More Pluto Facts

 

Why Do We Know So Little About Pluto? - There are precious few facts about Pluto as to its geological makeup, or what it looks like to the naked eye, due to its extreme distance couple with its very small size. Pluto is not visible with the naked eye, in fact is difficult to see with an amateur telescope. You have to know exactly where to look to have any chance of seeing it and if you do it will simply appear as a rather dim star. The Hubble telescope has taken some photos of Pluto, but even when digitally filtered and enhanced, very little can be seen out the surface except for a few dark blotches on an otherwise yellowish sphere. We'll hopefully find out quite a bit more when the New Horizon planetary explorer, launched in 2006, will do a fly by of Pluto after a 9 year journey. New Horizon has already taken photos of Pluto, but finding Pluto in one of these photos is a little like finding the character in "Where's Waldo?” One artist's depiction of the planet has it resembling the interior of Greenland. The surface temperature averages around -225 degrees Celsius, with the surface consisting largely of frozen atmosphere (nitrogen, methane, ethane and carbon dioxide) water ice, and rock. When Pluto is closest to the sun, a percentage of these frozen gases sublimates into a thin gas atmosphere.


We haven't even been able to track Pluto's orbit with a great deal of precision, again due to its distance and small size. Pluto has a rather weird orbit in that it is quite elliptical whereas the orbits of the other planets are relatively much more circular. Also, all the other planets circle the sun in more or less the same plane, called the elliptic. Pluto does not. Pluto has its own path at an angle to the elliptic. Once every couple of hundred years, Pluto finds itself closer to the sun than Neptune, and for about a 20 year period, Neptune becomes the outer planet. Of course if Pluto is not longer regarded as a full-fledged planet, then Neptune permanently holds the title of the most distant planet from the sun.


Pluto and Its Moons - One of the more unusual facts about Pluto is its relationship with its moon Charon. Whereas our Moon revolves around the Earth, relative to both revolving around the sun, Pluto and Charon revolve around one another. In fact the two behave like a twin planet in many respects. The two face each other, and if you were on Pluto, looking at Charon, it would hang motionless in the sky, never appearing to move.

If you lived on the other side of Pluto, you would never see Charon! Charon is only about 750 miles in diameter, but the other two of Pluto's moons are really tiny, with both being less than 40 miles in diameter. So standing on Pluto's surface you may or may not see Charon, depending upon what part of the planet you're on, and the other moons might look like small specks, while the sun more likely would appear as a very bright star.


Getting There - To get some idea of how far away Pluto is, the numbers in miles look something like dollar amounts bandied about by our government. The distance of the earth from the sun is one Astronomical Unit (AU), a distance of about 93 million miles. Pluto is just under 40 AU's away from the sun, or nearly 3.7 billion miles. One of the facts about Pluto is, during its travels it does get to within 30 AU's from the sun, still quite a distance. So it's easy to understand why it's going to take New Horizon 9 years to get there. When the explorer does arrive, we can be certain that, with some luck, we will find a treasure trove of additional facts about Pluto. So keep the year 2015 in mind!