How loud is a rock in a Mars rover wheel?

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How does sound travel on Mars?

The Curiosity rover is scraping a rock along in its wheels, but what would that actually sound like to our ears?

For Astronomy Magazine:

A few weeks ago, a large rock got caught in one of the wheels of the Mars Curiosity rover. It’s an occupational hazard: unlike a car on Earth, the rover’s aluminum wheels are open on the sides with large cleats. That design allows Curiosity to go over rough terrain, including jagged rocks that would destroy other kinds of wheels.

Looking at pictures of the rock inside the wheel, Mars spacecraft engineer Kristin Block of University of Arizona’s Lunar and Planetary Laboratory idly asked: how loud would the rock sound? [Read the rest for the answer at Astronomy…]


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…]

A tribute to a great African-American planetary scientist

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Meet Claudia Alexander, NASA Badass Who Never Got Her Due

In a field dominated by white men, Claudia Alexander was a pioneer

For The Daily Beast:

Comet 67P/Churyumov—Gerasimenko is a tiny world of ice and rock, just 5 kilometers long. The comet is shaped vaguely like a rubber duck, with steep cliffs and other prominent features that stand much taller in relation to the size of the world. One of remarkable features is a twin set of sharp “horns” on the head of the rubber duck, known now as C. Alexander Gate.

Claudia Alexander served as project scientist for the Rosetta mission, which is orbiting Comet 67P. Until her death in July, she helped lead the United States side of the project, coordinating the various scientific and engineering aspects of the mission. Last week, her colleagues named the C. Alexander Gate in her honor and memory, with her European Space Agency counterpart Matt Taylor making the announcement.

Alexander is the first, and so far only, African-American woman to achieve such a prestigious position on a space mission, and she did it twice: once for the Galileo spacecraft to Jupiter and again for the Rosetta probe to Comet 67P. In fact, she was also the youngest ever appointed when she was picked at age 40 to be the final project scientist for the Galileo mission in 2000. [Read the rest at The Daily Beast….]

Traces of salty water on Mars … and more mysteries!

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[Credit: Randall Munroe]

Water Found on Mars Could Be First Signs of Martian Life

NASA’s Mars Reconnaissance Orbiter found traces of water that comes and goes on Mars—aka flowing water

For The Daily Beast:

We seem to discover water on Mars about once a year. Well, that’s not quite true: we’ve known Mars has water for quite a while. However, there are a lot of mysteries still to solve about how that water behaves and where it’s located. In particular, we’d like to know if water sometimes flows on the surface of the planet, which would tell us a lot about the cycles both above and below ground. And of course water is essential for life as we know it—finding flowing water, even transient flows, would make Mars seem a little more Earth-like.

The problem is that any liquid water evaporates quickly in the bone-dry Martian desert, and other processes can leave traces that mimic dried-up flows. When so little water is involved in the first place, it leaves us looking for the Martian equivalent of water spots on a long-dry drinking glass. And those spots are chemical traces—salt and other minerals once dissolved in the water—which must be identified by robotic spacecraft from orbit.

Today, scientists using NASA’s Mars Reconnaissance Orbiter (MRO) have identified some of those traces: a little bit of water comes and goes on Mars’ surface. [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…]

A possible ocean like ours on the moon Europa

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Europa’s Salty Sea

My first contribution to the brand-new magazine Hakai:

You can find bits and pieces of Earth seemingly scattered around the solar system. The surface of Mars looks a lot like Earth’s deserts; Titan’s atmosphere isn’t far off (minus a lack of oxygen); and the moon shares Earth’s basic geology. If you want to see oceans like ours, new research suggests your best bet is Jupiter’s moon Europa.

“Oceans like ours” in a chemical sense, that is. There are no fish or whales or coral on Europa. But Europa’s massive ocean is a salty one—and according to planetary geologist Kevin P. Hand and geochemist Richard W. Carlson, the specific salt that fills its sea, sodium chloride (or table salt), is the same salt that is crucial to life on Earth. [Read the read at Hakai…]

Hakai is focused on coastal ecosystems, which is a little off the beaten path for me, but they indulged me in writing about oceans on another world. And of course there’s physics hiding in a lot of areas, so I’ll hopefully be writing more for them in the future. In the meantime, check out the magazine: it looks really great!

Bathing asteroids with nuclear weapons

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A gentle nudge with a nuke: deflecting Earth-bound asteroids

From Ars Technica:

In 2013, a small asteroid exploded in the atmosphere over Chelyabinsk, Russia. The sonic boom from the event sent more than a thousand people to the hospital, mostly from flying glass from shattered windows. The Chelyabinsk meteor was a relatively small chunk of space rock—asteroid researchers think it was probably about 20 meters (66 feet) across—but exploding over a city made it a noteworthy event. It’s probable many similar asteroids hit Earth on a regular basis, but most don’t happen to fly over metropolitan areas; they fall into the ocean or over lightly populated regions.

However, Earth has played target in the cosmic darts tournament before. Meteor Crater in Arizona, the Tunguska impact in Siberia in 1908, and most famously the Chicxulub asteroid in Mexico (which played a part in the extinction of the dinosaurs) are just three of many known examples. That’s why many people are looking at viable options for planetary defense: destroying or turning asteroids aside before they can hit Earth. And planetary defense is one reason the United States’ National Nuclear Safety Administration (NNSA) has given for not destroying some of its surplus nuclear warheads. [Read the rest at Ars Technica…]

A space robot arrives at a new world: Dawn at Ceres

The asteroid dwarf planet Ceres, in a view showing the intriguing two bright spots. [Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA ]

The asteroid dwarf planet Ceres, in a view showing the intriguing two bright spots. [Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA ]

Sunday is my birthday, and NASA kindly decided to give me a whole asteroid. I got to write about it for The Daily Beast.

NASA’s Dawn Spacecraft Made It to Dwarf Planet Ceres

From The Daily Beast:

When I was young, I obsessively read through a National Geographic science book called Our Universe, a good overview of current astronomy and especially the Solar System. Voyager 2 was cutting edge at the time, which gives you a hint of when this was. One chapter was devoted to asteroids, the small rocky bodies scattered throughout the inner Solar System and especially the region between Mars and Jupiter. At that time, we didn’t have clear photos of any of them, so the book had paintings of Ceres, Vesta, Pallas, and several asteroids. My mental image of Ceres for more than 30 years has been that artist’s impression: a perfectly spherical, heavily cratered object, colored a light gray.

I mention this because for the first time in history, we now have real photos of Ceres, thanks to NASA’s Dawn spacecraft. Dawn entered orbit around Ceres today, providing us with our first close-up views during its approach. [Read more at The Daily Beast…]

Methane on Mars: life or just gas?

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Methane on Mars: life or just gas?

From The Daily Beast:

Methane is a familiar chemical, whether you know it by that name or not. It’s the major component of natural gas, which heats my house and possibly yours too. Methane is also a large part of human gas, which means I could start this article with a fart joke if I really wanted to. (However, it’s not the smelly part, which is provided by sulfur compounds.) Lakes on Titan are full of methane, and the chemical is a major component of the giant planets Jupiter, Neptune, and so forth.

Mars is a different case, and an interesting one: it doesn’t have a lot of methane in its atmosphere at any given moment. However, several probes—most recently the Curiosity rover—have measured methane in the Martian atmosphere. Methane on Mars could possibly reveal that the planet is more active geologically than it seems, or even that it harbors microscopic life. [Read more at The Daily Beast….]