Eratosthenes' Measurement of the Earth
The Greek astronomer Eratosthenes was born in Cyrene. After studying in Alexandria and Athens, he was appointed to be the librarian of the Great Library of Alexandria, which at the time was the center of science and learning in Egypt. This gave him access to many books and studies, and it gave him an understanding of many different topics. As a result, he made several contributions to the world of mathematics and science, such as the armillary sphere, and more importantly, the measurement of the circumference of the earth.
A good example of all the traits mentioned in the previous section, Eratosthenes' keen mind and observational skills helped him discover how he could calculate the circumference of the earth. Eratosthenes knew that during the summer solstice in Egypt, the sun shown directly into a well in Cyrene. At that same time, he knew that the angle of the sun on Alexandria would be 1/50 of a full circle. Knowing these two facts, and knowing the distance between the well and Alexandria, he was able to calculate the circumference of the earth using the angle.
In modern times, technology has been able to calculate the real circumference of the earth, and it turns out that Eratosthenes' measurements were just off by 1%. This means he still got it right considering certain factors, and it is amazing that he did so. Had he not noticed that the sun shown directly into that well and how it angled Alexandria, he may not have been able to make a great contribution to astronomy and to science. Eratosthenes' measurement of the circumference of the earth was used for many years till it was proven that he made a small mistake, some say it was due to the fact that he did not know that the earth was not a perfect circle.
Biology
The fact that living things exist on the planet is a miracle. Everything on earth had to be just right. The materials found on earth had to all be complete and had to be complete at the exact time that the climate became warm enough to begin supporting life. These perfect conditions are considered to be one in a million, which is what makes earth so unique. So far, ours is the only planet in the universe that we know can and does support life.
Because of this perfect mix, life on earth flourished. When humans began studying life and living things, biology was born. Like astronomy, biology has come a long way as a science. It has a rich history ofmany mistakes. Life on earth is one of the hardest things to understand because each organism or living thing is different. This is one of the reasons why biology did not gain much ground until some forms of technology were invented, such as the microscope. However, since it gained momentum, biology has evolved with great speed, and now it has become a truly interesting study with many new discoveries being made and being understood all the time.
In modern times, it has come to the point that we owe biology our lives. Because of our understanding of living things and how they work, we now know how to cure ourselves from disease, how to aid dying organisms or how to protect certain species, and how to balance a certain habitat or ecosystem. It has also given us the knowledge of how to use our bodies to its full potential and how our bodies work. Many of the objects that help us now, we owe to the study of biology.
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