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Hawaiian Moonscapes

Dave North

Anyone who's been to Hawaii knows they have a different take on things.

We recently made a trip there, in part to get a different take on the Moon and planets.

Okay, a good part of the reason was to catch Mars high in the sky during this low opposition, and we did (only briefly, though, as the weather was not all that cooperative).

All was not lost.

The Big Island (where we spent all our time) is basically Volcanism Central for Earth. And the greater portion of what we see on the Moon was formed from volcanism.

(The notable exception, of course, is impact cratering, which often led to volcanic events - such as the basaltic floods in the maria).

Anyone going to Hawaii with the idea that they would see moonscapes as they appear today would be largely disappointed (with one notable exception).

The Big Island volcanoes are all wayyy too new to look like the Moon, which stabilized from a macrovolcanic point of view some billions of years ago, and since has been pulverized to sandy dust.

Much of the basaltic flow on Hawaii runs from brand new to hardly old enough to notice the difference - from a lunar point of view.

But what you can see is how the Moon looked when it was young, and how that might lead to what we see today.

In that respect, you couldn't ask for a better place.

Perhaps the most striking thing you'll see is the large, collapsed lava tubes in the newer flows from Pu'u O'o, which has been the main site of activity for the last 15 years or so.

I had always thought the usual story involved huge tubes that drain, and after some thousands or millions of years, finally collapse from some strain or nearby impact.

Not so.

Some of the large tubes collapse almost immediately after draining, and that's not uncommon.

From that we learn that many of the sinuous rilles (which probably formed this way) may have been visible in their present state since not too long after they formed!

This was a real revelation for me.

Speaking of lava tubes, by far the best I've ever seen for variety of size, color and formation are right in the suburbs of Hilo.

You can drive right up to them and walk in, if you have a flashlight.

There are no admittance fees, no supervision, just caves.

It's wonderful. Go.

Another impressive visual is Mauna Loa, which translates as "Long Mountain."

It's very well-named, since it is the classic shield volcano on our planet. The rise from base to top is quite gradual, and it's hard to believe from looking at it that it's nearly 14,000 feet tall.

It's just so ... well, long!

That really gets across the idea behind the large shield zones like Rumker, and even more notably the huge shields on Mars (including the largest mountains in the solar system).

Mauna Kea, where all the telescopes are, translates as "white mountain" or "sun god mountain" depending on your source.

Either name is also apt.

And there you'll find the one true moonscape we found on Hawaii, right at the top where the telescopes are!

It's made of old cinders that have been windblown into gradual heaps, and the effect is almost identical to pictures I've seen of the moon. It is, perhaps, the best place on Earth to walk on the Moon.

Not too far down is a small barren valley strewn with rocks that could easily pass for the photos sent back from Mars.

Amazing. Three planets within a few miles of each other...

New lava is shiny, shapely, and fascinating. Nowhere else have we seen such a complex and beautiful volcanic display.

It was not possible to see any open flows, though we did catch sight of some Red Hot Lava (is that a rock group?) through a window into a lava tube.

So in that regard, it doesn't look lunar at all there. But once, the Moon did look something like Hawaii.

And as much as I like the Moon now, I have to admit Hawaii looks a lot better!

Mail to: Dave North
Copyright © 2001 San Jose Astronomical Association
Last updated: July 19, 2007

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