32 votes
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Why do most dwarf planets have mass comparable to moon?

Two orders of magnitude is a very large range. The Moon has a mass of $7.342 \times 10^{22}$ kg, so your question is, why do most dwarf planets have a mass between $10^{20}$ and $10^{24}$ kg? By ...
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  • 1,903
24 votes
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Undiscovered dwarf planets

Dwarf planets are observed by the sunlight they reflect. Undiscovered dwarf planets at the outer boundaries of our solar system are simply fainter than the other things mentioned. If they can't be ...
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  • 114k
17 votes

Why do most dwarf planets have mass comparable to moon?

Consider tomatoes.... There are cherry tomatoes, salad tomatoes and beefsteak tomatoes. Why do all salad tomatoes have about the same size (to within a couple of orders of magnitude)? Well if I ...
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  • 87.7k
15 votes
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Why doesn't the IAU consider Quaoar to be a dwarf planet?

It probably is a dwarf planet. (It almost certainly is a dwarf planet.) The naming procedures at the IAU are that "Objects that have an absolute magnitude (H) less than +1 [...] are overseen by two ...
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  • 87.7k
14 votes

Is Jupiter a dwarf planet?

I suggest taking a look to https://en.wikipedia.org/wiki/Clearing_the_neighbourhood . Quoting it, In the end stages of planet formation, a planet (as so defined) will have "cleared the ...
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  • 1,560
14 votes
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What would the sun look like from aphelion of The Goblin's orbit?

Yes, easily. 1955 AU is a long way, but it is only 0.03 of a light year. The sun would still be less than 1/100 of the distance to the next star. The brightness of the sun would be much less: about ...
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13 votes
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How did scientists determine an estimate of the number of planets greater than Sedna's size to exist in the Inner Oort Cloud?

Unfortunately, the paper is not available on ArXiv (oh, what hardships we must overcome!), but I have found it here. In it, where the "900" figure is mentioned (2nd page, I believe), the authors (...
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  • 33.7k
12 votes

Is Pluto still a dwarf planet?

Yes, Pluto is still a dwarf planet. According to the IAU website, it still fits the criteria for a dwarf planet, fails to meet the criteria for a planet, and still carries the "dwarf planet" label, ...
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  • 33.7k
11 votes

Is Jupiter a dwarf planet?

Do I have a point here or am I missing one? You are missing several points. Point 1: "Clearing the neighborhood" does not mean getting rid of every last spec of mass in the vicinity of a planet. The ...
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  • 27.1k
9 votes

Is the Dwarf Planet class really necessary?

A lot of the naming conventions were originally "because they remind us of things we already called this", or simply "tradition". How we name things has slowly but surely adjusted with time as more ...
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9 votes

Up to 384 minor planets (including Pluto) qualify as planets?

That actual IAU Resolution B5 adopted at the IAU General Assembly in 2006 states: (1) A planet is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity ...
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  • 7,135
8 votes
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How does 2015 RR245 compare to the other KBOs predicting "Planet 9"?

It was the first thing I thought too, but I would say it won't count in the statistics. The earlier paper by Batygin & Brown was talking about bodies orbiting further out. 2015 RR245 orbits ...
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  • 2,377
8 votes
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What would be the sizes of the bodies created from Jupiter's trojans?

The mass of the Trojans (both camps as far as I know) is estimated at around 0.0001 Earth masses (reference) (Note that this number is debated). The density of them vary but the highest found is ...
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6 votes
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What does it mean for a planet to be just 300 kms across?

The reports that Goblin is a planet are incorrect. It is a dwarf planet, at best. Dwarf planet and planet are mutually exclusive terms. Planets are objects whose masses are so large that they have ...
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6 votes
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How long does it take Dawn to orbit Ceres?

As of March 6, 2015, Dawn has entered orbit around Ceres. But it's really so far only "captured by Ceres' gravitational pull". Then, it was still 61,000 km from Ceres. It's slowly spiraling down ...
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  • 778
6 votes

Planets and Pluto? Neptune?

I answered this same question at physics.SE. I specifically joined this part of the SE network to address this duplicate question at this site. The astronomy community faced two crises with regard to ...
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6 votes
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How did Biden become VP? (naming of 2012 VP113)

This has to do with how minor planets obtain provisional names (see also Wikipedia). The year is divided into 24 half months, with a particular letter associated with each one. Each of these half-...
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6 votes

Undiscovered dwarf planets

All bright enough dwarf planets in the vicinity of the Sun have already been discovered, for all others only the Keck observatory in Hawaii is able to discover any. Once the Vera Rubin observatory ...
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  • 1,538
5 votes

Pluto- Current theories regarding its geological nature?

Geothermal activity can originate from a combination of: Residual heat from planet formation: During the formation of a planet, half of the potential energy of the parent region of dust and gas can ...
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  • 181
5 votes

Why was Dawn's (the spacecraft) flight path circular?

Dawn was not exploring L3. But instead it explored both Vesta and Ceres. In order to do so in a cost-saving manner, Dawn was also a mission demonstrator for an interplanetary mission equipped with ion ...
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5 votes
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Would planet explode without gravity?

Even rocky planets would explode. I think there are two ways to see this. From the perspective of forces, the earth is in equilibrium between the compressive force of gravity and the elastic ...
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  • 2,525
5 votes

Undiscovered dwarf planets

distant galaxies and clusters, locate supermassive black holes Galaxies and clusters are very bright objects. That's intuitive: galaxies contain a lot of stars, each of which are roughly as luminous ...
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  • 3,243
4 votes
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Is there a reason why the IAU differenciates objects in the SS orbiting the sun into a particular classification but it doesnt for satellites?

History, and recent history at that: At one time (1980) things seemed clear enough: There were planets (Mercury-Pluto), Asteroids (mostly between Mars and Jupiter) and Satellites. No one care much ...
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3 votes

Why 225088 Gonggong is not a dwarf Planet yet?

As the comments already say, an object being a dwarf planet is a matter of convention. If the IAU says it's a dwarf planet, it's a dwarf planet. Otherwise, it's not. The requirements you are listing ...
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  • 496
3 votes

Planets and Pluto? Neptune?

There is actually disagreement on this matter (within the IAU?). Dr. Alan Stern (lead of the New Horizons mission) for instance points out that "this rule is inconsistent" (e.g. see Pluto vote '...
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  • 3,311
3 votes

What is the danger for Ceres of collision with other asteroids?

Sadly, a well referenced answer to this question likely lies behind academic publisher paywalls. However, Wikipedia claims: Collisions between main-belt bodies with a mean radius of 10 km are ...
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3 votes

Looking for a Solar System Simulator including the smaller celestial body, for macOS

Celestia can run on MacOS. With is, you can travel in the solar system and in time. It can give you a good idea of how far things are from each other.
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  • 16.7k
3 votes

Why do most dwarf planets have mass comparable to moon?

The currently accepted theory of how Luna (the Earth's moon) formed is the Giant Impact Hypothesis though there is still debate about that. Should that theory be true, it suggests that dwarf planets ...
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2 votes

When the set of official dwarf planets is expected to increase?

As I noted in a previous answer, the official body for naming and classification of astronomical objects is the International Astronomical Union, or IAU. They are the ones responsible for designating ...
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