Exactly how long is a day

In addition, larger tidal bulges from more water mass result in more Earth-slowing friction. Just ask me. I think one of many examples is necessary here. The Three Gorges dam in China took 9 years to complete and fill with 40 cubic kilometers of water. All of the glaciers in Switzerland have in total about 60 cubic kilometers of ice. During the same nine years, the Swiss glaciers lost 9 cubic kilometers of ice. The water from all of the Swiss glaciers that went into the oceans, evaporated, rained, and was trapped behind the 3 Gorges dam was not enough.

There were another 31 cubic kilometers necessary, that had to come from other glaciers and oceans. This shows how difficult this problem is. The water that came from the Swiss glaciers sped up the earths rotation, but the water that evaporated from the South China Sea and was trapped behind the Three Gorges dam slowed down the earths rotation. Yes, Sweden and the rest of Scandinavia are rising because the pressure of the ice from the last ice age has been removed, and this would cause a slight rise in sea level Some parts of the ocean become deeper because of the geological shift , but the next project of the Chinese on the Yangtze River is almost twice the size of the 3 Gorges, for two reasons.

First, the 3 Gorges dam does not help reduce flooding on the Yangtze river to the extent hoped. Second, the 3 Gorges dam provides only about 1. Another example, if you are a Vietnam war era veteran, look at a current picture of the Mekong river. The water levels are way down because of a different Chinese dam project. When taking all of these hydroelectric projects world wide together, I come to the conclusion, that the rise of the land mass of Scandinavia, and the melting of glaciers, while significant, can not be used without considering the hydroelectric projects, to determine the rate of the earths rotation, and most computer models do not properly factor in the amount of hydro power generated electricity needed in the future, and its effects.

I mean no disrespect, however this is exactly backwards per the figure-skating example we each keep citing. And just as more dams are planned for China, in other places the lack of flooding and free water flow is causing issues for both human agriculture and the environment. This has led to a number of dams having to significantly scale back power production while the flows are being increased or decreased to match seasonal needs downstream, and in some cases it has led to them being removed altogether.

You are correct in this, though: the whole problem is particularly complex. Whatever the net effect of glacial melt or hydroelectric projects, the issue is not very easy to model, and in the end is mainly a lot to do about nothing terribly significant.

Skip to content. Their dots would be so close to 0 it would be hard to tell the difference between them. Graphs work best when the numbers are similar in size, usually with the same number of digits. Now that you know how to make a graph, you can show all kinds of information this way. You can graph the time it takes to get to school each day, the number of pieces of pizza your friends can eat, and how many people like the color blue or green. Go on and get graphing!

The Short Answer:. The longest day among those planets is 25 hours. That means our number line will go up to Along the bottom, write the names of the planets.

Make a dot above the name of the planet next to the number of hours its day takes. Our graph is coming together! What do we do now? Color in the area below the dot to make a bar graph. More about the Earth! Learn all about Earth!

Learn about Earth's atmosphere! Day Length On Earth, a solar day is around 24 hours. This is called a sidereal day. On Earth, a sidereal day is almost exactly 23 hours and 56 minutes. The Earth rotates about its axis exactly once, or degrees, in about 23 hours and 56 minutes.

The hour day we all know and love is called a solar day. This is why our day is longer than 23 hours and 56 minutes, which is the time required to spin a full degrees. A day is approximately the period during which the Earth completes one rotation around its axis, which takes around 24 hours.