What if an alien civilization was a billion or more years older than ours and detected Earth in its early history? “For billions of years of Earth history, an alien astronomer may have even been sufficiently misled to conclude that Earth was sterile—despite the fact that life was flourishing in our ocean at the time,” says Stephanie Olson, an astrobiologist at the University of California, Riverside with NASA’s Astrobiology Institite.
Could one of Earth’s most intelligent species be an alien, ‘seeded’ on the planet by an interstellar genetic code? Scientists speculate that the clue might be found in the ancient precursor to life, RNA.
“We’ve taken a major step back in time, beyond what we’d ever expected to be able to do with Hubble. We see GN-z11 at a time when the universe was only three percent of its current age,” observed Pascal Oesch at the University of Geneva and head of the Galaxy Build-Up at Cosmic Dawn team about the discovery of a 13.4 billion-years -old galaxy. It’s mind-boggling by comparison to think that Earth is only 4.5 billion years old.
The weird shapes and colors of the tiny Martian moons Phobos and Deimos have inspired a long-standing debate about their origins. The dark faces of the moons resemble the primitive asteroids of the outer solar system, suggesting the moons might be asteroids caught long ago in Mars’ gravitational pull. But the shapes and angles of the moons’ orbits do not fit this capture scenario.
“It was shocking to realize that the Milky Way had a large sibling, and we never knew about it,” said Eric Bell, University of Michigan professor of astronomy in 2018 about his discovery that the Andromeda galaxy (also named M31), our closest large galactic neighbor, shredded and cannibalized a massive galaxy two billion years ago.