New research by Yale astronomers suggests that our Moon may harbor clues that Venus may have had an Earth-like environment billions of years ago, with water and a thin atmosphere. Their findings follow recent studies suggesting that our sister planet may have been the solar system’s first habitable planet.
Scientists conjecture that Venus may have resembled Earth for its first three billion years, with vast oceans along with speculation that strange dark patches, “unknown absorbers” that have been detected floating inside the clouds of Venus capturing large amounts of solar radiation may prove to be extraterrestrial microorganisms that exist in the upper atmosphere –the most Earth-like location in the solar system, roughly equivalent to the air pressure at the summit of Mount Kilimanjaro.
10 Billion Rock Fragments Over the Eons
Astronomers Sam Cabot and Greg Laughlin say “pieces of Venus — perhaps billions of them — are likely to have crashed on the moon.”
Asteroids and comets slamming into Venus may have dislodged as many as 10 billion rocks and sent them into an orbit that intersected with Earth and Earth’s moon.
“Some of these rocks will eventually land on the moon as Venusian meteorites,” said Cabot, lead author of the study. Cabot observes that catastrophic impacts such as these only happen every hundred million years or so — and occurred more frequently billions of years ago.
A similar phenomenon may have occurred on Earth 66 million years ago when an asteroid hit Earth with an impact equivalent to 10 billion Hiroshima bombs. This Chicxulub impact at the Yucatan Peninsula released the equivalent of 100 million megatons of TNT creating a 20-mile deep, 110-mile hole and sterilizing the remaining 170 million square miles of the ancient continent of Pangaea, killing virtually every species on Earth. It was comparable to an impossible magnitude 12 earthquake–enough force enough to lift Mount Everest back into space at escape velocity, potentially scattering fragments of dinosaur bone on the Moon.
Moon’s Geology Museum
“The moon offers safe keeping for these ancient rocks,” Cabot said. “Anything from Venus that landed on Earth is probably buried very deep, due to geological activity. These rocks would be much better preserved on the moon.”
Many scientists believe that Venus might have had an Earth-like atmosphere as recently as 700 million years ago. After that, Venus experienced a runaway greenhouse effect and developed its current climate. The Venusian atmosphere is so thick today that no rocks could possibly escape after an impact with an asteroid or comet, Cabot said.
Two Critical Factors
Laughlin and Cabot cited two factors supporting their theory. The first is that asteroids hitting Venus are usually going faster than those that hit Earth, launching even more material. The second is that a huge fraction of the ejected material from Venus would have come close to Earth and the moon.
“There is a commensurability between the orbits of Venus and Earth that provides a ready route for rocks blasted off Venus to travel to Earth’s vicinity,” said Laughlin, who is professor of astronomy and astrophysics at Yale. “The moon’s gravity then aids in sweeping up some of these Venusian arrivals.”
Upcoming missions to the moon could give Cabot and Laughlin their answer soon. The researchers said NASA’s Artemis program is the perfect opportunity to collect and analyze unprecedented amounts of lunar soil.
Laughlin said there are several standard chemical analyses that can pinpoint the origin of moon rocks, including any that came from Venus. Different ratios of specific elements and isotopes offer a kind of fingerprint for each planet in the solar system.
“An ancient fragment of Venus would contain a wealth of information,” Laughlin said. “Venus’ history is closely tied to important topics in planetary science, including the past influx of asteroids and comets, atmospheric histories of the inner planets, and the abundance of liquid water.”
In a separate initiative, Breakthrough Listen is funding a research study into the possibility of primitive life in the clouds of Venus. The study is inspired by the discovery, announced this month, of the gas phosphine, considered a potential biosignature, in the planet’s atmosphere. The science team will comprise world-class physicists, astronomers, astrobiologists, chemists and engineers, led by Sara Seager, astrophysicist and planetary scientist at the Massachusetts Institute of Technology.
Venus upper atmosphere harbors dark patches –first observed by ground-based telescopes more than a century ago–might be forms of sulfur, ferric chloride or, as Carl Sagan speculated, even microscopic life.
The Daily Galaxy, Max Goldberg, via Yale University/AAAS Eurekalert
Image credit: Venus via Shutterstock License