The speed of light is the limit with whichmove a material object in space, unless, of course, taking into account the hypothetical mole holes, with which, according to the assumptions, objects can move in space even faster. In an ideal vacuum, a particle of light, a photon, can move at a speed of 299,792 kilometers per second, or approximately 1.079 billion kilometers per hour. At first glance it may seem surprisingly fast. No, it's really fast. But on the scale of space, such a speed can be painfully slow, especially when it comes to radio communications and flights to other planets, in particular, those outside our solar system.
In order to make it easier for anyone to understand the limited speed capabilities of light, NASA Goddard Space Center planetary scientist James O’Donoghue has created a series of animated videos.
"I made these animations with an eye on howYou can more clearly and quickly explain the whole context of what I wanted to reflect in them. When I was still studying, I had to manually draw complex concepts in order to understand for myself what was at all in question, ”O’Donoghue admits.
In a conversation with Business Insider O’Donoghuesaid that only recently learned how to make these animations. His first job for NASA was to prepare a video about the rings of Saturn. After that, he began to animate other difficult to understand cosmic concepts, for example, a visual comparison of the size and speed of rotation of the planets of the solar system. According to him, this work, published on his personal Twitter page, attracted great interest.
His latest work is an attempt to visually demonstrate how fast and slow photons can be at the same time.
Visual demonstration of the movement of photons around the Earth
In the first animated video, O'Donoghue showed how quickly light can move relative to the Earth.
The length of the equator of our planet is approximately40 thousand kilometers. If it did not have an atmosphere (the particles that it contains can slow down the light a little), then the photon moving along its surface would make almost 7.5 full turns in 1 second (or 0.13 seconds per revolution).
Despite the fact that in such a scenario, the speed of light seems incredibly fast, the video also demonstrates that it is finite.
How fast the light travels the distance between the Earth and the Moon.
In the second video, O'Donoghue covers a greater distance from the Earth to the Moon.
On average, the distance between our planet and itsnatural satellite is 384,000 kilometers. This means that the moonlight observed in the sky overcomes this distance in 1.255 seconds, and the way there and back, for example, when transmitting radio messages between the Earth and spacecraft, will take 2.51 seconds.
It should be noted that every day this timeincreases as the Moon moves about 3.8 centimeters away from Earth every year (the Moon constantly depletes the energy of the Earth’s rotation through gravitational-tidal interaction. The effect of this effect is a change in the satellite orbit).
How fast light travels the distance between Earth and Mars.
In the third video, O’Donoghue demonstrated a problem that many planetologists face daily.
When NASA Aerospace Agency EmployeesIf you try to download and receive data from a spacecraft, for example, the same InSight probe, which is currently operating on Mars, then the transmission of messages occurs at the speed of light. However, it is not enough to control the device in "real time". Therefore, the teams must be carefully thought out, compressed as much as possible and sent to the exact time and place, so as not to miss the target.
The fastest messaging between the Earth andMars is possible at the moment when the planets are at the point of closest approach. However, this happens only about once every two years. In addition, even in this case we are separated by a distance of about 54.6 million kilometers. O'Donoghue’s clip shows that at such a distance, light takes 3 minutes and 2 seconds to get from one planet to another, or 6 minutes on both sides.
On average, Earth and Mars share a distance of 254 million kilometers, so on average, two-way messaging takes about 28 minutes and 12 seconds.
The farther the distance, the more depressing is the "efficiency" of the speed of light.
Breakthrough Starshot space nanosonde illustration accelerated by a very powerful laser beam and directed to the Alpha Centauri star system
The speed limit of light creates even more problems.for spacecraft further away from Earth. For example, the same probe "New Horizons", which is now located at 6.64 billion kilometers from us, or "Voyager-1" and "Voyager-2", which reached the boundary of the solar system.
Very sad situation becomes, if speechis about sending a message to another star system. For example, the nearest exoplanet known to us, Proxima b, is about 4.2 light years from us (about 39.7 trillion kilometers). Even if we take the fastest spacecraft at the moment, the Parker Solar Probe, capable of reaching speeds of 343,000 kilometers per hour, even it will need about 13,211 years only to fly to Proxima b.
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