Knowledge COOL | COOL to create a "astronomical ruler"

Daily distance: "scale" of astronomical ruler

In the early days, humans observe the position of Venus and the sun in the sky, and calculate the ratio of the radius of the Earth's orbital to the Direct Ride of the Venus Rotation. With this proportion, you can measure the distance between the day and ground by observing the "Venus Ling Ri".

The so -called Venus Ling Day is a straight line on the earth, Venus, and the sun. On the surface, we can see that there is a small black dot moving slowly on the surface.

Harley calls the astronomers all over the world to different places, and at the same time observe the Venus Singer to estimate the distance. Based on the observation results of the observation results of astronomers, the distance between the earth and the sun was about 152 million kilometers (about 60,000ths of light years).

The first generation of astronomical ruler: triangle vision method

We can use the "triangular dialogue method" to calculate your distance from a certain star through the "triangular dialogue method".

What is the "triangle vision method"? We can try to quickly look turns to look at a close -range object, because the observation of different sights, we will find that it jumps left and right in our sight!

Looking at the stars in the same way, because the distance is too far, the differences observed by different eyes are too small to ignore, so it seems that the stars can't move.

All in all, we can judge the distance between objects and us by judging the amplitude of objects. This is the triangle vision (triangle is observed objects and two observation points).

The triangle vision method can help us judge the distance between the stars and us, but the distance between the two observation points needs to be widen -such as the Earth's turn. At this moment, a star is observed, which is equivalent to narrowing his right eyes to see the stars; after half a year, the same star is observed, which is equivalent to narrowing the left eye to see the stars.

We know the distance between the earth, and through mathematical methods, we can calculate the distance between the earth and the star.

Second -generation astronomical ruler: Father turning the star

There are so many stars in the sky and dazzling. Which star should we observe? Don't worry, there is a kind of star that is suddenly dark- "making a father into a star", which can help us.

Father's stars are aging stars. The body will continue to become larger and smaller, and the brightness will become brighter and darker. The longer the bright and dark change cycle, the greater the absolute brightness. The brightness and distance also become a square inverse relationship, which can directly calculate the distance through the brightness.

Then, we can calculate the distance of a specific parent -making star through the "Triangle Dialogue", and use this parent -making star as a scale to compare the distance between it and other stars to calculate the distance of more planets.

The latest astronomical ruler is really dazzling!

In addition to creating a father -to -star, astronomers also came up with many methods to measure the distance between celestial bodies, such as IA supernovas. These methods complement each other's advantages, providing accurate and effective measurement for the astronomical distance at each scale.

PC: Second gap, 1PC is about 3.261 light years

Through various measurements, the size of the observable universe calculated by scientists is 93,000,000,000,000 light years. Compared with the distance that can surround the earth, which can be surrounded by more than 3,000 laps, it is simply a drop in the sea. Our world is far wider than imagined. Looking forward to the starry sky, our lives will be wider.

(This content is published in the 425th issue of "Pearl River Youth" magazine)

Author | Deng Haowen

Picture | Yuan Yongshan

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