Big Rock Candy Mountain
Six year old Zach is our designated maker of fundamental discoveries. Santa brought him a light projector to use in tracing pictures (what art directors call a Lucy machine). He was thrilled:
“I didn’t even know I wanted this!” he exclaimed. “How could Santa know?”
His reaction was enough to thrill me, too, and to soften my own disappointment.
All I wanted for Christmas was a time machine, but nobody gave me one. Of course I knew it was improbable, but then – among the people reading this might be some great great great grandchildren living in the future, when time machines are common. I had hoped one of them might have cared enough to bring one back – even an old, used one.
But no. And now I know why. I just read an interview with Australian astrophysicist Paul Davies, who says that no time machine they’ve been able to imagine could take anyone back to a time before the machine was built.
Rats!
Davies doesn’t always play the killjoy. A few minutes earlier in the interview, he had acknowledged that we don’t really know the chemical processes that gave rise to life, but then added:
“However, we do know that life appeared first on Mars, and then it came to Earth.”
I love remarks like that — astounding possibilities, casually tossed off as commonplace. Truth is, he was exaggerating – we don’t know that — but he does have good reasons for saying we do.
First, Mars is a smaller planet, so it cooled faster, thus sooner than Earth and was first to have the moderate temperatures that could spawn life.
Second, being smaller, Mars has weaker gravity than Earth, so rocks dislodged from the early Martian surface by the impacts of comets and meteors (which were extremely plentiful back then) could easily be hurled into Earth’s gravitational field.
The traffic has gone both ways, but the busiest lanes are from Mars to Earth.
Here I was hoping for a time machine, but at the momentous dawn of life’s origin on Earth, by what cosmic conveyance does it arrive?
Rocks.
That’s what I want next year, Santa – rocks.