It is my pleasure to introduce Dr. Eric McKenzie, associate director for the department of astronomy at the University of Maryland. He received his Ph.D. from the University of Florida, and his research has focused on galaxy evolution at specific wavelengths of redshifted light. He also helped me get some of my facts straight for the Tomorrow News Network story “The Orion War.”
This week, he has answered some questions about galaxy evolution and what the early universe was like. Today is the final installment of his interview.
James Pailly: If you could go back in time to visit a planet in one of these young galaxies, what do you think you’d find there? Any chance you might meet an alien life form?
Dr. McKenzie: I’m no astrobiologist, so I’m speaking a little off-the-cuff, but here are some thoughts.
As mentioned earlier, there were fewer heavy elements in the early universe. With hydrogen predominating, the population of planets would presumably favor gas giants like Jupiter rather than terrestrial planets like Earth. Water would be relatively uncommon due to the need for oxygen atoms. It’s a good guess that life would be carbon-based, like Earth’s. (Scientists have speculated that silicon-based life forms may be possible, but silicon would be quite rare in the early universe.) Technology could be a challenge for early alien civilizations, since on average they would have smaller quantities of useful materials to work with. Consider the conflicts that have been fought on Earth over scarce natural minerals – the problem would be exacerbated!
Early civilizations would also face the threat of an increased likelihood of supernovae. With the early universe’s higher star formation rate, many stars were being born, but the largest ones were only living a few million years and dying in supernova explosions. This wouldn’t be very healthy for civilizations living in nearby star systems, nor for emerging life which might one day result in a civilization.