If we had a blue sun then the earth would be much hotter as the blue sun would also be much hotter.
If the Sun were cooler, say 2,500 degrees C, it would look red, like the stars Antares and Betelgeuse.
Or if the Sun were hotter, say 15,000 degrees C, it would look blue, like the star Rigel.
The Earth's atmosphere acts as a kind of light filter. Some colors are filtered more than others.
If the Earth stopped spinning then everything including people would go flying eastward.
Moving rocks and oceans would trigger earthquakes and tsunamis.
The still-moving atmosphere would scour landscapes.
Earth rotates because Sun attracts the earth and thus pulls earth towards it secondly due to earths revolution around sun it tends to go away from sun in direction of the tangent hence a rotational force (torque) acts on earth and it tends to rotate.
The Earth is always spinning.
Every day, you are turned upside down and back again.
You will also probably have traveled thousands of kilometers and as much as 40,000 kilometers if you live near the equator.
At the equator, the Earth is spinning at about 1675 kilometers per hour – much faster than an airplane.
But, for the most part, we don't feel the Earth itself spinning because we are held close to the Earth's surface by gravity and the constant speed of rotation.
Our planet has been spinning for billions of years and will continue to spin for billions more.
This is because nothing in space is stopping us.
If the Earth had no tilt then the seasons would stay the same as the tilt of the earth is responsible for the change in seasons and without tilt of the earth the length of daylight and the intensity of solar heating seen by a person standing at a single place on the surface would be the same all year round.
If the Earth was bigger than it is now then the earths and the planet's mass would increase eight times, and the force of gravity on the planet would be twice as strong and life would also be built and proportioned differently.
If Earth were twice its size, you'd be heavier, because the force of gravity increases as the planet's density and radius increase.
It would take more energy to resist gravitational pull, so the structures we have today wouldn't be strong enough to stand as tall as they do now.
If the moon were only half as large as it is now there would be no tides in the ocean and waters.
Tides are caused by the moons gravitational pull and so if the moon was only half as large then it wouldn't have the gravitational pull for the tides.
(Each lunar revolution takes about 29.5 days).
If the moon were half its mass, then the ocean tides would have been correspondingly smaller and imparted less energy to it.
Only one other planet has moons which is Mars which has two small moons.
If we had no moon then tides would fall, nights would be darker, seasons would change, and the length of our days would alter.
Although we likely would still survive without the moon but it does help with life.
If Earth had two moons it would be a bad thing and catastrophic.
Because if the earth had two moons or an extra moon would lead to larger tides and wipe out major cities like New York and Singapore.
And the extra pull of the moons would also slow down the Earth's rotation, causing the day to get longer.
The Moon is Earth's only natural satellite.
At about one-quarter the diameter of Earth, it is the fifth largest satellite in the Solar System, the largest satellite in the Solar System relative to its major planet, and larger than any known dwarf planet.
If Earth had two suns then the earth would likely be much hotter in the summertime and maybe warmer in the winter.
The two suns would probably appear to orbit each other roughly edge-on as seen from Earth, which would lead to a strange new phenomenon: an eclipse of the sun by another sun!
Because of the 10-day orbit, Sun 1 and Sun 2 would pass in front of each other every 5 days.
If the sun on earth went out then all the plants and animals as well as humans would eventually die out.
Not only do plants require the sun to survive but so do animals and humans.
As humans we get vitamins from the sun which we need to survive and without the sun we would not survive either.
Within a few days of the sun going out, however, the temperatures would begin to drop, and any humans left on the planet's surface would die soon after.
Within two months, the ocean's surface would freeze over, but it would take another thousand years for our seas to freeze solid.
In other words, it's extremely unlikely that life on any planet can survive the death of its sun but new life could spring from the ashes of the old once that sun shrivels up and turns off its violent winds.
So, the wind may be against us now, but one day it will be gone.
For us on earth, the sun is a source of life.
Even in Antarctica, the coldest place on our planet, temperatures seldom drop below minus 50°C.
Without the sun's radiation, the temperature would be anywhere near the absolute zero of minus 273°C.
Life would have never continued nor even have come into existence.
Earth has at least 1.5 billion years left to support life, the researchers report this month in Geophysical Research Letters.
If humans last that long, Earth would be generally uncomfortable for them, but livable in some areas just below the polar regions.
If the moon exploded, the night sky would change.
We would see more stars in the sky, but we would also see more meteors and experience more meteorites.
The position of the Earth in space would change and temperatures and seasons would dramatically alter, and our ocean tides would be much weaker.