Astronomers search 100000 galaxies for signs of life

A massive scan for heat signatures across the cosmos has turned up no signs of highly advanced civilizations.
By Kathy Fey | Apr 15, 2015
In hopes of answering the ever-present question of whether Earth is the only home to life in the universe, scientists have started a rigorous scan of the skies, so far searching 100,000 galaxies for tell-tale heat signatures, and have so far turned up no evidence of technological advancement anywhere but here.

According to Nature World News, the researchers were not surprised at the findings. "This is a pilot project, and I would have been stunned to see aliens using all of the starlight in a galaxy somewhere," Jason T. Wright of Penn State University said.

This recent search for intelligent life was aimed at finding any life from that may have become technologically advanced and widespread. Known as a Kardashev Type III supercivilization, such a civilization would have expanded to occupy an entire galaxy and draw power from the stars therein. Such a galaxy-wide use of energy would create a notable heat signature.

"Whether an advanced spacefaring civilization uses the large amounts of energy from its galaxy's stars to power computers, space flight, communication, or something we can't yet imagine, fundamental thermodynamics tells us that this energy must be radiated away as heat in the mid-infrared wavelengths," Wright said in a statement. "This same basic physics causes your computer to radiate heat while it is turned on."

The team collected data using NASA's WISE satellite, which was designed to detect the kind of radiation that the galaxy survey was seeking. Although none of galaxies surveyed radiated evidence of a supercivilization, astronomers still have hope of one day detecting technologically advanced life.

"Our results mean that, out of the 100,000 galaxies that WISE could see in sufficient detail, none of them is widely populated by an alien civilization using most of the starlight in its galaxy for its own purposes. That's interesting because these galaxies are billions of years old, which should have been plenty of time for them to have been filled with alien civilizations, if they exist. Either they don't exist, or they don't yet use enough energy for us to recognize them," Wright said.

"As we look more carefully at the light from these galaxies," said Wright, "we should be able to push our sensitivity to alien technology down to much lower levels, and to better distinguish heat resulting from natural astronomical sources from heat produced by advanced technologies. This pilot study is just the beginning."

The study was published in the Astrophysical Journal Supplement Series.

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