What would happen if earth axis were parallel to the sun?

Answer 1

I think you meant to ask: " What would happen if the Earth's axis were laying down flat in the plane of the Earth's orbit, so that one end of it pointed directly at the sun every six months ? "

If that were the case, then Half of the Earth would have 24 hours of daylight once a year. On the same day, the other half would have 24 hours of darkness.

Let's say you're at a place where it's 24 hours of daylight:

The closer you are to one of the poles, the more days after that would continue

to be daylight around the clock, for the next 3 months.

Eventually, after that number of days, you'd begin to have nights, very short at first, but getting longer and longer for the rest of the 3 months.

After 3 months, every place on Earth would have 12 hours of daylight and 12 hours

of darkness.

For the next 3 months, your hours of darkness would increase, while on the other half of the Earth, the hours of daylight would increase.

After 6 months, your half of the Earth would have 24 hours of darkness, and

the other half would have 24 hours of daylight.

Now, the closer you are to one of the poles, the more days after that would continue to be dark around the clock, for the next 3 months.

Eventually, after that number of days, you'd begin to have daylight, very short at first, but getting longer and longer for the rest of the 3 months.

After 9 months total, every place on Earth would have 12 hours of daylight and

12 hours of darkness.

For the next 3 months, your hours of daylight would increase, while on the other half of the Earth, the hours of darkness would increase.

After a full year, your half of the Earth would have 24 hours of daylight again,

and the other half would have 24 hours of darkness again, and the whole thing

would repeat for the next year.

Climate-wise . . .

Wherever you are, your weather would get warmer and warmer during the

part of the year when you have more than 12 hours of daylight, level off when

you start having nights, and start getting cooler and cooler when you start having

more than 12 hours of darkness.

On the equator, the sun would oscillate between the zenith and the horizon

twice annually, and would never set. So I expect the warmest climate would

still be in a band around the equator.

At each pole, the sun would be above the horizon for a solid 6 months, and then

below it for a solid 6 months, just as it is now. But instead of taking 3 months to crawl 23.5° up from the horizon and the next 3 months to droop back to the horizon, the sun would zip from the horizon to the zenith in 3 months, and then take another 3 months to return to the horizon.

I'm thinking that this would bake the poles mercilessly for half the year, and freeze

them utterly for the next 6 months, so that, besides having the lowest average

annual temperature, the polar regions would also have by far the widest extremes

of temperature, and would be the harshest, most lifeless places on Earth, and

would make today's polar climate look like a lush garden in springtime by comparison.