I was fairly familiar with Greek and Roman legends from various children's books that I had read, and of course I did know about the solar system and the names the other planets have. And so I suppose I just thought that this was a name that hadn't been used. And there it was. The rest was entirely my grandfather's work. Madan mentioned the suggestion in a letter to his friend Herbert Hall Turner, an Oxford astronomer. In the years since that groundbreaking flyby, nearly every conjecture about Pluto possibly being an inert ball of ice has been thrown out the window or flipped on its head.
The New Horizons team worked for 15 years to plan and execute this flyby and Pluto paid us back in spades! Pluto is about 1, miles 2, km wide. Pluto orbits the Sun about 3. A year on Pluto is Earth years. A day on Pluto lasts hours, or about 6 Earth days. Pluto has a thin atmosphere of nitrogen, methane and carbon monoxide.
The atmosphere has a blue tint and distinct layers of haze. Pluto has 5 moons. The largest, Charon, is so big that Pluto and Charon orbit each other like a double planet.
Venetia Burney, just 11 years old at the time, suggested the name Pluto in When Pluto was reclassified in from a planet to a dwarf planet, there was widespread outrage on behalf of the demoted planet.
As the textbooks were updated, the internet spawned memes with Pluto going through a range of emotions, from anger to loneliness. But since the release of New Horizons images showing a very prominent heart-shaped feature on the surface, the sad Pluto meme has given way to a very content, loving Pluto that would like to once again be visited by a spacecraft.
The Disney cartoon character Pluto, Mickey's faithful dog, made his debut in , the same year Tombaugh discovered the dwarf planet. There is speculation that Walt Disney named the animated dog after the recently discovered planet to capitalize on its popularity, but other accounts are less certain of a direct link. But either way, the joke connecting the two, as told in the Mel Brooks film "Spaceballs " remains:.
We were lost. None of us knew where we were. By the end of the Prague General Assembly, its members voted that the resolution B5 on the definition of a planet in the Solar System would be as follows:.
A celestial body that a is in orbit around the Sun, b has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium nearly round shape, and c has cleared the neighbourhood around its orbit. A new distinct class of objects called dwarf planets was also decided on.
It was agreed that planets and dwarf planets are two distinct classes of objects. The first members of the dwarf planet category are Ceres, Pluto and Eris, formerly known as UB Eris was named after the IAU General Assembly in read more Eris is the Greek god of discord and strife, a name which the discoverer Mike Brown found fitting in the light of the academic commotion that followed its discovery. The dwarf planet Pluto is recognised as an important prototype of a new class of Trans-Neptunian Objects.
The IAU has given a new denomination for these objects: plutoids. Today the resolution remains in place and is a testament to the fluid nature of science and how our view of the Universe continues to evolve with changes made by observations, measurements and theory. On 14 July , NASA's New Horizons spacecraft flew past Pluto, providing numerous imaging, spectroscopy, and in situ datasets that have dramatically altered our knowledge about Pluto and its system of five moons.
The images established that Pluto is larger than Eris and is the largest body in the Kuiper Belt. The images also revealed a remarkable landscape containing a variety of landforms, including broad plains, mountain ranges several kilometres high, and evidence for volcanoes.
Pluto's surface is unusual for its diversity of surface compositions and colours. Some regions are as bright as snow and others are as dark as charcoal. Colour imaging and composition spectroscopy revealed a highly complex distribution of surface ices, including nitrogen, carbon monoxide, water, and methane, as well as their chemical byproducts produced by radiolysis. It has also been determined that some surfaces on Pluto are completely free of visible craters, indicating that they have been modified or created in the recent past.
Other surfaces are heavily cratered and appear to be extremely old. No new satellites were detected, nor were rings. Small satellites Hydra and Nix have brighter surfaces than expected. These results raise fundamental questions about how a small, cold planet can remain active over the age of the Solar System.
They demonstrate that dwarf planets can be every bit as scientifically interesting as planets. Equally important is that all three major Kuiper belt bodies visited by spacecraft so far — Pluto, Charon, and Triton — are more different than similar, bearing witness to the potential diversity awaiting the exploration of their realm.
Stern, A. Q: What is the origin of the word planet? A: The word planet comes from the Greek word for "wanderer", meaning that planets were originally defined as objects that moved in the night sky with respect to the background of fixed stars. Q: Why is there a need for a new definition for the word planet? A: Modern science provides much more information than the simple fact that objects orbiting the Sun appear to move with respect to the background of fixed stars.
For example, recent new discoveries have been made of objects in the outer regions of our Solar System that have sizes comparable with and larger than Pluto. Historically Pluto has been recognised as the ninth planet. Thus these discoveries have rightfully called into question whether or not the newly found Trans-Neptunian Objects should also be considered as new planets. Q: How did astronomers reach a consensus for a new definition of planet? A: The world's astronomers, under the auspices of the International Astronomical Union, deliberated on a new definition for the word planet for nearly two years.
Continued evolution of the definition through debate and further discussion allowed a final consensus and vote. Q: What new terms are used in the official IAU definition? A: There are three new terms adopted as official definitions by the IAU. The terms are: planet, dwarf planet and small Solar System body. Q: In plain language, what is the new definition of planet? A: A planet is an object in orbit around the Sun that is large enough massive enough to have its self-gravity pull itself into a round or near-spherical shape.
In addition a planet orbits in a clear path around the Sun. If any object ventures near the orbit of a planet, it will either collide with the planet, and thereby be accreted, or be ejected into another orbit.
Q: What is the exact wording of the official IAU proposed definition of planet? A: A planet is a celestial body that a is in orbit around the Sun, b has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium nearly round shape, and c has cleared the neighbourhood around its orbit. Q: Does a body have to be perfectly spherical to be called a planet? A: No. For example, the rotation of a body can slightly distort the shape so that it is not perfectly spherical.
Earth, for example, has a slightly greater diameter measured at the equator than measured at the poles. Q: Based on this new definition, how many planets are there in our Solar System? Q: Is that all, only eight planets? In addition to the eight planets, there are also five known dwarf planets.
Many more dwarf planets are likely to be discovered soon.
0コメント