All posts for the day October 10th, 2015

Pluto at Last, by Nadia Drake, photographs by Dana Berry

Astronomers have known that there must have been something beyond Pluto since the 1840s, when they decided that the orbits of Uranus and Neptune were being affected by a large body beyond them. It took another 90 years for them to actually find Pluto, which turned out to be a lot smaller than they had expected it to be. At first, they assumed it had to be about the size of the Earth, but farther out than it looked, but over time, they realized that Pluto was just really, really tiny. It turns out that the irregular orbit of Uranus and Neptune is because the scientists miscalculated the mass of Uranus. Once that was corrected, the orbits of Uranus and Neptune make sense.

Not too long after this issue was published, New Horizons flew past Pluto, taking the first-ever photographs of the dwarf planet’s surface. It took so long for New Horizons to reach Pluto that Pluto was still a full planet when it left Earth in January 2006. Pluto was demoted to “dwarf planet” status in August of 2006.

As an aside, I do love Eris’s name. Eris is the dwarf planet that is twice as massive as Pluto that was discovered in 2005. Since Eris is larger than Pluto, if Pluto was still considered a planet, they should have considered Eris to be one, as well, but then they discovered other dwarf planets around the same size as, or larger than, Pluto. If this kept up, they would have to keep adding new planets as things in the range of Pluto’s size continued to be discovered. In the end, as we all know, Pluto was demoted to the newly created category of “dwarf planet.” Since this new planet sowed strife and discord among the scientific community (and also among the population in general), Eris seems to me to be the perfect name.

Of course, as I’m writing this, New Horizons’s flyby of Pluto is done. New Horizons just sent back new photographs of Charon, Pluto’s largest moon and soon the spacecraft will be heading into the Kuiper Belt, which is full of dwarf planets and other objects. They estimate that, unless it has some kind of mechanical failure, New Horizons will continue on its current path for another 20 years. You can see where New Horizons is now at the Johns Hopkins Applied Physics Laboratory website.

Mountain Men, by Jeremy Berlin, photographs by David Burnett

Mountain Men is an overview of the American Mountain Men association, who are a group of people (largely, but not exclusively, men) who reeenact the lifestyle of the fur trappers of the old west. And they do actually trap animals and tan their hides. The website, but not the printed issue, has a photograph of a freshly skinned beaver hide that one of the members is going to tan. This isn’t my sort of thing, but if we were all the same, how boring would that be?