If Earth were to rotate only 100 times per year?

fewer days between birthdays... but longer days at that.

Eventually Earth's rotation rate will slow down that much, and it will continue slowing down, because of the moon getting farther away from the Earth. Eventually the Earth will be tidally locked to the moon as the moon is currently tidally locked to the Earth. All this assumes that the year will be the same length as it is now. There is a fundamental problem here. We define time by Earth's rotation around its axis and the Earth's revolution around the sun. How do you measure time and what is your reference point for measuring time when the rotation rate changes constantly, and the revolution rate around the sun will change when the sun's mass changes significantly?

We'll have either evolved as the Earth evolves, or have humans or what humans have evolved into living on other planets by then, or we will eventually succeed in destroying ourselves.

Wow, that paranoia echo effect from the 1950's and 1960's is getting awfully loud.

The longer days will heat up one side of the planet for longer periods of time, resulting in higher temperatures and a more arid climate. The nights would be longer, resulting in a large temperature differential which would result in most animals unable to survive the changes in temperature.

The weather patterns would change completely. Larger, more pwerful areas of high pressure due to the heating, resulting in less precipitation globally (inability to form "fronts" where clouds would normally precipitate).

The end result would probably be the loss of most plant life, then animal and human life. Some species of plants/animals would be able to adapt, changing the ecosystem of the planet completely.

Each day would be about 90 hours long...

give or take.

There would only be about 8 days or so

in a month.

And about 96 days in a year.

Approximated in my head.

The days would be longer?

Nights would get colder, days hotter.

Life would be RADICALLY different. We probably wouldn't even look like a recognizable human.

id be much younger. :)