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An artist's rendition of the new discovery of the three new planets, orbiting a star previously thought to hold none.  (Source: ESO)
More new Earth like planet discoveries pour in

Planets just aren't quite as unique as they once were thought to be.  During the medieval times, it was thought that the Earth was the center of the universe about which the sun and planets rotated. 

With time it was realized that the Earth was just one of the solar planets orbiting the sun, but skepticism that planets existed outside the solar system remained strong.  However, with the advent of new techniques and more power telescopes researchers began to discover extrasolar planets at a rapid pace, starting in the 1988, with the discovery of planets orbiting the star Gamma Cephei.  Meanwhile a large new orbiting body was discovered on the fringes of our own system, while Pluto was downgraded to a mere "Plutoid".

Some of these planets were deemed somewhat Earth-like in that they were smaller than gas giants, might have water, and could be made to be habitable.  Other extrasolar planets were similar in size to Earth, but were way to hot to inhabit with current technologies.

Now European astronomers have continued the run of discoveries of smaller planets with the discovery of a trio of "super-Earths" rotating around the star HD 40307, located 42 light-years from Earth towards the southern Doradus and Pictor constellations.  The new planets have masses of 4.2, 6.7, and 9.4 times the mass of Earth and orbits of 4.3, 9.6, and 20.4 days respectively.

The star they orbit is a normal star, approximately the same size as our sun.  According to Didier Queloz and Michel Mayor, expert planet hunters who led the discovery team, the planets are too hot to support life as we know it.

However, despite this slight disappointment, the discovery raises the intriguing possibility of a so-called "crowded universe" teeming with undiscovered planets.  HD 40307 was long thought to hold no planets -- it is clear now that the discovery was only possible with the advances in detection.  There are likely many smaller planets that have yet to be detected.  In total 270 extrasolar planets have already been found.

Stéphane Udry, a colleague of Mayor, describes the advance stating, "With the advent of much more precise instruments such as the HARPS spectrograph on ESO's 3.6-m telescope at La Silla, we can now discover smaller planets, with masses between 2 and 10 times the Earth's mass."

Mayor who works at the Geneva Observatory states, "Does every single star harbour planets and, if yes, how many?  We may not yet know the answer but we are making huge progress towards it.  Clearly these planets are only the tip of the iceberg.  The analysis of all the stars studied with HARPS shows that about one third of all solar-like stars have either super-Earth or Neptune-like planets with orbital periods shorter than 50 days."

The slowly unfolding picture of a universe full of planets brings two key possibilities.  First, the possibility of expansion and colonization outside the solar system, and secondly, the possibility of extraterrestrial life.



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RE: If space is so massive...
By phattyboombatty on 6/18/2008 6:46:39 PM , Rating: 0
quote:
If the universe is infinite (or really, really, amazingly huge), then if Earth exists with intelligent life, obviously the probability is greater than zero.

The question is "What is the probability of there being life other than on Earth?". Obviously, if the question is "What is the probability of life existing in the universe?", that probability would be 1, because we know that life does exist. It is currently impossible to express a probability for the existance of life other than on Earth because we don't know of any other examples. It's similar to asking what is the probability of pulling a blue marble out of a bag, where you have no idea what color marbles are in the bag.
quote:
Thats one winner for life, and two close-calls, in one solar system.

How exactly do you define "close-calls"? We haven't even been able to replicate abiogenesis under presumably ideal conditions in a controlled laboratory setting. What evidence do you have to suggest that life was just about to evolve on Mars and Europa but didn't quite make it?
quote:
We can't possibly be that special; to even think we could be almost seems arrogant.

The universe doesn't care about what may or may not be "special" to humans. If it happened once, it happened once. If it happened a million times, it happened a million times. This weird sort of self-confidence issue that a lot of people have regarding the Earth's place in the universe is strange to me.


RE: If space is so massive...
By idconstruct on 6/18/2008 7:15:34 PM , Rating: 3
You can't just selectively exclude earth from a probability based on the universe when the earth is very clearly part of it.

quote:
With a probability greater than zero and an infinite universe, logic dictates there must be countless other Earth-like planets.

I think there's something about that quote you must not understand.^

quote:
Obviously, if the question is "What is the probability of life existing in the universe?", that probability would be 1


yes this is nit-picky but a probability of 1 is like saying: The Universe = Earth
The probability is actually 1*10^-(BIG NUMBER)... yes it is small, but it is greater than zero. As such, if you multiply that by an infinite universe, you have infinite other planets with life.

quote:
It's similar to asking what is the probability of pulling a blue marble out of a bag, where you have no idea what color marbles are in the bag.


Well, considering we've pulled quite a few marbles out of the bag already and one of them was indeed blue (earth) how is it unreasonable to assume there could be more in the bag? Especially considering there's upwards of millions or billions of marbles in the bag?


RE: If space is so massive...
By cyclosarin on 6/22/2008 12:46:44 AM , Rating: 2
He isn't discounting the Earth. He's saying Earth is reference point 1, find reference point number 2 before you start extrapolating data.

You're trying to debate on an emotional level based on your belief structure and you aren't comprehending the debate on a logical level. He's already said there could be millions of 'earths' out in the universe, he also said we could be the only one. We have no proof either way at this point.


RE: If space is so massive...
By masher2 (blog) on 6/18/2008 9:52:50 PM , Rating: 1
> "We haven't even been able to replicate abiogenesis under presumably ideal conditions in a controlled laboratory setting"

I'm surprised you didn't sprain a finger when you typed the word "even" in that sentence. Once we've "replicated abiogenesis", we've created life itself. It's something that took nature billions of years and a laboratory the size of a planet (if not larger) to accomplish...and you're upset because we haven't been able to replicate that in our extremely limited experiments of the past 50 years or so?

The fact is, while we haven't replicated the entire process, we've made enormous strides in many areas. We've shown that inorganic molecules can spontaneously form into organic nucleotides -- not under "controlled laboratory conditions" but under conditions the primordial earth would have had. We've seen those nucleotides self-assemble into larger units, and likewise seen the spontaneous formation of protocells, which exhibit behavior remarkably similar to the simplest eukarotic life.

At our current rate of progress, within the next 250 years or so, we'll not only have replicated the entire process, but we'll be custom-building our own lifeforms, to whatever designs we wish.


"And boy have we patented it!" -- Steve Jobs, Macworld 2007

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