What Is a Lichen?

A Debate Over How The Universe Began

Even though it’s commonly accepted today, the Big Bang theory was not always the universally accepted scientific explanation for how our universe began. In fact, the term ‘Big Bang’ was coined by a prominent physicist in 1949 to mock the idea.

In the middle of the 20th century, researchers in the field of cosmology had two warring theories. The one we would come to call the Big Bang suggested the universe expanded rapidly from a primordial, hot, and ultra-dense cosmos. Conversely, the so-called ‘Steady State’ theory held that the universe, at any given point in time, looked roughly the same.

The story of how the Big Bang became the accepted theory of physics is also a story of two men. One, Fred Hoyle, was a steady state supporter who thought the universe would last forever. Meanwhile, George Gamow, the major public advocate of the Big Bang, begged to differ. They debated in the pages of Scientific American and in competing popular books, as both dedicated scientists and earnest popularizers of their field.

And while Gamow ended up winning the debate, for the most part, the two men managed to come together in one way: They accidentally explained the origins of every element of matter by being part right, and part wrong. The truth, it turned out, would lie in the middle. Ira talks to physicist and science historian Paul Halpern about this story, detailed in his book, Flashes of Creation: George Gamow, Fred Hoyle, and the Great Big Bang Debate.

 

The World According To Sound: Listening To Black Holes Collide

In this piece, you can actually listen to gravitational waves, the ripples in spacetime made by the tremendous mass of colliding black holes. It is possible to hear them, because their wavelengths have been shifted all the way into the human range of hearing by MIT professor Scott Hughes.

Drawn together by their immense gravity, nearby black holes will swirl faster and faster until they are finally absorbed completely into one another. When the pitch rises, it means the force of gravity is increasing as the black holes collide.

Not all black holes come together at the same rate or release the same amount of gravitational waves, so each combining pair has its own particular sonic signature. Some black holes collide quickly. Others slowly merge. Some produce relatively high pitches, because of the intensity of the gravitational waves, while others have a low bass rumbling. Some even make the sound of a wobbling top as the two black holes swirl around each other, before eventually meeting and becoming totally absorbed into one another.

 

A Maggot Revolution In Modern Medicine

In a bloody battle during World War I, two wounded soldiers were stranded on the battlefield in France, hidden and overlooked under some brush. Suffering femur fractures and flesh wounds around their scrotum and abdomen, they lay abandoned without water, food, or shelter for a whole week. At the time, outcomes for these kinds of wounds were poor: Patients with compound femur fractures had a 75 to 80% mortality rate. By the time the soldiers were rescued and brought to a hospital base, orthopedic surgeon William Baer expected their wounds to be festering, and their conditions fatal. But much to his surprise, neither showed any signs of fever, septicaemia, or blood poisoning.

 

Read more at sciencefriday.com.

 

Trying To Determine Forest Health? Look To The Lichens

There aren’t very many old-growth forest left in North America. And while it would be wonderful to be able to preserve all of them, resources to protect those forest patches are also in limited supply. So if you’re forced to choose between two areas of old-growth forest, how do you prioritize which of these islands of biodiversity to focus on?

One of the standard ways to identify significant patches of forest is to look at the size of the trees. But new work published this week in the journal Frontiers in Ecology and the Environment suggests that examining the lichens in a forest plot may give a better picture of the ecological health of an area. Because lichens feed from the air flowing over them, they’re quite sensitive to changes in moisture, nutrients, and pollution, and need long, continuous periods undisturbed.

Troy McMullin, a research scientist in lichenology at the Canadian Museum of Nature in Ottawa, Ontario, joins Ira to talk about the stories lichens can tell about the forest ecosystem.

 

Transcripts are available on sciencefriday.com.

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