Dear colleagues and friends,
The mandatory topic this week is of course the solar eclipse that will occur next Monday, April 8. And precisely on this subject, an esteemed colleague shares this article written by Robert Knobel and Kristine Spekkens, published on April 5, 2024 in the magazine The Conversation and translated by us for this space. Let's see what they tell us about it...
Eclipse fever has gripped North America, where many people talk, worry and even obsess over the total solar eclipse of April 8.
The eclipse itself is beautiful and moving, and it's an incredible opportunity to excite and engage the community in the scientific advances that eclipses have brought us and all the potential discoveries we could see in the future, including the possible discovery of life on other worlds.
In a solar eclipse, the Moon passes between the Earth and the Sun, casting its shadow on the Earth. The surprising coincidence is that the Moon, about 400 times smaller than the Sun, is also about 400 times closer to us than the Sun, so they appear the same size from the Earth's surface.
When the Sun, Moon, and Earth align, the shadow cast by the Moon follows a narrow path that moves across the globe as the Earth rotates and the Moon and Earth continue their orbital dances around the Sun.
Palpable emotion
Most of North America will have a partial eclipse on April 8. Totality will occur along the diagonal path of total shadow for a few precious minutes.
The enthusiasm surrounding the eclipse is palpable, coming from children and adults, from locals and visitors. Municipalities are concerned: Niagara Falls is forecasting the visit of up to one million people and Kingston predicts up to 500,000.
This is partly due to the rarity of a total solar eclipse: they occur about 375 years apart at a given location on average, and the next one anywhere in Canada doesn't happen for another 20 years.
But the buzz also stems from how beautiful a total eclipse can be. A partial eclipse is interesting. Everyone should use a sunscreen or pinhole camera to safely observe how the moon gradually covers the solar disk.
But along the narrow path where the Sun-Moon-Earth alignment is perfect, we'll see a few brief minutes of darkness during the day, we can see the Sun's faint corona, and we'll see a sunrise in every direction.
Experiencing a total eclipse allows everyone to be both an astronomer, who thinks about our place in the solar system, the Milky Way and the universe, and an aesthete who marvels at the beauty of the sky.
Astrological contributions
For millennia, many societies viewed eclipses as dangerous omens, a reasonable fear given how strange it is to see darkness during the day. Predictions about when the next eclipses would occur became important for leaders. The Babylonians thought that the eclipse could predict the death of the king, while the Mayans believed that diabolic spirits would come out to attack people.
Today's scientists may scoff at astrology, but it was this potential astrological fatality that led ancient civilizations to create increasingly accurate models of how the Sun, Moon, and planets moved.
As measurements became more precise, the old Earth-centered solar system model was replaced by Johannes Kepler's representation of the Sun in the focus of elliptical orbits, leading to Isaac Newton's theory of gravity.
Careful measurements (originally intended for astrology and partly due to concerns about eclipses) contributed to our understanding of the universe and how it works.
Historical shows
In 1842, with a total eclipse in Europe, the narrative changed and solar eclipses became tourist attractions. Astronomers such as British astronomers Francis Baily and George Biddell Airy traveled to see the eclipse.
But it was the vivid descriptions of writers such as the Austrian Adalbert Stifter that captured the world's attention: “Never, ever in my entire life have I been so moved, so moved by terror and sublimity, as in these two minutes; it was nothing more than as if suddenly God had uttered some words and I understood them.”
Interest in eclipses increased both for the public and for professional astronomers. It was by studying the light of the Sun's faint corona, only visible during eclipses, that the element helium was discovered.
It was by observing the curvature of light coming from distant stars that Albert Einstein's theory of general relativity was confirmed, which brought him worldwide fame.
A Shared Passion
The global passion for witnessing and experiencing the eclipse is something that science educators cannot ignore. Across the continent, astronomers and teachers are educating people on how to observe safely using pinhole cameras or eclipse glasses.
Science educators explain to a fascinated audience how the Sun, Moon, and Earth must align perfectly for a total eclipse to occur. We all hope that the weather will be good to be able to see the corona and explain why it is somehow hotter than the surface of the Sun.
Nowadays, eclipses are not necessarily studied to make new discoveries. However, astronomers use a similar dimming of distant stars as evidence that an exoplanet must have passed in front of them. We have discovered thousands of worlds, confirming that exoplanets are common. We can now measure the slight change in the color of light during a transit similar to an extrasolar eclipse to detect water and signs of life in the atmosphere of an exoplanet.
So the hype over the April 8 total solar eclipse is worth it. For us, it's not just sublime beauty. It's an opportunity to connect with large crowds as excited as we are. It's an opportunity to link what we're seeing with the vastness of space, millennia of history, and the promise of understanding our universe more broadly, all in three minutes in the shadow of the moon.
