[Previous Page] [Back to Main Page]
1. What are the most interesting things about Pluto? What are the most unique aspects of Pluto?
2. What has been learned recently about Pluto?
4. Is Pluto the 8th planet right now?
5. What year was the bright spot on Pluto discovered?
What are the most interesting things about Pluto? What are the most unique aspects of Pluto?
Some of our interest in Pluto is that of studying an planet of extremes.
1.Most distant planet (on average). 2.Smallest planet. 3.Pluto-Charon binary system are the most nearly equal in mass. 4.Very cold and thin atmosphere. 5.Surface covered in exotic frosts, methane (CH4), nitrogen (N2), carbon monoxide (CO). 6.Pluto's surface may well have some of the brightest and darkest suface areas in the solar system. Bright from frost and ice, dark from organic molecules. 7.May have an "active" surface from winds and frost migration coupled with large change in its distance from the Sun. 8.Some models predict that Pluto's atmosphere will disappear completely when it is furthest from the Sun. No other planet or satellite boasts this large of a seasonal change. Only comets beat Pluto in this respect. 9.Its internal composition provides important clues as to planetary building blocks in the outer solar system. We've studied the inner solar system (mostly the Earth and the Moon) and to fully understand the formation of planets we'd like to know what is inside Pluto.
What has been learned recently about Pluto?
Just about everything we know about Pluto has been learned since 1980. Prior to that time all we really knew was where to look to find it and how long its day is (rotation period). Astronomers have finally been able to figure out quite a few things more recently. Some of these are:
1.Size of Pluto and Charon: we know these number to within about 20 kilometers or so. 2.Surface composition of Pluto (methane, nitrogen, CO, probably dark organic compounds). 3.Surface composition of Charon (water ice). 4.Bulk densities of Pluto+Charon 2.0 g/cc (we don't quite know the individual densities yet, there's still some debates raging over this). 5.Atmospheric composition and structure of Pluto. Mostly nitrogen with trace methane. Warm upper atmosphere (100 K) and gets cold (~40 K) very fast within 10 km of the surface.
Is it possible to put Pluto in orbit around the Earth?
Moving a planet is something we may never learn how to do. Even as small as Pluto is, it would take a tremendous amount of energy to move it even a little bit. Besides, if we did bring Pluto that close to the Sun, it would heat up and all the water ice on its surface would melt. About half of Pluto is made up of water ice and after it melted it would create a planet wide ocean with no place left to stand.
Now, perhaps in the next 1000 years we might learn how to move small asteroids around. Some of these asteroids already come pretty close to the Earth. Those close neighbors would only take a relatively small amount of coaxing to put them in a useful orbit near the Earth. These objects wouldn't be any more habitible than our Moon so perhaps it wouldn't be worth the bother. After all, we've already got the Moon handy, right?
Is Pluto the 8th planet right now?
If you count the planets in order of their distance from the Sun, right now, then yes, Pluto would be the 8th closest planet to the Sun. However, out of Pluto's 250 year long orbit, it is the 8th planet only 20 years out of that time. Another way of counting the planets is to look at their average distance from the Sun. On average, Pluto is further from the Sun than Neptune so with that definition we'd still say that Pluto is the 9th planet. My own preference is to call Pluto the 9th planet even now but either way is just fine.
What year was the bright spot on Pluto discovered?
This is a pretty hard question to answer. It's easy to say when we first saw Pluto in pictures taken in 1930. The bright spot on Pluto is more complicated. Back in 1954, Pluto was first seen to change in brightness. This change is caused by Pluto's rotation. When Pluto's is at it's brightest we know that that part of Pluto's surface must be brighter than all the rest. So at that time we knew that there was a bright spot on Pluto's surface. We didn't really see it until the new Hubble Space Telescope pictures were taken of Pluto, but we've known it was there all along.