Q: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
The question “are we alone in the universe?” has fascinated people for centuries. In 1959 two Cornell University physicists described how we might answer that question through interstellar communication. Philip Morrison and Guiseppe Cocconi analyzed how two civilizations separated by many light years of space might use electromagnetic radiation to communicate. 
  
 Electromagnetic radiation is the general term for the more familiar light and radio waves, but also includes gamma rays, x rays, ultraviolet rays, and infrared. All of these forms of electromagnetic rays or waves travel at the speed of light, the fastest possible speed. The only difference between these types of electromagnetic waves is the length or the wave or the “wavelength.” Since the waves all travel at the speed of light, another way to characterize the wave is by the number of waves received per second. This is the frequency of the wave. 
  
 Morrison and Cocconi considered how well the types of electromagnetic waves passed through interstellar space. While space is usually described as a vacuum, it does contain some gas and dust. Over great distances that gas and dust absorb many types of radiation but radio waves pass through nearly unimpeded. For interstellar communication, a particular range of radio frequencies, “microwaves” from 1 GHz to 10 GHz, are particularly good choices. At lower frequencies our galaxy emits prodigious amounts of radio waves creating a loud background of noise. At higher frequencies the Earth’s atmosphere, and presumably the atmosphere of other Earth-like planets, absorbs and emits broad ranges of radio frequencies. The result is a quiet “Microwave Window” through which efficient radio communication is possible. 
  
 The Microwave Window has another interesting feature to recommend it as a place for interstellar communication: the “Water Hole.” Some atoms and molecules in space emit radio waves at particular frequencies. Hydrogen atoms emit at 1420 MHz (a wavelength of 21 cm). Hydroxyl molecules, composed of one atom of hydrogen and one atom of oxygen (OH), emit at four specific radio frequencies ranging from 1612 MHz to 1720 MHz. When a hydrogen atom combines with a hydroxyl molecule it forms a molecule of water, the most essential molecule for life as we know it. Thus, the range of frequencies from 1420 to 1720 MHz is called the Water Hole. It has been a popular frequency range for many SETI programs. 
  
 While the Microwave Window is a “cosmic quiet zone” the existence of the radio emission lines marking the Water Hole illustrates a problem: distinguishing communication signals from natural astrophysical emission. Most cosmic radio sources as “very broadband.” They “broadcast” over a very wide range of frequencies. For example, the radio emission from a quasar would span most of the diagram above and the amount of power would change very slowly over the frequency range. As mentioned above, hydrogen and hydroxyl emit radio waves at particular frequencies. The diagram below shows the power emitted by a cloud of hydroxyl (OH) molecules near a red giant star. The cloud rotates around the star so some of the molecules are moving toward us and some are moving away. The Doppler Effect shifts the frequency of the radio waves to higher (moving toward us) and lower (moving away) frequencies. The resulting spectrum (power vs. frequency) shows two peaks. These features are very narrow compared to most astrophysical sources. 
  
 Signals produced by technology for communication can be much narrower than any known astrophysical source. The bottom half of the diagram shows the spectrum of the signal from the Pioneer 10 spacecraft. The frequency scale has been expanded by nearly a factor of 10. The narrow signal component on the left is further expanded by a factor of 100 to show the very narrow frequency components of the data in the signal. This illustrates a clear way to distinguish extraterrestrial communication signals for astrophysical signals: look for very narrow frequency components. Most SETI programs take this approach, breaking the radio spectrum into many millions of very narrow frequency channels 
  
 Where to Look 
  
 Searching for extraterrestrial signals can be likened to searching for a gold nugget buried in a field. We have identified the field that we will explore: the Microwave Window in the radio spectrum. We have a way to distinguish the gold nugget for other pieces of metal: look for very narrow bandwidth signals. But, with limited resources (telescope time, electronics, etc.) what is the best strategy to search through the field? 
  
 There are two basic strategies. We could examine the entire field but only sift through the top few centimeters of soil. If a gold nugget is near the surface anywhere in the field, we’ll have a good chance of finding it. We could study the chemistry and geology of the surface and select particulars spots where we will dig deep looking for gold. If the gold is buried well below the surface, this strategy has the best chance. 
  
 In SETI, there are two basic search strategies. Sky surveys sweep a telescope over large areas of the sky looking for strong signals that may come from any direction. Targeted searches point a telescope at the direction of selected stars. By dwelling on a star for long periods of time, a targeted search is sensitive to weaker signals. 
  
 We will pursue both strategies with SETI on the ATA. ||||| Nearly four decades after it was received, astronomers still can’t say with 100% certainty that the ‘Wow!’ signal was not an interstellar radio beacon from some far-flung extraterrestrial civilization. But the signal --- which got the Wow! moniker after an astronomer first scribbled those letters in the margins of the incoming data --- was never reacquired. 
  
 Even so, Bob Dixon, Ohio State University’s (SETI) Search for Extraterrestrial Intelligence program director at the time, once told me that the signal had to have at least originated at a distance from beyond the Moon. 
  
 What is known is that the signal was received just after 11 PM local time on August 15, 1977, at OSU’s now defunct Big Ear Radio Observatory. Its position on the sky came from the direction of the star cluster M55 in the constellation of Sagittarius. Yet more importantly, it closely-matched the narrow emission line of hydrogen at 1420 megahertz , a radio-quiet spot long touted as a potential interstellar hailing frequency for E.T. civilizations. And at the time, it was also the strongest such SETI (Search for Extraterrestrial Intelligence) candidate signal ever seen. 
  
 “So, ‘Wow!’ was appropriate,” Dan Werthimer, chief scientist at the University of California at Berkeley’s SETI program, told me. But he says it would be more convincing if the signal had appeared one after another along the Big Ear’s two different radio observing beams. 
  
 That, says Werthimer, would be more of an indication that it was an artificial radio beacon from an interstellar point source. But we occasionally see Radio Frequency Interference (RFI) that's modulated in just the right way that makes it look like it is consistent with a distant point source, says Werthimer. But as he emphasizes, if the signal were really from E.T. and was in the telescope’s observing sights for at least a few minutes, the source of the signal should have moved from one beam into the other. 
  
 “It didn't,” said Werthimer. “So, I'm 99% confident that the signal the OSU guys saw was RFI.” 
  
 Still, there’s another possibility and that is that the signal did originate from beyond the moon, but was produced by two active comets orbiting within our solar system. That is, within the vicinity of the ‘Wow!’ signal’s position on the sky. 
  
 A 2015 paper published by The Washington Academy of Sciences proposed that during that summer of 1977, comets 266P/Christensen and P/2008 Y2 (Gibbs) “were transiting in the neighborhood of the Chi Sagittarii star group” and produced by a large hydrogen cloud around their nucleus. Because the frequency for the ‘Wow!’ signal fell close to the radio emission for hydrogen, the paper noted that these local cometary hydrogen clouds would be strong candidates as the signal’s source. 
  
 The comet hypothesis sounds somewhat plausible, but I still don’t buy it. If this cometary phenomena were at all statistically frequent, researchers would likely have picked up something similar over the last 50 years. And to my knowledge, this is the first time that anyone has argued that such narrowband emission is from a comet. 
  
 My personal best guess is that the signal was not RFI. But more likely, it was the product of some very distant or unusual and/or poorly-understood astrophysical phenomenon. 
  
 That’s not to say that E.T. isn’t out there somewhere. But the likelihood that we would only receive a lone radio beacon, that’s never repeated and could never be reacquired, also seems implausible. 
  
 Most people can live with the fact that there may be no one out there. Some prefer the notion that we are the ultimate undiscovered country in a cosmos teeming with intelligent life. But few like the idea that we narrowly missed E.T.’s one-off phone call. 
  
 Werthimer, however, says either the ‘Wow!’ signal’s rise and fall in strength was actually intrinsic to the signal, in which case he says it would have to be RFI. Or if the signal were from a distant source, he says, then it would be constant in power and its rise and fall in strength would be due to Earth’s rotation. 
  
 The remote possibility that it’s the real thing is what makes the ‘Wow!’ signal so haunting . You can dismiss it as Radio Frequency Interference (RFI) until the cows come home. But as Werthimer himself reluctantly acknowledged: “We can't rule out E.T.” |||||
A:
In 1977, a radio telescope recorded a 72-second signal coming from the direction of the constellation Sagittarius. Stunned, the astronomer who observed it wrote "Wow!" on the readout. Since it couldn't be explained, plenty argued the signal was proof of life beyond our planet. After 40 years, however, a researcher has finally burst their bubble. Antonio Paris of St. Petersburg College last year suggested the 1420 MHz "Wow!" signal actually came from hydrogen gas surrounding a comet—either 266P/Christensen or P/2008 Y2, which were in the area of the signal at the time but only discovered about 10 years ago, per Popular Mechanics. So when one passed by Earth earlier this year, Paris pointed a radio telescope at it. Unlike any other celestial source nearby, 266P/Christensen emitted a radio signal at 1420.25 MHz. Paris then pointed his telescope at three other comets selected at random. All appeared to emit a 1420 MHz signal, which hydrogen atoms naturally produce, per the SETI Institute. A SETI researcher told Forbes last month that the signal was likely radio frequency interference. But this shows that '77's 'Wow!' signal "was a natural phenomenon from a solar system body" and certainly not a message from aliens, Paris writes in the Journal of the Washington Academy of Sciences. Or, as the London Times puts it, the Wow signal just "officially lost its wow factor." (A coming telescope will be able to view nearby galaxies in "unprecedented" detail.)