How did the scientist calculate that the earth takes 365 days to revolve around the sun?

Answer 1

As Earth revolves around the Sun, it rotates, or spins, on its axis, an imaginary line that runs between the North and South poles. The period of one complete rotation is defined as a day and takes 23 hr 56 min 4.1 sec. The period of one revolution around the Sun is defined as a year, or 365.2422 solar days, or 365 days 5 hr 48 min 46 sec.

Answer 2

There are two questions here.

People have known for a very long time that the length of a year was 365 days. It doesn't take a scientist to know this. Careful observation of the sun e.g. when it rises, when it reaches the highest point in the sky, can tell you that the earth takes about 365 days to get back the the same point. Ancient stone observatories such as Stonehenge, built over 5000 years ago, seem to be designed to pinpoint the summer solstice (June 21). People knew it was 365 days from one solstice to the next.

The question of WHY the year is 365 days long was controversial for many centuries. The idea that the earth orbits the sun was held by some Greek philosophers, most notably Pythagoras, but it was not until the 17th century and the calculations of Copernicus and the observations and writings of Galileo that people started to accept that the earth orbited the sun and not vice versa. The idea was considered heresy by the Catholic Church.

Answer 3

Why are so many answers talking about the sun's position in the stars? That is the "sidereal" year, and that is not how the year was figured. The year was calculated by observing how far north and south the sun rose. In the autumn (northern hemisphere) every day the sun would rise further south and the days would be shorter. Until at last a day would come, early in winter, when the sunrise would turn around and start back north again. This was the winter solstice, and an excuse for a party. Most cultures have held a recognition of rebirth, involving holidays, festivals, gatherings, rituals or other celebrations around that time. The days would grow longer and people could look forward to spring. Now even in ancient times, many people could count up to 366. And some would count the days from one winter solstice to the next. Most often this was 365 days, sometimes 366. After many generations of counting, it became clear that the average was 365.2422 days. The idea of dividing the circle into 360 parts ("degrees") came _afterwards_. [Note: the sidereal year, as measured by the stars, is longer by about 1 day in 71 years. This would become obvious if a culture could keep track for several 100 years.]

Answer 4

If you place a pole in the ground and watch its shadow progress across the ground you can map the passage og the sun through the sky. If you do this two days in a row you will find that the path is not the same each day. If you use another stick to make a mark for each day that the sun does not come back to the same point then you will make 365 marks before it does. You can use your fingers but you'd better get some friends involved. That's the exact method that was used. There are sights around the globe where these observations are recorded by very primitive cultures. We can now tell the day that the records were made based on the slight variations in the path from today. Niffty huh?
Even early societies had individuals who were separated from the daily toil for survival and had time to persue more lofty ideas. These were usually "religious" figures but they accomplished the earliest scientific work. Science was not separated from religion for some time.

Answer 5

Thousands of years ago there was no TV. Ancient man had a lot of time to gaze up at the stars and be really bored. So they payed very careful attention to the position of the stars in the sky and how long it took for them to return to their original position. This is why a great deal of ancient architecture is lined up with specific events of the sun and stars. It was really the only entertainment they had. Not really a lot of science, just careful marking and counting, but often enough that is what scientists do so you can call them that if you want.

Answer 6

The earliest astronomers used the position of the sun in the sky, as marked by the length and angles of shadows. Elaborate structures were constructed to mark the sun's position on certain key days (such as the first day of spring to mark the beginning of planting season, etc). One such structure is Stonehenge in England.

In modern times, observations of the position of the stars have given us a much more accurate measurement of the orbital period of the earth.

Answer 7

By observing with extreme precision the position of the background stars over time as seen from a single specific position on earth.

Answer 8

He counted the days by making scratch marks on a rock. Several thousand years later, the decimal numbering system was invented and converted the scratch marks to a numeral.

Answer 9

The position of the sun in the sky, knowing the earth's axis is at 23.5 degrees.

Answer 10

the sun's position moves slightly day to day; their 'astronomers' saw that it took 365 days for the sun to be at it's northern-most position back to that same position.