Metro Science: Colliding stars, what bees see, and the science of grey hair
One of the most exciting discoveries of the year has proven that an old phrase in science, "We are made of star stuff" is completely, totally true.
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Astronomers have detected the echo of a long-ago, faraway explosion so huge it jiggled the jelly of space itself. And this time the jiggles, called gravitational waves, spewed from something we can actually see in the sky: A collision of two super-dense neutron stars. Explosions like this are the only way (we know of) that heavier elements get made from lighter ones. It’s how the matter we know and love — rocks, gold, the iron in our blood — came to be. What Carl Sagan said long ago was right: We’re made of star stuff.
What's happening in there?
Wait. What do two neutron stars colliding have to do with the gold in my wedding ring? To answer that question, you need to know where gold (and other heavier chemical elements like iron and lead) come from, originally.
Unlike lighter elements such as hydrogen and helium, they haven't been here since moments after the Big Bang. In simplified terms, they form when particles from lighter elements are smooshed together under immense temperature and pressure.
Even the core of our own sun doesn't have enough energy to make something as heavy as gold. Where can you find enough energy to carry out that chemical process (which is called nucleosynthesis)? A collision of two neutron stars, that's where. Just like the one that scientists have observed directly for the very first time.
So, the theory goes, in the distant past — sometime before the sun formed 4.7 billion years ago — two neutron stars collided in the celestial neighbourhood where our solar system stands today. It left a cloud of heavy-metal-rich space dust, and that dust coalesced to form our sun and the planet we love, complete with its gold deposits.
What are neutron stars?
They're some of the densest objects in the universe. They weigh about the same as our sun, but are 15 km across compared the sun’s 1.4 million km. Two of them colliding is an “extreme beyond extreme beyond extreme” event, said Canadian astrophysicist Eric Poisson.
Could it happen here?
Not a chance, Poisson said. There’s no way to recreate a nuclear reaction anything like this in a lab on earth. We’d never be able to make an object with that much mass, and even if we somehow did, it would mess up the gravity of the Earth.
So what did scientists see in August?
This explosion, which happened 130 million years ago, a septillion km away, flung out a jet of particles and light called a kilonova and bursts of radiation called gamma rays, which we've just sensed now. That's how long they took to get here, at the speed of light.
What about that space jelly?
When the stars collided, the BANG created ripples in spacetime, called gravitational waves. One hundred thirty million years later, they jiggled the Earth just enough for the Laser Interferometer Gravitational-Wave Observatory (LIGO) to detect. Past observations of gravitational waves have all been of black holes colliding, but this time was different: Neutron stars emit visible light. Once they got the wave signal, scientists scrambled to their telescopes and glimpsed the star merger in action. It looked like a blurry orb, near the constellation Hydra.
SCIENCE STORY: What bees see
Here's some exciting buzz: Bees can see something we can't. A new study in the journal Nature found that several common flowers have microscopic ridges on their petals that scatter blue and ultraviolet light. This means that, from a bee's eye-view, the blooms are surrounded by a fuzzy "blue halo" that tells them it contains tasty nectar they can turn into honey.
SOUND SMART: Your science vocabulary word for the week: "ISOTROPIC"
DEFINITION: An isotropic object or phenomenon is identical in all directions.
USE IT IN A SENTENCE: Deborah's hedgehog is almost isotropic: She looks the exact same from the front, the back and the sides.
Watch Metro science LIVE
Head to facebook.com/MetroCanada at 12 p.m. EST on Friday Oct. 20 to see Genna Buck explain the coolest science stories of the week and answer YOUR science questions. This week: Why does hair turn grey?