7 Of Your Shower Thoughts, Answered With Science

Are we drinking dinosaur pee? What do babies dream about? What would happen if you fired a gun traveling at the speed of light? Find out today!

We asked for the science questions you didn't want your name attached to, and now we're answering them. This time: questions you may have come up with while stoned, in the shower, or taking a crap.

1. "If there is no new water on Earth, is it possible that we're all drinking what was once dinosaur pee?"

Thinkstock / Alex Kasprak / BuzzFeed

Yes, you are drinking water molecules that, statistically speaking, likely passed through the bodily system of a dinosaur at some point. Dinosaurs existed on this Earth for over 183 million years — that’s a super-long time. This is important, because the amount of water on Earth is relatively fixed, and to be sure that dinosaurs consumed all the water on Earth, they need to have been around long enough for every bit of water on Earth to cycle into the drinkable part of the water cycle (a small percentage) many times over.

Randall Munroe, of xkcd and What If fame, calculated that all dinosaurs ever (discounting birds) likely consumed about 10²² or 10²³ liters of water throughout their reign. That is substantially more than the total volume of the oceans (10²¹ liters), which is where a vast majority of all of Earth’s water lies, meaning it’s highly likely that all of it went through a dino at one point.

2. "If birds of prey have better eyesight than humans, is it possible for humans to ever know how much better their sight is?"

Prettyvectors / Getty Images

It is true that many birds, and birds of prey in particular, have much better eyesight than humans. An eagle's vision, for example, is estimated to be around four to eight times more powerful than a human's. Not only is avian vision more powerful in most cases, most birds can also see into the UV light spectrum in addition to the visual spectrum humans are used to.

We can't have direct knowledge of what the ~experience~ of that vision would be, but we can deduce what its characteristics would look like just like an optometrist can tell you what a certain kind of lens will do to a person's vision without actually experiencing their vision. We can do this because bird's eyes work, generally, the same way as ours do: with rods, cones, lenses, pupils, etc. But these features are a bit different in birds. For one thing, their overall eyes are much bigger on both a relative and absolute scale. Birds have eye sockets that can take up to 50% of the space of their entire skull. Their pupils are also much bigger, which means more light reaches the retina. While humans have three photopigments in their eyes, birds can have four or five, and have a greater diversity of cones than humans. Their photoreceptors are often much deeper, which means they can magnify their vision more than humans.

Long story short: We can't experience it, but just by studying their eyes, we can tell how far a certain bird could see clearly, how wide its field of vision is, and what wavelengths of light it can see.

3. "What would happen if you shot a bullet that traveled at the speed of light while traveling at the speed of light yourself?"

Sophie Delar / Via en.wikipedia.org

First things first: You can’t make anything that has mass go the speed of light — it would take an infinite amount of energy to do so (thanks, Einstein). For context, it would take 1.711x10¹⁹ joules to get a Glock-size pistol (855 grams) to go 99.999% the speed of light. That’s the equivalent of 272,626 Hiroshima-size nuclear explosions.

Lots of weird crap happens when you approach the speed of light. Many of these things are referred to as Lorentz transformations — and they are quirky mathematical (but directly observed) solutions to the paradoxical truth that light is a constant speed no matter your frame of reference or speed of its source.

Time dilation is one such transformation. As something approaches the speed of light (like our Glock-sized pistol), time goes slower for that object compared to time experienced by an outside observer — if both the thing that launched the pistol and the pistol itself had a clock, much less time would have passed by for the clock on the gun compared to the stationary clock.

Another thing that happens is that as an object moves faster and faster, it is compressed along the axis of its direction of movement. This is called length contraction. Using the same example, a Glock-size pistol, which is 7.36 inches when stationary, would contract to be 0.033 inches when moving at 99.999% the speed of light from the perspective of an outside observer.

This all leads us to an uncomfortable conclusion: At the actual speed of light, time would cease to progress and space would be infinitely compressed. What would happen if you shot a gun in the absence of time and space? Fuck if I know…

4. "What do babies dream about?"

gifs-for-fun.tumblr.com / Via giphy.com

Outside of speculation, we have no way of knowing the answer to this question. What we do know, though, is that infants actually begin experiencing the kind of sleep that produces dreams in older individuals — REM sleep — even before they are born. After birth, they can spend up to 80% of their day in that kind of sleep. Researchers think that dreams begin at some point in their first year of life, based on their seemingly emotional responses during their sleeping, but it’s not clear.

If dreams are a haphazard accumulation of visual and tactile experiences tied together to form a loose narrative devoid of any meaning, as some researchers suggest, then it’s likely that an infant’s dreams are fairly limited to what it has experienced so far — some eating, some sleeping, some crying… but anything here would be speculative at best.

5. "Do blind people dream?"

CurryThighs / Reddit / Via giphy.com

As any blind person will tell you, people who are born blind do dream. There is no scientific consensus, however, on whether or not those dreams involve what sighted people think of as visual imagery. Think about the challenges of a sighted person describing their concept of visual to a blind person or vice-versa — it’s pretty much two different languages!

A 2014 study reported that congenitally blind people’s (those individuals born blind) dreams include increased focus on “auditory, tactile, gustatory, and olfactory dream components.” A controversial 2003 study suggested that congenitally blind people do actually have visual components to their dreams and that they are able to convey those visual representations through drawing. People who lose their sight later in life, though, do for sure retain visual components in their dreams.

6. "Why does superglue not stick to the inside of the tube?"

youtube.com

The glue is designed to chemically change once it is exposed to the atmosphere. Superglue is made from a class of chemicals called cyanoacrylates. When they are in the tube, they remain as shorter-chained molecules that do not bond to one another. Once exposed to something basic, like the moisture in the air, they rapidly bond with one another, forming long chains that connect to one another and whatever they are touching. This is also why the glue goes bad if you don’t seal the container.

7. "Why can't we prove that other intelligent life exists?"

Warner Bros.

This is a classic paradox in science called the Fermi paradox. The basic gist of the Fermi paradox is that, from a numbers standpoint, contact with other alien civilization seems mathematically probable. Think about it: Our sun is fairly typical, there are billions of stars like it in our galaxy, many stars like our own also have planets, and even at the rate of travel possible by our own society, the galaxy could be crossed on a timescale of millions of years (a fraction of time our planet has been around). Still, there is no evidence of contact from any other civilization. All we want is a little wave, alien bros!

There are a ton of explanations proposed for why we have not yet made any contact, but they are all pretty much conjecture. That’s why we want you to vote on which reason seems best to you: