]
I love my wife, and I feel for her. Really, I do. She has to put up with me.

Here's a conversation we just had:

Amy: Also, this looks like a neat idea - http://www.yankodesign.com/2009/08/24/getting-lost-is-not-so-trendy/
Matt: oh wow
Matt: that's awesome
Amy: That's what I thought :)
Matt: I'm still not sure I believe it though
Amy: lol, well it's just a design idea, i think?
Matt: ah
Matt: yeah
Matt: I could design one of those
Matt: except mine teleports you wherever you're going
Matt: and it's housed in a spaceship
Amy: That might be more noticeable than a chapstick sized gps projector :-P
Matt: sure, if you disengage the cloaking device
Amy: I love you
Amy has left the conversation.
linkpost comment

This. [Apr. 23rd, 2009|09:51 am]
link3 comments|post comment

Sort of occasional "Random playlist selections" entry [Apr. 10th, 2009|01:53 pm]
Ryan on twitter asked about a random sampling of my iPod playlist after I spent all night adding wacky 90's music to it. Here goes:

1: I Can't Dance - Genesis (1992)
2: I Hate Everything About You - Ugly Kid Joe (1992)
3: Rhythm of my Heart - Rod Stewart (1991)
4: All I Wanna Do - Sheryl Crow (1994)
5: Hold My Hand - Hootie and the Blowfish (1995)
6: I Can See Clearly Now - Jimmy Cliff (1994)
7: Please Forgive Me - Bryan Adams (1994)
8: Shine - Collective Soul (1994)
9: Jumper - Third Eye Blind (1999)
10: Baby I Love Your Way - Big Mountain (1994)
BONUS: Mambo #5 - Lou Bega (1999)
link7 comments|post comment

Stress [Apr. 8th, 2009|02:02 pm]
This is not an excuse to show off my new userpic
link1 comment|post comment

This is even funnier since I'm going back and rewatching Star Trek [Apr. 4th, 2009|03:36 pm]
link1 comment|post comment

More Star Trek [Apr. 1st, 2009|10:24 pm]
S02E22 - Shades of Gray

The official "Riker gets a lot of tail" episode
linkpost comment

I can't believe it [Mar. 31st, 2009|10:47 pm]
I just watched a Star Trek: The Next Generation episode that I've never seen!

It was called Up the Long Ladder. It was awesome!
link2 comments|post comment

[ viewing | most recent entries ]
[ go | earlier ]