The sun is humankind's constant. Like the moon and stars at night and how man fall asleep underneath the vast sky, the sun represents another day of living and making life something worth remembering. Because we're used to getting up the moment the sun rises and going to bed when the moon takes its place, it's easy to forget what the sun is made of and how it survives. The answer to these questions is exactly what will explain how the Earth will perish a few billion years from now.

Through a correspondence with Business Insider, astrophysicist Jillian Scudder of the University of Sussex explain why no matter what mankind will do to protect the Earth, the sun is the ultimate reason why it will perish.

The sun sustains itself by converting hydrogen atoms to helium atoms through the process of burning it in its core. Slowly but surely, the sun's core fills up with helium, which will cause it to shrink and trigger a faster nuclear fusion. That is to say, the sun ends up spitting out more energy.

This process of burning hydrogen atoms to helium atoms actually makes the sun brighter. In fact, every billion years, the sun gets 10 percent brighter. Thought it may not seem like much, 10 percent can be dangerous once it has accumulated more.

"The general gist is that the increasing heat from the sun will cause more water to evaporate off the surface, and be held in the atmosphere instead," said Scudder in an explanation to what will happen to the Earth once the heat becomes too much. "The water then acts as a greenhouse gas, which traps more incoming heat, which speeds up the evaporation."

The simple conclusion is this: the sun's energy will cause the atmosphere to release the water as hydrogen and oxygen instead of sending it back on land. Eventually, this will lead to a planet that has no water.

While there is no specific date as it is a billion years from now, the estimate is that the sun will manage to dry up the Earth in about 3.5 to 4 billion years from now.

But it doesn't stop there.

"Once hydrogen has stopped burning in the core of the sun, the star has formally left the main sequence and can be considered a red giant," said Scudder.

Following this sequence of events, the sun will eventually decrease in mass as well as its gravitational pull on the planets, which will make them drift away. By the time the heat of the red giant once known our sun will become too much, Mars will have been able to drift a safe distance away and Earth will be consumed and reduced to space ashes.

While this revelation is important in giving another reason why it's a good idea to look into Mars as our next planet, it also has more implication. The Earth needs to be cared for. The damages that our atmosphere has shouldered will only serve to hasten the process of letting the heat of the sun burn up everything that we know.