Rosanne Di Stefano of the Harvard-Smithsonian Center for Astrophysics, said in globular clusters 100-light-years away, there could be more advanced and complex aliens as these clusters date back to 10 billion years ago.
Presenting a paper at the 227th meeting of the American Astronomical Society. Di Stefano said the clusters date back to the early life of the Milky Way, 10 billion years ago compared to the Universe which is 13.7 billion years old. Despite age-related issues, he has argued that it also provided ample time for civilizations to evolve and become complex.
The clusters are densely packed groups of stars which may make excellent cradles for complex space-traveling life to evolve, he said brushing aside studies which said in the past that these environments may be too harsh for life.
"A globular cluster might be the first place in which intelligent life is identified in our galaxy," said Di Stefano, emphatically, while the research paper’s co-author Alak Ray of Tata Institute of Fundamental Research in India, said the stars found around noncluster stars lack significant amounts of these elements.
Although massive gas worlds tend to orbit stars, smaller rocky worlds similar to Earth can be found around stars with varying amounts of the heavy material. "It’s premature to say there are no planets in globular clusters," Ray said.
Stressing that the older age of the stars is an advantage, Di Stefano and Ray noted that bright stars like the sun would have been born, lived and died, leaving behind only faint, long-lived dwarf stars. These dimmer stars would require planets to orbit closer to their sun in order to maintain liquid water on their surface for life to grow. Their close orbits could help shield them from interactions with passing stars, said the authors.
As life on Earth is thought to have evolved after about 3.5 billion years, a 10-billion-year-old planet would give life time to not only bloom, but evolve into intelligent and technologically advanced beings. Life on these ancient worlds would have had ample time to become a spacefaring species.
"Once planets form, they can survive for long periods of time — even longer than the age of the universe," said Di Stefano.
UFO Phenomenon Real?
Since nearby stars in galactic clusters is 20 times closer than the sun’s nearest neighbors, "sending a broadcast between the stars wouldn’t take any longer than a letter from the U.S. to Europe in the 18th century.Hence, "targeting globular clusters with SETI search methods could reveal radio or laser broadcasts sent from one stellar system to the next," they added.
Not merely messages but even spaceships could travel more easily from one system to the next, Di Stefano noted. "The (NASA) Voyager probes are 100 billion miles (160 billion km) from Earth, or one-tenth as far as it would take to reach the closest star if we lived in a globular cluster," Di Stefano said.
Launched in 1977, Voyager 1 and 2 were sent to the outer solar system, which have passed the gas giants on to the edge of the solar system and into interstellar space. When they capture signals, then more will be revealed.