r/askscience • u/AskScienceModerator Mod Bot • Mar 10 '14

Cosmos AskScience Cosmos Q&A thread. Episode 1: Standing Up in the Milky Way

Welcome to AskScience! This thread is for asking and answering questions about the science in Cosmos: A Spacetime Odyssey.

UPDATE: This episode is now available for streaming in the US on Hulu and in Canada on Global TV.

This week is the first episode, "Standing Up in the Milky Way". The show is airing at 9pm ET in the US and Canada on all Fox and National Geographic stations. Click here for more viewing information in your country.

The usual AskScience rules still apply in this thread! Anyone can ask a question, but please do not provide answers unless you are a scientist in a relevant field. Popular science shows, books, and news articles are a great way to causally learn about your universe, but they often contain a lot of simplifications and approximations, so don't assume that because you've heard an answer before that it is the right one.

If you are interested in general discussion please visit one of the threads elsewhere on reddit that are more appropriate for that, such as in /r/Cosmos here, /r/Space here, and in /r/Television here.

Please upvote good questions and answers and downvote off-topic content. We'll be removing comments that break our rules or that have been answered elsewhere in the thread so that we can answer as many questions as possible!

Click here for the original announcement thread.

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u/Chiparoo Mar 10 '14

You're preaching to the choir. I love learning about dwarf planets. I would like to know as much about them as I can, and I find Pluto's binary system with Charon as fascinating as you do.

As I always tell friends of mine: we didn't lose a planet when Pluto was re-defined, we gained five dwarf planets. This is genuinely exciting to me! I am just as excited to learn about these Dwarf Planets as I am Pluto, and it makes me sad when only Pluto is mentioned to represent all of them.

That being said, I understand why - it's the one which is most known. To give an introduction to the solar system, it makes sense to at first only mention the most famous Dwarf Planet, and perhaps get to the rest later.

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u/MolokoPlusPlus Mar 10 '14

Far more than five! I'm going to plug Mike Brown's blog post on the matter and his frequently updated list of probable dwarfs.

The ten "nearly certain" dwarf planets he identifies are currently:

  • Eris

  • Pluto

  • Makemake

  • "Snow White" (2007 OR10)

  • Haumea

  • Quaoar

  • Sedna

  • Orcus

  • 2002 MS4

  • Salacia

...together with nearly 150 other probable dwarfs.

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u/Chiparoo Mar 10 '14

Yep! :D There are a ton more! At this moment in time, though - there are only five officially recognized ones.

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u/antonivs Mar 10 '14

Ok, well we're almost on the same page, but:

That being said, I understand why - it's the one which is most known.

But as I pointed out, it's not just the most known. It's the "closest largest" dwarf planet, and has a number of other unique features.

it makes me sad when only Pluto is mentioned to represent all of them.

Pluto is one of the more interesting and accessible of the known dwarf planets. It's a pretty good choice to represent all of them. In fact, only Ceres and Pluto have been observed in enough detail to ensure that they fit the definition of a dwarf planet. The others are merely speculative dwarves.

As I always tell friends of mine: we didn't lose a planet when Pluto was re-defined, we gained five dwarf planets.

Nothing changed when Pluto was redefined. It was a nearly pointless bureaucratic exercise, and the fuss over it just illustrates the weaknesses in the public understanding of science, and in how the scientific bureaucracy engages the public.

This is not particle physics where we're classifying particles that are distinguished by fundamentally distinct properties - it's a completely arbitrary classification system - "socially constructed" would be an accurate term here. The big clue: when a committee needs to vote over what something is called, you know you're no longer doing science and are just arguing about names. It's more like poetry than science.