What If The Earth Spun The Other Way

Other than the sun rising in the west and setting in the east, would it make any difference which way the Earth spins.

For the sake of the question let’s just say from the time the earth was created it spun the opposite. Because obviously if the Earth stopped and then went the other way, of course everything on earth would be thrown about and destroyed.

And also could something in theory change the way the Earth spins? Like if an asteroid hit it, could it cause the Earth to rotate the other way

I’ve read that the reason the Earth’s equator doesn’t line up with the ecliptic is due to an impact. Sorry, too lazy to cite.

It would make a huge difference in weather patterns, with prevailing winds coming from the opposite direction. Temperature, rainfall, and local climate would be affected. Also, it would affect the erosion of coastal areas, in ways I’m not qualified to say. There’d probably be ome effect from the Earth’s rotation and the Moon’s orbit being opposite, instead of in the same direction (which, come to think of it, would affect the length of the Earth’s day, which has been getting shorter do to interaction between the Earth and the Moon.)

You mean longer.

It could. It would have to be a VERY big asteroid which would cause a VERY big collision. No chance of you surviving; it would be FAR worse than the one thought to have decimated the dinosaurs. And that’s an understatement.

It was once thought that something like that caused the asteroid belt between Mars & Jupiter, although the more modern theory is that a planet in that orbit never came together in the first place. In any case, it would be one hell of an impact and the Earth would never be the same, if it survived at all. Most likely it would shatter into many pieces going off in different directions, each with their own fate.

One of those. :slight_smile:

Would it matter in terms of physics or developemental evolution.

What I mean is let’s say that the Earth was spinning the other way and THEN first life forms came. Would it be somewhat safe to say life would have developed pretty much the same way.

I would discount things such as, like the asteroid that hit the Earth and helped kill off the dinosaurs would’ve hit somewhere else so the result would be someone different.

You have the power within yourself to make the Earth spin the other way. Face due south and then pretend it’s due north. Voilà! The sun now rises in the West and sets in the East, and nobody got hurt.

The great ocean gyres would rotate the other direction. As a result, the upwelling areas off California and Peru wouldn’t be there for instance, and equatorial upwelling would occur on the east coast of continents. The Gulf stream would head the other direction also. I used to give this question as an exercise to my oceanography students.

Also, as mentioned above, weather patterns would probably move from east to west.

If you mean would there be humans or even mammals, then no. There’s too much randomness in evolution to expect the same life to evolve. There’d probably be animals and plants, because those are such basic forms. There would probably be trees, just because it’s such a useful form. But they wouldn’t be the ones we see. Similarly, there’d probably be flying animals, maybe even with feathers, but they wouldn’t be birds as we know them.

Life might still have came up with DNA, just because it’s so useful, but maybe the coding system from the DNA to the amino acids would be different. Even the particular nucleotides used might be different. I don’t know if there’s some non-DNA way of doing the same thing as DNA that might have occurred instead.

None of that is due to the Earth spinning the other way, per se. Even lesser differences before life formed would change everything by now.

Extending what ZenBeam said, at a gross level there is no reason to expect an opposite spin in and of itself be either more or less hospitale to life. But re-running the biosphere’s evolutionary movie, so to speak, would produce a completely plot line & outcome.
But … biological evolution is not the only thing which would take a different random course through the random space of possibility.

The earth’s climate over the years has, at times, been very hostile to life. Massive ice ages, extreme heat, massive changes in the abundance of gasses in the atmostphere (Great Oxidation Event - Wikipedia).

Some of that is driven by the shape of the continents versus the oceans, which is continuously changing even today according to more-or-less random factors.

As an example of a change, consider that the current continents have a bunch of dry land along the equator and at the mid latitudes. Imagine that instead all the dry land was concentrated in two polar caps with a continuous equatorial ocean. Now wait for an ice age which covers 100% of the dry land with ice to a depth of several miles. Leave it that way for 100,000 years. Then slowly melt off the ice. Result: very different situation for life on Earth.

The reverse spin didn’t necessairly cause that in the strict sense of causation, but it is a perfectly reasonable outcome from re-running the geological history of the planet. As are hundreds of other distinct scenarios. What if instead of large continents we had about 57 million more or less 1 mile-square islands? That’s the same land area as now, just distributed very differently.


I refuse to say I live in the Great White South.

No thread on this topic would be complete without a little light entertainment in this form.

Fixed Mangetout’s link.

North and South would still be the same. But does that mean istead of living in the Midwest, my part of the US would be the Mid East?:eek:

Obviously, if the Earth reversed direction, all right-handers would be left-handers and vice versa.


^It’s a link^

The day would be 8 minutes shorter, forcing us to add 2 days to the year and screwing up our calendars big time.

The reason for this is the difference between Sidereal time and solar time which now has the Earth rotating an extra 4 minutes. If revolution was unchanged but rotation reversed, the sun would reach zenith 4 minutes prior to the Earth’s sidereal day instead of 4 minutes after.

Instead of starting a new thread, what would happen if the earth slowly just stopped?

Depends on what you mean by “stopped.” Do you mean relative to the background stars, in which case, the day would be 365 days long, or do you mean relative to the Sun?