Sky and Telescope - June 2018 - 18
by Ralph D. Lorenz
s astronomers, we reach out to the universe. We point
our telescopes and send spacecraft to discover what's
happening Out There. When we look up at the aged
face of the Moon, for example, we see the scars of the solar
system's violent past. Impacts by asteroids and comets have
blasted giant craters in planetary surfaces, and indeed
continue to do so. Craters on our own planet, however, are
few and far between, because our active world reshapes itself
through plate tectonism, volcanism, and erosion.
But occasionally, a view out of an airplane window will
remind astronomers and geologists that, sometimes, the
universe reaches out to us!
In an effort to understand how the cratering process
may work on other worlds, I have hiked in about 20 impact
structures on Earth. Technically, I even live near one (the
Chesapeake Bay isn't obviously shaped like a crater, but its
impact origin was recognized about 20 years ago). But with a
few exceptions, the view from the ground doesn't let you take
in the overall structure. An aerial view is much better, and in
fact many terrestrial impact structures were ﬁrst discovered
in aerial photographs or spacecraft views.
As a planetary scientist engaged in a number of projects
- recently, for example, as a participating scientist in the
Japanese Akatsuki mission at Venus - I am obliged to travel
frequently. The international nature of space exploration
means trips to lots of interesting places. Happily, I love ﬂying.
I always get a window seat, mostly for the geology (although
it's the chance of seeing the aurora borealis that motivates
There's more to see from
your airplane window
than the sky.
J U N E 2 018 * SK Y & TELESCOPE