The time of light from the sun to the earth. How long does light take to reach the earth

If you know the speed at which light “flies” and the distance from the Sun to the Earth, then it will not be difficult to calculate the time it takes for it to cover such a distance.

We know the speed of light from school course physics- approximately 300,000 km / s, and more precisely - then 299792458 m / s. But the approximate value for most calculations is sufficient.

The distance from the Sun to the Earth is also known, but already from the school astronomy course - about 150 million kilometers. This distance, by the way, is taken as a standard measure of length and is called an astronomical unit. Of course, on a cosmic scale this is a very small value, but within solar system quite useful.

So, we divide the distance by the speed, and we get the time of the "flight" of light from the Sun to the Earth - 8 minutes and 19 seconds. Everything - everything! Light travels 150 million kilometers in a matter of minutes! But that's because the distance is not too big...

How long does it take light to reach Earth from other objects?

This is also very interest Ask. In astronomy, even another unit for measuring distances has been introduced - the light year. This is the distance that light travels in vacuum - outer space, in a standard year. This distance is calculated and equals 9,460,730,472,580,800 meters, or more than 63 thousand astronomical units. Of course, there are other units - light second, light minute, light hour and others - the distance that a light beam travels in a corresponding period of time. Even the light age can be calculated...

So, it takes about 1.2 seconds for light to travel from the Moon to the Earth. By the way, radio waves also propagate at the speed of light, so you can imagine the difficulties in controlling the Lunokhod when the signal arrives and leaves with a delay. It is even more difficult to control more distant interplanetary vehicles - there delays are minutes, or even hours.

From the Sun to Pluto, light reaches in 5 hours, but there is not at all the edge of the solar system. Further there is also the so-called Oort cloud of many asteroids and other debris. The light "flies" to the outer edge of this cloud for a whole year and a half. But the limits gravitational influence The sun is even wider - as much as one and a half light years. This is simply an unthinkable distance that people will overcome very soon.

By the way, the nearest star to us - Proxima Centauri, is at a distance of more than 4 light years, and although it is somewhat smaller than our Sun, it is included in a multiple system of several stars, and their total weight quite solid. This means that their gravitational influence also extends for at least 2 light years, that is, our Sun and “their Suns” interact, practically “hold hands”. Here's to you direct influence stars...

In general, the fact that light does not propagate instantly creates interesting phenomena. For example, the well-known polar Star is more than 400 light-years away from us. We see the light she gave off in the time of Columbus! And it's still pretty close...

These huge distances are practically a trifle compared to galactic scales. For example, light travels from the center of our galaxy to us for about 30,000 years. And from the nearest "neighbor" - the giant Andromeda galaxy M31 - 2.5 million years. And this is from the "neighbor"!

The most gigantic formation in the universe - Great Wall Sloan, is a "wall" of galaxies, a huge cluster of them. This object stretches 1.37 billion light years in length, and is a billion light years away from us, that is, the light from it takes a billion years to reach us!

And, finally, from the edge of the Universe, light “flies” to us for more than 13 billion years. And then there is nothing ... Or maybe there is, but we, apparently, will never know ...

How long does it take for sunlight to reach Earth? It's obvious that sunlight propagates at the speed of light. Photons emitted from the surface of the Sun take some time to travel through the vacuum of space and reach our eyes. On average, sunlight travels from the Sun to Earth in 8 minutes and 20 seconds. If the Sun suddenly disappeared from our universe, then you would have a little more than 8 minutes before you noticed something was wrong.

How do you get those 8 minutes 20 seconds? We revolve around the Sun at a distance of about 150 million kilometers. Light travels at a speed of 300,000 kilometers per second. Dividing one by the other, we get 500 seconds, or 8 minutes and 20 seconds. The resulting time is an average as the Earth moves in an elliptical orbit around the Sun. The shortest distance is 147 million kilometers and the longest is 152 million kilometers. At the nearest point, light takes 490 seconds to reach the Earth, while at the most distant point, light takes 507 seconds.

Things get much more interesting when we consider the journey of photons inside the Sun. You probably know that photons are produced as a result of thermonuclear reactions inside the Sun's core. These photons are emitted and absorbed in the radiative zone of the star countless times before they finally reach the surface. Ultimately, the photons that hit your eyes were actually created tens of thousands of years ago. So the journey to the Earth, which takes just over 8 minutes, is only a moment in the life of a photon.

From all this, it becomes clear that looking into space you are looking into the past. The light from our nearest star, Alpha Centauri, takes about 4 years to reach us, so when we look at this star, we actually see what it looked like 4 years ago. But there are galaxies that are millions of light years away from us. If suddenly in one of these galaxies there is a civilization with highly developed technologies, then they can even observe dinosaurs roaming the surface of our planet.

quoted1 > > > How long does sunlight get to Earth?

speed of light- what time is sunny the light is coming from the Sun to the Earth: a description of the Earth's orbit in the photo, the distance and place of the third planet in the solar system.

It seems strange, because everyone thinks that the Sun just shines and everything happens as if instantly. Sun rays moving towards us at the speed of light and moving in a vacuum environment. In short, the whole journey takes 8 minutes and 20 seconds. Yes, the irony is that if our star suddenly disappears somewhere, then it will reach us only after 8 minutes.

Understanding the speed of light is important in astronomy, so let's turn to mathematics. The distance from the Earth to the Sun is 150 million km, and the speed of light is 300,000 km/s. We divide and get the specified time. But this is an average.

Let's also remember that our planet rotates in an elliptical orbital path and the distance changes by 147-152 million km. Then, at maximum approach, the speed will be 490 seconds, and at a distance - 507 seconds. But further is even more interesting.

A fusion takes place inside the solar core, which leads to the formation of photons. It all starts in the form of gamma rays, which are absorbed many times by a star, travel inside it, and only then break through to the surface. But the most amazing thing is that the actual light that reaches you was created tens of thousands of years ago! He managed to escape and in 8 minutes finally get to you.

Yes, when you look into space, you literally see traces of the past everywhere. Reflected moonlight moves towards us for a second. But Alpha Centauri takes more than 4 years. Now think about the stars in other galaxies that take millions of years just to see their beautiful glow.

Let's look from the other side. If there are intelligent aliens who are now considering our planet, then they will see only dinosaurs. This is why the speed of light is important to scientists and cosmologists.