astronomy

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1stTime4MeInMCU, w ESO VLT discovers new exoplanet around the nearby Barnard star, only 6 light years away.

Aww that’s cute. Barnard’s star has kind of an interesting history of exoplanet claims that were sadly ruled out after further examination. Great to hear we finally have good evidence.

ekZepp, w ESO telescope captures the most detailed infrared map ever of our Milky Way
@ekZepp@lemmy.world avatar
daisyKutter, w Betelgeuse has a tiny companion star hidden in plain sight
@daisyKutter@lemmy.ml avatar

Named Lydia?

Zachariah, w Betelgeuse has a tiny companion star hidden in plain sight
@Zachariah@lemmy.world avatar

After more than a century of speculation, data seem to confirm that Betelgeuse (the brightest star in the Orion constellation, shown here) has a much smaller star as an orbital companion.

Two independent studies found evidence of a star about the same mass as the sun, orbiting Betelgeuse about once every 2,100 days.

Lemming6969, w Dark Matter Black Holes Could Fly through the Solar System Once a Decade

What if dark matter is some form of black hole or exotic ultra dense material made entirely out of the missing antimatter, which for whatever reason doesn’t otherwise interact with electromagnetism? 2 birds, 1 stone.

Bluetreefrog, w Dark Matter Black Holes Could Fly through the Solar System Once a Decade

The book, Seven Eves is about one of these hitting the moon.

Davel23,

The cause of the incident is never specified in the book.

thebardingreen,
@thebardingreen@lemmy.starlightkel.xyz avatar

The book Earth by David Brin is about one of these hitting the Earth

Gork, w Dark Matter Black Holes Could Fly through the Solar System Once a Decade

What would happen if one of these tiny black holes hit Earth? The article doesn’t really talk about it.

Donjuanme,

Absolutely nothing.

Also not sure why they wouldn’t evaporate nearly instantaneously. Sounds to me like more dark matter bunk.

deegeese,

Passing near the earth, we’d get some strange tides. Passing through the earth, it would eat earth.

Rhaedas,

Nonsense. The event horizon on such things is incredibly small, as is the mass vs. that of Earth.

deegeese,

You don’t need the event horizon, you just need local gravity around 1G. For the masses described in the article, that radius is from hundreds of meters to 10s of kilometers.

Rhaedas,

Which still wouldn't do what you suggest. The mass is the same, so it has the same effect from a distance. Unless by "eat earth" you meant it would take in dirt until it suck to the core, still about the same mass.

lemming, w Dark Matter Black Holes Could Fly through the Solar System Once a Decade

I thought these were disproved by lack of gravitational microlensing?

InvertedParallax,

The main way you’d see that kind of microlensing is if they aggregated.

But given the way gravity works, they should aggregate, otherwise why call them black holes?

Classy,

If they were relatively evenly distributed would that counteract lensing?

InvertedParallax,

Yes, it would just be surprising because, gravity should make them not be evenly distributed.

The whole thing with dark matter is that it’s this magic stuff that causes gravity but isn’t affected by it, which… is not how gravity normally works.

Though there is still room for it, we just need a better framework other than “I added 3 and 5 and got 12, so obviously I must mean to add 3 and 5 and 4 too”.

MartianSands,

You’re mistaken. Dark matter, whatever it is, isn’t affected by anything except gravity. It interacts with gravity just like “normal” matter.

The evidence is also significantly better than you’re describing

InvertedParallax,

Then it should also coelescce, particularly since it doesn’t have the em force to keep it repelled, the universe should be dominated by massive dark matter black holes.

Yes, there’s math that explains part of the distribution, but also there is 0 force opposing any collapse we’d have a lot more neutron stars and other degenerate matter catalyzed by dark matter.

We have hypotheses like this when our observations don’t make sense and we need to explain them, it’s definitely a possibility but we still have room to understand the large scale physics at play.

MartianSands,

You don’t need a force to prevent collapse if there’s no drag force to slow things down. It would actually be almost impossible for a cloud of dark matter to collapse since any individual particle has momentum and no way to slow down, so they’ll all be in some sort of mutual orbit

InvertedParallax,

I’m guessing you’ve seen as many lorentz attractor simulations as I have, what always happens is something like tidal effects or angular momentum means 90% slow down while a few particles get shot out of hell at ludicrous speed.

The effect is similar to drag, and is basically how we get entropy even without em effects.

superkret, w Dark Matter Black Holes Could Fly through the Solar System Once a Decade

If dark matter is fully explained by such black holes, their most likely mass, according to some theories, would range from 10^17^ to 10^23^ grams—or about that of a large asteroid.

In case this doesn’t tell you a lot, 10^17^g is half the weight of Mount Everest, and 10^23^g is 4x the weight of the Antarctic ice shield.

halfapage,

deleted_by_author

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  • Davel23,

    One, if it was a football stadium the size of Mount Everest.

    floofloof,

    I can only do Olympic swimming pools or bananas.

    remotelove,
    @remotelove@lemmy.ca avatar

    The earth is estimated to “weigh” 13,170,000,000,000,000,000,000,000 pounds. (That is weird when you think about it. The weight of the earth being based on what something weighs on earth, I mean.)

    Mt. Everest is only about 357,000,000,000,000 pounds and is just a tiny fraction of the mass of the earth.

    So. My point is that we need a better way to portray scale of things in the universe. AUs work to a point but then we have to quickly move to parsecs. Parsecs quickly give way to light years. (Or vice-versa, depending on how you visualize things better.) Light years kinda work, but only for between 14-26 billion years. Even after all of that, I can hardly still fathom the size of Mt. Everest. (This was a rant, but not an angry rant.)

    floofloof,

    The earth is estimated to “weigh” 13,170,000,000,000,000,000,000,000 pounds.

    Mt. Everest is only 357,000,000,000,000 pounds

    My point is that we need a better way to portray scale of things in the universe.

    Well, for a start, God uses the metric system.

    Mr_Blott,

    Fuckin everyone uses the metric system

    RandomVideos,

    Even aliens building the pyramids used the metric system

    butwhyishischinabook,

    God uses base 12, he doesn’t arbitrarily settle on base 10 just because he has that many fingers.

    chonglibloodsport,

    Weight in pounds isn’t the right unit here. Weight varies depending on the strength of the gravitational field you’re in, whereas mass does not. A kilogram here on earth weighs 2.2lbs but on the moon it only weighs 0.36lbs.

    Rato,

    In the English Engineering System, the unit of mass is 1 pound mass (lbm), and is equivalent to the amount of matter that weighs 1lb at 1G. I won’t argue that EES is a good system, but it does at least have a kludged unit for mass. It has an equally kludged unit for force, too, called pounds force (lbf).

    remotelove,
    @remotelove@lemmy.ca avatar

    I called that out. It was the weight of the earth… on earth.

    barsquid,

    I cannot fathom the size of anything on an astronomical scale. I have seen the videos that zoom out and show Earth at scale with the Sun and then the Sun at scale with other stars. No matter how many times I view the facts it will be incomprehensibly large.

    HurlingDurling, w Dark Matter Black Holes Could Fly through the Solar System Once a Decade
    @HurlingDurling@lemmy.world avatar

    Cool, one more thing to keep me up at night

    aaaaace,
    onlinepersona, w Dark Matter Black Holes Could Fly through the Solar System Once a Decade

    Would a regular asteroid be able to wobble the earth as described in this article? Or is it just black holes that should do so?

    I seem to remember reading that primordial black holes weren’t yet a proven phenomenon and I have trouble imagining them myself. Wouldn’t they have hawking radiation too which we would be able to detect?

    Anti Commercial-AI license

    Mango, w Astronomers discover biggest ever seen black hole jets, which blast hot plasma well beyond their own host galaxy

    If it can be infinitely dense inside a black hole, doesn’t that mean the scale doesn’t matter and that the ‘inside’ is pretty much it’s own whole universe with different physics rules?

    imakeninjascry, w Astronomers discover biggest ever seen black hole jets, which blast hot plasma well beyond their own host galaxy

    Mathematically, it’s possible, but scientists are still skeptical about whether or not they are real. They’re called white holes and you can actually create a model of one in your kitchen sink. If you let the water just hit the bottom and spread out evenly in all directions, you can kind of visualize the way it’s supposed to work. Action Lab on YouTube actually has a pretty good video about it which I suggest watching if you’re interested. youtu.be/p3P4iKb24Ng?si=b3_RHuj0J3F_7DC1

    foofiepie, w Astronomers discover biggest ever seen black hole jets, which blast hot plasma well beyond their own host galaxy

    Ok. Permission to ask a mad question. Apologies in advance.

    If black holes ‘suck’ everything in… could there be the equivalent of the ‘other side’ of one, that’s mysteriously ejecting a tonne of plasma?

    Not saying that’s what this is, just prompted the thought.

    imakeninjascry,

    Mathematically, it’s possible, but scientists are still skeptical about whether or not they are real. They’re called white holes and you can actually create a model of one in your kitchen sink. If you let the water just hit the bottom and spread out evenly in all directions, you can kind of visualize the way it’s supposed to work. Action Lab on YouTube actually has a pretty good video about it which I suggest watching if you’re interested. youtu.be/p3P4iKb24Ng?si=b3_RHuj0J3F_7DC1

    chuckleslord,

    Tangent, but you don’t need to include the question mark or anything after in most urls. Definitely not YouTube links. It’s just YouTube telling itself who shared the info (you) and they use that to track shit. But the link works just as well without it, and you’re not voluntary spying on yourself.

    imakeninjascry,

    Neat! I didn’t know that. I just copied and pasted. Thanks for the info.

    rottingleaf, w Elon Musk destroys astronomy

    Can we just do things the conservative way and lay more wire?

    And where that doesn’t help, use packet radio links?

    And where that doesn’t help, use mesh networks?

    Why do they have to do it all the ugly and pretentious way?

    HurlingDurling,
    @HurlingDurling@lemmy.world avatar

    If he could he would arrange the sattelites to spell his name on the sky

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