SearchResearch Challenge (7/27/16): Mind the gap!

The biggest surprises... 

... are sometimes the ones you don't see at first.  They're the kind of little things that slowly creep into your consciousness and make you wonder... why is it that this is so??  

Long-time readers will remember the one of the harder Challenges of the past ("How much death at the roadside?") when we tried to figure out why there are gaps in the plant cover next to many roads in California. We discovered in that Challenge that the state Dept. of Transportation (CalTrans) regularly sprays herbicide on the edge of the road to prevent weeds from taking over the road.  

This week we have another "gap in the weeds" Challenge.  

Not long ago, I went for a run up on Black Mountain, one of the local peaks in the Santa Cruz mountain range.  If you look carefully on the right side, you can see the typical summer-time wave of fog coming in from the Pacific Ocean.  On typical summer evenings, that fog (aka "Karl") comes in from the sea to cover San Francisco.  Luckily, Black Mountain is usually high enough that the fog comes around, not over, the peak.  

Selfie of me running in the early morning at the peak of Black Mountain

It was on this run that I noticed something that was pretty small, but very odd.  Here are 3 pictures I took on that run of a strange phenomenon.  (Remember that you can click on the images to see larger versions.)  

What struck me about each of these pictures is that there's a noticable gap between the green plant and the grassland next to it.  Oddly, this doesn't happen ALL the time, but it does happen a lot.  

The plants here are chamise (Adenostoma fasciculatum), but I'm pretty sure I saw gaps like this around coyote brush (Baccharis pilularis) in the same area.  

This strange plant-free boundary around most (but not all!) of the plants on Black Mountain led me to this week's Challenge:  

1.  What causes the odd, plant-free gap around the plants in these photos?  

If it helps (and it might, or might not), these photos were taken on August 13, 2013, at 37.3195203,-122.1630756  Which looks like this in the Google Earth photo:  

Looking carefully at this clump of chamise and coyote brush, you'll see this kind of gap all around these plants.  (The light color perimeter is where you can see the soil 

What's going on here?  I looked very carefully, and this gap at the periphery aren't trails of people or deer.  (You can see deer trails weaving between the clusters of bushes, especially to the west of the drop pin.)  

So... What's causing this?  Any ideas?  Let's do some of that SearchResearch and figure it out! 

Once you've figured it out, be sure to let us know HOW you figured it out.  What sources did you refer to?  And best of all, how did you know to search for that?  We all want to learn from your crazy SearchResearch skills!  

Search on!  

Search Challenge (2/10/16): Why an arc of lakes?

You know that odd sensation you get... 

... when you first notice something that you should have seen before now?  

I mean, sometimes you'll look at something you've seen for years, and then a new feature just sort of pops out at you.  

Ever have that happen to you? 

It happened to me recently when I was looking at a map of North America.  We've all seen this about a zillion times, and yet, this time, I saw something different.  Here's the map as we usually see it: 

From Google Maps. The blue dot in California shows you where I am. 

And THIS time, it struck me that there's a big line of big lakes stretching across Canada and into the US.  Here's another way to look at it that makes the arc of lakes very clear: 

Here's another version of the same map.  (I've labeled some of the lakes to save you a couple of minutes of searching.)  

Image from Google Earth, with my annotations of the major lakes on this arc.

See that?  Although I've looked at maps of North America just about my entire life, I'd never noticed that the lakes line up so neatly. This striking observation leads to today's Search Challenge. 

1.  Is this arc of lakes across the top of North America just an accident of geography?  Or is this actually the consequence of some gigantic geological process?  

I suspect I know the answer to this, but I'm going to enjoy the search process along with you. 

The Search Challenge here is "how do you look for something like this?"  If you're not already a geologist, how can you find out enough about the topic to ask a reasonable question of Google?  

Let us know your answer... and your process (including the most useless time sink diversions that take you off the path to the answer)!  

I'll be reading the comment stream this week, and will chime in from time to time.  

This will be fun.  

Search on!