[Lex Computer & Tech Group/LCTG] Jupiter

[Ken Pogran]

john rudy wrote on 10/21/21 9:29 PM:
>
> https://www.space.com/jupiter-impact-flash-october-2021-photo-video 
> <https://www.space.com/jupiter-impact-flash-october-2021-photo-video?utm_source=SmartBrief&utm_medium=email&utm_campaign=58E4DE65-C57F-4CD3-9A5A-609994E2C5A9&utm_content=1C7E61C7-D770-4011-8C97-70B82E886A77&utm_term=719739a7-5996-4aa2-b2d0-f37dd1d62f80>
>
> Its huge gravity causes it to be a vacuum cleaner picking up stuff 
> that might otherwise fly into earth.  This is an interesting story
>

The point John makes is actually one element of the Rare Earth 
Hypothesis <https://en.wikipedia.org/wiki/Rare_Earth_hypothesis>, which 
"argues that the origin of life and the evolution of biological 
complexity such as sexually reproducing, multicellular organisms on 
Earth (and, subsequently, human intelligence) required an improbable 
combination of astrophysical and geological events and circumstances." 
[Wikipedia]

 From the Wikipedia article 
<https://en.wikipedia.org/wiki/Rare_Earth_hypothesis>:

"According to the hypothesis, complex extraterrestrial life is an 
improbable phenomenon and likely to be rare throughout the universe as a 
whole. The term "Rare Earth" originates from Rare Earth: Why Complex 
Life Is Uncommon in the Universe (2000), a book by Peter Ward, a 
geologist and paleontologist, and Donald E. Brownlee, an astronomer and 
astrobiologist, both faculty members at the University of Washington."

I saw this book in paperback in a bookstore not too long ago, and 
finished reading it just recently. (My wife thought it a very odd choice 
indeed for a "summer beach read"!)

One of many elements of the hypothesis is that, as John wrote, Jupiter 
serves as a "vacuum cleaner picking up stuff that might otherwise fly 
into earth."  Ward and Brownlee argue that, before Jupiter (and, to a 
lesser extent, Saturn) formed, the inner planets like earth were 
regularly bombarded by asteroids and other large space debris. 
(According to one theory, one such impacting object was so large that a 
major piece of it broke off upon impact and flew out to became the 
earth's moon, which would explain why our moon is so different in terms 
of size and orbit from those of other planets).

Some of these impacts would have been so energetic that they would have 
effectively "sterilized" the earth of any life that might have existed. 
But once Jupiter formed, it shielded the earth from further large 
impacts because of its size and position in the solar system, removing 
one factor that inhibited the development of life on earth.

This only one of many elements of the Rare Earth Hypothesis. I find the 
Hypothesis quite compelling.

Winkler mentioned it ever-so-briefly in his "Intelligent Life" talk on 
October 6 as counterpoint to the earlier, more prevalent notion 
(attributed to Carl Sagan, I believe?) that our sun is a very average 
star,  the earth is a very average planet, and life should therefore be 
a very average occurrence throughout the universe.

The Rare Earth Hypothesis, on the other hand, argues that while very 
primitive life forms may well abound  elsewhere in the universe, there 
is so much uncommon about the earth's situation (astrophysically and 
geologically) that the likelihood of complex life existing elsewhere is 
extremely small.

Ken Pogran



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