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/sci/ - Science & Math

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9885808 No.9885808 [Reply] [Original]

Thoughts, /sci/?

>> No.9885845

>>9885808
Nothing would change in terms of our orbit. Our planet would still freeze to death.

>> No.9885853

>>9885808
Isn't the gravity well of a black hole much "steeper" than that of a star? Wouldn't the closer planets get pulled in while the more distant planets would start to drift?

>> No.9885863

>>9885853
no

>> No.9885999

>>9885853
There's actually a version of Gauss' Law for gravity, a consequence of which is the pic OP posted.

>> No.9886000

>>9885808
It's right. A black hole is just a star.

>> No.9886237

black hole is just a star that sucks light

>> No.9886240

>>9885853
No, gravity is always proportional to 1/r^2

>> No.9886264

>>9885808
Could there be a black hole equally massive to our sun?

>> No.9886283

>>9886264
dont think so, but im also interested in how big it would be, must not have much volume at all

>> No.9886341

>>9885845
>What is geothermal heating
>What is the greenhouse effect
>What is hawking radiation
',:^)

>> No.9886351

>>9886264
>>9886283

Do we still think they can "evaporate" over time? If so, at some pint on that started out more massive than Sol could pass through being as massive as Sol...

>> No.9886360

>>9886341
>What is geothermal heating
Enough to keep some seas under the ice, like any one of the iceball moons in the solar system
>What is the greenhouse effect
Meaningless without a significant external source of thermal radiation
>What is hawking radiation
Entirely insignificant from a stellar mass black hole

>> No.9886365

>>9886351
Would they not just "evaporate" into being a regular star? Plz no bully.

>> No.9886375

>>9885808
yeah ok... that's cool and all but the real question here is who would win? our lava sun or a black hole sun?

>> No.9886383
File: 48 KB, 350x350, 36BC1285-4485-4A65-815D-25708629AA46.jpg [View same] [iqdb] [saucenao] [google]
9886383

Correct.

>> No.9886421

>>9886264
>what is Schwarzchild Radius
Yes, black holes can have any mass (theoretically), and the event horizon radius (Schwarzchild Radius) can be calculated r = 2GM / c^2. The SR of the sun would be 2954 meters.

>>9886283
>must not have much volume at all
You can find the volume by using the SR in V = 1/2*pi*r^3. The volume of the Sun's mass as a black hole would be 1.08E11 m^3, compared to its current volume of 1.4E27 cubic meters, so the black hole is several orders of magnitude smaller.

>>9886237
No.

>> No.9886429

>>9886421
>black holes can have any mass (theoretically)
I thought black holes were black holes because of how massive they were.

>> No.9886430

>>9886365
I'ma go with "no," as that would require moment when everything formerly within a black hole suddenly was no longer within a black hole -- and we all know that black holes are the Spanish Inquisition of space, NOBODY ESCAPES!

>> No.9886435

>>9886429
They form from stars based on how massive the star is. There are other theoretical ways they could have formed, in sizes WAY down the scale of Size-i-ness.

>> No.9886553

>>9886429
Its not just mass but also densité, in theory earth ,if condensed enough could collapse into a black hole ( in theory)

>> No.9886560

>>9886240

Newtonian Pleb.

But still, gravity is a consequence of energy, momentum, mass and angular momentum content of a spacetime region (and spin). As long as those are the same, you cannot differentiate the resulting gravitational fields.

>> No.9886590

>>9886365
I don't know practically anything about Hawking Radiation, but I'm going to go with no. In reality, black holes are formed mostly (entirely?) at the end of a rather massive star's life, after nucleosynthesis has long ceased in the star. Basically, even if the black hole "evaporated" enough to no longer be a black hole, it wouldn't be able to turn back into a star because it's all out of "star fuel."

However, even if the black hole evaporated much (which I don't believe to be the case), it would continue being a black hole, and the event horizon would simply shrink to match the mass loss. But again, I don't know much about Hawking Radiation, this is just an intuitive guess from what I do know about stars' life processes.

>>9886430
It seems to me like you're thinking about it sort of wrong. If, say, a planet fell into a black hole somehow, and then somehow the black hole "disappeared," the planet would not just show up again. It's not like it stays intact behind a really dark curtain, but rather the atoms of the planet are turned into a soup of fundamental particles, like anything else that falls in. You're right that NOBODY ESCAPES! but it's because that once anything gets too close, it ceases to be anything intelligible and ordered like a planet.

>> No.9886760

>>9886560
>Trying this hard to appear like you know GR well enough to call someone a pleb

>> No.9886767

>>9886560
Are you trolling? I think you're trolling

>> No.9886804

>>9885808
>massive blackhole
>Black being the absence of mass is somehow "massive"

2/10 bait, unless you can answer what gives "massiveness" to a blackhole.

>> No.9886816

>>9886429
You might be thinking of super-massive black holes

>> No.9886818

It would decay very quickly meaning we would no longer have anything to orbit and fling into space. The black hole may produce some light but probably not enough

>> No.9886821

>>9886804
This is obviously bait, but I'll bite. Black holes have mass, it's just incredibly dense. They're "black" because they're so dense and massive that light (which makes things visible aka not black) cannot escape them. Black is absence of light, not mass.

>what gives "massiveness" to a black hole.
Mass. Particles. Most of space is absent of mass, but it's not all a huge black hole. Even a brainlet like (you) should be able to figure it out.

1/10 bait.

>> No.9886823

>>9886804
6/10 bait

>> No.9886831

>>9886804
Are you retarded? They’re black because they’re so massive that they keep photons from leaving them.

>> No.9886833

>>9886804
>Black being the absence of mass
That's why black peoples is so fast. They massless.

>> No.9886855

>>9886430
>black holes are the Spanish Inquisition of space, NOBODY ESCAPES
One could say, when you go black you never come back.

>> No.9887464

>>9885808
We would freeze to death

>> No.9887487

So many cringey people here that don't understand black hole physics, even the basics.

1) "small" black holes don't exist because you need incredible density for it to overcome the Chandrasekhar limit which is necessary for it to have enough mass to become "black" and not just a really big star. And since you said the black hole was the same "mass" as the sun, you're already below the limit for a black hole to form with conventional matter.

But lets say that you had some kind of ultradense theoretical material that could push the Chandrasekhar limit. If that condition was met, then gravitationally, there would be no difference between the black hole and the sun. There would be other obvious differences (no solar wind, heliosphere would disappear, and other minor changes).

>> No.9887526

>>9886264
theoretically yes, but given that most stellar mass black holes are the product of stars several times the mass of the sun going supernova it would take a while for hawking radiation to reduce one to the sun's mass

>> No.9887565

>>9887464
After a while obviously, but Earth wouldn't fall into it or fling to outer space. Pic is from the intro of the video iirc.

>> No.9887613

>>9885853
Only between the original radius of the body and the event horizon.

>> No.9887779

>>9886341
Things that you apparently know about, but know nothing about.

>> No.9887780

>>9887487
"Small" black holes do exist, theoretically, because black holes reduce in mass over time, assuming they aren't gobbling up mass to make up for it.

What you mean is that a star like our Sun won't become a black hole, because it doesn't have enough mass.

>> No.9887798

>>9887487
Primordial black holes in theory could exist at solar masses or much less. And there's no such thing as "enough mass to become a black hole"
Turn your cringe inward my child.

>> No.9887828

Wont it get cold af? A black hole with solar mass radiates much less then a star.

>> No.9887831

>>9887828
black holes don't radiate at all, hence 'black' holes

>> No.9887835

>>9887831
You w0t m8

>> No.9887874

>>9885845
And be showered in deadly Hawking radiation

>> No.9887877

>>9887835
>>9887874
Isnt hawking radiation just virtual particles and whatnot? Not observable, only theorized.

>> No.9887948

>>9887877
Nope. Just regular old particle-antiparticle pairs that are created in a vacuum just like everywhere else.
Would be a stretch to assume this didnt happen at the edges of black holes, and they do evaporate albeit veery slowly and only if they are large enough.

>>9886351
They do evaporate, but the vast majority are too small to even radiate the amount of mass that they gain from cosmic microwave background radiation. Eventually in a very distant future when the background radiation has all but stopped, they will all evaporate, but these timespans are insanely big compared to the age of the universe.

>> No.9887952

>>9887948
how does it escape the gravity well?

>> No.9887962

>>9887952
The particles? They dont. Nothing can actually escape from beyond the event horizon.

When a particle-antiparticle pair is created from a vacuum fluctuation, for a very short time net energy is created, but since they usually annihilate again since they are so close, the energy gets "repayed" almost instantly, bringing the energy back to its constant.
Now if this process happens directly on top of the event horizon of a black hole, and one of the particles is trapped within, while the other flies off into the other direction, they cant annihilate and the energy cant be returned to normal.
Thats when the Universe decides to use the closest source of energy available: the curved spacetime around the black hole.
So now you have one of the particles flying off, one being eaten by the black hole, but the energy equivalent of their combined mass being removed from the curved spacetime (less curvature means less mass), so net the black hole loses the mass of one of the particles.

>> No.9888098

How do you think this would change religion and culture, given that the sun is the primary symbol of justice and hierarchy?