What would happen if everything was right

What would happen if the earth were connected to the sun?

There are many questions here and I am more certain of the answers to some than others. But I'll try anyway.

The first and most important question is what the temperatures would be like. This is the one I'm least sure about. The reason I'm not sure is because it depends to a large extent on many things that would likely be very different on a tidal-locked earth. These include the greenhouse effect (which depends heavily on water vapor), the albedo (which depends on the number of clouds and the ice) and, above all, the wind speed.

If there was no heat transfer from the hot to the cold side, we might expect temperatures to be similar to the temperature range on the moon - around -150 ° C on the cold side and more than 100 ° C on the hot side. However, when the planet has an atmosphere, it transports heat from the hot to the cold side, which can significantly reduce the temperature difference. This could only work if the rate of heat transfer (and therefore wind speeds) were quite high, because if it gets too cold on the cold side, the atmosphere will start to freeze. This leaves less air for heat transport, which leads to more freezing, etc. in a feedback loop that would result in an airless world. This is probably the most likely outcome of a tidal-locked Earth-like planet - but not that interesting from a fictional point of view, so I'll focus on how a habitable world might be plausible.

A sufficiently high rate of heat transfer might be possible if the hot side were very hot, possibly due to a large greenhouse effect and constant exposure to sunlight. I'm not sure if this would mean that the hot side would have to be so hot that the ocean would boil, but I suspect it is. In this case, we would expect most of the water to be found in the form of ice on the cold side - but perhaps some of it could be found in a liquid state near the limit. One would hope that there could be some sort of water cycle - I imagine something like glaciers being constantly melted by the warm air pouring in from the hot side, with the meltwater flowing in huge rivers (or even flowing seas) hot side flows where it evaporates and runs back to fall as snow on the cold side.

Next we need to consider what the airflow patterns would look like. The situation on Earth today is complicated, but the basic principle is that the air at the equator heats up, then rises, then moves at great heights to the poles, and then cools down (due to the release of thermal radiation into the space) , then sinks again and drives back to the equator. The prevailing winds near the ground tend to blow towards the equator. On a tidal-locked earth, I would expect a more extreme version of this phenomenon. The flow patterns in the middle of the hot side would probably be crazy messy - there would be a lot of energy to power storms, especially if there was a water circuit to provide moisture - but in the region near the border I would expect a fairly stable convection cell, in which hot air blows on the cold side at high altitudes, sinks and blows back on the hot side at low altitudes. So a person standing on the surface near the boundary would be exposed to very strong prevailing winds towards the sunlit side. How strong these winds would be I cannot say, and it is also very difficult to say how much cloud cover or precipitation there would be. In general, however, a higher temperature difference means that more energy is flowing into the weather systems, and on this world the temperature difference would be greater than on Earth. Hence, in general, we would expect the dynamics of the atmosphere to be stronger and more violent.

It should be noted that heat can be transferred as latent heat and not just as hotter and cooler air. Water absorbs heat when it evaporates and releases it when it condenses. So if there is a strong water cycle in which a lot of cool liquid water flows to the hot side and a lot of warm water vapor is carried from the atmosphere to the cold side, you can achieve higher heat transfer without the need for such strong winds. In this scenario, someone on the surface would experience a prevailing wind towards the sunlit side, but if they look up at the sky they will see clouds moving in the opposite direction.

An additional complication on Earth is the Coriolis Force, which causes the prevailing surface winds to blow around the Earth, not just from the Pole to the Equator, and hurricanes to form as well. It also creates the jet currents. But a tidal-locked earth would hardly rotate, so there would be no Coriolis force and these phenomena would not occur - the prevailing winds near the border would blow directly towards the sun and rotating hurricane-type storm systems would be extremely rare, if so they even existed.

The next question is whether there would be a separate north and south ocean. I don't think that would be the case. This idea comes from the fact that the earth's rotation causes the oceans to bulge around the equator - but also all of the rock bulges out, which is why we don't just have one large ocean around the equator. I think you can imagine that if the earth somehow stopped rotating, the oceans would flow towards the poles, but the rock would move much more slowly so there would be a period of time when there would be oceans in close to the poles, but would land around them The equator. But over longer geological timescales the rocky part of the earth would also change shape, and you would have roughly evenly spaced oceans again.

The same applies to the question of whether the sun causes permanent tidal curvature in the oceans. It would, but it would also bulge the shape of the planet so you wouldn't necessarily have the entire ocean on the sides facing and facing away from the sun. I think the fact that the water would tend to freeze on the cold side would have a much bigger impact on the water distribution than anything else. Of course, if there was a moon, the moon would still be causing tides.

Next comes the magnetic field - I don't feel qualified to answer this one. I've always wanted to understand how the Earth's magnetic field is created, but I've never found a good explanation, so I don't know how plausible it is to imagine it working without the Earth's rotation. The importance of the magnetic field is to prevent the atmosphere from being slowly blown away by the solar wind. It would therefore be necessary that the atmosphere of this planet persist in the long term.

I'm also not sure how to answer the question about the moon. It seems hard to imagine how the moon could be in orbit, but the earth is still tide-tied to the sun, but I'm not an expert.

Another possible big difference is plate tectonics. If the oceans are frozen on the cold side, this will put a lot of strain on the plates there, which will likely change the dynamics of the entire system - but unfortunately I cannot currently imagine what the result would be. Plate tectonics is very important for recycling elements over very long periods of time. The water cycle on this planet tends to move nutrients to and from the hot side, so you will need geological activity to recycle them over the long term.

Another important thing to think about is photosynthesis. It will be very difficult for plants to survive on this planet as the hot side will be very, very hot and the cold side will have no light. There would likely be a lot less life on this planet than there is on Earth, with most of it existing on the edges of the hot side. (The prevailing winds and water currents here come from the cold side, so things can stay relatively cool even though the sun is always in the sky.) When the cloud cover is 100%, photosynthesis also becomes more difficult due to the reduction in the available light. This is important because it could mean there isn't enough oxygen to support human life. I think when designing this fictional world there is a compromise between a strong water cycle to carry a lot of heat and a weak water cycle that is weak enough light reaches parts of the surface.

You mention the possibility of life on the dark side. That's not impossible, of course, but you'd have to ask yourself what would it be eating. Most of the life on the ocean floor, for example, eats goose bumps, which are made up of dead matter that drips from the surface. The source of energy is ultimately sunlight, which is converted into chemical free energy by photosynthetic plankton. So while there might be some life on the dark side (e.g. geothermal energy from hydrothermal vents under the ice), there might not be much of an ecosystem there unless a constant source of chemical energy somehow transported the bright side Page. However, it is difficult to imagine how this could happen without the composition of the atmosphere being very different from that of Earth.

I hope this gives food for thought. It's all very speculative, of course, and there can be important things that I didn't think of or where I did something wrong due to a lack of specialist knowledge - so reservation .


rotating hurricane-type storm systems would be extremely rare . How about a single mega-hurricane in the middle of the hot side?


@Krumia it might be possible. In fact, due to the planet's rotation around the sun, there is a very weak Coriolis force that could be sufficient to maintain such a system, especially since we would expect a permanently large convection cell at this point. (But given the scenario in my answer, such a storm would not be readily observable for the inhabitants of the planet who live in the twilight zone.)