What if, the Earth didn't have the Moon as a natural satelite, but instead had a smaller version of the sun, just enough to provide the same ammount of heat and still be able to orbit arround the Earth due to gravity.A mini-sun.What would this be like.Would a year, be a month now?Is this theoretically possible?

I don't know that much about astronomy, but I'm pretty sure that won't work. It's a cool idea for a sci-fi, but realistically won't happen. The sun is pretty small for a star, if I'm not mistaken.

If it were still orbiting Earth with the same mass and pull the way the old rocky moon was, a month would still be a month and a year would still be a year. It's not as if time changes magically based on the material of the thing orbiting.

so long as it's gravity and mass were equal to the moon nothing would change.... except you would have a lot of grumpy earthlings because they cant get any sleep.

But take this into consideration. What if the Earth were tidal locked with the sun, where the Earth just spun fast enough that as it revolved around the sun the same side of Earth always faced the sun, much like the moon with Earth.

But since the sun would rotate arround it's axis, and the Earth would rotate arround it's axis, and the sun would rotate arround the Earth, I'm pretty sure it would be night time somewhere.

Seems like its contents would be pulled out of it into a spiral around the earth.

Look into the Moon Cycle, every time there'd be "no moon" it would be night.

true, but the moon is usually in such a angle where it can be visible from the night side of earth. There probably would be some instances where the "dark" side of earth would be dark for at least a few hours while the sun side of earth would have dual suns ( like Tatooine).

The Sun rotate around the earth? Buddy, your science textbook is hundreds of years out of date....

But he also said that it would emit the same amount of light as the sun. so when it reached certain angles the "dark side" of Earth would at least start to experience "dawn/dusk" lighting.

That would (possibly) occur on partial days, but not when the sun is opposite your location, as light (no matter how near) cannot travel through the earth. Perhaps a good portion of the area around the "dark side" will be a dusk setting, but not the entire earth.

Edit: On partial days, the portion would still be in the same, elevated position, so it'd just put out a less strong light. Like a cloud in front of the sun.

And if we're really assuming it outputs the same light as the sun (which he didn't mention in the OP) then our eyes -- if they even came to exist -- would have evolved totally differently, as it'd be near-impossible to see with that much light. I'm leaning toward some sweet sonar action.

I would just like to point out that the sun, if it was the size of the moon, wouldn't have enough mass to sustain to generate the gravity needed to hold itself together. On that note, the temperature on Earth would be ungodly.

Ah, I thought it was light when he said heat... which if that is the case couldnt we assume the light would be ~equal? Plus if the revolution speeds between moon and sun2 were the same then there would be dark periods but they would be short lived (a few hours) before dawn/dusk lighting began to occur and then full blown daylight again.

Yeah, that's probably the case. I think an interesting question would be how life would have evolved and changed under these circumstances. Since the sun is where we get our energy, and why we sleep at night, would we just need less sleep with a shorter night? Imagine how much more productive we would be if we spent half the time we currently do sleeping.

Man I would get so much gaming done.... Stupid sleep

"One small step for man, one giant .... aaaaarrrrrrrhhhh... Oh God, it burns!" :::static:::

It'd be cool for fantasy or space opera, but not science fiction.

Global warming.

X2

We already have global warming.

If the Moon was replaced with a sun roughly the same size, wouldn't the Earth die? I thought we needed the gravitational pull that the Moon had for numerous things on Earth. The sun is only a star, not a planetoid, and I am unsure if stars have gravitational pulls.

He is saying that the sun2 has the same heating and lighting effects on earth as the real sun does for it's distance, meaning if you were under that sun it would be just like being under the real sun. Also assuming it still provides the same amount of gravity pull on earth as the moon, though he did not specify that.

No, we don't.

Not if you live in any other part of the world (as in: yes, we have global warming. Don't know what they teach you in America).

Anyway, considering the sun (moon) would be so close, even though it would be so much smaller...wouldn't the heat still be too much for humans to live on the surface of the Earth?