Guardians of the Galaxy…er, black holes vol. 3

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Part 3 of my 4-part series on black holes for Medium members is up; part 1 is here and part 2 is here. If enough of you read, they may keep me around to write more, so please read and share!

Seeing the Invisible

Black holes are invisible, but astronomers have developed a lot of ways to see them through the matter that surrounds them

No Rocket Raccoon, but my latest does have a guy named Grote. [Credit: National Radio Astronomy Observatory/moi]

For Medium:

In 1937, a deeply weird engineer named Grote Reber built a telescope in the lot next to his mother’s house in Wheaton, Illinois. Home observatories aren’t unusual, but Reber’s project was the first telescope designed to look for radio waves from space, and he was only the second person in history to find them. Karl Jansky, the first radio astronomer, had accidentally discovered astronomical radio waves while working on shortwave radio communications.

But Reber set out deliberately to study the cosmos in radio light. He found that the center of the Milky Way emitted a lot of radio waves and discovered an intense radio source in the constellation Cygnus. By the 1950s, astronomers found many other radio galaxies (as they were creatively named) that emitted very powerful radio waves from small regions at the centers of those galaxies.

As we learned in Part 2 of this series, the sources of the radio waves in the Milky Way and beyond turned out to be supermassive black holes: powerful gravitational dynamos millions or billions of times the mass of our sun. As with Reber’s discoveries, the study of black holes has been driven by invention and creativity. In fact, every new advance in astronomy has led to new discoveries about black holes, and new technologies are being invented for the purpose of studying these weird objects.

Read the rest at Medium…

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The Care and Feeding of Black Holes

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

Part 2 of my 4-part series on black holes for Medium members is up; you can read part 1 here. If enough of you read, they may keep me around to write more, so please read and share!

The Care and Feeding of Black Holes

How intrinsically invisible objects become the brightest things in the universe

For Medium:

In the late 1950s, astronomers began spotting a number of bright sources of radio waves and visible light. These sources were pinpoints resembling blue stars, but further investigation showed they had to be something very different. For one thing, these quasi-stellar objects, as they were known then, were extraordinarily distant, much farther than any single star would be visible.

The spectra of these new quasi-stellar objects, or quasars, as physicist Hong-Yee Chiu abbreviated their name in 1964, showed they were emitting light through a completely different mechanism than starlight. The quantity of light quasars emitted to be visible across the universe meant they had to be driven by gravity.

Based on the data, astronomers concluded that each quasar was powered by a black hole millions or billions of times the mass of our sun. These supermassive black holes pull huge amounts of matter onto themselves, accelerating it until it glows very brightly. Additionally, the black hole jets a lot of matter away from itself rather than eating it, and those jets also glow intensely. These processes turn the ordinarily invisible black hole into something bright enough to see from billions of light-years away, outshining whole galaxies.

[read the read at Medium…]

My new series on black holes!

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

I’ve just started a new series on black holes for Medium members. The first part is available now, with three more parts to come. And if enough of you read, they may keep me around to write more, so please read and share!

Exploring Black Holes: Frozen Stars and Gravitational Dynamos

Black holes are gravitational superheroes. Here is their origin story, including World War I, magnificent mustaches, and Albert Einstein

For Medium:

February 11, 2016, was a landmark day. After many decades of searching, scientists announced they had detected gravitational waves for the first time: disturbances in the structure of space-time that travel at light speed. But there was a second triumph of physics hiding inside that one. The waves gave us the best evidence so far for the existence of some of the most fascinating objects in our universe: black holes.
Few scientists these days doubt that black holes exist. But in a way, all our evidence for them is circumstantial. Black holes, by their very nature, are difficult to observe. All light falling on them is absorbed, rendering them nearly invisible.
On the other hand, black holes are the strongest gravitational powerhouses possible. When they strip matter off stars or out of interstellar gas clouds, that material heats up and shines brightly. It’s a seeming paradox: invisible objects that end up being some of the brightest things in the universe. The black holes known as quasars can be seen billions of light-years away. [read the rest at Medium…]

City ant, country ant, and climate change

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Acorn ants as seen through a microscope. [Credit: moi]

I know, I know: it’s been a long time since I last had something published. This is largely because I took a little time off to finish my novel. With the first draft done, I needed to catch up. As a result, I have six or seven (depending on how you count) articles that are finished, but which won’t be published immediately. Anyway, here’s the first of those, published today:

What City Ants Can Teach Us About Species Evolution And Climate Change

Is the rapid evolution of a certain ant species to urban environments a preview of life on a warming planet? Some researchers are trying to find out.

For Undark Magazine:

Acorn ants are tiny. They’re not the ants you’d notice marching across your kitchen or swarming around sidewalk cracks, but the species is common across eastern North America. In particular, acorn ants live anywhere you find oak or hickory trees: both in forests and in the hearts of cities.

That’s why they’re so interesting to Sarah Diamond, a biology professor at Case Western Reserve University in Cleveland. “We’re comparing this little forest island within a city to traditional forest habitats,” she says. Specifically, she and her colleagues are looking at how well city ants can tolerate higher temperatures compared to their rural cousins. The experiment is made possible by what’s known as the urban heat island effect, which describes the tendency of the built-up infrastructure of cities — think heat-absorbing concrete and asphalt, for example — to create a hotter environment than less developed areas. [read the rest at Undark Magazine]

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…]

Albert Einstein: Physicist and Social Justice Warrior

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From left: Former Vice-President Henry A. Wallace, Albert Einstein, Lewis Wallace, and Paul Robeson. Einstein had invited Wallace (who was running for President in 1948) and singer/actor/civil-rights activist Robeson to his house to discuss anti-lynching activism. Robeson asked Einstein to co-chair his  organization, American Crusade Against Lynching (ACAL). [Credit: Bettmann / Getty Images]

From left: Former Vice-President Henry A. Wallace, Albert Einstein, Lewis Wallace, and Paul Robeson. Einstein had invited Wallace (who was running for President in 1948) and singer/actor/civil-rights activist Robeson to his house to discuss anti-lynching activism. Robeson asked Einstein to co-chair his organization, American Crusade Against Lynching (ACAL). [Credit: Bettmann / Getty Images]

How Albert Einstein Used His Fame to Denounce American Racism

The world-renowned physicist was never one to just stick to the science

For Smithsonian Magazine:

By the spring of 1933, the most famous scientist in the world had become a refugee.

Einstein was a more fortunate refugee than most. By that time he was already a Nobel Prize winner and media celebrity, recognizable around the world. That fame made him a high-profile enemy for the new Nazi government in Germany, but it also guaranteed him safe places to go. Ultimately he ended up in America at the Institute for Advanced Study in Princeton, New Jersey, where he would spend the rest of his life.

Einstein saw racism as a fundamental stumbling block to freedom. In both his science and his politics, Einstein believed in the need for individual liberty: the ability to follow ideas and life paths without fear of oppression. And he knew from his experiences as a Jewish scientist in Germany how easily that freedom could be destroyed in the name of nationalism and patriotism. In a 1946 commencement speech at Lincoln University, the oldest black college in the U.S., Einstein decried American racism in no uncertain terms.

“There is separation of colored people from white people in the United States,” said the renowned physicist, using the common term in the day. “That separation is not a disease of colored people. It is a disease of white people. I do not intend to be quiet about it.” [Read the rest at Smithsonian Magazine]

Evolution, entropy, and beards

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The Hidden Connections Between Darwin and the Physicist Who Championed Entropy

These magnificently bearded men both introduced a dose of randomness and irreversibility into the universe

For Smithsonian Magazine:

Of all the scientific advances, evolution has been the hardest on the human ego. Charles Darwin’s revolutionary theory, laid out in his groundbreaking 1859 book On the Origin of Species, threatened to overturn humanity’s exalted position in the universe. Yet in the same era, a quieter—and seemingly unrelated—scientific revolution was also taking place.

The concept of entropy in physics began harmlessly enough, as an explanation for why steam engines could never be perfectly efficient. But ultimately, entropy also threatened an established hierarchy. And in fact, entropy and evolution were more than casually related. [Read the rest at Smithsonian]