Listening to the sounds of the cosmos

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Last year, I went to a conference in Florida to hear — and in some cases meet — some of the leading thinkers in the study of gravitational waves. These waves are disturbances in the structure of spacetime itself, and could provide information about some exciting phenomena, if we can learn to detect them. The universe as heard in gravitational waves includes colliding black holes, white dwarfs locked in mutual orbits, exploding stars, and possibly chaotic disturbances from the very first instants after the Big Bang. This story marks one of my first big magazine articles, which I wrote for Smithsonian Air & Space magazine.

The Universe is Ringing

And astronomers are building observatories to listen to it

For Smithsonian Air & Space:

Think of it as a low hum, a rumble too deep to notice without special equipment. It permeates everything—from the emptiest spot in space to the densest cores of planets. Unlike sound, which requires air or some other material to carry it, this hum travels on the structure of space-time itself. It is the tremble caused by gravitational radiation, left over from the first moments after the Big Bang.

Gravitational waves were predicted in Albert Einstein’s 1916 theory of general relativity. Einstein postulated that the gravity of massive objects would bend or warp space-time and that their movements would send ripples through it, just as a ship moving through water creates a wake. Later observations supported his conception. [Read the rest at Air & Space….]

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A white dwarf murder mystery

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What killed the white dwarfs? (Aside from the giant explosion)

Merger or extra matter? Two papers come to opposite conclusions

For Ars Technica:

Type Ia supernovae are explosions that occur when white dwarfs strip matter off a companion star, exceed their maximum possible mass, and blow up.

No, wait: type Ia supernovae are the explosions caused when two white dwarfs collide.

While it’s reasonably certain that white dwarfs—the Earth-size remnant of stars similar to the Sun—are involved, the observational evidence for how these supernovae actually explode is messy. This week’s issue of Nature is a prime example: two back-to-back papers provide evidence for a white dwarf-companion star explosion and a two-white-dwarf collision scenario, respectively. Ultimately, these apparently contradictory results could mean there are two distinct types of white dwarf supernovae… or that we still don’t understand what’s going on.

The stakes are high. Unlike other supernovae, which involve the death of a star much more massive than the Sun, type Ia supernovae all explode in very similar ways. The pattern of light they emit during and after the explosion provides a reliable measurement of how far away they are. Since supernovae are bright enough to be visible from billions of light-years away, astronomers use them to measure the expansion and acceleration rate of the Universe, as recognized in the 2011 Nobel Prize in physics. Because they are so important to cosmology, researchers want to understand what objects are involved in the explosion and exactly how they blow up. [Read the rest at Ars Technica…]

Looking to the heavens for neutrino masses

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Looking to the heavens for neutrino masses

From Symmetry Magazine:

Neutrinos may be the lightest of all the particles with mass, weighing in at a tiny fraction of the mass of an electron. And yet, because they are so abundant, they played a significant role in the evolution and growth of the biggest things in the universe: galaxy clusters, made up of hundreds or thousands of galaxies bound together by mutual gravity.

Thanks to this deep connection, scientists are using these giants to study the tiny particles that helped form them. In doing so, they may find out more about the fundamental forces that govern the universe. [Read the rest at Symmetry]

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!

That’ll do, MESSENGER. That’ll do.

[ This blog is dedicated to tracking my most recent publications. Subscribe to the feed to keep up with all the science stories I write! ]

Mercury Killed The MESSENGER Probe

From The Daily Beast:

Pour one out for MESSENGER space probe. Today, at around 3:30 PM EST, MESSENGER crashed into the planet Mercury, no doubt shouting “SCIENCE!” as it went. That final crash marks the end of an amazingly successful scientific mission, extended to four times beyond its original plan, that brought us a new understanding of the smallest planet in the Solar System.

Since entering Mercury’s orbit in March 2011, MESSENGER (which, awkwardly, is the acronym MErcury Surface, Space ENvironment, GEochemistry, and Ranging) has studied the planet’s gravitational field, the structure of its craters, and the chemistry of its surface. The probe discovered water in the form of ice hiding in craters near the poles and organic molecules on Mercury’s exterior, and signs of a complicated past in the interior. [read the rest at The Daily Beast…]