In an episode of the TV series Mobile Phone , how did the light of the flashlight stay in the sky?

In the TV series "Mobile Phone", there is a scene about the protagonist Yan Shouyi writing in the sky with a flashlight when he was a child, presumably everyone has played such a scene when they were children, and today, with the rapid development of photography technology, you can already create a highly imaginative photographic work with a camera and flashlight, which is "light graffiti".

"Light graffiti" is a photographic method that uses a camera to create a special effect on a moving light source for a long time in a dark environment. The pioneers were Michael Bosanko, a photographer from Wales, England, who used only a flashlight and a camera to create dazzling and bizarre graffiti photographs through light.

Light graffiti" trick.

Light graffiti, also commonly known as light painting, is a photographic technique that creates a photographic effect by rapidly moving a light source or camera to generate light and shadow trajectories at night or in a dark space. The following points are available for your reference when shooting:

1.Have a DSLR or other normal digital camera that supports bulb and long shutter speeds ready.

2.Be sure to have a tripod.

3.Prepare the lumines. Any glowing object like a flashlight, glow stick, lighter, or even a cell phone will do.

4.Press the shutter and another person scribbles in front of the camera with a luminous object in hand, and the time is controlled within 30 seconds. If you have a model, hold the same position for 30 seconds.

5.The light should ensure that it can enter the lens when painting, and the retention time of the light source and the angle of the lens can be controlled.

6.If you want to photograph a human figure, you can let a real person play the role of a model, pose and trace the outline along the path.

7.The words "light graffiti" appear to be written in reverse, similar to woodblock carving.

8.If it is a normal digital camera, it is best to set the **time to more than 6 seconds.

9.Shooting must be done in a sufficiently dark place.

At night, if we shine a flashlight at the sky, we can see a beam of light flying into the distance. If the flashlight is turned on for only one second and then turned off, then, what about the light gone? Is the light gone, or does it continue to spread?

In fact, the light emitted by the flashlight does not disappear, but continues to move at the speed of light of nearly 300,000 kilometers per second. Just because we can't see doesn't mean we don't exist, and the light that travels in the direction of the universe doesn't enter our eyes anymore, so we can't see it.

The photons produced by the flashlight can pass through the Earth's atmosphere and enter the universe. The universe is very empty, and these photons can continue to travel freely in space until they encounter other objects and are absorbed. If photons are not absorbed, they will never disappear in the universe.

Since light advances a distance of 1 light-year over the course of 1 year, the radius of the solar system is 1 light-year, so it only takes 1 year for these photons to fly out of the solar system. Tens of thousands of years later, photons will fly out of the Milky Way. Over a long period of time, the photons will travel to more distant and vast intergalactic space, reaching other distant extragalactic galaxies.

Unless these photons enter the black hole and cannot escape in the extremely curved space of the black hole, no celestial body's gravitational pull can bind the photons.

Light is an electromagnetic wave, which is essentially an electromagnetic field that is transformed interactively. Light propagating in a vacuum does not require energy to sustain it, they will always maintain the speed of light because the photons have no resting mass and do not interact with the Higgs field, so the speed does not drop off from the speed of light.

Because of this, we can receive photons from 13.8 billion years ago on Earth - cosmic microwave background radiation, which are the first photons in the universe that can travel freely, and were produced 380,000 years after the universe was large. It's just that these photons can't be seen with the naked eye, because the structure of space is constantly expanding, causing the wavelengths of photons to travel through space to become longer and longer, and now they have become microwaves that can only be detected by radio telescopes. These photons will not disappear from the universe entirely, but will become longer and lower in energy as the universe continues to expand.

On the other hand, when the light of the flashlight hits the sky, we can see a bright pillar of light. This is because when light travels through the air, it is scattered in all directions by dust floating in the atmosphere. Some of this light is scattered to the ground, and when it enters our eyes, we can see the pillars of light.

There are also some rays of light that will continue to travel towards the universe and never return.

If astronauts turn on their flashlights in space, they will not see the pillar of light. Because space is almost a vacuum, photons travel in a straight line and are not scattered into the astronaut's eyes. Therefore, as long as an astronaut in space or on the moon looks in a direction where he cannot see the sun, he does not need to be completely facing away from the sun, and he will see a sky full of stars, and those stars will not be drowned in the sun's light.

When the flashlight shines into the sky, will the light disappear or will it continue to fly? Scientist: Heading into space.

Yes. Because light also has a lifespan, light waves will disappear when they encounter resistance in the air and cannot penetrate the air.

The light emitted by the flashlight against the sky does not go away. We seem to disappear only because the flashlight is less concentrating and the light is weak. Because if the light does not encounter an obstacle, then it will continue to travel.

The light has not gone away, but we can't see it because the energy is so weak. The light doesn't just disappear for no reason.