Dear MEL Topic Readers,
Bill Nye explains light-years and the vastness of the universe
The distance from the Sun to Earth is about 150 million kilometers. Since light travels approximately 300,000 kilometers per second, it takes over eight minutes for sunlight to reach our planet. In other words, the Sun we see on Earth is that of about 8 minutes ago. This Sun-Earth distance is called 1.00 Astronomical Unit (AU), which is used to scale the distance within our solar system. For example, the farthest planet in our solar system is Neptune, which is about 30 AUs from the Sun. It takes 4.3 hours for sunlight to reach this distant planet. Now, our nearest star, Proxima Centauri, is 40,000,000,000,000 (40 trillion) kilometers, or 268,770 AUs away. Since light travels about 9.46 trillion kilometers a year, it would still take over four years to get there if you traveled at the speed of light or light speed. Now, you might understand what unit to use to scale the distance. Within our solar system, Astronomical Unit (AU) is just sufficient. But when you talk about stars and galaxies, the light-year is more convenient. To your surprise, the most distant star ever seen is still 28 billion years away from us. How many kilometers is that from the Earth?
Enjoy reading the article and learn about why light-year is used to measure the distance of the universe.
https://edition.cnn.com/2023/03/31/world/bill-nye-light-year-scn/index.html
Bill Nye explains light-years and the vastness of the universe
The distance from the Sun to Earth is about 150 million kilometers. Since light travels approximately 300,000 kilometers per second, it takes over eight minutes for sunlight to reach our planet. In other words, the Sun we see on Earth is that of about 8 minutes ago. This Sun-Earth distance is called 1.00 Astronomical Unit (AU), which is used to scale the distance within our solar system. For example, the farthest planet in our solar system is Neptune, which is about 30 AUs from the Sun. It takes 4.3 hours for sunlight to reach this distant planet. Now, our nearest star, Proxima Centauri, is 40,000,000,000,000 (40 trillion) kilometers, or 268,770 AUs away. Since light travels about 9.46 trillion kilometers a year, it would still take over four years to get there if you traveled at the speed of light or light speed. Now, you might understand what unit to use to scale the distance. Within our solar system, Astronomical Unit (AU) is just sufficient. But when you talk about stars and galaxies, the light-year is more convenient. To your surprise, the most distant star ever seen is still 28 billion years away from us. How many kilometers is that from the Earth?
Enjoy reading the article and learn about why light-year is used to measure the distance of the universe.
https://edition.cnn.com/2023/03/31/world/bill-nye-light-year-scn/index.html
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