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Why do you say that we think that "every other world out there copy's us"? A rock on Mars is not a copy of a rock on Earth (or vice-versa), I have never saw anyone saying that if there is life in other planets it will be a copy of the life from Earth (or vice-versa).
Originally posted by jsettica
I don't know what we are, or if we are even capable of understanding where we are or what this all means to say just because we live on this planet and think that every other world out there copy's us is just a indication of how little we know of what is out there. Much the less of how it all works.
How do you know that's the way "they" (if "they" exist) think?
I still think until we fix our own world, and show to other beings that are watching us that we can change how we do things, and make this world a better place to live on.
Originally posted by Illustronic
reply to post by MajorKarma
The government can't fully hide black projects because they would be built by private contractors from companies that are publicly traded. Stockholders would not swallow vast amounts of hidden expenditures, would they/you/I?
Originally posted by elevenaugust
Since then, the exoplanet catalog, regularly updated, never cease to increase the amount of new discoveries, to gain the number of 548 as of today, including 68 Earth-size planets
This increasing volume is due to the constant progress of the detection techniques:
How do you know that's the way "they" (if "they" exist) think?
I know I wouldn't think like that if I was in their (hypothetical) position
All we're saying here is that we have a better means of detecting something that is already there.
Mostly true, I agree.
Originally posted by jsettica
How do I know, it's vary simple first you must realize that we are a vary materialistic world driven by what, just look around you and see what this world is all about, I not saying we are all like that but lets just say this is how we function.
It may look like several different things. It may look like some of the people from Earth are not really that materialistic or power hungry, and they just want to get more knowledge.
And then we go out into the universe and look for life when we kill enough life on this planet on our own. How do you think that looks from others looking in.
Yes, it could, but it could also be the opposite, people that follow that way of thinking appear to think that evolution can only lead to a more peaceful and, for the lack of a better word, "philosophical" society, as if evolution favoured peace and thought instead of the survival of the fittest (whatever aspect that may present to the ones evolving).
Could it not be possible that after 100 of million of years of inhabitance that a being far more advance that us have come to the conclusion that live is more important than that bar of gold or that car in your drive way of how much money you have in your bank.
To show them that there is another way of doing things and that that way works.
And if they are at that stage why would they want to even show them selfs to a world that can't get there priorities right.
Earth is not a world in which everything that is different (different when compared with what?) is killed, and we were never at a position like that, in which Earth is confronted with beings not from Earth.
Would you want to visit a world that killed every things that was different to it's self, because of fear of what loosing your stuff.
That is your interpretation, I don't think anyone of those looking for life outside Earth are looking for like that is the same as us or so that we can go to war with them.
To think that we want to find life out there that is the same as us, so what we can go to war with them is that what we want to find or have them find us.
Maybe, I know that fish in an aquarium know that they are watched and recognise people.
If you owned an ant farm do you think the ants know that your watching them.
Again, why do you say that? Do you know for sure that we are being watched? That, if we are, that's how they think? The fact that we don't see them doesn't mean that they do not exist, but it doesn't mean that they exist.
We are on an ant farm do you think we notice them watching us. They wonder and ask when your going to stop killing your selfs. Just because we don't see them or have proof of them does not mean they don't exist.
Again, why do you say that? Do you know for sure that we are being watched.
The planetary system around the red dwarf Gliese 581, one of the closest stars to the Sun in the galaxy, has been the subject of several studies aiming to detect the first potentially habitable exoplanet. Two candidates have already been discarded, but a third planet, Gliese 581d, can be considered the first confirmed exoplanet that could support Earth-like life. This is the conclusion of a team of scientists from the Institut Pierre Simon Laplace (CNRS, UPMC, ENS Paris, Ecole Polytechnique) in Paris, France, whose study is published today in “The Astrophysical Journal Letters”.
Are there other planets inhabited like the Earth, or at least habitable? The discovery of the first habitable planet has become a quest for many astrophysicists who look for rocky planets in the “habitable zone” around stars, the range of distances in which planets are neither too cold nor too hot for life to flourish.
In this quest, the red dwarf star Gliese 581 has already received a huge amount of attention. In 2007, scientists reported the detection of two planets orbiting not far from the inner and outer edge of its habitable zone. While the more distant planet, Gliese 581d, was initially judged to be too cold for life, the closer-in planet was thought to be potentially habitable by its discoverers. However, later analysis by atmospheric experts showed that if it had liquid oceans like Earth, they would rapidly evaporate in a 'runaway greenhouse' effect similar to that which gave Venus the hot, inhospitable climate it has today. A new possibility emerged late in 2010, when a team of observers led by Steven Vogt at the University of California, Santa Cruz, announced that they had discovered a new planet, which they dubbed Gliese 581g, or ‘Zarmina’s World’. This planet, they claimed, had a mass similar to that of Earth and was close to the centre of the habitable zone. For several months, the discovery of the first potential Earth twin outside the Solar System seemed to have been achieved. Unfortunately, later analysis by independent teams has raised serious doubts on this extremely difficult detection. Many now believe that Gliese 581g may not exist at all. Instead, it may simply be a result of noise in the ultra-fine measurements of stellar ‘wobble’ needed to detect exoplanets in this system.
Today, it is finally Gliese 581g’s big brother – the larger and more distant Gliese 581d - which has been shown to be the confirmed potentially habitable exoplanet by Robin Wordsworth, François Forget and co-workers from Laboratoire de Météorologie Dynamique (CNRS, UPMC, ENS Paris, Ecole Polytechnique) at the Institute Pierre Simon Laplace in Paris. Although it is likely to be a rocky planet, it has a mass at least seven times that of Earth, and is estimated to be about twice its size. At first glance, Gliese 581d is a pretty poor candidate in the hunt for life: it receives less than a third of the stellar energy Earth does and may be tidally locked, with a permanent day and night side. After its discovery, it was generally believed that any atmosphere thick enough to keep the planet warm would become cold enough on the night side to freeze out entirely, ruining any prospects for a habitable climate.
To test whether this intuition was correct, Wordsworth and colleagues developed a new kind of computer model capable of accurately simulating possible exoplanet climates. The model simulates a planet's atmosphere and surface in three dimensions, rather like those used to study climate change on Earth. However, it is based on more fundamental physical principles, allowing the simulation of a much wider range of conditions than would otherwise be possible, including any atmospheric cocktail of gases, clouds and aerosols.
To their surprise, they found that with a dense carbon dioxide atmosphere - a likely scenario on such a large planet - the climate of Gliese 581d is not only stable against collapse, but warm enough to have oceans, clouds and rainfall. One of the key factors in their results was Rayleigh scattering, the phenomenon that makes the sky blue on Earth. In the Solar System, Rayleigh scattering limits the amount of sunlight a thick atmosphere can absorb, because a large portion of the scattered blue light is immediately reflected back to space. However, as the starlight from Gliese 581 is red, it is almost unaffected. This means that it can penetrate much deeper into the atmosphere, where it heats the planet effectively due to the greenhouse effect of the CO2 atmosphere, combined with that of the carbon dioxide ice clouds predicted to form at high altitudes. Furthermore, the 3D circulation simulations showed that the daylight heating was efficiently redistributed across the planet by the atmosphere, preventing atmospheric collapse on the night side or at the poles.
Scientists are particularly excited by the fact that at 20 light years from Earth, Gliese 581d is one of our closest galactic neighbours. For now, this is of limited use for budding interstellar colonists – the furthest-travelled man-made spacecraft, Voyager 1, would still take over 300,000 years to arrive there. However, it does mean that in the future telescopes will be able to detect the planet’s atmosphere directly. While Gliese 581d may be habitable there are other possibilities; it could have kept some atmospheric hydrogen, like Uranus and Neptune, or the fierce wind from its star during its infancy could even have torn its atmosphere away entirely. To distinguish between these different scenarios, Wordsworth and co-workers came up with several simple tests that observers will be able to perform in future with a sufficiently powerful telescope.
If Gliese 581d does turn out to be habitable, it would still be a pretty strange place to visit – the denser air and thick clouds would keep the surface in a perpetual murky red twilight, and its large mass means that surface gravity would be around double that on Earth. But the diversity of planetary climates in the galaxy is likely to be far wider than the few examples we are used to from the Solar System. In the long run, the most important implication of these results may be the idea that life-supporting planets do not in fact need to be particularly like the Earth at all.
Originally posted by elevenaugust
Originally posted by Ultraman2011
Thanks for posting,very interesting stuff. Do you feel without actually venturing out into space (even with probes), we would be able to determine if life existed on any of these planets with the telescope alone?
Yes, I do believe it! We already detected organic molecules in exoplanet atmosphere at least two years ago, but this is not enough for saying that life do exist on this planet.
There are other conditions needed, such as:
1- Earth-sized planet
2- Located in the habitable zone:
By analyzing the colors of infrared radiation detected by TPF (Terrestrial Planet Finder, with a coronagraph and interferometer), astronomers can search for atmospheric gases such as carbon dioxide, water vapor, and ozone. Together with the temperature and radius of the detected planets, this information will allow astronomers to determine which planets are habitable, or even whether they may be inhabited by rudimentary forms of life.
3- The presence of Ozone + nitrous oxide or methane:
Follow the Ozone
The existence of large amounts of oxygen in a planet's atmosphere alone would be a strong indicator of life.
In the Earth's atmosphere, oxygen is a byproduct of photosynthesis, the process by which green plants and certain other organisms use sunlight to convert carbon dioxide and water into carbohydrates.
Furthermore, oxygen molecules don't remain in the atmosphere, but combine with other molecular types in a process known as oxidation.
Therefore, a planet with an atmosphere rich in oxygen (like Earth) would imply a source to keep it replenished (life).
However, we know of non-biological processes that can also result in an oxygen-rich atmosphere. The runaway greenhouse effect on Venus is one example. A frozen, Mars-like planet big enough to hold its oxygen would be another.
So, the presence of oxygen alone -- while exciting and significant -- couldn't be taken as an unambiguous indicator of life. Furthermore, oxygen doesn't produced spectral lines that can be easily observed in the infrared. However, ozone, a form of oxygen, does.
The detection of ozone coexisting with a reduced gas such as nitrous oxide or methane could be taken as convincing evidence not only that a planet is habitable -- but that it may be inhabited.
Such large-scale clues can't tell us about the complexity of the discovered life; it could be either algae or a developed civilization. It is also possible that planets without oxygen could sustain life.
Photosynthesis might conceivably occur with another element, such as sulfur, playing the role of oxygen. In the search for life, we must control our preconceived assumptions of what it means to be living.
The findings of Terrestrial Planet Finder would guide a possible subsequent mission called Life Finder. Like its predecessor, Life Finder would consist of an array of telescopes flying in formation. The telescopes would combine infrared light to produce high-resolution spectra of the atmospheres of distant planets.
Scientists would use this information to search more closely for markers of biological activity, such as seasonal variations in the levels of methane and other gases, changes in atmospheric chemistry and spectral variations in the dominant biomass.
I showed that both point 1- and 2- were already respected, by the recents exoplanets findings, so we are waiting for point 3- to be found, which is not an insurmontable task; we have the technology, the have the abilities, time will work in this direction.
A rocky alien planet called Gliese 581d may be the first known world beyond Earth capable of supporting life as we know it, a new study suggests.
Astronomers performing a new atmospheric-modeling study have found that the distant planet likely lies in the "habitable zone" of its host star — that just-right range of distances that allow liquid water to exist. The alien world could have oceans, clouds and rainfall, according to the study.
Those are pretty big ifs, of course.
The study assumes that Gliese 581d, which is about seven times as massive as Earth, has a thick, carbon-dioxide-based atmosphere. That's very possible on a planet so large, researchers said, but it's not a given. [Video: Life-Sustaining "Super Earth" Gliese 581d]
The Gliese 581 system: Worlds of possibilities
Gliese 581d's parent star, known as Gliese 581, is a red dwarf located 20 light-years from Earth, just a stone's throw in the cosmic scheme of things. So far, astronomers have detected six planets orbiting the star, and Gliese 581d is not the only one intriguing to scientists thinking about the possibility of life beyond Earth.
Another planet in the system, called Gliese 581g, is about three times as massive as Earth, and it's also most likely a rocky world. This planet is located right in the middle of the habitable zone around the parent star, making it a prime candidate for liquid water and life as we know it — if the planet exists.
Some researchers question the analysis used to discover the planet, and say they cannot confirm 581g in follow-up studies. The planet's discoverers, however, are standing by their find. [The Strangest Alien Planets]
Gliese 581d orbits outside of 581g, far enough away from its star that researchers first thought it too cold for life when it was originally discovered in 2007. But a strong greenhouse effect may warm 581d up substantially, perhaps enough to support liquid water.
That's the tentative conclusion of the new study, as well as several other recent studies by different research teams that also modeled Gliese 581d's possible atmosphere.
Modeling an alien atmosphere
The planet Gliese 581d receives less than a third of the solar energy that Earth does from our sun, and it may be tidally locked (a situation in which one side of the world always faces its sun — a permanent day — and the other faces away, producing eternal night).
After Gliese 581d's discovery, it was generally believed that any atmosphere thick enough to keep the planet warm would become cold enough on the night side to freeze out entirely, ruining any prospects for a habitable climate, researchers said.
The research team tested that possibility in the new study, developing a new kind of computer model that simulates alien planets' atmospheres and surfaces in three dimensions. The model is similar to those used to study climate change on Earth.
When the team ran the model, they found that Gliese 581d probably can indeed host liquid water if it has a dense carbon dioxide atmosphere. Even though the planet is relatively far away from its dim red dwarf parent star, it could be warmed by a greenhouse effect, with daytime heat circulated around the planet by the atmosphere.
The team, led by scientists from the Laboratoire de Métrologie Dynamique (CNRS/UPMC/ENS/Ecole Polytechnique) at the Institut Pierre Simon Laplace in Paris, France, published their results in The Astrophysical Journal Letters.
The work remains speculative.
To determine conclusively if Gliese 581d is truly habitable, future work will probably have to detect and characterize its atmosphere directly. And that is likely years off, since it requires the development of new and advanced telescopes.
A planet with eight Earth masses has more volatiles than an Earth size planet to build up such a dense atmosphere. This prevents the atmosphere from freezing out due to tidal locking. In case of an eccentric orbit of Gl 581d (e = 0.2), the planet is habitable for the entire luminosity range considered in this study, even if the maximum CO2 pressure is assumed as low as 5 bar. In conclusion, one might expect that life may have originated on Gl 581d. The appearance of complex life, however, is unlikely due to the rather adverse environmental conditions. To get an ultimate answer to the profound question of life on Gl 581d, we have to await future space missions such as the TPF/Darwin. They will allow for the ﬁrst time to attempt the detection of biomarkers… in the atmospheres of the two super-Earths around Gl 581.
Darwin/TPF-I and TPF-C could eventually reveal what the actual properties of the atmosphere of Gl 581c and Gl 581d are. From their thermal light curves we could infer if a thick atmosphere is making the climate more or less uniform on both the day and night hemispheres of these planets, despite a (nearly?) synchronized rotation… Visible and mid-IR water vapor bands could be searched in the atmosphere of Gl 581d to conﬁrm its habitability. Mid-IR spectra of this planet could also reveal other greenhouse gases at work. Spectral observations of Gl 581c could potentially distinguish between a Venus-like atmosphere dominated by CO2 or an H2O-rich atmosphere. The detection of O2 on this planet would generate a fascinating debate about its possible origin: as either a leftover of H2O photolysis and H escape or a biological release. There is certainly no doubt that Gl 581c and Gl 581d are prime targets for exoplanet characterization missions.