Om nom nom: a black hole ate a star and left crumbs for us to see

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

And if I can be shameless: Forbes pays according to traffic, so the more of you who click on the link below and read my stuff, the better they pay me. Ahem.

A Black Hole Ate A Star And Left Crumbs Of Light For Astronomers To Discover

colliding galaxies Arp 299

The colliding galaxies Arp 299, as seen in visible light (the background) and X-rays (red, green, and blue foreground). [Credit: NASA, JPL-Caltech, GSFC, Hubble, NuSTAR]

For Forbes:

Astronomers captured the last moments of an unlucky star that got too close to a black hole. However, they didn’t know that’s what we were seeing right away, because the whole scene of carnage was hidden by clouds of gas and dust. Now, with multiple types of observations and more than ten years of data, we have new insights into the way black holes shred stars, as reported in a new paper in Science.

Black holes, like Cookie Monster, are notoriously messy eaters. That’s good for astronomers, though, because the cosmic crumbs a black hole spills during its meal emit a lot of light. If a star gets too close to a black hole, the gravity tears it to pieces in an act known as “tidal disruption”, but only part of the star’s material actually falls in. (This is a more extreme version of the same forces that raise tides on Earth, and which destroyed a small moon to create Saturn’s rings.) The rest of the star gets channeled into a powerful jet that streams away from the black hole back into space.

[Read the rest at Forbes…]

Advertisements

How to find newborn planets without seeing them

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

And if I can be shameless: Forbes pays according to traffic, so the more of you who click on the link below and read my stuff, the better they pay me. Ahem.

Astronomers Use The Doppler Effect To Find Three Newborn Planets

For Forbes:

We can’t witness the birth of our own Solar System, but the Atacama Large Millimeter/submillimeter Array (ALMA) is providing a picture of how it may have happened. ALMA spotted signs of three giant planets forming around a young star in our cosmic neighborhood. The technique astronomers used to study these planets is one that can be used to find other newborn worlds, and see exactly how clouds of gas and dust turn into something like the Solar System.

The star, which astronomers gave the memorable name HD 163296, is only about 4 million years old, which in cosmic terms makes it a baby. Researchers used ALMA to take detailed images of the disk of dust and gas surrounding the star, which showed three gaps. By studying the motion of carbon monoxide gas within the disk, the astronomers showed it was being moved by massive objects living in those gaps — a telltale sign of newborn planets. These findings were published in a pair of articles in Astrophysical Journal Letters.

[Read the rest at Forbes…]

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

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

And if I can be shameless: Forbes pays according to traffic, so the more of you who click on the link below and read my stuff, the better they pay me. Ahem.

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…]

Earth is a freeeeee faaaallin’ laboratory for testing general relativity

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

And if I can be shameless: Forbes pays according to traffic, so the more of you who click on the link below and read my stuff, the better they pay me. Ahem.

Scientists Check Einstein’s Predictions Using Earth Itself As The Laboratory

For Forbes:

The modern description of gravity, Albert Einstein’s general relativity, is one of the most successful and best-tested theories we have. The core of that theory is a set of principles that say basically “physics is physics, wherever you are and no matter how fast you’re moving”. In particular, an experiment performed under the influence of gravity alone should work exactly the same as if you’re performing the same experiment deep in space without any gravity at all.

That’s a tricky concept to verify, but scientists at the National Institute of Standards and Technology (NIST) in Colorado have provided the best test for it yet, using Earth itself as the laboratory. They performed precision experiments in atomic physics (one of NIST’s specialties) and compared those results to those obtained at labs around the world, with data taken over a period of 14 years. The result: general relativity’s predictions were upheld once again.

[Read the rest at Forbes…]

Using math to understand why species don’t out-eat each other

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

This article is a little different from the fare you’re used to getting from me: it’s for SIAM News, which is the glossy magazine for members of the Society for Industrial and Applied Mathematics (SIAM). The audience for this magazine, in other words, is professional mathematicians and related researchers working in a wide variety of fields. While the article contains equations, I wrote it to be understandable even if you skip over the math.

Competitive Adaptation Prevents Species from Eradicating Each Other

For SIAM News:

Evolution is frequently rough and unforgiving; individuals within a species compete for food, reproductive partners, or other resources. Species fight each other for survival, especially when preying on one another.

Mathematical biologists often simplify these dynamics to predator versus prey. Real-world populations of predator and prey species within a given ecosystem cycle between booms and busts. In various cases, multiple species—including both predators and prey—coexist with similar diets. For example, a cubic meter of seawater can harbor several species of plankton, consisting of tiny plants and animals (see Figure 1).

One would naively expect reproductive success (more offspring) or competitive performance (eating more than your neighbor) to lead to one species’ domination. But that does not occur. While many of these organisms consume the same food, one species does not out-eat the others; the plankton swarm’s overall diversity remains fairly constant. Biologists refer to this phenomenon as the “paradox of the plankton” or the “biodiversity paradox,” among similar terms.

[read the rest at SIAM News]

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

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

And if I can be shameless: Forbes pays according to traffic, so the more of you who share and visit and read my stuff, the better they pay me. Ahem.

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…]