Looking for pieces of Venus? Try the moon

Date:
October 7, 2020
Source:
Yale University
Summary:
A growing body of research suggests the planet Venus may have had
an Earth-like environment billions of years ago, with water and
a thin atmosphere.



FULL STORY ==========================================================================
A growing body of research suggests the planet Venus may have had an
Earth-like environment billions of years ago, with water and a thin
atmosphere.


==========================================================================
Yet testing such theories is difficult without geological samples
to examine.

The solution, according to Yale astronomers Samuel Cabot and Gregory
Laughlin, may be closer than anyone realized.

Cabot and Laughlin say pieces of Venus -- perhaps billions of them --
are likely to have crashed on the moon. A new study explaining the theory
has been accepted by the Planetary Science Journal.

The researchers said 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, a Yale graduate student and lead author of the study.

Cabot said catastrophic impacts such as these only happen every hundred
million years or so -- and occurred more frequently billions of years ago.

"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.

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."

========================================================================== Story Source: Materials provided by Yale_University. Original written
by Jim Shelton. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Samuel H. C. Cabot, Gregory Laughlin. Lunar Exploration as a
Probe of
Ancient Venus. Planetary Science Journal, 2020 [abstract] ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201007123033.htm

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