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Three Tiny Exoplanets Suggest Solar System Not So Special
ananyo writes "Adding to its already long roster of firsts, NASA's Kepler spacecraft has found the three smallest extrasolar planets ever detected — all of them smaller than Earth, and the most diminutive no larger than Mars. The newly discovered trio forms a miniature planetary system orbiting a cool, dim red dwarf star called KOI-961. Because they are so close to their star, the three exoplanets are too hot to support life. But unlike most previously known exoplanets, the vast majority of which are Jupiter-scale gas giants, all three are thought to be rocky worlds like Earth and the other worlds of the inner Solar System."
Yes, that star's habitable zone is probably closer than our Sun's, but the planets are still way to close to be considered in that star's habitable zone.
FTFA:
At the AAS meeting, the discovery team announced that all three planets orbiting KOI-961 whip around the star in less than two days. The outermost body is the tiniest, with a diameter half that of Earth, or about the same as Mars, and a temperature of about 400 degrees Celsius. The inner two planets are larger, with diameters about three-fourths that of Earth. But that is still smaller than Venus. Because the planets are all small and close to their star, much of the atmosphere they may once have had would have evaporated, leaving behind bare rock, Marcy says.
If what I just said sounded like a troll, it was probably just a failed attempt at humor.
miniature planetary system orbiting a cool, dim red dwarf star called KOI-961
Seems fishy ...
While that is true, it is nearly impossible for us to determine such things right now. That's why current searches are looking for things that appear to be earth like for the simple reason that we know what to look for. Until we can find other things that we KNOW are life we can hardly begin to speculate on if we are detecting things that might be life but not as we know it. As we get more comfortable in detecting these kinds of things we'll be much much better equipped to come to conclusions for things we haven't seen.
There is a correlation between galaxy arms and possible habitable planets. The idea is not only does the planet have to be the right size, correct distance from the star etc, but also that its location in the galaxy matters!
Apparently passing through arms of a spiral galaxy is not good for sustaining life. I guess the density of the stars and solar systems must account for that.
For a starter, http://en.wikipedia.org/wiki/Rare_Earth_hypothesis#The_galactic_habitable_zone
So, Kepler is up, in orbit, doing it's thing. Scientists expect to learn a lot, from finally being able to see alien worlds that are a similar size to earth.
Those of us who are non-scientists know that this isn't really going to be that exciting, unless they find something that differs from are assumptions. We expect that there are many small planets out there, that have not been visible until Kepler. We know that we will never actually "see" these planets. Kepler is just able to watch for periodic changes in brightness of the star, which indicates planets crossing our view of the star. Based on the period, we can "guess" the diameter of orbit, and the size of the planet.
When we see a spectrum of light produced by a stellar body, we know something of its composition. But, we aren't seeing that with alien worlds. We just see the star that they orbit getting dimmer. So, we'll never know the real composition. Once again, we "guess" the composition based on the size of the orbit, and the mass of the planet, both of which we guessed, based on the periodic nature of the brightness.
In a matter of 3 weeks, slashdot has seen 4+ articles about planets "discovered" by Kepler. None of them have findings different from what we've expected, yet they've all received prime coverage by pop-science publications. This leads me to a new theorem:
Kepler (spacecraft) is a spammer!
Wake me up when we get interesting news.
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Why? TOAC had a point. A very valid point. What's funny about this is that on the same page I saw this article, I saw an article entitled "Should science rethink the definition of "Life"?". It even said "With the increase of extremophile discovery in recent years perhaps it's time to reassess what the definition of "life" should be."
And here you are arguing the poster just wants people to believe his or her viewpoint without ever countering the actual counterargument you complain about.
Ad hominem character assassination just isn't cool.
I've read this nice book on how (1) *animal* life (or an equivalent with slightly different chemistry - but still complex and multicellular) might be rarer in the Universe than we previously thought - mainly due to temperature stability problems during the long evolution of said organisms (main sequence stars shining progressively (and significantly) brighter as they age and the ecosphere having somehow to cope with it, which in case of Earth means some kind of CO2 feedback mechanism that tends to stabilize the temperature in a fairly narrow band of temperatures and that might be quite rare in the universe - again, a speculation), whereas (2) an alien equivalent of extremophilic bacteria might actually be much more common than we thought and could make up the greatest potion of Universe's biomass (just as it is on Earth). The question here is whether there are other interesting self-replicating molecules than just DNA and RNA. If not, then I guess we have quite a good idea as to how alien life looks like. (But I love to be proven wrong every now and then...)
Ezekiel 23:20
But at that level of pedantry, we might as well assume that life can exist within a star itself, and that planets aren't really important. Or for that matter, maybe these plants are actually large balls of cheese! Until we actually land on extrasolar planets, we can hardly begin to speculate on if what we are detecting are actually rock and gas.
Astronomy offers only very limited opportunities for observation and basically none for testing. We must supplement what data we can gather heavily using theories and understandings rigorously tested on Earth. While we can't rule out Star Trek style energy beings, for example, we can look at plasmas and their behavior and realize that forming synaptic pathways out is it would basically be impossible. We can draw up some pretty loose limits on life... If it's cold enough that helium is about the only liquid available or so hot that what hasn't melted are only impermeable rigid ceramics, the probability life exists is nil. If it's too hot for a man built machine to function, then it's probably too hot for life as well. It's just a matter of extending what we know about chemical processes, materials and mechanics... Too hot or too cold and making functional and reliable processes, let alone life, is too hard.
In this case, they are estimating a temperature of 400C. For comparison, silicone and fluoroelastomers top out at about 300C, while highly engineered fluorocarbon oils can only barely get to 400C . Simple hydrocarbons, among other things, can beat that but are highly reactive and can't survive in a reactive environment (particularly with oxygen). Nitrates decompose around that temperature too. So in what medium would life exist? A eutectic salt mixture? But those are so corrosive, what would then contain it? These are the questions the look at and can't answer when they say "life doesn't exist". (And all this doesn't even cover other issues, like the radiation hazards of being closer to the star.)
If we see a rocky planet at 200C, then we can really discuss how stuck we are on water based life being the only option and how open our minds should be. But this one? It's dead, Jim.
which in case of Earth means some kind of CO2 feedback mechanism that tends to stabilize the temperature in a fairly narrow band of temperatures and that might be quite rare in the universe - again, a speculation
The "quite rare" speculation is certainly based on definition. It would be correct to say "quite rare" if even a fraction of a percent of stars have an Earth-like planet. The "quite rare" may not be correct considering that such a small fraction could be billions of planets.
It is quite amusing that humans want to consider ourselves unique and somehow believe we will be the superior beings when life is discovered elsewhere. I certainly hope not, because it is quite depressing to consider we are the best of what the universe has to offer.
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First Man thought the earth was the center of the (universe) the solar system
Then he thought the sun was at the center of the (universe) the galaxy
Then he thought the galaxy was at the center of the universe
Then he thought planets were rare and that earth sized planets even rarer. Not so! (it looks like)
Not only is Man no longer at the center of the universe in any figurative sense, metaphorically he is even less so. Solid matter (let alone organic compounds) are a vanishingly small component of what makes up the universe with Dark energy, Dark matter and matter in superheated plasma, black holes or cold interstellar clouds making up the rest.
All that remains is to (hopefully) find that Life is not rare then Intelligent Life is not rare and that Technological civilizations are not rare.
But hey, even if so, at least we've got Paris Hilton I mean Kim Kardashian!
How many suns exist?
From: http://www.esa.int/esaSC/SEM75BS1VED_index_0.html :
"there are something like 10**11 to 10**12 stars in our galaxy"
From: http://www.universetoday.com/36610/how-many-galaxies-have-we-discovered/ :
"Astronomers think that there are hundreds of billions galaxies in the universe"
Ok, so estimate 500 billions - thats 500 000 000 = 5 x 10 ** 8
That would be 5 * 10 ** 19 = 50 000 000 000 000 000 000 possible stars/suns
That's a number beyond human comprehension and applying any statistical probability will return a true chance.
So - be assured that "we" are not alone and with current means can never visit other planets within one person's life-span.
What the heck! In the meantime, the basis for live as it was existing up to now on this planet the human race is going down the tube!
GP has a point. We have no tools to search for life (outside of the solar system), we can only search for certain materials (e.g. water, carbon) and certain temperature ranges.
Kepler detects planets by seeing periodic small drops in the brightness of the host star as the planet passes in front of it. That is only going to work for planets with a pretty short orbital period (I don't know the limit) since they depend on multiple observations to get the orbital characteristics. Neptune with is 100+ year period would not be measurable and unlikely to be observed even once during the mission.
OTOH, most of us have the capacity to recognize the flaws of our species, and we are willing to accept economic inefficiencies in exchange for meeting intangible social and cultural benefits. We really aren't that bad, for the most part.
Techies tend to have mild BPD, believing most highly in rationality, criticism and determinism, so we're all a bit brain damaged when it comes to sociology and anthropology. I bet a lot of /.ers would think the Vulcans are a better species than humans, for example. They'd probably keep thinking that right up until the Vulcans make the perfectly logical choice to exterminate 10% of their population to correct their 10% structural unemployment.
Once I saw a demo by a forest person about some geological features. He had a 2 m stick and said this represents the age of the earth (making comments about subsections). Then he asked what the age of humanity would be on that scale and to give the answer, he put a sheet of paper on top of the stick. The thickness of this paper represents the time humans are on this planet.
To put this (and you) on a cosmic scale and time with galaxies, universes and super clusters of universes wanting to make any guesstimates you are attempting, I wish you good luck!
If amino acid building blocks are found on comets coming from outside our solar system, live in complex forms may be a common appearance on that vast scale - or not, who cares?
Humans have a temporary appearance on this planet, just see what they are making of it....
More advanced civilizations elsewhere may have concluded that tending their own planet and living happily there is the way to go - why bother about some stuff light years away when the environment you evolved in is just right, enjoyable and precious.