There is nothing faster than light, right? But the sunlight you feel right now on your skin or the sunlight you see outside could be 50 million years old.
How? Let’s start with the obvious, this does not mean that it takes 50 million years for the light to travel from the sun to the Earth. It takes only 5 hours for the light to travel from the sun to Pluto so it takes considerably less time for the light to travel from the sun to Earth. What are we talking about here? The light that will reach the planet Earth today was maybe created at the center of our sun more than 50 million years ago.
Here are the basics. Light travels at 186,388 miles per second. The Earth is on average 92.96 million miles away from the sun. If you do the math, this means that it takes approximately 8.31 minutes for the light to leave the sun, and to hit planet Earth. Here is a thought to think about. If the sun would disappear, it would take us around 8 minutes to realize that. What’s even more interesting for scientists is the thought that the light waves were kicking around inside the hot sun at least for tens of thousands of years or even 50 million years.
Our sun has a radius of about 432,000 miles and the light can travel that distance in two seconds, but it is not that simple. Inside the sunlight particles called photons don’t make a straight line and they take a path that is known as “drunkard’s walk.” Basically, imagine a drunk man who can’t walk a straight line and every time he takes a step it’s a random step to the left or right instead of a straight-line step. To calculate how long it would take for a drunk man to reach the destination, you can take the number of steps he would normally take (for example 10 steps) and square it. This means that after 100 zig-zag steps, he would finally reach his destination. Back to the photons. The same logic could be used to calculate how every photon travels from the core of the sun to its photosphere.
Everything starts at the core of the sun where billions of hydrogen atoms fuse and they create something that we know as helium. During this process, two types of particles are created: gamma rays (high-energy photons which interact with the physical matter in a great way) and neutrinos (elementary particles that barely interact with matter). The neutrinos shoot through the sun easily. From the other side, every time the gamma-rays collide with atoms, they are easily absorbed and re-emitted in a random direction.
If we are trying to figure out how long it would take for an average photon to get from the core of the sun to the palm of your head, then the answer is tough, and it could vary from anything from 10 thousand years to 50 million years. Why? Simply, because it’s not a straight-line walk, it’s a drunkard’s walk. That drunk man might take 100 steps to get from point A to point B which usually would take 10 steps for an average person, but it might take him 50 or 70 steps as well. The same rule does not apply to everyone.
It all comes down to the length of the photon’s drunken step.
Until we know how dense the core of the sun is, we will never know the exact answer to this question.