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Fraser
2003-Jul-10, 05:25 PM
SUMMARY: The European Space Agency is planning a series of space-based observatories designed to search space for evidence of Earth-like worlds. But an easier target to spot should be waterworlds; six times the mass of the Earth and covered with an ocean 100km deep. The CNES/ESA mission Corot will launch in 2005, and should just barely be able to spot dimming stars as these "waterworlds" pass in front. Even more powerful Eddington will launch in 2008 and should be able to see planets half the size of Earth. Finally, Darwin will launch in 2014 and search for signs of life on Earthlike planets.


Comments or questions about this story? Feel free to share your thoughts.

ogdog
2003-Jul-10, 06:14 PM
I only have to say. I can't wait until we do find definitive proof of extraterrestial life. Intelligent or otherwise. It is great to see all this research going into these sorts of things. :rolleyes:

DippyHippy
2003-Jul-11, 05:06 AM
Hmmmm... the thing that surprised me most about this story was not the advance in technology this heralds, but rather that oceanic planets are thought to exist...

I always thought they were theoretically impossible (can't remember the argument why) - can anyone shed any light on this? :huh:

Dips

Planetwatcher
2003-Jul-14, 06:47 PM
Water world. Sounds like the name of a movie. ;)

Earth could be a water world if our polar ice caps were all melted.

It's believed there is water on Mars, and possibly Jupiter's moon Europa, and Saturns moon Enceldius, although they would be ice rather then liquid.

A couple theory ideas come to mind as to why such water worlds would not exist.

One being that for liquid water to exist on a planet, it would have to be in an Earth-like orbit from it's parent star. Or it would be all ice, or all vapor.
And even in an Earthlike orbit, some of it is frozen, which of itself can be considered a land mass.
Any high points of terrain would become contenents much like Earth.

Another possibility is the first chapter of the Bible refers to all the water under the heavens being gathered into one place, and dry land appearing, which became Earth. But then a few chapters later, it was said the windows of heaven opened to cause the flood experienced by Noah.
That would open the possibility that some of that water from when the windows of heaven opened, ended up someplace else, so who really knows.

It strikes me as odd that we will likely be able to see Earth size planets in just a few years, dozens of lightyears away, yet the proponents of the Nemisis theory
who claim there is a brown dwarf or gas supergiant planet on the outskirts of our own solar system can't see something which is suppose to be 15 times the size of Jupiter, at less then half a lightyear in distance.

Fraser
2003-Jul-14, 07:09 PM
Astronomers detect the distant planets by the effect they have on the star they orbit. They don't actually "see" them. Although a few relatively close brown dwarfs have been discovered, they're incredibly dim and difficult to see unless you know exactly where to look.

So, the only way astronomers could detect the "Nemesis" is by its gravitational effect on our planets, and people have been working hard to see if there's any truth to that. Personally, I'm skeptical. And my friend, Bad Astronomy's Phil Plait, has been hard at work debunking the recent silliness.

http://www.badastronomy.com/bad/misc/planetx/

Go Phil!

Bjarne
2003-Jul-16, 01:34 AM
I recall with some amusement a running joke some years back on the topic of "ET" et al. it went something like this:

"If there is intellegent life out there, why haven't we seen any evidence? Well, that's really simple. Let us say that you are amember of the "galactic consortium" and sent to Earth to study the peoples. Having been on earth for some time and observed first hand the goings on...how quickly would YOU advocate Earth's admission. Knowing what you do!??" The resulting comments based upon the hostility shown by humans would bar us for some time!

On a happier note: Perhaps there are both planets and intelligent life out there. I think it would be great but truth be known I doubt very much it'll happen anytime soon. But the research involved would be wonderous!!!

The link to Bad Astronomy is one everyone should visit. Especially those in hollywood. I like some of the movies that come out but for the most part the science is ronge or out of wack a bit.

DippyHippy
2003-Jul-16, 03:34 AM
Fraser, you beat me to it!

I was researching a freelance piece on "Planet X" and read very thoroughly Phil's pages on the subject... and I have to say, that having once believed that yes, there could be a brown dwarf out there, I'm now very sceptical.

That said, there are still many people - and even some astronomers! - who believe another planet exists - and for a variety of different reasons. I especially like to read about the crackpots. Some of the things I've seen posted are quite astounding!! (Not to mention downright funny)

Dips

Fraser
2003-Jul-21, 07:00 PM
Okay, I just talked to Alain Leger, he's the researcher who's done much of the research into the possiblity of waterworlds. He's in the Alps right now with a bad connection to the Internet, but he gave me his original research. Here's the introduction:



A new family of planets is considered which is in between rocky terrestrial planets and
gaseous giant ones, Ocean-Planets. We envision that these planets would have formed in an ice-rich environment and migrated closer to their star, in the Habitable Zone. We present hereafter preliminary internal models of these putative planets. We assume that their mass is between 1 and 8 times that of the Earth, and that they are made of equal amounts of metals + rocks and water ice. We show that in the likely case where other light gases (N2/NH3, CO/CH4, H2, He, Ne) are not present in major
amount, either due to formation processes and/or to subsequent escape, the planets can possess a surface water ocean, whose depth should not exceed ~100 km. These planets should be detectable by COROT, and would be ideal targets for future missions such as DARWIN / TPF. Finally, the simultaneous presence of O3, H2O and CO2 is pointed out as a possible biosignature, which is not the case of O2 , H2O and CO2 . If they are rather abundant and as resistant to evaporation and atmospheric escape as models predict, the COROT mission (launch scheduled in 2006) should detect several of them.

mostwanted
2003-Jul-22, 08:14 PM
the COROT mission can only detect the planets due to their dimming effect on their orbiting star, and it does have no spectrometer to analyse the atmosphere of those planets, let alone their composition, so what guarantees that the planets COROT will detect are merely water worlds, they can be jupiter-like planets and COROT can do nothing about that?!!so what am i missing here..anyone plz!

Planetwatcher
2003-Jul-27, 07:38 PM
I too once believed the nemesis theroy, or perhaps it was more I wanted to believe it. I too am much more skeptical now.

However I don't think another planet we have yet to detect isn't out of the question.
Although I have my doubts of it being larger then our gas giant planets.

Again a water world could be any planet with enough liquid water to make a sea, as long as it doesn't have high land masses.