Tuesday, February 22, 2011

Of Kepler and Drake

I have made a few mentions to the Kepler Mission in my previous posts. It really is one of the most amazing and fantastic missions that NASA has going on right now. And recently, they released the data on 155,000 stars. This wasn't even the entire sample taken by Kepler, the rest of the stars were released to the public through stuff like PlanetHunters.org. And Kepler is still running! Which means there will be more observations, and more planets observed. The first set of data was taken over 4 months. So every planet that transits a star in that 4 month period is observed. If we are looking for Earth-sized planets, that is only 1/3 of Earths entire year. So the longer Kepler looks, the more planets will become observable as they transit.

Now, from the 155,000 stars released there included 1,235 candidate planets. Those numbers split as 68 Earth-size, 288 super-Earth-size (about twice the size of Earth), 293 are Neptune-size (about four times the size of Earth), and 165 candidates are the size of Jupiter (11 times the size of Earth). Those numbers themselves, from a relatively tiny patch in the sky, triple the known number of planets.

More after the page break.



So this is where the fun begins. Using these numbers and making estimates based on them and other known planets, the astronomers on the Kepler team have determined that 1 our of 2 stars has planets. Now that might not seem right from comparing 1,235 candidate planets to 155,000 stars. But the important things here are that this data is only 1/3rd of an Earth-like year, so these numbers need to multiplied by at least 3 to account for that. If the planet is further out, then the orbital period is longer. So, even by multiplying by 4 as a benefit of the doubt to Earth-like planets, we end up with 4,940 planets. Jupiter takes almost 12 years to orbit our Sun.

Now that aside, not all planets transit in front of their host/parent star. This depends on where there orbital plain is aligned. We are lucky to see so many in line such that the transits are visible from our solar system. But that isn't really luck, it lends to the idea that orbital plains are not uniform, but unique to each star system. In fact, one of the other forms of detecting planets is watching for the slight jiggle of a star as a planet orbits. So taking into account all these possibilities for planets, these astronomers have arrived at roughly every other star having planets.

Even more amazing then that, roughly 1 star out of 200 have planets in the habitable zone. There are at least 100 billion stars in the Milky Way galaxy (our home). So at least 50 billion planets, and at least 500 million in the habitable zone. The not-to-hot, not-to-cold sweet spot where life could exist.

500 MILLION possibilities for life to arise in our galaxy alone. This is a number that I never thought I would see in my lifetime, and I consider myself young, a month away from 25. It is an important number that satisfies the first three values of the Drake Equation. The Drake Equation if you do not know is used to estimate the number of detectable extraterrestrial civilizations in the Milky Way, and it looks something like this:

N = R* fp ne fl fi fc L
where:
N = the number of civilizations in our galaxy with which communication might be possible;
and
R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
f = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space.
In summation, given what we know, the first three values of the Drake equation equal 500 million planets that could potentially support life in our Milky Way. The numbers beyond that are hypothetical at this point until the next astronomical leap forward. But it gives hope to those who have an optimistic view for life. These 500 million planets may not develop life, and those that do might not even develop intelligent life. But out of 500 million possibilities, can we really be the only one? It is possible, I wouldn't bet on it though, you'd be more likely to win the lottery (usually never gets about 1 in 100 million).

But perhaps we did win the cosmic lottery for our Galaxy, maybe even the Universe. Now that we have real numbers to look at, things look a bit clearer, but more questions are raised. There are several practical, religious, cultural, and societal implications that come from this knowledge. Generally this arises from the Fermi Paradox. The Fermi Paradox simply asks, 'Where are they?' Where are the extraterrestrial intelligences despite the high estimates for their existence. And this is where I will pick up next time, I will look at the Fermi Paradox in relation to the Kepler Mission findings.

A couple of sources and interesting reads:
http://www.popularmechanics.com/science/space/telescopes/kepler-nasa-telescope-questions-5172767
http://www.google.com/hostednews/ap/article/ALeqM5gEP97VOwoGXKV6vv8EX033MYPRew?docId=104d3f519c7443169a7df8c17bb4a406
https://secure.wikimedia.org/wikipedia/en/wiki/Drake_equation


27 comments:

A. said...

Damn i love space, the endless possibilities!

Kerykeion said...

If we can get over our petty differences, I think we could reach the furthest expanses of the universe

724427 said...

Thanks for the news, never knew they were actually going to do that.

Innovations said...

i love learning about space

Anonymous said...

Theres millions of life-forms under my fingernail and between my teeth, and I don't even need to walk out the front door to encounter countless more. We've got life at the bottom of the sea, in volcanoes, artic and arid regions... even our cyberspace has simmulated life-memes.

Yes, I would be very suprised indeed to think that no life would be on these planets... what about looking for city lights on the plaents, or is the resolution not that powerful and the planets still too far...

Every Day said...

GREAT! we are already mapping our next move for galactic conquest!

synoptixs said...

space is awesome!!

gekomaster said...

We are lucky to live in this age.

obi said...

nice to know we have plans ;)
thanks for the news.

ixg said...

Personally, I don't care about extraterrestrials existing or not, but I'm excited about humans expanding elsewhere, and knowing that theres a high probability for other habitable planets is just awesome!

Buckaroopopcorn said...

> But out of 500 million possibilities, can we really be the only one?

I'm of the opinion this is the case. I would guess there might be one earth per galaxy. I think this just because the probabilities of life beginning and being sustained long enough seem really terribly remote. Granted we don't know what life looked like originally but from how complicated it is now (DNA,RNA proteins etc) I imagine it's a pretty rare occurrence.

cooperlife said...

yay science. Discovery channel has a whole special about the possibility of alien life presented by Stephan Hawking in "Into The Universe"

Alan said...

Man I really hope in this lifetime we find proof of life outside Earth.

PekkaK said...

Oh man, equations!

tetcrh said...

When you put it like that, it's hard not to believe...

I think it's very likely that ET is out there somewhere, but the chances of finding alien life within a distance we'll be able to travel in our lifetimes? Pretty low I'd guess.

Awesome post man, followed!

Chuck said...

The first Blog I've found that GENUINELY interests me. I firmly believe we are not the only planet in our galaxy which supports life.

The depressing part tho.. never in our lifetimes will we venture beyond just looking at these stars - most of which are so far away no human could travel there before dying of old age. *Sad face* :(

Venus said...

the number of star systems is just astonishing...

Robert Fünf said...

Wow. I can't believe there are that many possibilities in our galaxy, alone.

Anonymous. said...

Space is kul.

Jessica said...

These is pretty intresting. Thanks for the updates on space!

Kindros said...

It is crazy how we focus so much on ourselves and forget there are other worlds out there. I'm sure if we found one that was inhabitable and we could get there, it would just be Avatar in real life.

Zach Roan said...

Sigh reading your blog makes me wish I was born later so I could zip around in a space ship and see the beauties of space with my own eyes.

Pop Tart Fine Dining said...

I think life on the possible dozen of planets they found is extremely likely. Hell, even if it's bacteria found in water, then it's still life on other planets. It's highly likely that beings already exist elsewhere, and I believe doubting it is ignorant.

Scott said...

Very cool. Information like this makes me wish I had gone into science instead of business sometimes.

AnthropoSeptic said...

I was just reading up on this today, but as usual, your posts are more informative than the news stories on the subject. Your blog has legitimately increased my understanding and appreciation of astronomy. Thanks, bro.

Havuelete said...

Great post, very well explained.
I think Johannes Kepler would be amazed and honoured that a space mission with his name has already discovered so many planets, and could discover other life forms.

husar said...

Well done,very interesting and clever. Good post:D

+followed :)

Post a Comment

Comments are moderated, please no advertising or profanity. This also helps me see who is dropping by.