Within a week, the average global surface temperature would drop below 0°F. In a year, it would dip to –100°. The top layers of the oceans would freeze over, but in an apocalyptic irony, that ice would insulate the deep water below and prevent the oceans from freezing solid for hundreds of thousands of years.
If the sun was no more, then Earth would be drawn to a new centre of gravity. The gravity of Earth and the rest of the solar system would be affected and – with there being no constant energy supply from the sun – Earth would start drifting into space.
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. It's always raining somewhere in the world.
If suddenly the Sun vanishes, the gravitational force between the Sun and the Earth will disappear. So, the Earth will no more be able to orbit around the sun. Thus, it will start moving in the direction of velocity in a straight line.
Eternal night would fall over the planet and Earth will start traveling into interstellar space at 18 miles per second. Within 2 seconds, the full moon reflecting the sun's rays on the dark side of the planet would also go dark.
Within a few days, 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.
The gravitational pull of the moon moderates Earth's wobble, keeping the climate stable. That's a boon for life. Without it, we could have enormous climate mood swings over billions of years, with different areas getting extraordinarily hot and then plunging into long ice ages.
Applying this to your thought experiment, if the Sun disappeared instantaneously, we poor folks on the Earth would not notice it until about 8 minutes and 20 seconds after it had happened due to the light (and gravity wave) travel time from the Sun to the Earth.
If the moon disappeared, the oceans would have smaller tides. This in turn will affect water organisms like crabs, mussels, starfishes and snails as they depend on the tides for survival. This impact on the coastal ecosystem will lead to an imbalance in the food chain and eventually cause mass extinctions.
The latest ice age peaked about 20,000 years ago, when global temperatures were likely about 10°F (5°C) colder than today. At the Pleistocene Ice Age's peak, massive ice sheets stretched over North America and Eurasia.
At night, when there's no sunlight, clouds are still trapping heat. It's sort of like clouds are wrapping Earth in a big, warm blanket. So clouds can have both a cooling effect and a warming effect.
Since there is no way to conduct heat, the temperature of the objects in the space will remain the same for a long time. Hot objects stay hot and cold things stay cold. But, when the sun's radiations enter the earth's atmosphere, there is a lot of matter to energize. Hence, we feel the radiation of the sun as heat.
In our own galaxy (the Milky Way) there are at least 300 billion stars. We call stars “Suns” when they are the centre of a planetary system, like how Earth and the other planets orbit our sun.
Barrow can go two months without seeing any sunlight, because it is located just a few hundred kilometres from the Arctic Polar Circle. Perhaps to compensate for this, Barrow experiences what is knowns as “midnight sun”, when the king of the sky comes out in May and it won't set again for 3 months.
It is the pull of the Moon's gravity on the Earth that holds our planet in place. Without the Moon stabilising our tilt, it is possible that the Earth's tilt could vary wildly. It would move from no tilt (which means no seasons) to a large tilt (which means extreme weather and even ice ages).
If the Sun randomly exploded today or tomorrow, humanity wouldn't survive. However, if the explosion isn't powerful enough and we would know in advance that it will happen, we might have a chance to prolong our existence for a couple of years.
Earth will interact tidally with the Sun's outer atmosphere, which would decrease Earth's orbital radius. Drag from the chromosphere of the Sun would reduce Earth's orbit. These effects will counterbalance the impact of mass loss by the Sun, and the Sun will likely engulf Earth in about 7.59 billion years.
Far outside our solar system and out past the distant reaches of our galaxy—in the vast nothingness of space—the distance between gas and dust particles grows, limiting their ability to transfer heat. Temperatures in these vacuous regions can plummet to about -455 degrees Fahrenheit (2.7 kelvin). Are you shivering yet?
Before Earth and the Moon, there were proto-Earth and Theia (a roughly Mars-sized planet). The giant-impact model suggests that at some point in Earth's very early history, these two bodies collided.
The Earth formed over 4.6 billion years ago out of a mixture of dust and gas around the young sun. It grew larger thanks to countless collisions between dust particles, asteroids, and other growing planets, including one last giant impact that threw enough rock, gas, and dust into space to form the moon.
if there was no scattering or absorption, the sky would appear black in the daytime and if there was more absorption or scattering, the sky might appear to be yellow, orange, or red all day long.
The rings and space
However, the rings would likely scatter any radio signals from satellites and spacecraft in equatorial orbits, limiting their usefulness. Still, the rings would likely interfere with astronomy, hindering ground views of the nighttime sky, Scharf said.