I strongly disagree. Memorizing a list of names is not important for learning. We don't ask kids to memorize the names of all the rivers or mountains on Earth or of all Jupiter's 67 moons. The only reason generations of kids were taught to memorize a list of names is because for most of that time, we knew very little…
Laurel Kornfeld
laurelkornfeld
No, this is not the case. The IAU ruling does not make a lot more sense to scientists and educated people than the thinking before it. That is why 300 professional astronomers signed a formal petition rejecting the IAU definition and continue to reject it to this day. Pluto is not a planet "because of convention." It…
But at that time, during the 19th century, astronomers had no way of knowing that Ceres, unlike the majority of objects they subsequently found, is rounded by its own gravity and therefore a planet. Their telescopes were not powerful enough to resolve Ceres into a disk. Today, we know Ceres is spherical and therefore…
Yes, Ceres is a planet because it is in hydrostatic equilibrium—squeezed into a round shape by its own gravity. Why is that a problem?
If you count dwarf planets as a subclass of planets, the way Alan Stern does, then Pluto is not that tiny. So far, it is the largest dwarf planet in the solar system. The only size that matters is the threshold for being large enough and massive enough to be in hydrostatic equilibrium. There is a wide spectrum of such…
Just because four percent of the IAU says something does not make that gospel truth. Like many astronomers, I reject the notion of that third criteria and do not believe an object has to clear the neighborhood of its orbit to be a planet.
The latest data indicate Eris is marginally smaller than Pluto though about 25 percent more massive. In November 2010, when Eris occulted a star, a team of astronomers led by Dr. Bruno Sicardy was able to more accurately measure Eris's size and found it is not larger than Pluto. However, being more massive, Eris…
Two of those moons are larger than Mercury. That doesn't make Mercury—or—Pluto not a planet. Pluto is not a snowball because it is estimated to be 70 percent rock. In fact, planets like Pluto are the most numerous in our solar system. According to the geophysical planet definition, Pluto, Eris, and the spherical moons…
Pluto isn't a snowball. It is estimated to be 70 percent rock. Two of the moons you mentioned are also larger than Mercury. According to the geophysical planet definition, all these objects are planets because they are rounded by their own gravity—the moons included. All size is relative. Just look at a to scale…
The latest data suggest Eris is not larger than Pluto but marginally smaller. This was determined by Dr. Bruno Sicardy and a team of astronomers he worked with in November 2010 when Eris occulted a star, enabling a better measurement of Eris's size. Eris is about 25 percent more massive than Pluto, which likely means…
Pluto is still a planet today. Dwarf planets constitute a third class of planets in addition to terrestrials and jovians. Our solar system is much larger and has many more planets than we once thought.
No one has to beg. Why the assumption that Pluto's planet status needs the legitimacy of the IAU? Science does not work by decree from on high. According to the equally scientific geophysical planet definition, a planet is a non-self-luminous spheroidal body orbiting a star or free-floating in space. Pluto meets that…
Dwarf planets are planets too. That was the intent of New Horizons Principal Investigator Dr. Alan Stern when he coined the term "dwarf planet."
Pluto never stopped being a planet and does not need the sanction of 424 astronomers, who equal four percent of the IAU, to affirm its status.
Pluto is NOT a "minor planet." That term is a synonym for asteroids and comets, objects shaped by their chemical bonds only because they are not large enough or massive enough to be rounded by their own gravity.
Dwarf planets are NOT minor planets. The term "minor planet" refers to asteroids and comets, objects too small to be rounded by their own gravity and therefore shaped only by their chemical bonds. David Grinspoon confirms this in his book "Is Pluto A Planet." For discussion from the perspective that dwarf planets are…
There aren't only eight planets in our solar system. Not only is that not set in stone; it doesn't even have consensus among astronomers. Only four percent of the IAU voted on the controversial planet definition, and most are not planetary scientists. Their decision was formally opposed in a petition by hundreds of…
There aren't only eight planets in our solar system. Not only is that not set in stone; it doesn't even have consensus among astronomers. Only four percent of the IAU voted on the controversial planet definition, and most are not planetary scientists. Their decision was formally opposed in a petition by hundreds of…