They do actually appear the same size in the sky though, which is why we get perfect eclipses. The Moon is slowly getting further away from Earth so it won’t be forever. We’re just in a lucky moment of time in the universe.
It really is just a coincidence.
A pretty rare coincidence. I’ve read that if there was a thing like interstellar tourism, the earth would be quite popular for the solar eclipses, as it’s very rare that the size of the moon (in perspective) covers the sun exactly.
welp to buy some real estate real quick before this interstellar tourism boom shoots up the prices
What about planets blocking the sun from moons?
Planets are like pinheads in comparison.
I know you’re right, have read it elsewhere before. But I can’t figure out why that would happen. I doubt Earth is loosing mass. Does the moon slow down over time due to impacts or what causes this?
If it slowed down it would get closer, not further. The truth is, any orbit is only stable given a specific timeframe. The longer that timeframe, the less likely any given orbit is to remain. The moon has just a little bit more speed than the Earth can hold onto, so it is in an extremely slow escape, and always has been.
The moon has just a little bit more speed than the Earth can hold onto
Unfortunately that’s not how orbital mechanics works :(
If the moon had instantaneously more speed than the earth can hold onto (e.g. more centrifugal ‘force’ than balanced by the gravitational force), the moon will accelerate up, until the forces become balanced. This makes a elliptical orbit, like this:
Apparently the reason the moon is getting further away is that it’s gaining energy from earth’s tides
anyway you should play ksp
If it had a stable orbit before and then slowed down, I thought it’ll get a more elliptical orbit, being both closer and further, or fall into Earth.
My logic was that a stable orbit closer to the center needs higher speeds to counter higher gravity and vice versa.
So if the moon would get hit in a way that makes it slow down and get pushed further away from Earth at the same time, it could keep a roundish orbit, or not?
What’s with that specific timeframe? Is it due to the orbit never being perfect? Or random slight influences from other not too far, heavy objects?
Thanks for the explanation, the moon being a little fast for it’s orbit and therefore slowly spiraling out of Earths gravity makes sense to me now.
You actually have gotten a bad explanation. There’s no such thing as being “a little too fast” which would cause this effect, and there definitely is no “spiraling out” due to inherent speed/momentum.
An object in orbit of another remains in orbit as long as its horizontal velocity is high enough to not be pulled into a collision with the parent, but low enough to not escape the gravitational pull altogether. The closer to the parent, the stronger gravity affects the object, so you have to go faster horizontally to keep “missing” the parent, making gravity only pull you into a circle around it instead. That’s why it’s also called orbital speed: the object is not going straight in a line, it travels at speed in an orbit.
If you want to change an orbit, you need to accelerate or decelerate. This energy has to come from somewhere. And obviously, the direction you accelerate in matters. If you speed up horizontally, increasing your orbital speed, you’ll get further away from the parent, but by moving further away, your orbital speed will decrease and be lowest at your furthest point. Then, if you don’t keep accelerating, you’ll start to get closer to the parent again, which makes you go faster. This is an elliptic orbit.
If you go fast enough horizontally, you eventually can get so far away that the parent’s gravity influence becomes negligible, and the gravitational influence of another parent matters more. This is called reaching escape velocity. If you leave earth orbit, this is usually the sun.
If you were to simply slow down the object in its orbital speed, the object would get closer to its parent until it collides.
If instead of accelerating the object “forward”/horizontal to human observer on earth, you’d accelerate “up”/away from the earth, you interestingly would not cause the object to get further away from its parent. Yes, you’d move higher up, but that would also mean that you equally slow down along the “forward” axis. So as explained before, if you stop accelerating, the object will start being pulled by gravity again until it reaches its now even closer than before proximity to its parent, half an orbit later on the other side. Because it’s now closer to the parent, it has sped up and will then start moving away again, another elliptic orbit has been achieved.
And if you accelerate “sideways”, so neither away from the surface nor forward along the orbital path, you actually change very little: you only affect the inclination of the orbit. Usually we think of objects going around the equator, but they don’t have to. An orbit can go any which angle, even rotating around the poles, going South to North or vice versa.
So long story short, how does the moon speed up? It doesn’t have and rocket engines or similar. The reason is the vast difference the earth and the moon rotate around themselves. The earth takes 24h to rotate. The moon takes roughly 27.3 days to rotate a single time. This causes the Earth to “push” the global tidal waves around its oceans much faster than the Moon gets pushed. This actually causes the moon to get “dragged along” a tiny little bit on every tidal rotation. This not only speeds up the rotation of the moon itself: the moon is so slow that it doesn’t have time to transfer all that rotational energy before the tidal wave on Earth has moved on the surface to be a bit on front of the Moon. This is the moment where the Earth’s center of gravity is a tiny bit “forward” of the middle of the Earth. This in turn pulls the moon forward along its orbital path, speeding it up horizontally. Obviously, this also means that Earth’s rotation gets actually slowed down by the same amount.
All these effects are incredibly tiny! The moon moves “away” at 3.8 cm per year, whereas it will take 50 years for an earth day to be a single millisecond longer.
Quite the opposite: the Earth is tightening mass.
i could go for a car sized burger right now
I could go for a burger-sized car
mmm, crunchy
I could always go for a car sized burger
Man, these people needs to put things in perspective
Could we get some more pixels?
3 take it or leave it
Hmmm. Fine. I’ll take it.
The Book of Enoch is wild though. It reads like a first hand account from a bronze age tribal getting abducted by aliens.
The Goat Herders Guide to the Galaxy
I tried to read through the Wikipage, but it was just too dense for me so I asked an AI to summarize which I think it did pretty well:
The Book of Enoch, also known as 1 Enoch, is an ancient Jewish apocryphal text attributed to Enoch, the great-grandfather of Noah. It is not considered canonical by most branches of Judaism or Christianity but is significant in the study of early Jewish thought and the development of Christian theology.
The book is divided into several sections:
- The Book of the Watchers: This section describes the fall of the Watchers, a group of angels who descended to Earth and took human wives, leading to the birth of the Nephilim, giants who caused chaos. Enoch is chosen to intercede on behalf of the Watchers, and he receives revelations about the coming judgment.
- The Book of Parables (or Similitudes): This part contains three parables that focus on themes of judgment, the coming of a messianic figure, and the fate of the wicked. It emphasizes the importance of righteousness and the ultimate triumph of good over evil.
- The Astronomical Book: This section provides detailed descriptions of the movements of heavenly bodies and the calendar, reflecting an interest in astronomy and timekeeping.
- The Book of Dream Visions: Enoch recounts two visions that symbolize the history of Israel, including the judgment of the wicked and the reward of the righteous.
- The Epistle of Enoch: This final section contains exhortations to righteousness, warnings about the coming judgment, and reflections on the fate of sinners.
Overall, the Book of Enoch explores themes of divine judgment, the nature of evil, and the hope for redemption, making it an important text for understanding early Jewish and Christian eschatology.
I tried to read through the Wikipage, but it was just too dense for me so I asked an AI to summarize which I think it did pretty well:
So you’re saying a bot did a good job of summarizing a thing that you didn’t read? Wat?
I’ve seen a pattern of comments that start the same way as what you quoted for what it’s worth.
I appreciate the insinuation that I don’t know how to read an article… no, I skimmed and dived as much as I normally would but realised that topic was too complex for a full dive and that the abstract was too sparse for a good overview…
Wait, isn’t Enoch heretical or whatever?
Apocryphal for most sects. Heretical for Rabbanic Judaism.
The most interesting thing about it I think is that it was thought lost for centuries, but there was a well-known translation in Ethiopian. When the greater Christian population heard about it, it was assumed to be a forgery, but it was still studied and translated.
It wasn’t verified as “authentic” until the discovery of the Dead Sea Scrolls in the 1950s, where ancient Greek and Aramaic copies were discovered that match the Ethiopian translation, establishing the provenance of the Ethiopian version.
I like big buns and I cannot lie.
I can’t believe i just stumbled upon a random father Ted reference!
Was hoping to see this in the comments.
“I’m… crushing your head!”
So the prophecy is fulfilled
Where can I buy this burger?
You can’t. You have to win it in a contest.
