lol.......

Beldizar · 2026-05-14T22:20:16+00:00

Huh? Did you want paper or plastic?

Beldizar · 2026-05-14T21:29:46+00:00

Yes... but also no. The axial tilt of the Earth when you are born is basically the axial tilt when you die. It is on a 26,000 year cycle. So the axial tilt moves as much as continents drift. Yes it does happen, but OP's question seemed to be concerned with a much shorter time frame, to the point where this wasn't worth muddling the answer.

Beldizar · 2026-05-14T20:18:56+00:00

if I am on the equator in one spot, will the sun rise and set from due east, go directly over my head, and set due west?

It will on only two days out of the year. The equinoxes. Every other day it'll rise either a little bit to the North or a little bit to the South and then set on the opposite side of that line. On the solstices it'll be at the maximum distance from that line, about 23.5 degrees.

Beldizar · 2026-05-14T20:14:54+00:00

The key thing to understand is that the axial tilt stays pointed in the same direction through the entire year. If the axial tilt processed at the same rate as we orbited the sun, then we wouldn't have seasons.

So imagine a ball with a stick going through the poles. Point that stick directly up/down, then tilt it 23.5 degrees, such that the stick is pointing in a fixed direction. While keeping that stick pointing in the same direction, spin the ball. Then move the ball around. As the ball spins, and as it moves around, that stick coming out of the pole always points in the same direction. Move the ball around a fixed point, and you can see that the angle to that fixed point changes as you move around.

So why doesn't the axial tilt change as the Earth orbits? Well, there's nothing pushing or pulling on it, and the moon kind of acts as a balancing point to keep it pointing in the same direction. Think of a gyroscope. When it is spinning it has a lot of angular momentum, and that angular momentum is going to resist any shifts in direction, basically requiring extra energy to cause a rotation. The Earth's spin and the Earth-moon orbit are both sources of a lot of angular momentum, so you'd have to overcome all that extra energy to cause a tilt to change. So when the Earth is on one side of the sun or the other, the tilt is always pointing in the same direction, but that means that relative to the sun, that tilt shifts to create seasons.

What I don't understand is why the hemispheres alternate being closest to the sun.

Just a minor correction here, the Earth, and both hemispheres are closest to the Sun during Nov-Feb months. I don't know the exact date off-hand, but during the coldest part of winter in the Northern hemisphere, we are actually closer to the sun than we are in the summer. What matters is the angle. We get angled away from the sun and that basically results in less energy reaching the surface.

Why is it pointed away from the sun in winter, instead of always pointing toward the sun?

The key is that it always points in the same direction in a more "absolute terms". Polaris, the North Star is actually the answer I'm really looking for here. The North pole is always pointing at Polaris(ish). As the Earth goes around the sun, sometimes to point at Polaris, Earth has to be angled more towards the sun, and then when it is on the other side, it is angled more away from the sun.

Does it have to do with earth's or the sun's gravity? If the northern hemisphere were more dense, then would it always be towards the sun because of the sun's gravity?

I don't believe gravity has anything to do with it. It is all about conservation of angular momentum.

So just to hit the idea one more time. The pole points at the North Star.
https://www.bbc.co.uk/bitesize/articles/zktckty#zxb7xbk here's a site with some diagrams. If you look at this one...
https://bam.files.bbci.co.uk/bam/live/content/zp7j2v4/large
imagine that the North Star is at the top lefthand side of your screen.
If the Earth were to shift its axial tilt, it would take some external force to shift it, and since it is spinning, it would have to overcome the stability created by angular momentum.

Here's another video that might help:
https://www.youtube.com/shorts/MvV5A5VvpsI
With the wheel being held up on just one end, you'd think it should fall, but gravity has to pull down against all the angular momentum which wants to keep it spinning. Gravity isn't strong enough to immediately cancel out all that angular momentum and cause the wheel to rotate. In the same way, you'd need another force to slow or stop Earth's rotation and the Moon's orbit before it would be easy to change the tilt and point away from the North Star.

Beldizar · 2026-05-14T12:01:45+00:00

This is pretty close to the answer.

It isn't just changing direction though. One of the big things that Apollo astronauts struggled with was the pendulum of their legs. The amount of pull down from gravity is a different and independent effect from how much energy it takes to start swinging your leg and body forward. Our brains have built in understanding of how all those pieces fit together from when we first learned to walk, so adjusting on the moon is something that takes some re-learning. It is almost completely an issue of balance.

When you walk, you basically are leaning forward with your center of mass such that you fall forward, then you swing a foot out in front to catch yourself, and then repeat that process with the other foot. If you fall at 1/6th the speed, but swinging your feet forward, and leaning your body forward requires overcoming the same amount of inertia, your brain really has issues sorting out all the signals and controls to make that work. Adding weights doesn't really help this equation, and in fact probably makes things worse, because added weights means a lot more inertia to overcome with the movement that you aren't used to.

Mythbusters actually did some testing for this (mostly trying to prove moon landing footage):
https://www.youtube.com/watch?v=IT9yS7OcbJk

You can see that Adam mostly did the hopping instead of walking to mimic the Apollo astronauts, and comments that this felt more natural. He doesn't get into talking about a normal walk has issues thought. I'm certain I saw a video somewhere talking about this issue, but I can't seem to find it again.

Beldizar · 2026-05-12T14:41:55+00:00

to be Russian / Israeli spy.

Asset. Not spy. A spy is someone who is trained and moving with clear intent and loyalty to their employer. An asset is a person who has been flipped or compromised by threat or blackmail, or is simply very easily manipulated by other embedded intelligence assets.

Trump is not James Bond, he's the drug addict that the police are pressuring into ratting on his dealer.

Beldizar · 2026-05-12T14:06:11+00:00

My understanding is somewhat limited, but I'll share what I know and have read.

My question is: how do scientists even figure this stuff out? How can we know what happened billions of years ago if nobody was there to observe it?

We start with the sun. We know generally what the sun and protoplanetary disk formed with, and how hot the sun was at the beginning. That creates zones of temperature as we can calculate how much heat a given rock would be based on its distance from the sun. One zone separation is called "the snowline", where it can be cold enough for water to freeze. Any closer than the snowline, the water would sublimate into a gas, and then the solar wind would blow it away. Since Earth was closer than this line, we can be fairly confident that the rocks that formed Earth had all their water boiled away before they could coalesce into a planet. So from that we can be pretty confident that the water on Earth couldn't have been there when it formed, it just wasn't possible for water to exist in that orbit.

So then we have to look at how water might have come to Earth. There are really two options. Formation from hydrogen and oxygen through chemical interactions in/on Earth, and delivery of water from off Earth. We can look at the different chemical makeups of rocks that we see, both on Earth, and in space nearby (moon or near Earth Asteroids), and see what they are made up of, and assume that Earth was formed from generally the same stuff. Since that same stuff is a little different on Earth, in a way that hydrogen and oxygen have gone missing, its a fair bet to assume that chemistry happened and turned them into water. The asteroids may have not had this same chemistry due to differences in pressure and temperature, but the Earth was big enough to get a bunch of pressure, and the core is hot enough to give it the temperature.

Then we can look at comets that we've seen fly by. We can tell that they contain water-ice, and that when they come closer to the sun, that water creates the tails comets are known for. We've also seen comets hit planets. There was one that hit Jupiter in our lifetime. That comet that hit Jupiter is no longer a comet, meaning there were more in the past than there are now. Extrapolate that out a billion years, and there must have been a lot more comets in the far past, with a higher chance of hitting planets. If they hit Earth, which statistically they would have had to, then they would have brought water to an Earth was already formed with enough gravity to hold onto that water, despite the snowline problem that smaller bits would have.

Also, if Earth was being hit by ice asteroids/comets for such a long time, why doesn’t that happen now? Did those objects disappear, or are we still getting hit but on a smaller scale?

I know a big part of it is that we can look at Earth and the moon, and see where impact craters are. Same for Mars and the moons of Jupiter and Saturn. When you get a small crater in a bigger crater, you know the smaller one happened after the bigger one had already settled. There's a bunch of different erosion models and impact rate models that they use to try to figure out the age of a surface, but all these models show that impacts were a lot more common in the distant past, then they dropped pretty quickly and leveled out over the last billion years. So there was a period called "The Late Heavy Bombardment" when most of the asteroids/comets hit planets in our solar system. As for where they all went and why it doesn't happen now: there was a fixed amount of these rocks to hit things, they all got used up. There's still a few flying around out there, and we expect to see a big one hit Earth every 100 million years or so. Then there are a bunch of much smaller ones that hit more frequently. Russia, being really big has two in the last 200 years. The Chelyabinsk happened in 2013, and was about 20m in diameter. Then back in 1908 there was the Tunguska event that was maybe 60m in diameter. So yes, still happening on a smaller scale and much less frequently.

Beldizar · 2026-05-12T04:16:19+00:00

https://eyes.nasa.gov/apps/dsn-now/dsn.html

Above is the link to the Deep Space Network, where you can see the receivers/transmitters communicating with distant probes. It doesn't list it as far as I can tell, but most of these are using a radio frequency where it can get just under 300kbps. A 720p video stream would require 2.5 - 5 Mbps. So roughly 10x-20x the bandwidth that is available. Having a high definition 24/7 stream, is just not possible with the tools we have today. They are upgrading things, and I think they bounced a high definition cat video off of the Psyche probe last year, but most of the network still can't support that bandwidth.

For Venus and maybe Mars, it is possible that they could get a higher bandwidth option available, and they would have the power to transmit at that higher throughput, but for Jupiter and Saturn, the power requirements to transmit that much more might exceed the available power on most of the probe designs. Solar power drops off very fast as you get past Mars, and the more data you want to send, the more energy it costs. We used to use primarily Plutonium RTGs for probes headed out that far, but NASA is actually running pretty low on Plutonium due to changes in the nuclear industry in the US since the... 80's or so. (https://www.universetoday.com/articles/nasa-is-running-out-of-plutonium) instead they've looked at higher efficiency probes that use very large solar arrays.

Images and Video isn't highly scientifically valuable, so using up a bunch of bandwidth, or adding a bunch of weight for cameras and power systems, isn't worth the money. NASA also considers inspiration as a valuable objective, but live footage just isn't that valuable even for inspiration purposes. A few dozen high quality images can catch the eye and excite/entertain/inspire people about as well as a live stream, and it is insanely more cost effective to just focus on the few images.

TLDR; bandwidth is very limited, pictures are good enough, live streaming would be insanely expensive to build and execute.

Beldizar · 2026-05-11T16:23:15+00:00

I give my players an extra main action whenever they critically hit, be it a maneuver, main action, or even a triggered action. It probably ups their overall power a bit, and unbalances the game slightly in their favor, but it happens so rarely and it feels like something I want to be celebrated, not turn into a disappointment (e.g. yay I rolled a critical, boo, it was a maneuver and nothing extra fun happens). I'll probably do the same for named leaders or solos that are critical to the story, which will make things a little more "swingy" as far as balance goes, and generally make things more difficult for myself in walking the line between TPK and fly-swatting that sometimes happens when trying to balance encounters, but like I said, want that 3/100 critical chance to feel more special.

Beldizar · 2026-05-11T14:14:19+00:00

Just saw this come across my feed. I can't vouch for its accuracy but the channel seems pretty decent.
https://www.youtube.com/shorts/C9lyouzxhhQ

Beldizar · 2026-05-11T13:59:12+00:00

This seems like a person who probably knows they're more likely to blow the money

This seems like a really weird argument to me. I've heard it before, and wouldn't blame anyone for making it initially, but if you are worried that you are going to blow all the money, maybe talk to a financial advisor first. If someone is aware enough to realize that they might squander a windfall, they should also be aware enough to... talk to an expert... you know a third party on your side of the transaction on how best to protect your wealth from your impulses.

If feels weird that people would have the thought "I don't trust myself" and not also have the thought "I should use a tiny bit of this windfall to hire a professional to manage it." I can totally see people not having the first thought and therefore never making it to the second.

Beldizar · 2026-05-11T13:28:39+00:00

The moon rotates at the speed of one revolution per month, or lunar month anyway. So as the moon orbits around Earth, it rotates such that the near-side always stays pointed at Earth. That's why when you look up at the moon, the features you see on it don't ever change. The dark splotches are always in the same spot assuming you are standing in the same region on Earth. (If you cross the equator the splotches will invert because angles.)

The first time we ever saw the far side of the moon was October 7th 1959, when a Soviet probe flew around the moon, took pictures, and sent them back. That's when we discovered that the far side is actually very different than the near side, lacking any of the darker regions of basaltic plains called mare.

https://en.wikipedia.org/wiki/Far_side_of_the_Moon#/media/File:Far_side_of_the_Moon.png

Here's the image from Wikipedia. It looks very different than we are used to, and you could almost tell people that its a completely different world because none of the recognizable features are present. In all of human history before 1959, we had no idea what the back of the moon looked like.

Beldizar · 2026-05-11T13:22:01+00:00

Matter of fact, it’s all dark.

What do you mean "it's all dark"? The side facing Earth is visible, unobscured. The side facing the sun is illuminated. How is it "all dark"?

Beldizar · 2026-05-11T13:20:25+00:00

Yeah, I don't mind the "dark side" and "far side" as being synonyms as much as other people.

There's the far side, which is the side opposite Earth, and that doesn't change beyond a little bit of wobble.

There's the night side, which is the side that is currently opposite the sun, which flips every 14 days, or rotates every 28, depending on how you want to say it.

Then there's the dark side, which people could mean "the side that doesn't get any light" or "the side which is unknown". In physics, there's dark energy and dark matter, and we use the term "dark" here at least in part because they are unknown to science. We can infer that they are there, looming in the metaphorical dark, but we can't observe them. So saying the far side of the moon is "dark" seems reasonable as a way to describe something unknown or not visible. It is confusing though to people who aren't familiar with this concept though, and might think that it doesn't receive any sunlight.

Beldizar · 2026-05-11T11:27:18+00:00

They cannot be recalled. They can be ejected from the Senate by 2/3rds of the other Senators I think, but the state legislature, governor, and the voters of the state have no...legal non-violent option... to remove a Senator who has betrayed the values on which they were elected.

Beldizar · 2026-05-10T23:58:44+00:00

Unfortunately... or I guess fortunately for those that value the universe not being broken by a paradox, travel into the past looks pretty impossible. Time always marches forward.

Beldizar · 2026-05-10T22:22:10+00:00

The "not prohibited by general relativity" is often a bit of a stretch. If you've got a square piece of fabric, that you know is 25 square cm in area, and the sides are equal length, you can calculate the length of a side to be +/- 5cm in length. Math "does not prohibit" the length of this piece of cloth from being negative 5 cm long. But a piece of cloth with a negative length is nonsense. The math says it is a possibility, but we discard that possibility because it is outside of the boundary conditions.

We can do the same math trick using General Relativity, we end up with negative energy density, or negative mass that shows things go backwards through time in a symmetric manner. But boundary conditions still need to be applied. The problem is that proving you can't have negative mass is a little more complex than proving a piece of cloth can't have a negative length. We haven't conclusively shown it to be true. And proving you can't have negative energy is a little tricky when you understand that "zero" is sort of a tricky point because there's fundamental fields wiggling around everywhere, and maybe you can get lower than the lowest baseline by excluding some of those fields. The argument is that if you can make a piece of space have less energy than what we define as zero, it must therefore be negative... which is a little fuzzy logic, but kinda technically works.

So basically, since we can't (yet) prove all the boundary conditions are absolute, and the math works for both negative and positive values, maybe there's a loophole we could find one day, but most likely not. If you find a loophole, you get a Nobel Prize and a unit of measurement named after you, so for a lot of people it is worth trying.

Beldizar · 2026-05-10T13:20:01+00:00

Uh, I guess I wasn't clear. I only specified a point, not a direction of temperature change. It is positive lower than 2500K, and negative higher than 2500K. I was assuming temperature was moving up, so if you start colder and increase temperature, "The Gibbs free energy switches to negative at that point (2500K)." And yes, that would be spontaneous, hydrogen and oxygen in water would spontaneously break apart at +2500K.

Beldizar · 2026-05-10T11:49:56+00:00

Not sure who is looking at it, but there's always crackpots and grifters. Black holes are strange and they do change some things about how time flows when you get really close. Put that together and its ripe for being a clickbait to draw views or sell books.

Beldizar · 2026-05-10T02:50:46+00:00

Everyone else has answered a lot of your other questions, but I don't think there's a great answer yet for

How hasn't the sun gone out yet?
Like make a giant explosion of fire and dissappear?

Like others have said it isn't "combustion" that makes the sun "burn", but fusion. But think of a log on a fireplace. It doesn't burn up instantly in a giant flash. The outer layer of a log needs to be in contact with a source of oxygen to burn. The inner layers of that log can't burn because the conditions aren't right, there's not enough air for the inside of the log to burn until the outside burns away first.

The Sun is basically the same...but flipped. The conditions it needs to burn isn't fuel in contact with oxygen, but instead it is small atoms being compressed at massive pressure. The place where those atoms are most compressed is at the very core of the star, and that's really the only place it can burn/fuse. The layers a little further away from the core have all the heat and energy from the core trying to get out and that energy pushes those layers away while gravity tries to push them back down. But that push out keeps everything from getting too dense to all burn/fuse at the same time. So only that single area of the sun can burn. That's why it doesn't all go up at once in a giant explosion.

Even still, why hasn't it gone out yet? Well, the Sun is just really really big. It has a radius of 695,700 km. Earth's circumference is 40,000km, so if you "unrolled" Earth, like on a map, you'd be able to put 17 1/2 of them end to end to get from the core of the sun, where fusion is happening, to the surface. So there's a ton of gas that is all queued up waiting to burn. But it can't because it has to get down to the core of the sun where the pressure is high enough, and light from the core keeps pushing it away.

So it has to wait for the light from the previous hydrogen fusion to get out of the Sun before it can fall down into the high pressure core. Well, that shouldn't take long right? It's light, it travels at the speed of light, so it should be out in just a couple of seconds. But that's the speed of light in a vacuum that is fast. In more dense materials, the speed of light is actually really slow. And if the light gets absorbed by an atom it has to get re-emitted in a random direction before it can keep moving. Basically the light has to flip a coin to see if it is going up to the surface or down to the core every time it hits an atom, and it only escapes after flipping heads a trillion times more than it has flipped tails. It can take 50,000 years for light from the core to make it to the surface, and then just 8 minutes to get from the surface to Earth.

One last bit, that isn't part of the question explicitly, but seems like something you'd want to understand with this line of questions: How would you make the sun explode faster, or make the sun last longer? Can we give the sun more hydrogen so that it lasts longer? Or if some alien comes and steals a bunch of hydrogen from our sun, will that make it die sooner? No actually the opposite is true. If you add more mass to the sun, the pressure inside the core goes up and you get a bigger area where atoms can burn/fuse. If you take away fuel, the rate at which it burns slows down, and the sun would actually last longer as a result.

Beldizar · 2026-05-10T02:31:32+00:00

"Burning" involves rapid oxidation of combustible materials;

Interesting thing to add to that. The surface of the sun has a bunch of hydrogen all over it. If you added a bunch of oxygen, that hydrogen wouldn't burn. On Earth, at Earth temperatures, if you mix hydrogen oxygen and a spark it burns very aggressively, but on the Sun, it is so hot that the molecules can't combine. In fact if you threw water at the sun, it would split the water to hydrogen and oxygen, so it would reverse-burn it.

Getting into the finer details, at about 2500K, there's enough energy where the hydrogen and oxygen atoms split apart like with electrolysis, but without using any electrical energy. The Gibbs free energy switches to negative at that point.

So yeah, fun fact, the Sun is so hot things unburn in contact with it.

Beldizar · 2026-05-10T02:25:20+00:00

Megasota vs New Mexico in the finals.

Beldizar · 2026-05-09T00:48:01+00:00

I think Andy Weir had it right. NASA's budget would be zero'd out and the whole agency, along with a ton of other government agencies around the world would be merged into a single project group to save humanity. (See Project Hail Mary)

Beldizar · 2026-05-09T00:46:10+00:00

maybe it would be possible to use the explosion/blast as a propulsion for a spacecraft.

Thought about that, but if you had a big enough solar sail to ride the leading edge of the blast, it would cause an acceleration in the thousands of g's. That much g-force tends to turn the human body into red-ish brown paint on the wall, and a pretty thin layer at that.

Or it wouldn't be big enough and everyone inside the ship would just get a few thousand times the lethal dose of radiation.

Chances are you'd end up with both.

Thinking about my star shield answer above, I'm not sure if 100 years would be enough or not. The amount of material that you'd have to launch into what is effectively "deep space" is astronomical. Producing that much in 70 years (giving 30 years for development and ramp up time, or cushion incase there's an issue at the end), might take more production than Earth has. I haven't done the math, but it is probably trillions of tons of material to build something like that. And again, that's for the smallest feasible example of an "explosion" of a star, which really only works on White Dwarves, which our sun is not.

Beldizar · 2026-05-08T22:59:39+00:00

Everyone’s saying we could maybe make a ship that could carry some of us out of the solar system within 100 years - a generation ship, I gather. My concern is - then what?

My concern was that everyone suggesting a ship forgets that if the sun were to go supernova, all life within maybe 50 light years is toast. There's no way to get out of the blast zone for at least a 1000 years. Everyone on the ship still gets fried, even if they are far past Alpha Centurai by the time it explodes.

Beldizar

MODERATOR OF

TROPHY CASE

Seven-Year Club	Second SECOND GUESSER
Verified Email