An ancient Martian riverbed. It may be the birth place of your genetic ancestors.

solar system is a dangerous place with erratic missiles; comets, meteors, and wayward asteroids, flying around, anarchist bombs hell bent on genocidal destruction, like the one that blew the dinosaurs into extinction. It was even theorized that one massive projectile hit Earth, splitting off the Moon, a grand scale version of a subatomic particle targeting a nucleus and blowing it to smithereens, splattering innocent bystanders with fragments.

The public is generally aware of the collision issues. Didn’t they see Armageddon with Bruce Willis saving the world from an asteroid? As a digression, who in their right mind would NOT support a missile to missile defense system given that the incoming may be capable of smashing the entire planet back to microbes, or worse? Are you really interested in a world where life has to spontaneously regenerate from chemicals?
Given the general knowledge of the astro-collision issue, I’m surprised that most people, including scientists never considered the splattering aspect, particularly the epidemic spreading of living organisms. You would think they would have learned that from The Invasion of the Body Snatchers.
In the 1980’s scientists first deduced that we had been splattered by Mars long ago, maybe before there was life on Earth. At first, all the Martian meteorites that were found were just chunks of once molten sterile lifeless stuff. Meteorite ALH84001 changed that. This meteorite has chemical signatures, PAHs (don’t ask), other minerals, and sausage-like objects that are similar to some bacteria.
Of course NASA was delighted and published an interesting paper that came to an earth shaking conclusion:
“Although there are alternative explanations for each of these phenomena taken individually, when they are considered collectively, particularly in view of their spatial association, we conclude that they are evidence for primitive life on early Mars.”
It had long been believed that Mars, being smaller than Earth and also being in the habitable zone of our sun, may have cooled to a life nurturing environment before Earth. It’s a small jump to the idea that Mars splattered Earth with microbes from which all life on Earth evolved. That is, we are all Martian invaders.
This, of course, put NASA in the driver’s seat for further “origins of life” funding, and sent all the other origins researchers, those vested in other theories–the cesspool hit by lightening theory, the deep water volcanic vent percolating life theory, the deep crust pressing out cupcakes of life theory—they all went into berserker rage.
NASA’s report was shredded with criticism, the most damning of which was the age old boogeyman of science, contamination. In this case, not Mars contaminating Earth, but Earth bacteria contaminating the meteorite after it got here. Most scientists now are unconvinced that Mars seeded life on Earth, or even that there is/was life on Mars.
NASA must be laughing up their sleeve. They still hold the strongest hand in the origins of life investigation. Mars still needs to be checked for current and past life. Heck maybe we splattered life to Mars. The more we learn about life in the volcanic vents and the depths of Earth’s crust, the more we need samples of other planets and moons that have liquid water to see if they got splattered, or did the contaminating.
More next time.