These unsolved mysteries continue to perplex humanity's best and brightest. Welcome to WatchMojo, and today we’re looking at the biggest mysteries scientists are still trying to solve.
Category
🗞
NewsTranscript
00:00 We want you to tell us the answer.
00:05 The answer to what?
00:07 The answer to life, the universe, everything.
00:11 Welcome to WatchMojo, and today we're looking at the biggest mystery scientists are still trying to solve.
00:17 My head is filled with questions and I can assure you no answer to any one of them has ever brought me one iota of happiness.
00:26 Number 10. How does the environment influence genes?
00:30 Nature versus nurture is one of the biggest debates in modern science.
00:34 It's clear that everything from the way we look to the way we behave is governed by both our genetics and our environment.
00:41 But exactly how these interactions happen remains deeply enigmatic.
00:45 It wasn't until a landmark study was published in 2020 that we even knew how genes determined a person's height,
00:51 which it turns out comes down to roughly 10,000 genes working in tandem.
00:55 But far from being immutable, your genetics can be influenced by all kinds of things in your environment throughout your life,
01:01 from diet to how stressed you are, and we're a long way from understanding how exactly this works.
01:07 Number 9. Why do we sleep?
01:10 If you're healthy, you do it every single day, and if you ever go too long without it, you'll certainly feel the consequences.
01:16 But you may be surprised to learn that scientists don't actually know what sleep is for.
01:21 We need sleep, that's clear enough, but why? And why do we have to spend a third of our lives doing it?
01:27 Scientists believe it's a way for the brain to keep house and recover from the day's events,
01:32 though how exactly sleep achieves this is still quite mysterious.
01:36 There are many theories, but until we learn more about the human brain, or even brains in general,
01:41 we might not be able to unravel this mystery.
01:44 Number 8. What is ball lightning?
01:47 This phenomenon is so weird that scientists aren't even sure if it's real, despite being witnessed so widely.
01:53 Spherical objects apparently made of pure light or electricity are reported in foul weather,
01:58 literal balls of lightning flying through the air.
02:01 Interestingly, scientists have been able to recreate things that resemble lightning balls in laboratories,
02:06 but nobody knows whether they actually are creating ball lightning or not.
02:10 Even if they are, it's still unknown how those conditions are replicated in nature.
02:15 There are dozens of different theories, many with a lot of scientific evidence backing them up,
02:20 and many scientists are still investigating ball lightning today,
02:24 but we just don't know how it happens or what it really is.
02:28 Number 7. How did life on Earth begin?
02:40 We'll be talking more about the universe later, but one of the biggest mysteries facing our species is how exactly we got here.
02:47 There are six chemical elements believed to be crucial for forming life -
02:51 carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.
02:55 But how did they get to Earth, and why don't they all seem to exist on the other planets in our solar system?
03:01 Welcome to our factory floor!
03:05 We just don't know for certain.
03:07 The earliest evidence of life we've been able to find on Earth also dates back to roughly 3.7 billion years ago,
03:13 which is certainly a long time, but Earth itself is over 4.5 billion years old.
03:18 You must realize that the planet you lived on was commissioned, paid for, and run by mice.
03:26 So what triggered life to begin after so long without it?
03:30 Number 6. What's the oldest possible age for a human?
03:34 This is an interesting one. We know what the average age for a human is, which depends on various factors and demographics.
03:40 But what's the absolute upper limit on how long we can live?
03:44 Well, the oldest verified human ever was Frenchwoman Jeanne Calment, who lived for over 122 years.
03:50 And plenty of people have extraordinarily lived to be over 110.
03:54 But as medicine continues to advance, are we going to be able to prolong human life even more to unforeseen ages?
04:01 This is definitely a possibility, and is why we just don't know what the maximum age of a human is right now.
04:07 Number 5. Why is there more matter than antimatter?
04:11 Called the matter-antimatter asymmetry problem, this is a big question in physics.
04:16 We didn't have a description of antimatter until the 1920s.
04:20 But we know now that while regular, or baryonic, matter is made up of protons, neutrons, and electrons,
04:26 antimatter is made up of antiprotons, neutrons, and positrons.
04:30 Logically, it makes sense that there would be just as much antimatter as there is normal matter.
04:35 But this doesn't appear to be the case.
04:37 Physicists are working hard on this problem, since it's believed that the Big Bang should have created just as much antimatter.
04:44 Some unknown force or phenomenon may be at work across the universe that prevents antimatter from existing.
04:51 Number 4. What causes Alzheimer's?
04:54 Though tens of millions of people are tragically affected by Alzheimer's disease, the most common form of dementia,
05:00 we're still struggling not only to treat it, but also to learn why it happens at all.
05:04 There's a hereditary element, and certain things are believed to be risk factors,
05:08 but we're not sure what actually causes the cognitive decline seen in the condition.
05:13 Some studies have put forward theories, the most well-known of which is the amyloid hypothesis.
05:18 But many more scientists and doctors dispute those studies, and say they weren't rigorous enough.
05:23 And even if that theory is correct, it's existed for decades, and we still don't understand the disease or how we might one day cure it.
05:30 Number 3. What is dark matter?
05:33 Guidance system? Online. Autopilot? Present.
05:36 Dark matter indicator? Making a noise. All systems operational.
05:40 To return to the subject of matter, less than 5% of everything in the universe is normal matter.
05:46 Of the remaining 95%, over a quarter of it is dark matter, stranger even than the elusive antimatter.
05:53 We don't know what dark matter is, but we know it's there because it interacts with gravity.
05:57 Galaxies, for instance, don't have enough matter to maintain their shapes gravitationally if you only consider normal matter.
06:05 Therefore, some other type of matter must exist.
06:08 It's completely invisible to us, unable to reflect or emit light,
06:12 and we have no real way right now of knowing what it is, how it works, or how it came to exist and be so abundant.
06:19 I don't believe it! It's dark matter!
06:22 So this guy just unloaded a steaming pile of starship fuel?
06:26 His species must have filled the entire planet with it!
06:29 Number 2. What is dark energy?
06:32 If 5% of the universe is normal matter, and 27% is dark matter,
06:36 the remaining two-thirds are the most mysterious substance, if it can be called a substance at all, in existence.
06:43 Dark energy.
06:44 We know even less about dark energy than about dark matter,
06:47 and we only know it exists in the first place because of the observable acceleration of cosmic expansion.
06:53 The universe is still expanding, and expanding faster and faster,
06:56 and dark energy is somehow related to this, expanding to fill the gaps in space as everything gets further and further apart.
07:03 The universe is only going to get bigger, and dark energy is quite possibly to blame.
07:08 Before we continue, be sure to subscribe to our channel and ring the bell to get notified about our latest videos.
07:14 You have the option to be notified for occasional videos or all of them.
07:18 If you're on your phone, make sure you go into settings and switch on your notifications.
07:24 Number 1. Are we alone in the universe?
07:28 [Music]
07:33 The universe is so incomprehensibly vast that it seems absurd that Earth is the only planet out there capable of hosting life.
07:41 Scientists have found plenty of exoplanets that appear to be well-suited to it,
07:45 but we still have no evidence of extraterrestrial intelligence.
07:48 Statistically, it's more likely than not that there are other intelligent species in the universe, but where are they?
07:55 Why can't we communicate with them?
07:57 [Music]
08:02 There may be many explanations for this.
08:04 Maybe there were intelligent life forms that died long ago, or maybe space is just too big to even send messages between planets.
08:12 [Music]
08:24 [Music]
08:32 But the question of whether there's anybody out there remains one of the biggest mysteries for our species.
08:38 Let us know in the comments which mystery you hope gets solved first.
08:42 Did you enjoy this video? Check out these other clips from WatchMojo, and be sure to subscribe and ring the bell to be notified about our latest videos.
08:49 [Music]