Planet Nine or Planet Nein? The quest to understand the weird outer Solar System

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One Big Planet Nine, Or A Swarm Of Small Icy Worlds?

For Forbes:

The outermost Solar System is a confusing and complicated place. Once you get Neptune, the comets, Kuiper belt objects, and other small icy worlds orbit the Sun in odd patterns. A few of those, including the very distant world known as Sedna, have orbits that make very little sense compared with other Solar System inhabitants. For that reason, some astronomers think there’s a Planet Nine hiding far beyond Pluto’s orbit: a giant world roughly 10 times the mass of Earth.

But a new study by University of Colorado researchers proposed an alternative explanation. Astronomer Ann-Marie Madigan and her student Jacob Fleisig realized they could reproduce the strange orbits of icy worlds just by the way they interact with each other: no Planet Nine necessary. The idea is they sometimes swarm (in a broad sense) during their orbits, and when multiple Moon-sized bodies are in the same general region, it’s enough to kick other worlds like Sedna into their wild trajectories. It’s an eminently sensible explanation, and since two years of hunting for Planet Nine haven’t turned up anything, the hypothesis is definitely worth pondering more. However, we haven’t seen enough of these small worlds yet either, so the race is now on to see which explanation is correct.

[Read the rest at Forbes…]


The ice must flow to make Pluto’s dunes, but how?

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The Wrinkles On Pluto’s Heart Could Be Methane-Ice Dunes

possible dunes on Pluto

In this high-resolution image of Pluto’s heart, you can see wrinkles in the nitrogen ice. Those are possibly dunes made of methane, which raises an interesting question: how can such dunes form? [Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute]

For Forbes:

Sand dunes are found all over Earth: along the shores of lakes or oceans, deserts like the Sahara in Africa, and even underwater. Robotic space probes have also found dunes on Venus, Mars, and Saturn’s giant moon Titan.

Now researchers think they have found dunes on Pluto, which presents a huge (and fun) mystery. How can dunes form on a world where the atmosphere is a bare wisp, not enough to create the kind of winds responsible for making dunes elsewhere in the Solar System?

[Read the rest at Forbes…]

Ice volcanoes (and other mysteries) on Pluto!

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Does Pluto Have Ice Volcanoes?

That’s what some scientists believe. And it might have a heart, too

For The Daily Beast:

At the 47th Division for Planetary Sciences (DPS) meeting in Washington, DC, researchers with the New Horizons mission presented the latest findings from the July flyby of Pluto.

The main theme: We know so much more than we once did, but we are a long way from understanding exactly what makes Pluto tick.

The first surprise? Something that shouldn’t be there at all.

Maybe, researchers posited, Pluto has volcanoes of ice.

It’s one possible explanation for what was possibly the biggest surprise from July: the discovery that Pluto is still an active world. Earth has a thick atmosphere with lots of weather, a hot interior, and oceans. Pluto has none of those things.

But processes under the surface seem to keep things just warm enough inside to pump material up, in the form of volcanoes—not of magma, but of nitrogen, methane, and other volatile materials.

We see ice volcanoes on other worlds, but those are moons orbiting giant planets, where their interiors are churned up by the strong gravity and other processes. What is keeping Pluto warm enough to erupt is something we don’t yet understand. [Read the rest at The Daily Beast…]

Pluto: what’s in a name?

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Pluto and Other Truly Epic Space Photos

For The Daily Beast:

To quote another great space adventurer: “Almost there!”

The New Horizons probe, launched in 2006, will finally reach Pluto next Tuesday, providing the first close-up view of the tiny, icy world since we discovered it in 1930. We’re already seeing features never glimpsed before. It’s a truly historic occasion, right up there with the Dawn mission to the giant asteroid Ceres, known since 1801 but never seen clearly before this year.

But what is Pluto? [Read the rest at The Daily Beast…]

Yes, I dive again into the “is or isn’t Pluto a planet”, and declare a pox upon both parties. Well, at least I call the IAU definition “crap” and make fun of the Pluto monomaniacs who insist that of course Pluto is a planet. Either way, though: I love Pluto, and I am very much looking forward to Tuesday.

P.S. Though we now have some excellent photos of Pluto and are getting more literally daily, the featured picture for my article is the bottom of a frying pan. Go figure.

Blogging about science for Forbes Magazine

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As of this week, I will be blogging regularly for Forbes on planetary science, climate change, physics, and math. My first two posts are up; go check them out and please follow my blog!

Why are Pluto’s moons so weird?

Pluto is a strange little world, but its moons are even weirder.

Whether or not you want to call it a “planet”, it’s a body strongly influenced by two other worlds: the giant planet Neptune and its moon Charon. Pluto crosses Neptune’s orbit twice during its long sojourn around the Sun. But Charon (which I pronounce KAR-on, but you’ll also hear SHAR-on and other variations) is the big deal: the moon is more than 10 percent of the mass of Pluto. It exerts such a strong gravitational pull that both objects orbit a spot in empty space between them, and forces Pluto to present one face to Charon, just like Earth forces the Moon to keep the same side faces us. If you lived on the “far side” of Pluto, you’d never see Charon in the sky.

Pluto and Charon together have four much smaller moons: Styx, Nix, Kerberos, and Hydra. We don’t know much about those moons yet: Nix and Hydra were only discovered in 2005, Kerberos was found in 2011, and Styx in 2012. Even in our most powerful telescopes, they appear as dots. (Pluto and Charon aren’t much better off — they look like blurry disks even to the Hubble Space Telescope.) But looking at their orbits around Pluto and Charon, astronomers found something weird.

Those tiny moons dance in tandem. [Read the rest at Forbes…]

New analysis shows Earth is warming faster than we thought

Politicians may dither and talking heads bloviate, but the scientific consensus is clear: climate change is real, humans are responsible, and its effects are already being felt around the world. At the same time, some details are in question, including how fast climate change is increasing and which specific effects we see are due to it as opposed to other sources.

That’s the context for a new paper in Science today from researchers at the National Oceanographic and Atmospheric Administration (NOAA, which is somewhat ironically pronounced “Noah”). Thomas Karl and colleagues took a second look at global surface temperatures — the ordinary temperatures we’re used to seeing on weather news or in our phone apps — and found the official numbers on rising temperatures are too low. To put it another way: the consensus opinion is that we are currently in a global warming “hiatus”, but Karl and coauthors report instead that temperatures are climbing as fast as ever.

As if we didn’t have enough to worry about. [Read the rest at Forbes…]

The dwarf planet Makemake (pronounced MAHkayMAHkay) is about 2/3 the diameter of Pluto, and farther from the Sun. That makes it hard to observe. Astronomers using a set of telescopes in South America tracked it during an occultation: a brief interval when it passed in front of a faint star. By measuring the light curve—the variation in light as Makemake eclipsed the star—the researchers determined that the dwarf planet has no substantial atmosphere, and probably no sizable moon.

Makemake potentially occults three stars in a typical year, though not all of these are useful, due to the faintness of the background star. The current study involved an occultation visible from South America on April 23, 2011. Just as eclipses may be partial or total, the “shadow” of Makemake passed over a swath of the continent, allowing telescopes in various locations to measure the passage of the star behind different parts of the dwarf planet. The researchers tried to obtain data from 16 telescopes, but only 7 of those returned successful measurements.

Each telescope saw a clear, sharp drop in the background star’s light, a strong indicator that Makemake has no substantial atmosphere. [Read more….]

Makemake has no atmosphere, possibly a partly frosted surface