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Traveling at the speed of light through the solar system can be extremely slow, and these animations prove it

When we hear about “speed of light” The idea of ​​speed usually comes to mind, and that is that today the speed of light is the fastest that any material object can travel through space. Sure, this without considering theories, like wormholes and other things.

In ideal conditions, within a perfect vacuum, a particle of light (photon) can travel at about 299,792 kilometers per second. This is extremely fast if we compare it to what we have within our reach, such as a car or an airplane, but when we transfer this to space, on a planetary scale, it is no longer as fast as we imagine it.

James O’Donoghue, a planetary scientist who worked at NASA’s Goddard Space Flight Center and is currently at JAXA, set about creating a few incredible animations where you compare how the speed of light is at different scales and in different contexts. It is a wonderful work that shows us that the speed of light can also be slow, depending on where you look at it.

O’Donoghue created some videos where he shows in real time different scenarios of a photon traveling at the speed of light, which we see both on its YouTube channel and on its website, where we also see that there are two especially didactic sections that are the ones that have caught our attention: the image gallery and the animations. We show you how graphically it manages to make us understand this of “the slowness of traveling at the speed of light”.

The speed of light on Earth

If our planet had no atmosphere, a photon could travel near the surface, above the Equator, at almost 7.5 times per second. That is, 0.13 seconds per orbit.

The speed at which light travels between the Earth and the Moon

About 384,400 kilometers of distance there are between our planet and the Moon, this means that all the light of the Moon that we see is 1,255 seconds old. And a round trip between the Earth and the Moon at the speed of light would take approximately 2.51 seconds.

The speed at which light travels between Earth and Mars

In this third video we take a great leap back to see how a photon would travel between Earth and Mars. O’Donoghue explains that for this animation both planets and the Moon are 20 times bigger, this in order to make them visible on the screen.

When Earth and Mars are closest to each other, an event that occurs every two years or so, there is a distance of 54.6 million kilometers. Here the photon would take three minutes and two seconds to travel between Earth and Mars, that is, six minutes and four seconds for a round trip at the speed of light.

If we do not consider the closest point between the two planets, Mars is on average about 158 ​​million kilometers from Earth, so a round trip would take about 28 minutes and 12 seconds.

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The speed at which light travels between the Sun and Earth

Now let’s go further. According to O’Donoghue, in this video the Sun is twice as big and the planets 50 times, again the goal is for them to appear on the screen.

For this animation we have for the first time an astronomical unit (AU), which is equivalent to the average distance between the Earth and the Sun, that is, approximately 149.6 million kilometers. In the video they show us, in real time, that a photon would take 8 minutes and 17 seconds to travel at the speed of light from the surface of the Sun to the surface of the Earth.

It is also used to show us the time it would take the same photon to reach Mercury and Venus on their same journey at the speed of light.

The speed at which light travels between the Sun and Pluto

Now imagine that the photon must travel all over our Solar System, from the surface of the Sun to the surface of Pluto. That is, an approximate distance of 39.5 astronomical units (AU), remembering that an AU is equivalent to 149.6 million kilometers. In this case, we are talking about a trip that at the speed of light would represent 5 hours and 28 minutes.

In the video, which is also in real time, we can see the estimated time and distance that our already known photon would make if he happened to visit the rest of the planets of the system.

Many more videos to understand more aspects of the universe

In addition to these videos concerning the speed of light and Relativity, we also echoed your channel in terms of understanding the rotation of the planets and their relative position. Thus, we see a simple explanation for the (apparent) retrograde motion of Mars that the ancient Greeks would have liked to have already.

Cover Image | Spacex