With no sunlight, photosynthesis would stop, but that would only kill some of the plants—there are some larger trees that can survive for decades without it. Within a few days, however, the temperatures would begin to drop, and any humans left on the planet's surface would die soon after.
Submariners have gone without sunlight for periods exceeding 6-months, using vitamin D supplements. It is unlikely, though, that an adult could die directly and exclusively from prolonged darkness.
Without sunlight, it would be bleak on earth. There wouldn't be any plants, animals and people. There would be no other form of life. No fossil energy sources such as coal, oil and natural gas would be available to generate energy.
Vitamin D is no substitute for the sun - Journal of Allergy and Clinical Immunology.
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.
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.
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.
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.
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.
What makes the Earth habitable? It is the right distance from the Sun, it is protected from harmful solar radiation by its magnetic field, it is kept warm by an insulating atmosphere, and it has the right chemical ingredients for life, including water and carbon.
The Sun could not harbor life as we know it because of its extreme temperatures and radiation.
This means that the earth would not slow, which then means that the hours of our days would change. Suddenly, without the moon, our days would last between 6 and 12 hours, rather than the 24 hours we experience now.
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.
Green and purple stars do exist. The color of stars depends on their temperatures, and they emit radiation throughout the visible spectrum. But when a star emits peak radiation at a... "The sun would appear green if your eye could handle looking at it," said W.
At the Equator, the earth's rotational motion is at its fastest, about a thousand miles an hour. If that motion suddenly stopped, the momentum would send things flying eastward. Moving rocks and oceans would trigger earthquakes and tsunamis. The still-moving atmosphere would scour landscapes.
The air on mars is thinner than that on Earth. On Earth, 21 percent of the air is oxygen, which is what makes it the ideal place for human life. But on Mars, oxygen makes up 0.13 percent of the air. The majority is carbon dioxide, which is harmful to humans.
Highlights. Earth's temperature has risen by an average of 0.14° Fahrenheit (0.08° Celsius) per decade since 1880, or about 2° F in total. The rate of warming since 1981 is more than twice as fast: 0.32° F (0.18° C) per decade.
One day, the core will eventually cool down and become solid. Scientists believe that when that happens, Earth will become similar to Mars, affecting every planetary process as we know it. Recently, scientists estimated that Earth's interior is cooling faster than expected.
Because of the gravitational force between the Sun and the Earth, the earth orbit around the Sun. If suddenly the Sun vanishes, the gravitational force between the Sun and the Earth will disappear.