SETI: (Search for Extra-Terrestrial
Russians Detect Radio
Signal From Space.
Earth-like planet found "close."
An array of radio telescopes.
Is there intelligent life elsewhere in the universe?
That is perhaps the ultimate question in science.
At the annual American Astronomical Society conference in 2010-JAN, Simon "Pete" Worden, an astronomer who heads NASA's Ames Research Center in Moffett Field, CA, said:
"The fundamental question is: Are we alone? For the first time, there's an optimism that sometime in our lifetimes we're going to get to the bottom of that. If I were a betting man, which I am, I would bet we're not alone." 1
At the same meeting, the Rev. Jose Funes, director of the Vatican Observatory, said:
"These are big questions that reflect upon the meaning of the human race in the universe." 1
NASA's Kepler telescope is capable of monitoring the brightness of more than 100,000 stars simultaneously. It attempts to detect miniscule reductions in their light. That is often caused by a planet passing in front of the star. Further analysis gives some idea of the size and orbit of the planet. In the future, it might be possible to build a massive telescope to detect oxygen, water, carbon dioxide, and perhaps industrial pollutants from these planets. Detecting certain types of pollutants would prove the existence of intelligent life there.
On one hand, it seems quite possible that intelligent life exists on other planets that are circling around different stars elsewhere in the universe.
One indication might the relatively brief interval it took, after the Earth coalesced circa 4.5 billion years ago, until the most primitive forms of life developed here.
Until 2016, the oldest forms of life on Earth were found in stromatolites -- "macroscopically layered structures produced by microbial communities" 2 located in the Dresser Formation of the Pilbara Craton, Australia. They were dated to 3,480 billion years BP (Before the Present). However, a 2006-AUG article in the journal Nature announced a similar discovery made in the Isua Supracrustal Belt (ISB) in southwest Greenland. The latter stromatolites have been dated from 3,800 to 3,700 million years BP. 3 That is, they were alive "only" about 760 million years after the Earth itself coalesced. It is believed that much more primitive forms of life existed on earth even earlier, but their remains have not been detected to date. Thus, the first forms of primitive life on Earth seems to have developed relatively quickly after the Earth itself formed. There is a distinct possibility that life could be established and evolve elsewhere in the universe as it was on Earth, if conditions were right on another planet or moon in a different solar system.
Scientists estimate that at least 100 billion galaxies, 4 and 70 billion trillion (7 x 10 22) stars exist in the observable universe! That is equivalent to almost ten trillion stars for every human on Earth! If one includes the total universe, beyond what is observable from Earth, the number would be much larger.
An article in Space.com indicates that:
"...nearly every [nearby] star hosts at least one alien planet. ..."
"... virtually all red dwarfs throughout the Milky Way have planets, and at least 25 percent of these stars in the sun's own neighborhood host habitable-zone "super-Earths. ..." 5
The term "habitual-zone" or "circumstellar habital zone" is the range of possible orbits by a planet around its sun in which the planet can support liquid water on its surface, if its atmospheric pressure is sufficiently high. Water in liquid form is believed to be a prerequisite for life. A "super Earth" is a planet that is similar in size to our Earth. On the order of 20% of all planet candidates detected so far are approximately Earth sized. 6
There is no obvious reason why stars in other parts of the universe beyond the Milky Way -- our galaxy -- would not have similar planetary systems.
According to NASA:
"Although the details are not entirely understood, it is known that stars like the Sun form from spinning protostellar disks of gas and dust. The Earth and other planets of the solar system are believed to have developed from the remains of that disk. ... There is no reason to believe that the same process would not be effective throughout the galaxy. Thus, a first guess might be that other planetary systems would be like the solar system." 7
If conditions were similar on other planets circling around other stars, then one might expect life to form there as well during many planet's first billion years. This would probably be in the form of single celled living organisms. Wherever life was established, most scientists would expect that the process of natural selection would probably cause millions of species of life to evolve over the following billions of years. This makes the development of intelligent life possible on other planets.
By 2015-JUL, NASA's Kepler Space Telescope had confirmed the discovery of 1,030 exoplanets -- planets rotating around other stars. More exoplanets continue to be found. Of these, many are in the habital zone of their stars.
NASA has reported that:
"... a number of planets with masses near that of Earth have been detected." 7
During 2015-JUL, the Kepler mission confirmed the first near-Earth-size planet in the habital zone around a star very similar to our star. They referred to it as an "older cousin to Earth." At the time, Elisa Quintana, research scientist at the SETI Institute at NASA's Ames Research Center wrote:
"We know of just one planet where life exists -- Earth. When we search for life outside our solar system we focus on finding planets with characteristics that mimic that of Earth. Finding a habital zone planet comparable to Earth in size is a major step forward." 8
On the other hand, scientists in various SETI (Search for Extra-Terrestrial Intelligence) programs have been scanning the heavens, attempting to detect radio signals from other planets. They have been unsuccessful to date. If a signal could be detected, then this would almost certainly indicate the existence of another intelligent species of life elsewhere in the universe.
2015-MAY: Russian Astronomers detected a radio signal that might possibly have originated from from another planet:
Scientists in Russia reported detecting a strong radio signal using their RATAN-600 radio telescope in Zelenchukskaya, at the northern foot of the Caucasus Mountains. 9 It was at a wavelength of 2.7 cm which is equivalent to a frequency of 11 Gigahertz. This is a frequency similar to those used extensively by TV satellites rotating around Earth. 10 They tentatively identified the location as coming from the solar system surrounding the star HD 164595. It is located about 95 light years from our solar system, and was already known to have at least one planet that is roughly the size of Neptune in our solar system. It's sun is similar to our strength in size and brightness, but is a few billion years older than our sun.
An attempt has been made to estimate the strength of the transmitter that was detected. If it is transmitting its signal in all directions, then its power level would be 100 billion, billion watts. That amount of power is greater than the energy of all of the sunlight falling on our Earth! However, if the transmission was focused in our direction, if one assumes that they used a 1000 foot/300 meter diameter antenna, they would require a transmitter of over a trillion watts. This is approximately the total energy consumption by all the inhabitants of our Earth. Obviously, both options are orders of magnitude greater than the power level of which any Earth-bound transmitter is capable. 9
The scientists who discovered the signal now doubt that the signal was generated by extra terrestrial intelligent life. Still, it raised enormous interest when the Russians finally announced their findings to the world over a year later.
During late 2016-AUG, the Russian news agency TASS suggested that the signal was probably caused by terrestrial interference. On AUG-31, the Special Astrophysical Observatory of the Russian Academy of Sciences issued a statement saying that:
"... It can be said with confidence that no sought-for [SETI] signal has been detected yet." 9,11
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