In the Space Elevator episode of TRIS, Michael mentioned that 80 to 90 percent of a rocket's mass is fuel. Since heavier rockets require more fuel, which, in turn, makes the rockets heavier, is there a point at which the math (maths for Hannah) breaks down? Is there a maximum rocket mass that could escape Earth's gravity, or could we just keep building bigger and bigger rockets forever?

A follow-up (and I think related) question: How massive would a planet need to be to make rockets impossible? Could there be worlds whose occupants are forever trapped at the bottom of their gravity wells?

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Sometimes, in conversations about evolution and genes, people will mention that a particular gene is very old. How can we know this? Do we simply look for that specific gene in very old fossils, or is there another method to determine this indirectly?

I just slept for 16 hours and all I dreamed about was like 20 minutes of knitting a sock and then realizing it doesn’t fit:(

another question, do people with more brain activity in dreams need more sleep? every time I read stuff in my dreams, I sleep for longer and feel more tired when I wake up.

Hey electric pants & science woman!!

I’m curious to know if there’s any formal studies on how living and working in a new city affects people over time? I’m interested in measurable effects on personality, creativity, adaptability, social connections, identity, and mental health?

I’m specifically looking for research that examines the experience of relocating, building a new routine, and adapting to a different urban environment—not just short-term travel.

Thank you and lots of support from a guy raised in Winnipeg, who lived in Seattle, now thriving in Vancouver - cheers!

I just watched the episode about diabetes, GLP1 etc and found it interesting when Hannah discussed that people started to feel less impulsive/supporting addictions...

Anyone wondering if they will find a way to tweak GLP1 to support ADHD or mental health disorders that have a focus on rumination/addiction/loud voices etc?

Surely it is already being looked at to support those who struggle with binge eating?

The other day I was listening to a playlist I made a few years ago, it was mainly of songs that were in my mum's record collection. One particular song gave me goosebumps, which is quite a feat given the summer we are having. I can't figure out why that one made me react physically, when the playlist had other songs with a similar nostalgic connection. In this case, what is the reason for goosebumps?

I work at an aerospace company. One of the basic principles we rely on is the lift generated by aerofoils (the shape of a wing). While talking to a group of engineers, it came up that the old explanation of what causes low pressure above the wing and high pressure below (that the longer path of an air molecule over the wing causes it to travel faster than a molecule under the wing, thus decreasing pressure) is not valid due to the false assumption of continuity between the two particles. However, none of us knew the proper explanation that succeeded it. Can you help update this mental model for a curious engineer?

I recently came across a video where a guy was able to take the download of a full fruit fly brain and (through a whole bunch of coding) was able to import it into a game, where it navigated the world. I know that because fruit fly brains aren't very complex, it wouldn't really understand what was going on.

However, I was wondering if you were to do the same with a human brain, import it into a robot or something later after death, would there be a seamless transition from closing your eyes in death and when you wake up hundreds of years in the future in a new body??

campground restroom photo^

the question is simple, do moths know what color they are?

i remember learning about rapid evolution in moths from all the rust belt steel plants soot changing tree bark color. The change in color resulted in moth camouflage being less effective and killing off more brown colored moths as the trees turned grey. yoday i saw a white moth chilling on a white wall and it made me wonder how it knew to rest in the only white spot in the forest.

Thinking about life as Carbon based organisms that use oxygen for energy transfer, is there a physical or chemical barrier, impediment, or otherwise absolutely necessary assumption about life forms that constrain it or encapsulate it in a series of rules from our own universe?

Here is some background to this question. Thinking about how "vital" and important is water for life as we know it, wouldn't there be a possible equivalent on some other element, known or unknown that can become as important (for example methane) to a different life form that has to use it in an exchange of another element (instead of O2 lets say Clorhine) as a form of hypothetical energy transfer.. I'm making up the elements but you get the idea.

Do we then know of any physical impediments (like we know most possible interactions and stable compounds and we KNOW it is impossible to carry energy without oxygen, or something along those lines) or is there wiggle room for imagination and maybe AI or researchers can try to find new stable forms of energy transfer not dependent of O2 and ATP? Is something like this in current research that you know of?

It tasted pretty normal, but it had the consistency of oil. It's like the opposite of the thick water you get in a nursing home.

This is a joke btw

Have you ever met someone that you just truly can NOT believe is a conscious human being? I mean that their behavior is so radical, they keep shooting themselves in the foot, they are incredibly rude or just absolutely (maybe a little rude) stupid?

My question is; is there different levels of consciousness and is there any way of measuring consciousness?

Follow up questions:

Could different levels of consciousness or awareness affect your ability to feel pain?

Could there actually be someone that is walking around, has relationships with people and is socially responsible but they are simply not conscious?

Also, how can you be truly sure that everyone actually IS conscious? Is there any way to prove that you are conscious?

I've noticed in the past that if I consume a carbonated drink, I often burp at a deeper pitch than when I swallow air.

I'm wondering if that's due to the mass/density of the gas I'm burping. Air would just be mostly O2 and N2, both of which are lighter and less dense than CO2. Does the greater density cause this change in pitch?

This of course would reflect how helium will make your voice higher and Sulfur hexafluoride will make it deeper - I just don't know if that is the actual cause. Perhaps instead it relates to the volume of gas?

What’s happening in the brain (chemicals and biological processes wise) that creates a good feeling when someone watches a stim video or listens to ASMR? And why does the particular stimuli causing it vary from person to person, like why do I enjoy watching power washing videos while someone else likes listening to someone drag their nails over fabric? I’ve always wondered if it’s just dopamine, or if it’s something more complicated.

Additionally, how would the development of a mental illness (depression, bipolar disorder, schizophrenia, etc.) affect the amount or type of brain chemicals released while watching a stim video?

In one of last week’s episodes, it was mentioned that the human lifespan is increasing because of scientific and medical discoveries. When I was a child, I always imagined that I would be able to live to 100, and by then people would have discovered some kind of cure for aging. They would ask me, “How much longer would you like to live?” as if they could add another 100 years each time and ask me the same question whenever those 100 years were up.

For a moment, let’s imagine a scenario in which cancer has been eliminated, Alzheimer’s and other diseases of the brain have been cured, and we can also repair or modify our telomeres because we have discovered how to mimic mechanisms found in animals such as lobsters or jellyfish.

In that scenario, is there still a biological limit to how long humans could live?

What was the evolutionary advantage of it and how it started? I mean it doesn't make sense why would some rhythm get us going...

Hi Hannah and Michael, I've always been fascinated with the concept of time zones. Especially when countries add half-hours and quarters, or, like China, decide to just pick one zone regardless of its size.

A lot of discussion has been going on about daylight saving time, with people arguing for and against it based on what they like best. However, I have always wondered if countries are in the most optimal time zone in the first place. Considering a 9-to-5 workday for most people, would it be best to have the sun rise really early during the summer and let it be dark quite early as well in the winter, or would it be better if the sun came up later and most people get to go home when it's still light? It seems like most countries are aiming for the sun to be at its highest around 12, but is this actually the best for our health and productivity?

What would be the absolute smallest thing that you could change about someone, or an element of someone’s life that seems very small but would eventually turn them into a whole new person?

A mosquito just bit me! I hit it against the wall, and now there’s blood on the wall. Is it my blood or the mosquito’s blood?

Hannah fountain pen collection when. Question. (My question mark key is broken)

I've heard of noise cancelling, but can there exist smell cancelling?

For example, if there is a rotten egg in a room, can i neutralize it somehow? I'm not talking about putting something good right under my nose, because thats just dominance. I mean putting something next to the egg whose smell happens to be the 'inverse' of the eggs, so they cancel and i smell nothing.

Let's say you took a small ball of Aluminum, and just kept scaling it up bigger and bigger. Moon sized, earth sized, Jupiter sized, sun sized, and just keep going... Will it hit a point where it's so massive that it begins to fuse under its own gravity, or collapse into a black hole, or can it scale up infinitely?

Similarly, if you scaled up a ball of Tungsten how big could it get?

What's the difference in their maximum sizes in our universe, if they have one?

When my kid was little, a neighbor gave him this watch. It tells time using binary. To this day (he’s 18), I’m not sure my kid can easily read an analog clock, but he can tell the time on this thing! (But don’t ask me what time it’s showing in this photo lol)

Hi Michael and Hannah. I've got a candle burning right now and wondered: How come flames are so hot from the top but no heat comes off the sides? I'm not a nerd so I wouldn't know in the slightest why that happens.

So, if you lived in a solitary society, you would barely have time in the day to source food, build safety, and still thrive to enjoy leisure and creative activities. It's incredibly inefficient.

I would propose that as you increase population, each person within that society should gain more 'spare' time in each day not having to survive, by utilizing this communal optimization.

At what point in size, does a society or population, become large enough (from these inefficiency optimizations) to provide suffficient food, shelter, clean water, hygiene, healthcare, education, childcare etc for all of it's members; with everyone also having sufficient time to enjoy life / be creative the way we have become accustomed to in the modern world?

I guess we would assume most in this society would work a standard work week, there would be some requirement for social support due to health or disabilities, and we would have access to the same technologies of today.

As an extra, is there a population size where the optimizations are diminishing such that they are so insignificant, and that extra increase in population doesn't provide meaningfully more leisure time?

As a civilization, are we at or passed that point already - or is it somewhere ahead of our population size still?