Planets outside the Solar System (Exoplanets)

30-11-2010 20:36

To seek for planets revolving around the stars of our galaxy (Milky Way) and others, became a stimulating task for astronomers and astrophysicists of our time. It is worthwhile to mention here what Giordano Bruno said in the end of the 16th century, in his On the Infinite Universe and Worlds, Giordano Bruno (De l´Infinito, Universo e Mondi, Giordano Bruno, 1584):

Innumerable suns exist, innumerable earths revolve around these suns in a manner similar to the way the seven planets revolve around our sun. These worlds are inhabited by living beings.

It is attributed to Jesus the saying: “in the Father´s house many dwelling worlds exist” – it is worth to notice the similarity of this intuitive statement with the one of Giordano Bruno in De l´Infinito, Universo e Mondi, citation that was inserted in the beginning of this chapter. It is impressive, really extraordinary, how Bruno´s words are becoming reality through the recent racing for the discovery of new planets outside of our solar system, the already so-called exoplanets!

In 1991, it was discovered by the Radiotelescope of Arecibo, a star not similar to our Sun, around the pulsar PSR-1257+12. In 1995, another star, now very similar to our Sun, was discovered by Michael Mayor and Didier Queluz, close to the star 51 Pegasi. In May 1998, the Hubble telescope detected an image close to the star TMRC-1C. Finally, in 1999, for the first time using direct observation, it was discovered visually and telescopically, near the star HD269458, a new planet and its diameter was measured. Until 2001, there were already been catalogued about 21 exoplanets.

From there until today (May 2008), it already surpasses of 230 the number of discovered exoplanets in the short period of eighteen years! (15) With the advancement of the techniques used in those discoveries, in few decades, possibly we’ll have registered thousands of these discoveries. NASA and the European Space Agency have plans to launching future orbital missions, equipped with very sophisticated apparatus. These works will be done, also, in coordination with SETI – Search for Extraterrestrial Intelligence. Also, we can have the chance of visualizing, for the first time, an exoplanet.

Nowadays, the astronomers have already five methods to execute that work and each one serves to confirm the others. This work is possible, due to the progress of the visual methods, because, until recently, the astronomers had to base themselves in accurate measures of the speed of the star, in many cases, accomplished during several years. We will not describe the methods used for this purpose here; however, despite of not being our objective to deepen ourselves in this subject, we can inform that it is already possible to measure and calculate, among other things, the rotational speedy of an exoplanet, its mass, volume, density, the distance from the star and the characteristics of its orbit.

Our knowledge on the new solar systems is enlarging itself in a very unexpected manner, mainly if we take the pattern of the solar system as basis, where the nearest planet to the Sun is small, rocky (solid) and without atmosphere (Mercury). On the other hand, the intermediary planets have medium size, are rocky and have some type of atmosphere (Venus, Earth and Mars) and in one of them there is abundant life in all its plenitude. As to the most distant, they are essentially gaseous and gigantic (Jupiter, Saturn and Neptune). About the last planet of the solar system, discovered in 2005, the so-called Sedna, it is not yet available so much technical information. As mentioned above, the planet Sedna took the place of the planet Pluto as member of the solar system.

Surprisingly, it’s not with this distribution profile that exoplanets were discovered. Thus, “Planets that have 14 times the mass of Jupiter exist and they are closer to their star than the planet Mercury is of the Sun. Others have orbits highly elliptic varying their distances from the star almost as much as the size of the solar system. Most revolves around their stars in amazing speeds: one of them completes its solar year in less than three days. Thus, or it is very near to the star, or it revolves very fast (or both)! The smallest planet found until today is of the approximate size of the planet Jupiter and it revolves around a star very similar to the Sun. It was also found a planet that moves itself in an orbit at a distance almost equivalent to the distance from the Earth to the Sun, what shows the possibility of sheltering living beings.”(15)

Astronomy entered the 21st century with enormous and stimulating perspectives. Everything takes us to believe that “one day we will be able to visualize these planets, or even to determine indirect evidences that they shelter lives similar to ours. In that day, our conception about ourselves and about the destiny of the humanity will suffer an irreversible change.” (15)

5. The Marvelous Hubble Space Telescope

The Hubble space telescope was baptized with the astronomer’s name Edwin Powell Hubble (1889–1953), who, in 1924, discovered the existence of other galaxies, beyond the Milky Way Galaxy. This fantastic equipment, which sends about 5 gigabytes of information per day about the universe, has just completed 15 years of existence and it cost next to 2 billion dollars. Just to illustrate, in the year of its launching (1990) it sent more information about the universe than all that it was known on the universe till 1990.

Besides the technical information and astronomical parameters of the most varied nature, until April of 2005, it had sent to NASA about 700,000 photos of almost the whole universe, considerably enlarging the human knowledge on universe. This spectacular equipment was planned and designed in the decade from 40 to 50, constructed in the decade from 70 to 80, and put in orbit on April 24, 1990. Its resolution of 0.1 second of arc can “see” a soccer ball to 500 km of distance or to distinguish the lights of a car located at the Moon! This is a resolution ten times superior to the best telescope on the surface of the Earth.” (16)

If the Hubble had been placed in the ground, it would be a telescope of average power. The “power” of a telescope is indicated by the quantity of light that it can instantaneously receive from an object and this, by its turn, is function of its diameter. The Hubble is a telescope of the reflective type (its principal optical element is a mirror), with 2.40 meters of diameter. The two largest telescopes in the world are at the Mauna Kea Observatory, in Hawaii, which have 10 meters of diameter each. Now, there are twenty-eight telescopes larger than the Hubble in operation in the world. More than a telescope, the Hubble is a true space observatory containing the necessary instrumentation by several observation functions. It carries three cameras (of large field, including the vision of dark objects), an astrometer detector, a spectrograph of high resolution and one of high-speed spectrograph, besides a board computer. The new installed camera weighs 315 kilograms and it is so powerful that allows to register images one million times superior to the ones captured by the human eyes! (17) Besides photographing the objects and to measure with great precision their positions, the Hubble is capable to analyze in details the light that comes from them. The Hubble is in a low orbit at 800 km from the surface of the Earth and it spends only 95 minutes to give a complete turn around our planet. The energy needed for its operation is collected by two solar panels of 2.4 x 12.1 meters each, and it weighs about 11,660 kilograms. (16)

The Hubble telescope was repaired in the open space more than one time to correcting a serious defect in its optical system, because it failed when focusing the objects with the necessary precision (myopia), mainly by the darkest objects. This defect was “diagnosed” as a spherical aberration, an optical distortion caused by an incorrect form in its main mirror. Near the border, the curvature of that mirror was smaller than it should be, or say, approximately 1/50 of the thickness of one thread of the human hair. To change the mirror it would be something expensive and difficult. The adopted solution was to design a corrective optical system for its instruments. That optical system was installed with great success in December, 1993. (16)

Hubble exceeded to all their creators´ expectations, to the point of NASA to announce recently that the Hubble telescope would be deactivated due to lacking of budget and the recent problems with the space shuttle. This NASA statement generated protests in the astronomical community of the entire world. The Hubble’s objectives were all reached; and they could be summarized as being “to investigate astronomical bodies by the study of their compositions, physical and dynamic characteristics, to observe the structure of stars and galaxies, to study their formation and evolution, and to study the history and evolution of the universe. To reach those objectives, the Hubble research is divided into “Galaxies and Agglomerates, Interstellar Space, Quasars and Active Nuclei of Galaxies, Stellar Astrophysics, Stellar Population and the Solar System.” (16)

The Hubble substitute comes next. The great objective of its substitute, called of Next Generation Space Telescope (NGST), and that is also being called of (17) James Webb Space Telescope (JWST or, simply WEBB), to be launched between 2010 and 2012, is to arrive to the limits of the space-time, in other words, to arrive to the origins of the universe. This new space telescope will be in a much higher orbit than the Hubble, between the Earth and the Moon, out of the reach of the spacecrafts and it will operate at a temperature much lower than the Hubble.

That will bring a sensibility thousands of times more sensitive than the one of the contemporary telescopes installed in the terrestrial surface. (17). The NGST objectives: “to determine the age and size of the universe, to map its evolution and discover the mysteries of galaxies, stars, planets and of life itself. (18)

Just to complete this information, we could not stop to presenting some data on the Chandra X-Ray Observatory (orbital) that, with the Hubble, is responsible for the astronomical revolution of the last five years. Launched in July 23, 1999 by NASA, the Chandra Observatory has its name given in honor to the Indian physicist Subrahmanyan Chandrasekhar (1910–1995), who received the Noble Prize in physics in 1983. That Observatory has on purpose to research, to map and to detect sources of emission of X-Rays and Gamma Rays, as for instance, from the black holes, quasars, pulsars, supernovae, etc. Its orbit between the Earth and the Moon, with perigee at 16,000 km and apogee at 133,000 km shows a large eccentricity. It has two mirrors of 1.2 meters and four others of smaller diameters. Besides the detectors of X-Rays and Gamma Rays, it possesses sensitive cameras of Gamma-Rays and Spectroscope of Gamma-Rays. Eighty five percent of its orbit is above the Van Allen Radiation Belt (cloud of charged particles that involve the Earth), permitting 55 hours of observation in each cycle. There are other X-Rays observatories, so much orbital as based on the Earth, but they are far from the importance of the Chandra Observatory (19).

6. The Inflationary Theory

The theory of expansion of the universe, which physicists consider with the whole scientific rigidity, is a direct consequence of the Big Bang Theory. We should remember that physicist Albert Einstein foresaw, in the equations that support his Theory of the General Relativity (1915), the evolution of the universe. That hypothesis was corroborated in 1922 by Russian physicist and mathematician Alexander Friedman (Professor of George Gamow), who discovered a solution for the Cosmological Equations, which point towards a universe in expansion. In 1929, astronomers Edwin Powell Hubble (1889–1953) and Milton Humanson (1891–1972) confirmed the expansion of galaxies, and so the expansion of the universe, all in agreement with the Hubble’s law. According to that law, all the other galaxies stand back of our own galaxy – the Milky Way, in a velocity proportional to their distances from the Earth.

For long years, many evidences about the validity of the Big Bang Theory are being accumulated by astrophysicists, to the point that many of them affirm that this theory has today, 99.9% of validity. This almost certainty results of the discovery, in 1965, by Arno Penzias (1933– ) and Robert Wilson (1936– ), of the so-called “bottom radiation”, which resulted from the formation of the universe, when Light (Force) and Matter became apart one of the other, there about 13 billions of years ago. That because that radiation, which stays still present in the space, captured, not as light, but as a bottom noise in the form of microwaves, having its largest intensity in the frequency of 1.1 mm of wave length. Its name is bottom cosmic radiation and it is uniform in any direction in which we point the reception equipments. For that discovery, Penzias and Wilson were granted the Nobel Prize in Physics, in 1978. More recently, in 1990, the satellite COBE – Cosmic Background Explorer, launched by NASA (National Administration of Space and Aeronautics) mapped the regions where is intense the production of those microwaves. It is treated, therefore, of a fantastic radiography of the universe, 300,000 years after its formation, when the stars still had not begun their formation. From the end of 1998, numerous astronomical observations took astrophysicists to concluding that the rhythm of the expansion of the universe comes accelerating itself at a rate of 5% to 6% at each billion of years. The merit of the determination of that expansion rates has been attributed to the team coordinated by the North Americans Saul Perlmutter and Bryan Schmidt.

Alan Guth, respected physicist of MIT (Massachusetts Institute of Technology), begins his work entitled “One eternity of bubbles”, with the following phrase: (20)

If the inflationary cosmological theory of the cosmology is correct, this means that the universe is very far away from being what we have thought to be. Probably the universe is also much older than we thought, and it does not include just one, but an infinity of Big Bangs.

Despite the name, the classic form of the Big Bang Theory is not really a theory of an explosion, entirely. It really describes only the result of the explosion. It describes how the proto universe, hot and dense, it expanded and cooled itself, and it describes how the chemical light elements were synthesized during this expansion, and how the matter condensed to form galaxies and stars. However, the inflationary theory doesn´t say anything on what exploded, or what caused this explosion and, then, it does not make any prediction about the uniformity of the universe soon afterwards from the explosion.

His work is directed to other considerations in search of an explanation by which the physicists called as “void” and “false-void”, what doesn´t fit to be discussed in the context of this chapter. What really interests us to show here is that, despite the great validity of the inflationary theory, many questions still remains without answers.

Then, we should raise two ultimate doubts about that theory. First: which is the reason by which our universe would have been created and, second, why would have been created in the way it was created. It is of considering also that, in the initial instant, still not having created the space, how to expand some thing, be what it was, from the nothing or almost nothing to the everything or the almost everything, which is the current known space, and the one that will still be filled up with the process of its own expansion? That I think to be a great charade, difficult to explain and for which the human mind is still not prepared to understand.

Physicist Einstein, when proposed his Theory of the General Relativity (1915), considered that the expansion of the universe was homogeneous and that the space was finite and curved. Later, Edwin Powell Hubble established a proportionality constant to explain the moving away of galaxies (1929), what implicated in the reformulation of some Einstein’s considerations, since Hubble’s law establishes that the most distant galaxies and with them the universe expand at a higher speed. More recently (2000), astrophysicists are admitting that “The universe is flat as a board.” (11) So, nowadays, the tendency is to not consider a homogeneous expansion and a not curved space, completely the opposite of what Einstein admitted. After all, where the truth is?

On the other hand, in 1975, physicist Murray Gell Mann, responsible for the accelerator of particles at the Stanford University, established the new revolutionary principle in that the atomic particles, by themselves, could never be formed if, over the universal cosmic energy strange agents did not actuate to the material domain, with powers to structure them. (12) Which is the structuring agent then? Werner Karl Heisenberg himself, when formulating, in 1927, the Uncertainty Principle, observed that “particles thrown on a same target, in identical conditions, not always obeyed the same path, suffering an anomalous deviation without letting us to know the cause why they behave this way.” He was accustomed to saying that particles seemed sheep misled with own will. (12) After all, would not be it worthwhile to investigate which "own will" would be this? Who knows if it is not for lack of a deeper investigation of that invisible agent that moves everything and that seems more like an Intelligent Force that The Quantum Theory still didn't find its status of total acceptability on the part of all the modern physicists? They are questions to think about! It’s lacking to us to investigate that other non-material or immaterial domain.

7. Philosophical and Metaphysical Aspects

From what it was said, eminent physicists are working and trying to structure more tens of new theories, trying to adjust them to other patterns, without fleeing to the mathematical rigidity, as well as, to the common man's understanding. But a few physicists have the courage of exploring alternatives closer to philosophy and to metaphysics. With the pointed gaps above, it becomes necessary an approach to the unknown by other routes than not simply material, searching for an intelligent agent to explain facts and phenomena that are out of the exclusive materialism. What I am trying to say is that we need to recover the derived ideas of the duality Force–Matter, almost abandoned since Descartes and Leibniz, for not being considered serious things. Superstitions, groundless creeds and the religions, in general, have much to do with the almost carelessness of the scientists for the concept of duality. We will comment further this subject when treating on the Intelligent Force.

Some of the theories are variations of the Big Bang theory. That is the case of the Italian Paolo De Bernardis´ theory (2002). He is biased to support the Big Bang theory, but he does not accept the Big Crunch. In other words, according to him, there is not enough matter in the universe to revert the expansion backwards. In case the presence of dark matter in the universe turns out to be proven by physicists and cosmologists, De Bernardis theory will be invalidated, since “dark matter” would represent about 90% of the whole matter of the universe (14). The existence of the dark matter worries the physicists and cosmologists, now. According to De Bernardis, the universe would be flat and infinite with an eternal expansion.

Another theory, sponsored by physicists Paul Steinhardt (USA) and Neil Turok (United Kingdom) and published on April 2002 in the magazine Science, speculates that the universe would be cyclic with an endless sequence of Big Bangs and Big Crunches. But for that, it would be necessary the existence of the “dark energy” to be proven and we are very far away from that.

The scientists´ theoretical speculations have the merit of taking to the debate the ideas which are often logic and well based. However, we should not let to a second plan their content of intuition or inspiration, both meaning the same thing, although the last meaning is more accepted by skeptics and materialists persons. Normally, scientific speculations are born as raw hypothesis needing to be worked out. Some of them are transformed in myths, like the myth of the creation of the universe starting from the nothing, for later on to seek an explanation for what is the “nothing” or the “false anything.”

We should not be surprised that Vatican, since 1951, accepted the Big Bang Theory which, mutatis mutandis, is very similar to the myth of the biblical creation. On the other hand, the cyclic creation theory is somewhat similar to the theory of the eternal return, with evolution (phase of expansion) and involution (phase of contraction), but it does not consider the essentially evolutionary concept, always in a same direction, as the human concept of the arrow of the time that points always in direction to the future. This accommodation or coexistence between science and religion won’t resist to the final judgment, where Truth will triumph. While in science several different theories can coexist in a peaceful way, in religion, this is much more difficult. The religious dissentions, for instance, among Christianism, Judaism and Islamism, all monotheists, worshiping a same God, though with different names, are irreconcilable, due to their dogmatic fanaticism.

Therefore, one hopes that the future is reserved to science, where scientists are always disposed to admit their own mistakes when a theory fails and other shows to be better, or say, science is never put in irreducible position. And this is in the essence of science itself, which admits a progressive construction, where its history already showed that the so-called “scientific truths” are many times temporary, subjected always to an evolutionary revision of their theories and laws, in function of new evidences and realities. Of course, there are the stubborn and proud persons, but they always finish by bowing themselves to the truth.

Our conclusion about these concepts is that all human truth is temporary and it evolves in function of the wisdom or knowledge that, by its turn, accompanies the human evolution. In a global world, which is giving its first steps, this becomes more and more true. Having found the true path and respected the own cultures of each person or people, the world will find times of peace and much prosperity and another will be the earthly living.