A scientist at NASA proves that the speed of light is torturously slow through 3 simple animations. His clever physics animations show how long it takes light to travel around the Earth, from Earth to the moon, and from Earth to Mars. You can really see just how fast (and slow) the speed limit of the universe can be.
About The Speed Of Light
In a perfectly empty vacuum, a particle of light (which is called a photon) travels at about 186,282 miles per second (299,792 kilometers per second). That’s about 670.6 million mph (1.079 billion kilometers per hour). It is the fastest known way that any object can travel through space.
That seems incredibly fast, yes, but it is not. It is frustratingly slow when trying to communicate with other planets, even a nearby one, like Mars. And you can forget about worlds beyond our solar system because it would take so long to communicate that far that we’d be dead for thousands of years by the time a message is received.
The Animations And Their Creator
James O’Donoghue, a planetary scientist at NASA’s Goddard Space Flight Center, took it upon himself to depict the speed limit of the cosmos in a way that anyone could understand. He recently learned how to create animations and realized that he really enjoyed explaining difficult to grasp space concepts with them. O’Donoghue told Business Insider via Twitter:
“My animations were made to show as instantly as possible the whole context of what I’m trying to convey. When I revised for my exams, I used to draw complex concepts out by hand just to truly understand, so that’s what I’m doing here.”
How Fast Light Travels Relative To Earth
This video shows a photon skimming along the surface of Earth at its center (which is 24,901 miles around) if there was no atmosphere to slow it down. Air refracts and slows down light a little bit. In this scenario, the speed of light seems pretty fast being able to lap the equator almost 7.5 times in one second.
How Fast Light Travels Between Earth And The Moon
On average, there is about 238,855 miles (384,400 kilometers) of distance between our planet and the moon. At this distance, a photon of light takes about 2.5 seconds to do a round trip. The moonlight we are seeing at night is about 1.25 seconds old. Fascinatingly, this time is growing day by day as the moon drifts farther away from the Earth at a rate of about 1.5 inches (3.8 centimeters) per year.
How Fast Light Travels Between Earth And Mars
This animation illustrates the challenge that many planetary scientists deal with on a daily basis. For example, when NASA tries to talk to, or download data from, a spacecraft (such as the InSight probe on Mars). On average, that best-case-scenario distance is about 33.9 million miles (54.6 million kilometers) when the planets are at their nearest point to one another. This is an event, called the closest approach, that only happens roughly once every two years.
When the closest approach happens is when the fastest conversation is possible. Even then, it is much too slow to operate a spacecraft in “live mode” (as you would a remote-controlled car for example). At this shortest distance between Earth and Mars, it takes light 3 minutes 2 seconds to go from one planet to the next.
But on average, Mars is about 158 million miles from Earth — so the average round-trip communication normally takes about 28 minutes and 12 seconds. So, commands must be carefully thought out, prepackaged, and aimed at the precise location in space at the precise time so that they don’t miss their target.
The Farther You Go, The Slower The Speed Of Light Seems
It takes months for NASA to get data from the spacecraft such as New Horizon, which is now more than 4 billion miles from Earth. Likewise, for the Voyager 1 and 2 spacecraft, each of which have reached the space between stars. These spacecraft are at the farthest point humanity has ever seen. The images coming back are received months after they are taken.
Even farther yet is Proxima b which is the closest known exoplanet (outside our solar system). It is about 4.2 light years away, which is a distance of about 24.7 trillion miles or 39.7 trillion kilometers.
The fastest spacecraft to ever fly was NASA’s Parker Solar Probe. It reached a speed of about 213,200 mph. Yet, even at that speed it would take 13,211 years to reach Proxima b.
The farthest of all distances is the edge of space which is estimated to be about 45.34 billion light-years away in any direction and increasing (due to expansion). It is too big to fit on a screen of an animation. The closest anyone has gotten to illustrating the vastness of the universe is an image created by musician Pablo Carlos Budassi, which combines logarithmic maps of the universe from Princeton and images from NASA to capture it all in one picture. (see image above)