Scientists have unlocked a mind-boggling number of mysteries in recent years. They’ve mapped the human genome, discovered liquid water on Mars, and detected gravitational waves from a black hole merger. 

Even with these impressive results under their belts, scientists still struggle with some very simple mysteries. Here are five basic questions that science still has not answered.

1. What’s in the undiscovered parts of the ocean?

Many people are familiar with the observation that we know more about the moon than we know about the ocean floor. In one sense, it’s not so surprising. A good telescope can tell us a lot about the lunar surface while getting to the bottom of the ocean takes considerably more sophisticated equipment.

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Some scientists hypothesize that we will discover some species that we long thought were extinct in these unexplored parts of the ocean. We almost certainly will discover species that we’ve never seen before. With varied terrains and environments, there are sure to be a plethora of discoveries awaiting us at the bottom of the ocean. 

2. Is there alien life?

There are about 1,000,000,000,000,000,000,000,000 planets in 200 billion galaxies in our universe. You could say that there are good odds of alien life existing on at least one of those planets, and that would be a serious understatement.

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However, we don’t any hard evidence of aliens existing. Many of the groups that search for aliens are listening for various types of signals, but so far, they haven’t found many promising leads. Most of the other planets in the universe are extremely far away, so they are impossible to visit and possibly even too far away to detect signals from.

3. How does gravity work at the subatomic level?

We’ve learned a great deal about gravity in the last 400 years, but we still don’t understand the fundamental way that it works on the smallest levels. The force that keeps the Earth revolving around the sun and the ocean tides changing is more complicated than Isaac Newton could have anticipated.

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Nicolle Rager Fuller

Scientists can calculate the way gravity will affect objects in space or on other planets of different masses. However, when we go down to the subatomic level, this force becomes so weak that we can’t quite predict or understand how it works.

4. What’s inside a black hole?

Einstein increased our understanding of black holes with his theory of general relativity. He correctly hypothesized that black holes are created by the collapse of massive stars.

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According to Einstein, the black hole should get denser and denser until it becomes infinitely dense and small. Scientists now believe that quantum physics are needed to fully understand if the theory holds when a black hole reaches its smallest and most dense point.

5. What is the purpose of dreams?

This is one of the most perplexing questions out there, and we don’t seem particularly close to solving it. Scientists believe that dreaming somehow aids in memory and learning, but that doesn’t explain why dreams are sometimes surreal and bizarre.

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Experiments with rats indicate that sleeping and dreaming help rats complete mazes that they have some experience in traversing. Scientists believe that humans also use dreams to improve skills and memory, but it is unclear how dreaming actually accomplishes these feats.