Artist’s conception of the Kuiper belt. [Credit: Don Dixon]

When we talk about big advances in planetary science, we often are thinking about Mars rovers or the discovery of exoplanets. However, one area where we’ve learned a lot over the last few decades is the Kuiper belt: a region beyond the orbit of Neptune inhabited by small bodies of ice and rock. Before 1992, Pluto was the most distant known Solar System object, but between then and now, astronomers have discovered a wealth of Kuiper belt objects (KBOs).

A new paper (coauthored by Mike Brown of Pluto-killing infamy) describes a puzzle arising from a survey of many KBOs: some of them don’t fit in with the standard model of planet formation:

A new study of large scale surveys of KBOs revealed that those with nearly circular orbits lying roughly in the same plane as the orbits of the major planets don’t fit the Nice model, while those with irregular orbits do. It’s a puzzling anomaly, one with no immediate resolution, but it hints that we need to refine our Solar System formation models. [Read more…]

Some planet-like Kuiper belt objects don’t play “Nice”

The week in review (October 20-26)

Evidently, Nicole "the Noisy Astronomer" Gugliucci did not like it when I quoted Star Wars at her. All I said was "Aren't you a little short for a Stormtrooper?" [Credit: Melanie Mallon]

Evidently, Nicole “the Noisy Astronomer” Gugliucci did not like it when I quoted Star Wars at her. All I said was “Aren’t you a little short for a Stormtrooper?” [Credit: Melanie Mallon]

I had a wonderful time at GeekGirlCon; thanks again to Dr. Rubidium, AKA Nick Fury, for putting together the DIY Science Zone, and to everyone who made it a great event. I have a more formal wrap-up post in the works, but in the meantime, have some science writing.

  • The river of spacetime (Galileo’s Pendulum): As a follow-up to my earlier post, I extended the metaphor of dynamic spacetime. If spacetime is the river, gravity is the current, carrying matter and light along with it.
  • New type of quantum excitation behaves like a solitary particle (Ars Technica): In materials, the relevant entities aren’t particles, but quasiparticlesThese are quantum excitations that have mass, charge, spin, and all that jazz, but those properties depend on the specifics of the material…and of external influences. So, physicists would like to create quasiparticles that are less finicky, and behave more like free, solitary particles. That type of excitation is a leviton, and experimenters created them for the first time, as described in this new paper.
  • Taking Measure: A ‘New’ Most Distant Galaxy (Universe Today): It seems that every week, we see a new “most distant galaxy” announcement. However, this new find is special for two reasons: it’s a rare case where astronomers have measured the distance accurately using the galaxy’s spectrum, and the specific galaxy is producing new stars at a much higher rate than expected. Also, this is my first contribution to Universe Today!
  • For the love of Gauss, please stop (Galileo’s Pendulum): A somewhat ranting post in which I get grumpfy about the over-use and misuse of certain examples from the history of science in popular science writing.
  • What do we call a theory that is no longer viable? (Galileo’s Pendulum): As a follow-up to that previous post, I ponder better ways to think about the history of science, and propose (somewhat seriously) a term to describe theories that were once viable, but are now ruled out by evidence.