NEW PHOTOS OF PLUTO

The New Horizons probe has been slow to send back its images of Pluto, but they're coming in now and they're exceeding expectations.

Here's (above) an Everest-type series of mountains next to what appears to be a lava lake or a glacier.

Here's (above) the remnant of a shield volcano. It's possible that the lava coming out of Pluto's mantle was liquid water. 

Here's (above) a field of craters, most of which are about a kilometer across. They're not impact craters, but are cheese-type holes only ten feet deep in a bed of solid nitrogen. 

 Above, the five moons of Pluto and their relative sizes.

Above, that's Charon, the biggest of Pluto's moons. It's half the size of Pluto which makes it the largest moon in the solar system relative to the size of its host planet. This is an astonishing photo because it reveals a world which is divided into two distinct parts separated by a belt of stress cracks.

Seeing this reminds me of the speculation that Earth once had two moons, one following behind the other in the same orbit. The smaller moon caught up with the larger one and slowly squashed into it with the result that today half of our moon has a substantially thicker crust than the other half.

I call this speculation because there's another scenario that might also explain the thinner crust on our side. Advocates say that early on, our moon was closer than it is now, and was heated by the newly formed molten Earth. The heat softened the moon's crust on our side allowing volcanoes to spew out lava that changed the surface of the side facing us. This explanation has less credibility for me because it would lead to a thickening on our side, not a thinning, which is what we see.

Anyway, the squashed appearance of Charon lends support to the idea that some sort of gradual collision happened there.

That's all I have to say about Pluto, but I can't resist putting up this photo of Phobos, a moon of Mars. Phobos is much closer to Mars than our moon is to us, and it appears to be spiralling in for a crash. The white smears on the right are thought to be stretch marks as the moon is being pulled apart by tidal forces.

My source for this photo didn't include an estimate for the time of impact, so maybe it's no time soon. When it occurs the debris is expected to form a ring around the planet.

A MAP OF PRE - COLONIAL AFRICA

I don't know about you but I'm fascinated by historical maps. The best ones are seldom reproduced in poster size so if you want a spiffy one on your wall you have to pay collectors' prices for originals. If I could afford it, near the top of my list would be this one (above) showing Livingstone's route across Africa in the pre-colonial 1860s and 1870s.

It's hard to imagine now, but most of the sub-Saharan African nations we're familiar with today didn't exist then. Africa was "Darkest Africa." Few outsiders had a clear idea of what was in there. Livingstone's trek across the central plateau illuminated for the first time a wide swathe of the territories on either side of his route.

 His trip (above) was no bowl of cherries.

 This picture (above) may be from Stanley's account of finding Livingstone; I'm not sure.

Poor Livingstone was even attacked by a lion.

One of Livingstone's goals was to end slavery in Africa, and he succeeded in at least putting a crimp in it. During the colonial period the British arrested arab african slave sellers like the ones above. Unfortunately Livingstone's geographic findings opened the door to colonialism.

 You can see (above) why Africa has so many problems today. Modern national borders haven't much to do with the old ethnic boundaries.

The modern system system attempts to unite wildly disparate people into the same state. Those are Watusi above, a giant people.

They're in the same nation as the Pygmies, who are the world's smallest people. Seeing these pictures reminds me of the old saying: "One law for the ox and the squirrel is tyranny."

I'm also reminded of a book I read a long time ago called "Congo Kitabu" which claimed that the Pygmies were being enslaved by their giant neighbors, and were in danger of becoming extinct. Yikes!

BTW....on another subject....

Here's (above) the last picture of Pluto taken before the expected (and temporary) transmission blackout. That'll only last a short time, then we'll get better pictures from an even closer vantage point.

Gee, I have to say that this side of Pluto is disappointing. It looks like a common dirty snowball. No wonder it was demoted to dwarf planet status. The side facing Charon was a lot more interesting. It had a giant hexagonal crater, which needs to be explained. I've seen a few hexagons in space photos: one covers one of Saturn's poles and a couple more look like shock waves from deep space novas. 

Oh well, maybe trained eyes will deliver more meaning from the picture. 

THE LATEST ASTRONOMY PHOTOS: 7/2015

Above, the side of Pluto facing its largest moon, Charon, as seen by the New Horizons probe two days ahead of rendezvous. The nearest pass will show the other side of the planet and will be in much sharper focus. Unfortunately this is the best picture of this side of Pluto that we'll get on this mission. Nobody knows what the dark areas are and why they're so regularly spaced. 

This is exciting! When I was a kid I had a special affection for Pluto because it seemed like the most mysterious and unknowable place in the Solar System. I never dreamed that I'd be able to see it up close in my lifetime.

Here's a picture of Antares, one of the brightest stars in the night sky. That's Antares in the middle of the blue haze within the orange dust cloud. The star is red but appears here as white, maybe because false color was applied. Anyway, the reason I put this up is for the dense star field that fills the picture. Isn't that incredible?

With all those closely packed stars constantly spewing high energy particles I can't even imagine how radioactive that environment must be. You have to wonder if it'll ever be possible to explore that part of the galaxy.

Have you ever wondered why we don't see giant nebulae in the sky at night? There's at least one pretty big one nearby...how come we don't see it?

The answer is that the cloud is just too thin to be easily seen when it's this close, but cameras can see it. It looms over our cities at night. It's Sharpless 2-308 (above), a.k.a. The Bubble Nebula, and it covers more of the night sky than a full moon.

Here's (above) a familiar picture: The Southern Ring Nebula. But what's that straight line crossing it? Nobody knows.