From the stars to your eyes: the journey of light through time and space
⭐ Twinkle, twinkle little star, how I wonder what you are.
Up above the world so high, how do you reach my eyes?
💫 🪐 💫 🪐 💫 🪐 💫 🪐 💫 🪐 💫 🪐
Have you reflected on the stars?
You’re not the only one! This topic is fascinating, so let’s take a journey from the stars to your eyes.
Light we see from stars
The bright lights emitted by stars is called starlight, this refers to the wavelength of electromagnetic radiation given off by a star, typically observable at night that can be seen by the naked eye. Starlight is emitted through varying wavelengths, a “peak wavelength” is when a star gives off its brightest possible light, and the colours we see differ depending on their peak wavelength. This diagram will help visualize the different colours a star can give off based on each wavelength.
A stars journey in real time
The speed of light is the fastest possible speed in the universe, nothing travels faster, however, it doesn’t mean this is instantaneous, it actually takes quite some time to reach our eyes. The universe is insanely large, it’s basically unfathomable. To put this into context: light covers 186,000 miles every second.
The closest star to us is our magical sun, that being 93 million miles away from earth. Sunlight takes about 8 minutes and 20 seconds to reach us, meaning what you see when you look up at the sun, or any object in the universe for that matter – you’re looking back in time. Because of this, we have no way of knowing about the current state of our stars in the universe, for all we know a star we think we see today could have been demolished by a black hole. With that being said, due to the length of time it takes for light to reach us, everything we see in space is actually a look into the past, which also means the further an object, the more ancient it is to us here on earth!
When looking to the nearest stars next to the sun, they are found beyond the solar system where time turns from hours and days to light-years in order to make its way to us. One light-year is approx. 5.88 trillion miles (keep that in mind for reference sake). This star system lies about 4.37 light-years away in the Alpha Centauri triple-star system, meaning it takes over 4.3 years to reach us! The furthest star known to mankind has been named Earendel and sits 28 billion light-years away from us, unfortunately it can not be seen by the naked, eye you’ll need to borrow a telescope from NASA for that. This star was recently discovered by NASA in April 2022, prior to its discovery Icarus was the furthest individual known star, at 9 billion light-years away – I don’t even want to attempt to do the math on that!
The journey of light from the stars to our eyes is vast, and depending on what stars you're looking up at in the sky, what you are seeing is from the past and has actually taken minutes, hours or years to reach you!
“Everything we see in the sky belongs to the past”-Timothy Ferris