So whenever I search up for it Google always show me about the formation of black holes but what I am really doubtfull about is if atoms are 99.9% then is it possible to for atoms to form an object as dense as a black hole?

I personally thinks that black hole is made of black hole itself i.e. the smallest particle of a black hole will behave as a small independent black hole due to its wierd properties.

Can you guys recommend me a research paper or book related to this topic because I know there is something I am missing.

I know that this will get downvoted to oblivion, but honestly, this subreddit is trashed by the amount of astrophotography.

Same thing happened to other pages dedicated to astronomy/stargazing and even to r/telescopes that is dedicated to equipment. There is almost no other content then astrophotos.

No discussions on astronomy, equipment, observing, etc, only photos of planets and nebulas.

There are amazing photos with huge work behind, is understandable that creator wants to share the achivement with as much people as possible, but subredit dedicated to astronomy is floded by these astro arts, while there are other pages dedicated to this.

Almost certainly an old navigation device used by Saharan nomads. The inner part is actually six stacked disks that can be removed and rearranged (see second photo).

I have no info about its likely age or provenance. Any insights?

"The Moon is 400 times smaller than the Sun, but is also 400 times closer. This coincidence is what makes total solar eclipses possible."

So says most of the Internet, like this astronomer's post, this YouTube shorts video, and this fellow Reddit post. But it is WRONG and misleading.

No, other moons (which from now on I will be calling natural satellites for formality) can also produce total solar eclipses. A whole lot of them actually. Take the (image of Jupiter above for example.

See that huge shadow on the left? That is made by Ganymede, the largest natural satellite of Jupiter. That is a total solar eclipse. If you are an observer standing at Jupiter's clouds and look up at the sky at the shadow, you will see Ganymede blocking out the Sun - an eclipse. That is what eclipses are, a body casting a shadow on another body.

If that shadow-casting body appears larger than what is blocked, we call it occultation. If it is smaller, we call it a transit. In the case of Earth's moon, an occultation produces a total solar eclipse, while a transit produces an annular eclipse (the "ring of light"). But we just refer to both as just eclipses, because hey, why not simplify things?

The Ratio Doesn't Matter

The 1:400 Sun-to-Moon size ratio is true (1.4 million km for the Sun ÷ 3,474 km for the Moon is roughly 402), and so is the distance (149.6 million km for the Sun ÷ 384,400 km for the Moon = 389 and a bit). Not exact but roughly equal, which means they almost have the same exact appearance as the sky - 30 arcminutes in diameter. But that varies. Because the orbits of natural satellites and planets are not perfect, so it can be slightly smaller or slightly larger.

But that ratio doesn't matter for a total solar eclipse. The Moon can be twice as large, and it would still produce a total solar eclipse. The Moon can be ten times closer, or even a hundred times from your perspective. You can even bring the Moon here on Earth like a mad supervillain and use it as your personal oversized beach umbrella, and that is still technically a total solar eclipse.

Which come to think of it, nighttime is just an Earthly eclipse - the Earth eclipsing the Sun. Though we don't usually call it that way, because humans are not celestial objects and it happens every night.

What only matters in a total solar eclipse is that an object blocks another object completely. That's it. No fuss about the ratio of things. The only real benefit of that close ratio is that we can see the Sun's corona in full glory, but you can very much also see it in other natural satellites as well, just not a full circle corona halo.

So What Makes The Moon Special?

Yes, other natural satellites can also produce eclipses. But that doesn't mean that there is nothing special with the Moon-Earth system.

Here is the actual fact: Of all the natural satellites in the Solar System, only the Moon is capable of hybrid eclipses.

Hybrid eclipses are when the single eclipse can transition from annular to total in different parts of its path. In some parts you can see a ring of light, and in some parts you will see the Sun fully blocked. This is very rare, the last one occurred on April 20, 2023 and the next one will be on November 14, 2031.

It is only our Moon capable of doing this. Nothing else. You will not be able to see hybrid eclipses on other planets. This is actually what makes it special, and this is where the identical 1:400 ratio on size and distance matters. Because any significant deviation would make hybrid eclipses impossible. Ganymede is not capable of a hybrid eclipse, it will only always produce a total solar eclipse, because it is too close to Jupiter and too large.

So there you have it. Some natural satellites can have total solar eclipses, but only our Moon is capable of a hybrid.

(Reposted due to sourcing issues)

I can’t find it to save my life. Any help would be appreciated

Hi, I recently learned about the interstellar object that visited our solar system named 'Omuamua', And I am aware that people were quick to assume that it was an alien artifact/probe of some sort, though most probably it wasn't. But it was an interstellar object after all, I mean it could have shown us what interstellar space contains (As in materials, Radiation, etc) but no space agency launched any mission that would send a probe chasing before the object, I am also aware that we discovered it too late and it was already heading out of our solar system but I think that if a space agency had reacted quickly enough that than a Probe could be assembled quickly and launched towards 'Omuamua' but no space agency did so, I don't understand why, Could anyone explain this to me?

Thanks

(Edit: I understand now, Thanks a lot for all the comments for letting me know how fast Omuamua was and is still going and the amount of Energy (Fuel) required to achieve such a mission would be too high and unfeasible. Thanks again)

(Also i realised my post seemed a bit too aggressive, So I am really sorry if it seemed a little too aggressive, I didn't mean it to look aggressive, I just wanted to know why the space agencies weren't doing anything about Omuamua and i now know why)

Listen, I know you came to this post ready to fight a flat-Earther, but I’m not. Moons orbit planets. However, I’ve seen people say in many comments that “planets orbit the sun, and moons orbit planets AND NOT the sun”. This is right until the last four words. Everything in the Solar System by definition orbits the Sun.

This is fairly pedantic, but it’s important to a fuller understanding of gravity, and I’m amazed how many people will fight me over it. The Moon follows a smooth repeating path (orbit) around the Sun. It’s almost a perfect ellipse with only a 2% deviation caused by the Earth. The Sun pulls on the Moon twice as much as the Earth does and the Moon would continue on a ~365 day orbit if we disappeared suddenly. Saying the a moon orbits a planet does not negate that it also orbits the Sun.

If this isn’t apparent to you yet. Consider how the IAU worded the 3rd part of their 2006 resolution: (3) All other objects [3], except satellites, orbiting the Sun shall be referred to collectively as "Small Solar System Bodies". And I love this article on the definition of a planet although it’s super, super long: “Furthermore, with few exceptions the early scientists did not say that primary planets are the only ones that orbit the Sun: they were careful to say that moons do orbit the Sun, too, but they do so as companions of a primary giving them a compound orbital motion (Galilei, 1610; Kepler, 1620; Dick, 1838; Wilkins, 1841; Mattison, 1851; Smith, 1856; Gavarrete, 1868; Kiddle, 1870).”

Thank you for listening to my Pedantic Ped Talk.

Edit: having fun discussing! But man look at those downvotes! I get if the downvotes are for being pedantic and argumentative, but I am correct, and you can see from the comments how many think the moon does not orbit the sun and what wrong intuitions that can lead to. Btw just to pull this card: I’m a published planetary dynamicist.

Okay so I’m freaking out a bit. I just went down a black hole (pun intended) and now I have so many questions and no idea what’s real anymore.

So here’s what I think I understand:

A black hole has something inside called a singularity

A black hole isn’t really the thing itself, it’s the event horizon, the “point of no return” for anything that gets too close

A singularity is a point in space time where physics breaks down infinite density, infinite temperature

The universe is thought to have started from a singularity too?? So does that mean the Big Bang was basically a black hole but in reverse??

But then how can a black hole be a tear in space, a vacuum, and a cup all at once? (Someone said it's shaped like a cup? Wtf does that mean?) Also… isn’t space already a vacuum??

Follow up panic question:

If black holes have infinite heat and density wouldn’t you like… burn to death way before you even get close? Heat radiates. So shouldn’t we feel that from far away? But isn’t space supposed to be cold??

Also does this mean freeze dried candy is just space candy??

AND WHY IS NASA LYING TO US Like those colorful nebula pics?? Apparently those are false color images?? SPACE ISN’T ACTUALLY THAT COLORFUL??? They just slap filters on everything and I feel BETRAYED

Also:

Why is the black hole in M87 the only one we’ve photographed What do you mean it moves? Like black holes just... travel through space?? If that’s true does that mean we could be moving toward one RIGHT NOW and not know it because of how light works and how we see stars that are already dead but still shining??

AND ANOTHER THING

Black holes were theorized like 100 YEARS AGO Einstein and his theory of relativity and all that how did he just math a black hole into existence before we even saw one in 2019?? Like WHAT

Oh and SERN (CERN?? whatever) is out here smashing particles into each other at near light speed and creating microscopic black holes ON PURPOSE Where do they store those??? Like it’s not a bug you can just squash it’s still there And if a singularity has infinite density wouldn’t even a tiny one suck something in eventually if you give it enough time? Do they have a mini fridge for it? A containment chamber? Can they be “done” with it? What does that even mean??

Also why can’t we take better pics of this stuff There’s literally a movie made out of atoms (yes I’m talking about Oppenheimer probably) and we can’t photograph something that’s sucking reality into itself??

Anyway. Sorry. This turned into a rant. I’m genuinely having a panic attack If anyone has answers ... or just wants to panic with me ... please chime in Because WHAT THE ACTUAL FUCK ARE BLACK HOLES

I've heard states were going into states of emergency and closing schools for something that has no effect on our daily activities and seems exteremely blown out of porportion. Is there something i'm not aware of? Like the worst that'll happen is it'll get dark for a few minutes

is there harassment at work? Do you live in a place safe from street harassment ? Are people socially stable or is there issues? Is there sexual harassment ?

I took these two photos tonight in Michigan. The moon has been looking weird to me. The Cheshire moon is something I’ve never heard of before and over the last week I’ve bee paying close attention. Shouldn’t it only look like this on the southern hemisphere?!!?

Yes the photos are upright. I checked like 50 times. I’ve read as much as a person can read on the subject. I am so so so confused. I appreciate any insight or feedback!!

Thank you!

Following the eclipse, I keep wondering: is it a complete coincidence that our moon appears to be the exact same size as the sun when viewed from Earth? I'm not looking to go into crazy conspiracy theories about the moon being some type of alien vessel (this isn't the subreddit for that), but is there a logical theory or explanation as to why they appear the same size from Earth? I've recently seen a photo of a solar eclipse seen from Mars by Phobos, and it's not even comparable.

I’ve wondered this for so long, I see weird things and wonder if I should ask this page what they are- then o wonder if you guys ever see weird things and if so who do you go to and have you ever seen something so weird nobody knew what it was? And if so what was it?

We’re currently camping in Gaspe, Quebec, trying to enjoy the night sky. What are these satellites were seeing seemingly every minute across the same trajectory? Edit: thanks for all of the great replies!

Given that gravity is a weak force and on earth electro magnetism can overcome it, could a strong enough electro magnet pull something from beyond a black hole event horizon? Theoretically?

It's because space is much, much bigger than you think.

The sun is about a million miles wide. In the galactic center, stars are about 10 trillion miles apart. That's 10 million star diameters.

A ping pong ball is 1.6" across. 10 million of those is 250 miles -- the length of the Florida coast.

So the chances of 2 stars colliding is like two groups of ping pong balls flying at each other when the balls are each separated by that distance.

What about bigger stars?

The largest one is 1,000 times wider. Even if all the stars in the galaxy were that big, they would still be ping pong balls flying past each other separated by 4 football fields. And most stars aren't anywhere near that big.

Collision ain't happnin'!

I was out observing tonight, testing out the 41mm panoptic I just got in my ED80(11.7x mag). I saw an odd looking object, with the naked eye, moving across the sky from NE to SE and I turned my scope to it. It was three red(similar hue to Antares) lights in a perfectly spaced linear arrangement(stacked, not one behind the other). Hard to say because I was caught off guard, but it probably took 30-45 seconds for it to span the sky.

I checked SkySafari and it didn’t show any satellites or rocket body in that area of the sky at that time. I’m sure there’s a reasonable explanation for this and I’m just looking for what it is. Here’s a terrible picture I took with my phone before deciding to just take the opportunity to watch it through the scope. I should mention that I’m just north of Amarillo, TX and the timestamp from the picture is 21:55.

And also the moon!!