Monday, July 4

The Solar System in context: ten videos to understand the real speed of light and rotation of the planets

For many figures of distances and sizes of the stars that there are, Seeing the Solar System in real scale is still amazing. Used to the classic illustration of the Solar System, when we see a reproduction that respects the real distances and sizes of the planets, it is when we really realize how insignificant we are not in the Universe (this image tries to represent it), but simply in the Solar System.

Astronomer James O’Donoghue has in your YouTube channel a series of interesting representations of the Solar System and its members. These are representations based on actual measurements that allow us better contextualize how things work around the Sun. They are ideal videos to understand the size, although if we want it we can also hallucinate with the space for its beauty.

Eternal days on Venus, ephemeral days on Jupiter

The day lasts 24 hours, at least here on Earth, is what we have been taught since we were little. Although technically this is not entirely true, the day lasts 23 hours and 56 minutes on Earth. But it is that if we go to other planets or satellites of the Solar System, things vary even more. The rotation speed is different for each star in the Solar SystemVenus being the slowest of all and Jupiter the fastest planet to rotate on itself.

In one of the videos published by James O’Donoghue we can see the planets of the Solar System (along with Ceres and Pluto) turning on themselves and scale in size each. Two curiosities: the speed of Venus and the inclination of Uranus. Here the video:

We can also see this rotation on a two-dimensional map showing a strip of each planet. Each real hour corresponds to approximately one second of the video:

And if you want to see it in three dimensions this sphere combining the eight planets it also rotates each strip relative to each planet:

Sailing at the speed of light

Leaving aside the rotation of the planets a bit, it is time to see how fast light travels. We know that its speed is 300,000 kilometers per secondAlthough once again it is an approximation, the real speed is exactly 299,792,458 meters per second, it is the distance that a photon travels in vacuum during one second. Either way, they’re still just numbers, so let’s put them back into context.

This is how the transit of Venus conceived one of the most ambitious scientific projects in history

Starting with something “small”, let’s see how fast light turns the earth. If a plane were to go around the world around Ecuador at the speed of light, it could complete seven and a half laps in one second. Here is a video showing it:

To give the light a little more time, let’s see how long it takes to complete the distance between the Earth and the Moon. It separates us 384,400 kilometers, so if light travels at about 300,000 kilometers per second it will take a little more than a second to arrive. In other words, when we see the light we are actually seeing what it was like 1,255 seconds ago. In this video you can see the speed of light traveling from the Earth to the Moon and vice versa:

We also add Mars to the visualization. If the Moon seemed to you that it was far away, wait to add Mars, which is 54.6 million kilometers away (that is when its orbit is at its closest point to us). A ray of light takes a little over three minutes to get to Mars from Earth:

If we look “the other way” and want to see what separates us from the sun (and what is in between) the distance is even greater. The distance between us and our star is almost 150 million kilometers (149.6 million kilometers, also known as 1 Astronomical Unit). To travel this distance, light needs 8 minutes and 17 seconds, which is how long it takes for the sun’s rays to reach us. Again, it means that if we look at the Sun we see what it was like 8 minutes ago. The video with Mercury and Venus in between:

And now the mother of all representations, the entire Solar System, from the Sun to Pluto. To make this trip, the light has to take almost five and a half hours, it leaves from the Sun and reaches Pluto in 5 hours and 28 minutes traveling at 300,000 kilometers per hour (it has taken us decades to cross the Solar System with the probes Voyager). Here is a video of exactly 5 hours and 28 minutes at real speed of light:

Imagine that you travel at the speed of light, how would you see the planets go by? Actually, the human being by relativity would feel this step as an instant, although if we put a camera to record this trip, these would be the views when approaching each planet:

How high could a human being jump on each planet (and other stars) in the Solar System

Before finishing, another most interesting video: the escape velocity of all planets in the Solar System. What is escape velocity? It is the speed with which an object needs to move to move away indefinitely from a more massive body or system to which only gravity binds it. Come on, the speed at which you have to go to escape gravity.

As an extra ball, a last video showing once again the real speed of light. This time we see how it is distancing itself from the Sun passing through the orbits of the different planets and stars. At all times the distance traveled, the time it has taken and what is left until the next celestial object appears. The video ends on Jupiter, so it is approximately 45 minutes long. Enjoy the trip:

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