Wednesday, April 25, 2007

Astronomers find first habitable Earth-like planet?

Astronomers find first habitable Earth-like planet, EurekAlert!, 24-Apr-2007, Henri Boffin, European Southern Observatory (ESO) ...

[Above: Artist's impression of red dwarf star Gliese 581's planetary system, EurekAlert!]

Astronomers have discovered the most Earth-like planet outside our Solar System to date, an exoplanet with a radius only 50% larger than the Earth and capable of having liquid water. Using the ESO 3.6-m telescope, a team of Swiss, French and Portuguese scientists discovered a super-Earth about 5 times the mass of the Earth that orbits a red dwarf, already known to harbour a Neptune-mass planet. The astronomers have also strong evidence for the presence of a third planet with a mass about 8 Earth masses. This exoplanet - as astronomers call planets around a star other than the Sun - is the smallest ever found up to now [1] and it completes a full orbit in 13 days. It is 14 times closer to its star than the Earth is from the Sun. However, given that its host star, the red dwarf Gliese 581 [2], is smaller and colder than the Sun - and thus less luminous -the planet nevertheless lies in the habitable zone, the region around a star where water could be liquid! "We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius, and water would thus be liquid," explains St├ęphane Udry, from the Geneva Observatory (Switzerland) and lead-author of the paper reporting the result. "Moreover, its radius should be only 1.5 times the Earth's radius, and models predict that the planet should be either rocky - like our Earth - or covered with oceans," he adds. "Liquid water is critical to life as we know it," avows Xavier Delfosse, a member of the team from Grenoble University (France). "Because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life. On the treasure map of the Universe, one would be tempted to mark this planet with an X. The host star, Gliese 581, is among the 100 closest stars to us, located only 20.5 light-years away in the constellation Libra ("the Scales").

[Right: Loca­tion of red dwarf star Gliese 581 in the constellation Libra, Bits of News]

It has a mass of only one third the mass of the Sun. Such red dwarfs are intrinsically at least 50 times fainter than the Sun ..." [This presumably is the original misleading press release that most, if not all, the news stories are based on, e.g. ABC, BBC, Bits of News, Christian Science Monitor, CNews, National Post, New Scientist, New York Times, San Francisco Chronicle, SPACE.com 1 & 2, Sydney Morning Herald, The Australian, The Independent & USA Today.

While this is a great technical achievement to detect such a small planet, "5 times the mass of the Earth," at such a vast distance, "20.5 light-years away," the press release (and therefore the articles), omits to mention that:

1) A planet "5 times the mass of the Earth" is not "Earth-like." As mentioned in my posts of 22-Feb-06 & 14-Mar-06, even for "planets only a few times heavier than Earth ... the extra gravity ... would crush these [crustal] minerals into ... semi- conductors or metals" resulting in "enhanced heat flow from the planet's core to the surface, which means more volcanoes and more `planetquakes'" (Vergano, D., "Finding 'Super Earth' is a 'Goldilocks' errand," USA Today, February 19, 2006).

2) A "red dwarf" is "far less luminous than our sun, and any planets orbiting them would have to be very close to stay warm enough to allow the existence of liquid water on the surface":

"It is often said that the sun is a typical star, but this is entirely untrue. The mere fact that 95% of all stars are less massive than the sun makes our planetary system quite rare. Less massive stars are important because they are much more common than more massive ones. For stars less massive than the sun, the habitable zones are located farther inward. The most common stars in our galaxy are classified, as M stars; they have only 10% of the mass of the sun. Such stars are far less luminous than our sun, and any planets orbiting them would have to be very close to stay warm enough to allow the existence of liquid water on the surface. However, there is danger in orbiting too close to any celestial body. As planets get closer to a star (or moons to a planet), the gravitational tidal effects from the star induce synchronous rotation, wherein the planet spins on its axis only once each time it orbits the star. Thus the same side of the planet always faces the star. (Such tidal locking keeps one side of the Moon facing Earth at all times.) This synchronous rotation leads to extreme cold on the dark side of a planet and freezes out the atmosphere. It is possible that with a very thick atmosphere, and with little day/night variation, a planet might escape this fate, but unless their atmospheres are exceedingly rich in CO2, planets close to low-mass stars are not likely to be habitable because of atmospheric freeze-out." (Ward, P.D. & Brownlee, D.C., "Rare Earth: Why Complex Life is Uncommon in the Universe," Copernicus/Springer-Verlag: New York NY, 2000, pp.23-24)

as is the case with this planet Gliese 581c which "is 14 times closer to its star than the Earth is from the Sun." But then "As planets get closer to a star ... the gravitational tidal effects from the star induce synchronous rotation, wherein the planet spins on its axis only once each time it orbits the star. Thus the same side of the planet always faces the star. ... This synchronous rotation leads to extreme cold on the dark side of a planet and freezes out the atmosphere" (my emphasis).

3) "M dwarf stars" which Gliese 581 is, "exhibit flares" which "can increase the relative X-ray radiation by a factor of one hundred to one thousand compared with strong flares on the on the Sun" (my emphasis):

"M dwarf stars pose additional problems for life. Like the Sun, they exhibit flares. Some are stronger than solar flares, and because M dwarf stars are far less luminous, a flare's intensity compared with the star is that much greater. A strong flare on an M dwarf star can increase the relative X-ray radiation by a factor of one hundred to one thousand compared with strong flares on the Sun; the resulting increase in the ultraviolet radiation reaching the planet's surface would also be more intense .Not only would such flares threaten surface life, they would probably strip away a planet's atmosphere more quickly as well. The large starspots associated with flares would cause the star's brightness to vary on longer timescales (by about 10 to 40 percent), mimicking an eccentric planetary orbit. Starspots and flares decline steadily as a star ages. So while the passage of time would mitigate these problems, at any age an M dwarf host star will be a less constant source of energy than a star like the Sun." (Gonzalez, G. & Richards, J.W., "The Privileged Planet: How Our Place in the Cosmos is Designed For Discovery," Regnery: Washington DC, 2004, p.134)

which Wikipedia corroborates the above as among the "several factors which may make life difficult on planets around a red dwarf star":

Red dwarf ... Habitability Planetary (Wikipedia) habitability of red dwarf star systems is subject to some debate. In spite of their great numbers and long lifespans, there are several factors which may make life difficult on planets around a red dwarf star. First, planets in the habitable zone of a red dwarf would be so close to the parent star that they likely would be tidally locked. This would mean that one side would be in perpetual daylight and the other in eternal night. This could create enormous temperature variations from one side of the planet to the other, making it difficult for life to evolve. On the other hand, recent theories propose that either a thick atmosphere or planetary ocean could potentially circulate heat around the planet. Another potential problem is that red dwarfs emit most of their radiation as infrared light, while on earth plants use energy mostly in the visible spectrum. But, perhaps the most serious problem may be stellar variability. Red dwarfs are often covered in starspots, reducing stellar output by as much as 40% for months at a time. At other times, some red dwarfs, called flare stars, can emit gigantic flares, doubling their brightness in minutes. This variability may also make it difficult for life to survive near a red dwarf star.

4) Even if astronomers do eventually detect an exoplanet that appears truly Earth-like, i.e. truly Earth-size, is truly an Earth-like distance from its star; which is a single star that is truly a Sun-like G-main sequence star; in a truly near-circular orbit; in a truly Earth-like solar system; at "20.5 light-years away" (i.e. 20 x 63,240 AU = ~1,264,800 times the distance of the Earth from the Sun) yet being "among the 100 closest stars to us," realistically they are never going to know (see "Interstellar travel ...: Interstellar distances," Wikipedia) if it is really is Earth-like.

That is because, "there is more to finding another Earth than detecting a planet the same size and same distance from its star" since if astronomers discovered Venus at that distance they would hail it as the ultimate Earth-like exoplanet, yet close up "Venus has ... hellish conditions ... where 800-degree [Fahrenheit] winds are lashed by sulfuric acid rain":

"But it may not be so easy, suggests University of Minnesota physicist Renata Wentzcovitch and colleagues in the current Science magazine. ... The larger point is there is more to finding another Earth than detecting a planet the same size and same distance from its star, she says. Venus and Earth are very similar, she notes, but have significant differences in their interior chemistry. Venus has a more viscous interior that lead to a planet-sized earthquake hundreds of millions of years ago, she says, and that likely also explains the hellish conditions there, where 800-degree winds are lashed by sulfuric acid rain." (Vergano D., "Finding 'Super Earth' is a 'Goldilocks' errand," USA Today, February 19, 2006).

Quite frankly if these astronomers know all the above (and if they don't then they would be incompetent- which I assume they are not), then according to the late Nobel laureate physicist Richard Feynman's standards of good science, they are lacking "scientific integrity" and "honesty" in seeking to "fool the layman when ... talking as a scientist," by not giving "all of the information to help others to judge the value of" their "contribution; not just the information that leads to judgment in one particular direction" that they favour:

"But there is one feature I notice that is generally missing in cargo cult science. That is the idea that we all hope you have learned in studying science in school-we never explicitly say what this is, but just hope that you catch on by all the examples of scientific investigation. It is interesting, therefore, to bring it out now and speak of it explicitly. It's a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty -a kind of leaning over backwards. For example, if you're doing an experiment, you should report everything that you think might make it invalid-not only what you think is right about it: other causes that could possibly explain your results; and things you thought of that you've eliminated by some other experiment, And how they worked-to make sure the other fellow can tell they have been eliminated. Details that could throw doubt on your interpretation must be given, if you know them. you must do the best you can-if you know anything at all wrong, or possibly wrong-to explain it. If you make a theory, for example, and advertise it, or put it out, then you must also put down all the facts that disagree with it, as well as those that agree with it. ... In summary, the idea is to try to give all of the information to help others to judge the value of your contribution; not just the information that leads to judgment in one particular direction or another .... And it's this type of integrity, this kind of care not to fool yourself, that is missing to a large extent in much of the research in cargo cult science. ... But this long history of learning how to not fool ourselves-of having utter scientific integrity-is, I'm sorry to say, something that we haven't specifically included in any particular course that I know of. We just hope you've caught on by osmosis. The first principle is that you must not fool yourself-and you are the easiest person to fool. So you have to be very careful about that. After you've not fooled yourself, it's easy not to fool other scientists. You just have to be honest in a conventional way after that. I would like to add something that's not essential to the science, but something I kind of believe, which is that you should not fool the layman when you're talking as a scientist. ... I'm talking about a specific, extra type of integrity that is not lying, but bending over backwards to show how you're maybe wrong, that you ought to have when acting as a scientist. And this is our responsibility as scientists, certainly to other scientists, and I think to laymen. One example of the principle is this: If you've made up your mind to test a theory, or you want to explain some idea, you should always decide to publish it whichever way it comes out. If we only publish results of a certain kind, we can make the argument look good. We must publish both kinds of results." (Feynman, R.P., "Cargo Cult Science," in "`Surely You're Joking, Mr Feynman!': Adventures of a Curious Character," [1985], Unwin Paperbacks: London, Reprinted, 1990, pp.341-343).

Stephen E. Jones, BSc. (Biology).


Exodus 23:25-33. 25Worship the LORD your God, and his blessing will be on your food and water. I will take away sickness from among you, 26and none will miscarry or be barren in your land. I will give you a full life span. 27"I will send my terror ahead of you and throw into confusion every nation you encounter. I will make all your enemies turn their backs and run. 28I will send the hornet ahead of you to drive the Hivites, Canaanites and Hittites out of your way. 29But I will not drive them out in a single year, because the land would become desolate and the wild animals too numerous for you. 30Little by little I will drive them out before you, until you have increased enough to take possession of the land. 31"I will establish your borders from the Red Sea to the Sea of the Philistines, and from the desert to the River. I will hand over to you the people who live in the land and you will drive them out before you. 32Do not make a covenant with them or with their gods. 33Do not let them live in your land, or they will cause you to sin against me, because the worship of their gods will certainly be a snare to you."

5 comments:

Stephen E. Jones said...

Alexander

Again I have hit the Reject button when I meant to hit the Publish button! My apologies. This response is to the part of your comment that Blogger sent me.

>So,what is your point here?That astronomers are "not honest"?

My point is that they these particular astronomers are not being honest in that they are suppressing evidence (see points 1) to 4) of my post) that would cast doubt on their claim that this exoplanet Gliese 581c is "Earth-like" and "habitable".

As Richard Feynman said, it is lacking "scientific integrity" and "honesty" and seeking to "fool the layman when ... talking as a scientist," unless:

"Details that could throw doubt on your interpretation must be given, if you know them. you must do the best you can-if you know anything at all wrong, or possibly wrong-to explain it. If you make a theory, for example, and advertise it, or put it out, then you must also put down all the facts that disagree with it, as well as those that agree with it. ... In summary, the idea is to try to give all of the information to help others to judge the value of your contribution; not just the information that leads to judgment in one particular direction or another ..."

>I disagree-they just did their job.

They "did their job" in finding the exoplanet and I acknowledged it was "a great technical achievement." It is their interpretation of it as "Earth-like" and "habitable" (which entailed suppressing evidence against that interpretation) that I criticised.

>And while human body is not suited to travel to the distant planets,it might be possible to robots/machines.

See the Wikipedia reference I gave, which indicates that even to the "nearest known star ... 4.23 light-years away" the "fastest spacecraft yet constructed, achieved a velocity of ... 0.0235% the speed of light" and "At that rate, a journey ... would take 17,000 years" and "the longest space missions that have been initiated are expected to have an operational lifetime of about 63 years before failure of key components is likely to happen."

Gliese 581c is ~5 times that distance. It just is not going to happen, despite science fiction making it sound easy.

>Besides,there are a loit of Galaxies - how can we know what is there,or what is NOT there?

Thanks for making my point. We cannot know without going there that what appears to be an Earth-like exoplanet, really is Earth-like.

>I never had a problem with thinking,that there is Creator(s),and that the Universe itself might have purpose.

Great!

>What is honestly hard to think for me,that the humans are the "center purpose" or the "only purpose" of this vast Universe of billions of Galaxies.

Then whether you realise it, you are another victim of Epicureanism. Read Ben Wiker's book, "Moral Darwinism".

According to Christianity the "Creator" of "this vast Universe of billions of Galaxies", Jesus Christ (Jn 1:3; Col 1:16; Heb 1:2) took upon a human body, lived on Earth for 33 years, and died on the Cross for the sins of "humans."

That indicates that "humans" are the "center purpose" "of this vast Universe of billions of Galaxies."

That in fact was, as Michael Denton (himself an agnostic), the dominant view of Western Christian civilisation for ~1,500 years and it has never been refuted, but rather the opposite:

"It is remarkable to think that only five centuries separates the current skeptical ethos in the West from this profoundly teleological view of reality. The anthropocentric vision of medieval Christianity is one of the most extraordinary-perhaps the most extraordinary-of all the presumptions of humankind. It is the ultimate theory and in a very real sense, the ultimate conceit. No other theory or concept ever imagined by man can equal in boldness and audacity this great claim-that everything revolves around human existence-that all the starry heavens, that every species of life, that every characteristic of reality exists for mankind and for mankind alone. It is simply the most daring idea ever proposed. But most remarkably, given its audacity, it is a claim which is very far from a discredited prescientific myth. In fact, no observation has ever laid the presumption to rest. And today, four centuries after the scientific revolution, the doctrine is again reemerging. In these last decades of the twentieth century, its credibility is being enhanced by discoveries in several branches of fundamental science." (Denton, M.J., "Nature's Destiny: How the Laws of Biology Reveal Purpose in the Universe," The Free Press: New York NY, 1998, pp.3-4)

as is only to be expected if Christianity is true (which it is)!

>Similar thoughts were expressed by such religion scientists as Ian Barbour,Owen Gingerich,Keith Ward.

The problem is that "such religion scientists" are also infected with the dominant Epicurean (Scientific Materialist) philosophy of science. They would not be in science if they were not.

>They had courage to rethink something...

This is where the part of your message Blogger sent me ended.

It doesn't take much "courage" to go along with the dominant scientific materialist consensus, while giving it a vague `religious' spin.

They tend to adopt a form of "process theology" with its sub-Christian limited god.

What takes The real courage is to challenge the dominant scientific materialist philosophy as false (which it is since Christianity is true)! But again, they would not even be in science if they did that!

Stephen E. Jones

Alexander said...

Ok,Stephen.
Good answers, but they raise even more questions.
Christianity may be true,but according to researches,it's not going to the be dominant religion in,say,100 years from now.Furthermore,according to a lot of scientinsts("victims of Epicureanism":)),there is a good chance that just few centuries from now biological humanity will be replaced with AI.Science fiction?Funny?I don't think so.Who knows?How you can be SURE that it will NOT happen?
So,to summarize: if in 100 years from now Christianity or doesn't exist or in vast minority - is it still true?Or if in few centuries bilogogical humans replaced by "Homo machinus","Robo sapiens",whatever - what's then?
I don't mention the fact,that all species last not more than a few million years at most.And I don't mention Sun burned out etc...
By the way,I read a lot of Christian Eschatology.What is interesting,even among the Christians eschatological views are SO different !Some claim that New Earth will be similar to this one,some claim,that it will be radically different,in some different dimentions,others(most smart,I think) say it's just pointless to speculate about what will happen.I could continue. So,you see?I'm not talking about different vies between Christians and non-Christians,I'm pointing that even between Christians there are radically different views!
Well,time itself will tell what will happen.But I remain content with my Agnosticism and uncertainity

Stephen E. Jones said...

Alexander

>Ok,Stephen.
Good answers, but they raise even more questions.

[...]

Sorry, but as per my stated policies on my blog's front page "I no longer debate":

"Comments ... Since I no longer debate, any response by me will usually be only once to each individual on that comment, and then I will let him/her have the last word."

and you have had "the last word" (of debate) in comments on this post.

Stephen E. Jones

Anonymous said...

I agree. We have too little information, and the planets are too far away to ever know the turth.

Given how far away the planets are from us, and how greatly they can vary even when having similar sizes and distances to their suns, it's possible that lots of planets we believe are "uninhabitable" are, in fact, quite habitable.

Stephen E. Jones said...

Anonymous

>I agree. We have too little information, and the planets are too far away to ever know the turth.

Agreed.

>Given how far away the planets are from us, and how greatly they can vary even when having similar sizes and distances to their suns, it's possible that lots of planets we believe are "uninhabitable" are, in fact, quite habitable.

Disagree. If we are talking about life *as we know it* (otherwise science fiction will do), then life in our Solar System is only known to exist on Earth, which is why they are looking to other planetary systems.

That indicates there are many stringent requirements needed to support life.

None of the ~200 exoplanets astonomers have detected to date are *truly* Earth-like in an Sun-like planetary system.

The very fact that they hail as "Earth-like" an exoplanet that is *5 times* the mass of Earth and orbits its star (a *red dwarf*) in *13 days*, shows how hard up they are for a *true* Earth-like exoplanet!

What the astronomers have actually found is the *opposite* to what their propaganda claims, namely that Earth and its Solar System are looking more and more to be uniquely suited to life.

But that contradicts Epicurean materialist philosophy which seeks to show that Earth is nothing special so that there is no need for God:

"To achieve this reductionism even more completely, Epicurus found another ingenious way to help eliminate our natural awe. It may sound, at first, a strange way to do it, but he reduced the universe by expanding it. The universe, according to Epicurus, is unlimited, both in respect to size and in respect to the `number of bodies and the magnitude of the void.' [Inwood, B. & Gerson, L.P., "The Epicurus Reader," Hackett: Indianapolis, 1994, 10.41-42] That means that, given an infinitude of time with an unlimited number of atoms in an infinite expanse of the void, there will be `an unlimited number of cosmoi [the plural of `cosmos'], and some are similar to this one and some are dissimilar ... [for] there is no obstacle to the unlimitedness of worlds.' [Ibid., 10.45] ... in Epicurus's argument, the hypothetical infinity is useful for asserting that, since there is an unlimited number of atoms and they move eternally and combine easily, then there must be an unlimited number of worlds. This `plurality of worlds' argument is essential to Epicurean materialism, and is used again in the Enlightenment as a weapon to undermine Christianity (and continues to be used to the present day for the same purpose). Why, then, would a plurality of worlds be so useful to Epicureanism? The assertion of a plurality of worlds both rests on, and reinforces, the assumption that creation of complexity is easy, so easy that the combining and recombining of atoms creates not just one world, but many. So easy, indeed, that invoking a divine cause is completely superfluous. There must be a plurality of worlds, the materialist reasons, because an infinite universe during an infinite time using an unlimited number of atoms in perpetual motion, simply must produce a multitude of complexity out of simplicity. This belief is the origin of the `monkey-at-the-typewriter' argument, where even a monkey, randomly pecking away, can produce Shakespearean sonnets, if only it has an infinite amount of time to do it. The goal of this belief is to allow enough time and material so that chance can replace intelligence: if the monkey can replace Shakespeare, then almighty chance can replace almighty God. And so, even though there was no empirical evidence of eternal atoms, no empirical evidence that such atoms combine easily to form complex structures, no empirical evidence that the universe was infinite or the number of atoms unlimited, and no empirical evidence that there actually was a plurality of worlds, the *belief* in a plurality of worlds actually functioned, for Epicurus, to sustain the undemonstrated arguments on which his system itself rested. That is, the belief in a plurality of worlds reinforced the belief in the simplicity, of the atom and the case with which it could combine to create complexity. Whether for Epicurus or the modern materialist, the circular reinforcement ultimately serves to release adherents of materialism from the disturbing thought that a divine Intelligence is behind it all. Are we surprised to find that the late Carl Sagan, the chief spokesperson for materialism in the last quarter of the twentieth century, calculated that in the Milky Way galaxy alone, there would have to be one million civilizations capable of interstellar communication?" (Wiker, B., "Moral Darwinism," InterVarsity Press: Downers Grove IL, 2002, pp.41-42. Emphasis original).

Stephen E. Jones