astronomy

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LazerFX, w Brightness of first Chinese broadband constellation satellites alarms astronomers

And that’s because SpaceX at least try to minimise pollution (both light and radio). Not successfully, but it’s minimised.

The Chinese don’t give a fuck, just like they don’t give a fuck who their toxic rockets land on when launched over their own people.

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

Barnard b [2], as the newly discovered exoplanet is called, is twenty times closer to Barnard’s star than Mercury is to the Sun. It orbits its star in 3.15 Earth days and has a surface temperature around 125 °C. “Barnard b is one of the lowest-mass exoplanets known and one of the few known with a mass less than that of Earth. But the planet is too close to the host star, closer than the habitable zone,” explains González Hernández. “Even if the star is about 2500 degrees cooler than our Sun, it is too hot there to maintain liquid water on the surface.

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.

TommySoda, w Starlink is increasingly interfering with astronomy, scientists say

As someone that uses Starlink due to nothing else being in my area, I hate everything about this. Sure the convenience of having internet wherever I want is nice, but this still sucks. Especially since I’m a huge space nerd so this shit just hurts my soul.

AlexWIWA,

In your defense, there should be internet in your area but the government dropped the ball and let Comcast scam them.

TommySoda,

My favorite part is that bout 5 miles down the highway they have fibre optic. They’ve been “installing” it for about 4 or 5 years now. They’ve had the spool just sitting outside for half that time.

AlexWIWA,

God that’s just depressing

14th_cylon,

5 miles is doable with a wirless link. it of course depends on other factors, like having visibility, but it is not impossible.

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
@Bluetreefrog@lemmy.world avatar

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,
@Rhaedas@fedia.io avatar

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,
@Rhaedas@fedia.io avatar

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.

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,
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.

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

riodoro1, w Elon Musk destroys astronomy

But people are still shilling for starlink. I was always downvoted for mentioning the kessler syndrome or light pollution. All for progress, I guess we really need that fast internet in the middle of the atlantic.

MartianSands,

People down voting you for bringing up Kessler syndrome were correct to do so. It’s a complete non-issue for starlink-sized objects at that altitude.

Light pollution is a more reasonable objection, and the effects on the upper atmosphere of all those satellites burning up would be as well, but not Kessler syndrome

booly,

It’s a complete non-issue for starlink-sized objects at that altitude.

Yeah. The mass and altitude are too low.

The thing with Kessler Syndrome is that collisions create debris, which cascades with more collisions, until there’s too much debris. But each collision actually results in the loss of kinetic energy or gravitational potential energy overall, so that the subsequent pieces are less energetic and/or less massive. Start with enough mass and enough altitude, and you’ve got a real problem where it can cascade many, many times. But with smaller objects at low altitude, and there’s just not enough energy to cause a runaway reaction.

LordCrom,

Fellow dark sky supporter. Between all the led billboards, sprawl, and all the attempts at education failing… I doubt our children will have any view of the stars at all.

Unless there’s a hurricane that’s wipes out power… Stargazing was excellent for a few nights then.

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?

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