Subtitles section Play video Print subtitles Every location on Earth has been in the shadow of at least one total eclipse, but some places experience way more of these events than others. Like, someone who lives North of the equator is about twice as likely to see a total eclipse as someone south of the equator. Why on Earth would that be? Hi, I'm Cameron, and this is MinuteEarth. This disparity in total eclipses can only happen because of a celestial coincidence; although the Sun is 400 times bigger than the Moon, it's also 400 times farther away from us. So, as a result – from here on Earth – the Sun and the moon appear to be almost exactly the same size. I say “almost” because the Earth's orbit around the Sun is not perfectly circular. During some parts of the year, the Earth is a little farther away from the Sun – so the sun appears slightly smaller than usual. During these times, when the Earth, moon and sun line up, it's easier for the moon to effectively block the sun, causing a total eclipse. But other times of the year, the Earth is closer to the Sun, so the sun appears larger than normal. When the Earth, moon, and sun line up during these times of the year, the Sun appears larger and the moon might not totally block it, creating an annular eclipse, which is when the moon turns the sun into a bright ring of fire in the sky. And here's where the North-South divide fits in. In either hemisphere, eclipses are more likely in the summer, when the sun spends more time above the horizon, since it has to be daytime in order to see a solar eclipse. And it just so happens that summer in the Northern hemisphere happens at the farthest-out point of Earth's orbit, while Summer in the Southern hemisphere happens at the closest point. As a result, total eclipses are more likely to happen North of the equator; for any given spot in the Northern hemisphere, a total eclipse happens, on average, once every 330 years. In the Southern hemisphere, it's more like every 550 years. But even within the Northern hemisphere, total eclipses become more frequent with higher latitudes. There are a few different reasons why this might be. For one, at the highest latitudes, the summer sun rarely dips below the horizon, meaning that there is sunlight even at nighttime, as opposed to lower latitudes where nighttime is dark during the summer. Then there's the curvature of the Earth, which causes the moon's shadow to fall at a shallower angle at higher latitudes; eclipse paths near the Arctic circle can be more than four times wider than eclipses at lower latitudes. So statistically, the best place to see a total eclipse is around 80 degrees north; any given place along this line sees a total eclipse every 238 years on average. But remember, all these numbers are averages taken over a long period of time. Carbondale, Illinois – which sits at 38 degrees North latitude, which should see a total eclipse every 330 years on average – saw it's most recent total eclipse in 2017, yet will get its next one in 2024. And Christchurch, New Zealand, which should get a total eclipse once every 420 years – saw its most recent total eclipse nearly two thousand years ago, and will have to wait another four centuries for its next one. So when it comes to seeing a total eclipse, it's not just about latitude – it's also a matter of luck. If you live in North America, there's a great chance to have that experience soon. There's a total solar eclipse on Monday April 8th, which will take a long sweeping path through Canada, the US and Mexico. We're super excited about it, and we've teamed up with NASA's Heliophysics Education Activation Team to make videos like this to explore the science and wonder of solar eclipses. NASA HEAT's mission is to provide educational guidance for learners of all ages to deepen their understanding of our sun and its effects on Earth and the solar system in an effort to bring NASA out of the lab and into learning spaces like classrooms and even YouTube to inspire future scientists.
B2 US eclipse total sun earth hemisphere moon Why does the north get more total eclipses? 23 3 林宜悉 posted on 2024/03/28 More Share Save Report Video vocabulary