As one of the most impressive astronomical events we can witness from Earth, a total solar eclipse is a jaw-dropping reminder that our planet is part of an elaborate celestial dance. However, due to the Moon’s orbit around the Earth and the Earth’s orbit around the Sun not being perfectly level with one another, this precise alignment happens every 18 months or so. Additionally, the Moon is moving away from us at a rate of about 3.8 centimeters per year, meaning that total solar eclipses will eventually become more irregular and infrequent. According to some back-of-the-envelope math, this will happen in around 600 million years, with the very last total solar eclipse occurring in around 1.2 billion years. While this may seem like a long time, it is a short time compared to our species’ existence on Earth. As the Sun ages, it will become brighter, making Earth’s surface too hot for any life to thrive. Therefore, it is likely that there will be no one left to watch the very last total solar eclipse.