Space/Science — HabitableZone

Space/Science » in reply to Bill Hartmann (Scientist, textbook/fiction Author, & Painter)

More B*** S*** impact "science"
E.P. Grondine — (archived)

I'm sure this guy is a nice fellow, but....

"BH: Our technique at the Planetary Science Institute is to use the moon as calibration."

Yeah - why bother getting data by counting craters in images when you can "estimate" it. Better yet, use a body that has a close gravitational companion and then make extremely speculative estimates from that...

"We know the crater densities (i.e. diameter distribution) for lunar lava plains that are about 3.3 to 3.9 billion years old."

Yeah, but don't get the crater densities for anything later - they may upset you...

"Then we use dynamical estimates from observed asteroids and theory of asteroid scattering out of belt resonances [between planetary influences on orbits], to estimate the ratio of Mars/moon impacts for fixed size asteroids."

By the way, comets hit too. Ever hear of Shoemaker Levy 9?

"Then we apply some scaling factors for gravity and impact velocity."

"scaling factors"...whoo boy...

"Voila! We have the predicted crater density on Mars for 3.5 billion years; and from time dependencies measured on the moon and Earth, we have estimated time dependence, so we can predict "isochrons" or diameter distributions, for different ages on Mars."

Yeah, or you can count meteorites in images of Mars' surface and get another set of ages for different areas of Mars -

"Much of this is described in a tutorial."

I don't mind estimates, as long as the estimates qualifications are explicitly stated. But when anyone tries to present "estimates" as data I get real upset...

I got a one word description for this type of "science", and I don't need a tutorial to set it out: Bullshit.

And Bullshit is no substitute for NASA spending the money necessary to get a firm handle on this hazard.

ep

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