Scientists spot startlingly close black holes in Hyades star cluster

Not to alarm anyone, but the nearest black holes to Earth are closer than we previously thought.  Way, way closer, in fact.  Like, more-than-1,400-light-years-closer-to-Earth-than-the-last-one close. These new, uncomfortably close black holes were discovered by an international group of EU scientists looking at the Hyades …

[b0llchit]

The Asylum has shown the way

So don't worry: if a stray black hole was ejected in our direction we'd probably already be dead!

Don't worry? The gravity of the situation demands that we panic right away and find a way to move a black hole out of our way, pronto! Hell will be on top of us before you know it and we all die in the process. We need a solution before we all die a horribly stretched and spaghettificated death. The Asylum has created many good inspirational moving pictures to show the way. Time to make it real and do something about that invisible Black Threat we can't see, hear or smell.

[Neil Barnes]

Re: The Asylum has shown the way

we all die a horribly stretched and spaghettificated death.

Bless his noodly appendages, quick, while there's still time!

[b0llchit]

Re: The Asylum has shown the way

Ramen!

[Nik 2]

Re: The Asylum has shown the way

Take off and nuke it from orbit. It's the only way to be sure...

[Anonymous Coward]

Re: The Asylum has shown the way

"Take off and nuke it from orbit. It's the only way to be sure..."

at which the black hole will just say to itself: "ah, breakfast, very tasty !!" and continue on it's path, no doubt guided by a Vogon, with a fondness for classical poetry who'll just be happy to save expending a few missiles, to enable the new space highway to be built more quickly, and without the need to clear up any resulting debris field.

[m4r35n357]

Re: The Asylum has shown the way

Go Space Force!

[Anonymous Coward]

Re: The Asylum has shown the way

"Time to make it real and do something about that invisible Black Threat we can't see, hear or smell."

Of course the BIG issue is that if we assume that "space is big, really big" and that there is nothing physical in the way (between us and an ejected black hole heading our way), then how would we see it coming (given that it's black, as is most of the night sky)?

Some gravitational lensing *might* be spotted, if we just happen to be looking in the right direction (or maybe we already are looking "just in case").

But a sneaky black hole could just be heading our way and there won't be a lot we can do about it (until we've got some high capacity transport available and can build some geodesic domes (inspired from "Silent Running") and put them into orbit, ready for our mass exodus !

[eldakka]

Re: The Asylum has shown the way

> The gravity of the situation

Ba-dum tish?

[Frank Bitterlich]

Re: The Asylum has shown the way

I say: ready the Arks! Ark B should go first, so that when the survivors of humanity arrive on our new home world, they will find shiny-clean telephones and a thriving advertising economy. Oh, and someone needs to build electric cars on that planet, so how about sending a certain CEO, too?

[ian 22]

Re: The Asylum has shown the way

We are all going to hyades in a handbasket in any case.

[Antony Shepherd]

Black holes in the Hyades eh? The scolloped tatters of the King in Yellow must hide Yhtill forever.

[Pascal Monett]

"we'd probably already be dead"

In the category of rogue planets or stars, the possibility of direct collision is almost zero. But you don't need a rogue star, or black hole, to collide with Earth in order to destroy Humanity (and possibly all life on Earth as well).

A star or black hole passing close enough to our Solar System will throw planetary orbits out of whack, likely ejecting several, if not all. That would logically depend on how close it gets. But one thing is sure : if Earth gets ejected, we're all on a timer to the deepest freeze we will ever know.

However, even if none of our planets are actually ejected, the outer planets' orbits will certainly be perturbed, which will very likely in turn perturb the orbits of the inner planets. Not to mention everything in the Kuiper Belt will go nuts, and whatever is beyond as well.

So, even if the Earth possibly stays in its actual orbit, the amount of asteroids being josled by all this will be enormous, and there's every chance that we might see a new Late Bombardment in the years that follow.

The only question is, at what distance are we doomed by a passing star or black hole ? If it is two light-years away, are we safe ?

[Christoph]

Re: "we'd probably already be dead"

Yes, we'd be safe. Our nearest star is just over 4 light years away, so we must have had many passes within 2 light years since the solar system stabilised.

[Phil O'Sophical]

Re: "we'd probably already be dead"

Our nearest star is just over 4 light years away

<pedant>Our nearest star is just over 8 light minutes away</pedant>

[Tessier-Ashpool]

Re: "we'd probably already be dead"

I wouldn’t be too worried by a properly black black hole at that distance. But if it’s got an accretion disk spraying us with relativistic jets of matter, that’s a different kettle of fish. We’d be done for.

[Elongated Muskrat]

Re: "we'd probably already be dead"

If it was one with an active accretion disk, we'd be done for from a lot further away than a couple of ly - IIRC, we'd be talking hundreds, if not thousands, of light years, and still hoping that it's pointing roughly perpendicular to the plane of the galaxy, so that we don't get blasted by the jets precessing.

[Anonymous Coward]

Re: "we'd probably already be dead"

Yeah, the prospect of a wobbly death-ray isn't reassuring, but the earth is a infinitesimal target from that far out. We are more likely to meet our end on the receiving end of a much smaller rock using the Terra as a land-brake. Thankfully, the chances of that are also vanishingly small, at least in our lifetimes.

[m4r35n357]

Re: "we'd probably already be dead"

Pedantry ahoy! Relativistic jets are sprayed from the poles. Accretion discs are equatorial (and gravitationally bound to the black hole).

[Elongated Muskrat]

Re: "we'd probably already be dead"

Isn't it the case that accretion from the disc is what drives the relativistic jets, or have I misunderstood it? Isn't it a case that matter falling into the black hole from the accretion disc is accelerated due to conservation of angular momentum, and the radiation from its "spaghettification" is channelled by the vast rotating magnetic field of the black hole into the polar jets.

As I understand it, the orientation of that magnetic field is not aligned with the galactic plane, so anything producing relativistic jets "nearby" to us in a cosmic sense, had better not be oriented such that those jets are oriented near to the path of our solar system (which "wobbles" up and down through the galactic plane on a long timescale).

It is also my understanding that such "active" black holes tend to be large mass ones, and that there aren't any nearby to us; the nearest I know of is Sag A*, and that's way up there on the mass index. You certainly wound't be happy to be within several hundred ly of that.

I'm not sure why my post above garnered so may downvotes. Again, it's my understanding that you don't want to be in the path of a relativistic jet from a black hole, and that they tend to be tightly focussed enough that one crossing your path would really ruin your day even from 100ly away (well, ruin your day 100 years + a tiny bit into the future). Perhaps I worded it badly, or have my facts wildly wrong - an explanatory comment would be nice though (well, from those who aren't just habitual downvoters; you know who you are).

[Tessier-Ashpool]

Re: "we'd probably already be dead"

You're quite right. Relativistic jets are emitted normal to the plane of an accretion disk by its magnetic field, and are very much fuelled by it,

[ThatOne]

Re: "we'd probably already be dead"

> the nearest I know of is Sag A*

Don't mix stellar black holes and galactic black holes! Stellar black holes are common like dirt, they are the normal result of a fat star (any star > 3 solar masses) collapsing, while galactic ones (known as "Supermassive black holes") are the accretion of millions/billions of stellar black holes fused together, and have masses of millions/billions times our sun! They might be all black holes, but they are not in the same league. Sgr A* is (IIRC) around 10⁶ solar masses...

The ones potentially ejected from the Hyades are your garden variety stellar black holes, and would probably be 3 to a dozen solar masses. Quite compact, fiendishly difficult to spot unless you notice them wreaking havoc somewhere (and hopefully not in your own backyard)...

[Elongated Muskrat]

Re: "we'd probably already be dead"

That's kind of my point, those aren't going to have accretion disks (at least, not large scale ones), unless they come pretty damn close to something to eat (i.e. another star). In the game of cosmic billiards, getting close enough to another star in your path like that is one helluva trick shot.

OTOH, things with big old active accretion disks that throw out relativistic jets from their poles are, as you say, the supermassive ones, or at the very least, ones in a very busy neighbourhood (such as a galactic centre), where there are lots of other stars swirling around at sub light-year distances. If there was something like that going on within a few hundred ly of Sol, to be honest, the black hole wouldn't be the biggest problem.

I think the other class of stellar object that might be of interest in this sort of discussion would be close-orbiting binary system where one partner is a black hole that is slowly eating the other companion. If, instead, you have a stellar remnant such as a white dwarf with matter falling into it, that is basically what causes a type 1a supernova. Again, not something you want to be near, unless you like being periodically irradiated. You don't really want to be very close to something that periodically is 5 billion times brighter than the sun.

Thankfully, all those sorts of "interesting" stellar objects are safely some distance from us, although it will be a good light show when Betelgeuse blows up in a standard supernova.

[Anonymous Coward]

Time is a bitch

Here you touch on a point that is worth elaborating.

The material in an accretion disk is by definition undergoing heavy time dilation, even in stellar mass black holes. So there is huge delay from the point of view of an outside observer. This is an area of active research which is already finding that we see, again as outside observers, that black holes "burp" bursts of x-ray activity years after ingesting large amounts of mass. It is likely these effects continue produce bursts in output on increasing relative delays as the mass works deeper through the system.

While the analogy with the digestive tract is poor in this case, in the terms and traditions of this forum there could be quite a delay between an x-ray burst "burp" and a relativistic jet "fart", so one that feasted on material in an active star forming region back when dinosaurs roamed the earth could be primed to unload. (Again, in loose terms, I haven's seen a good paper on that yet, post links if you have any"

This is why thinking about black holes is so interesting, often counterintuitive, and complicated. That much gravity fucks with everything, bending and shifting everything in time and space.

[Yet Another Hierachial Anonynmous Coward]

Re: "we'd probably already be dead"

> if Earth gets ejected, we're all on a timer to the deepest freeze we will ever know.

But, on a positive note, that will mitigate global warming.

[cray74]

Re: "we'd probably already be dead"

The only question is, at what distance are we doomed by a passing star or black hole ? If it is two light-years away, are we safe ?

While Matthew McConaughey or Beowulf Schaeffer might experience extremes of gravity skimming the black hole, a black hole doesn't have a gravitational field of larger dimensions than a star of the same mass because gravitational force is a result of the distance between two objects and their masses. Same mass, same distance, same force. For example, instantly swapping Sol with a 1-solar mass black hole would leave all of the solar system's planets and lesser objects in unchanged orbits.

The most likely black hole to pass by is a stellar mass black hole, which would be 5 to 30 solar masses (give or take a few kilograms). Taking the worst case of 30 solar masses at 128,000 astronomical units (2 light-years with some rounding)...

1. The black hole has 443 times as much gravitational force on Earth as Pluto at 40AU

2. The black hole has 70 times as much gravitational force on Earth as Alpha Centauri A+B at 275,000AU

3. The black hole has 1/30th the gravitational force on Earth as Neptune at 30AU

4. The black hole has 1/650th the gravitational force on Earth as Mars at 0.5AU

5. The black hole has 1/14,806th the gravitational force on Earth as Venus at 0.3AU

6. The black hole has 1/20,850th the gravitational force on Earth as Jupiter at 5AU

7. The black hole has 1/1,720,000th the gravitational force on Earth as Luna at 0.0026AU

8. The black hole has 1/540,000,000th the gravitational force on Earth as Sol at 1AU

Another way to look at this is: a star 30 times as massive as the sun would need to get within about 5.2AU (Jupiter's orbit) to match Sol's gravitational force on Earth. It'd be a pain at some thousands of AU, too, probably bothering the Kuiper Belt.

So, while Jupiter and Venus warp Earth's orbit a bit over a 405,000-year period, a singular passage by a large black hole at interstellar distances won't do squat to Earth or the solar system. If the Oort cloud actually is out there then it might be disturbed and we'd need to deal with a flood of comets in a few million years, but close passages by stellar-mass objects have happened before. Scholz's Star buzzed Earth 70,000 years ago at a distance of 52,000 astronomical units.

There is a matter of radiation from the black hole's accretion disk, but that shouldn't bother Earth much unless the polar jets swept over us.

[_Elvi_]

Re: "we'd probably already be dead"

.. Or start looking for sine gravity waves on the surface of Mars ...

(just don't punch any random buttons ... could be quite unhealthy .. )

[M.V. Lipvig]

Re: "we'd probably already be dead"

Don't know why anyone is worried. We likely wouldn't even have a chance to wonder what's going on.

[Sceptic Tank]

Re: "we'd probably already be dead"

There is the problem of time dilation: for an outside observer there won't be time to wave goodbye while the rest of us will die a slow and horrible death in the gravity well.

[ThatOne]

Re: "we'd probably already be dead"

Actually you die quite fast, tidal forces ripping our planet apart long before relativistic stuff starts to happen. We're quite ill equipped to live without a planet...

[ThatOne]

Re: "we'd probably already be dead"

> at what distance are we doomed by a passing star or black hole ?

Depends on its mass of course. The Oort cloud goes out to almost 3.5 light years, and it contains enough stuff to pelt us out of existence.

Black holes are usually remnants of big stars, so they tend to be rather hefty. The rest is a question of luck: One single large enough block of ice falling on us would suffice to send us the way of the dinosaurs. Or they could all miss us. Do you feel lucky?

[Anonymous Coward]

Dirty snowballs

I think you touched on one of the more "right" answers here. If you want to talk doomsday, the red dwarf the other poster mentioned probably set it in motion 70,000 years ago. Might not land for epochs, but the universe doesn't care about our human shortsightedness or perspective only causality.

If something big is going hit us, it was probably set on that path a very, very long time ago by human standards.

[Christoph]

"The team isn't sure whether Hyades is unique in its black hole richness, or whether such objects are common in other star clusters"

If that was the first one they tried and they got a hit first time, it makes it quite likely that they are common.

[ThatOne]

Well, given that any star bigger than (around) 3 solar masses eventually collapses into a black hole, they must be extremely common. It's just we can't see them unless they misbehave... And given the tiny size of stellar black holes, their gravitational lensing would be extremely difficult to spot.

[Elongated Muskrat]

Given that black holes typically form when a massive star dies, and that process involves a supernova, and these things are, relatively speaking, on our cosmic doorstep, I'm left wondering if their formation coincides with previous mass extinction events?

[Claptrap314]

Be prepared to keep wondering. Since the detection method relates to the statistical behavior of the masses in the cluster, one would have to go back tens of millions of years, and then observer a discontinuity in the second derivative of the prediction of the locations, then map it to the excess accumulating to one part of the cluster....

Certainly, this is a worthy idea. Unfortunately, the threshold for a hypothesis is that it be "testable", and I'm not thinking that the chance of that is great.

[Elongated Muskrat]

Yeah, it's definitely not a hypothesis from me, more an out-loud pondering.

I think the way to work it out would probably be to look at planetary nebulae formed from the parent star going supernova, observe the size of the "bubble", extrapolate backwards to work out a rough timescale for when the star went pop, and see if it correlates with a known mass extinction event. I think I'm probably not the first to think of this, and, to be honest, if there were any large planetary nebulae near to us, I think we'd already have worked it out. Previous mass extinction events are likely down to more mundane things like Big Rocks Falling From the Sky™, large-scale volcanic events (such as the Deccan Traps), planet-scale glaciation events (Snowball Earth), and, further back, planet-wide atmospheric oxygenation.

[Big_Boomer]

Mass (not size) matters

If they are stellar mass black holes then coming close to our solar system would have an effect, much the same as having another sun pass close by. If, however they are smaller then they would need to get MUCH closer to have any real effect. Yes, there are theories that smaller black holes can be created and they may in fact be the mysterious "dark matter" that is hypothesized. As for one passing close enough to affect us, it's possible,..... but so is winning the Lottery Jackpot 5 times in a row. <LOL>

[Elongated Muskrat]

Re: Mass (not size) matters

Presumably, these are not "small" black holes, though, or the observations of their effect on the movement of stars in the Hyades wouldn't have been made. The "smallest" black hole yet observed apparently has a mass of 3.8 solar masses.

I believe that something that size would basically have to pass right by, or through, the Oort cloud to have any noticeable effect on the solar system, and that effect would probably be to throw some comets at Jupiter, which pretty much acts a rubbish sweeper for the solar system due to its mass and orbit.

[Winkypop]

4,000 holes in Blackburn Lancashire

Black holes can ruin your day.

But I find all the A holes more annoying.

[Anonymous Coward]

We should pay it a visit.

It would of course be a preposterously long term project, and you could lazily take decades putting it together, but that's close enough that we could lob a probe with mostly passive systems at it and then wait the short age of human civilization to see if we can detect a ping back. Might be a good use of a solar sail, at least for the extraordinarily patient. Bank shot it around a couple of the known stars and then have it start banging away prime numbers from behind the system and measure the variations in the time of flight of the signal?

Guessing if anyone remembered to check for the returning signal they'd probably have some kick-ass receivers by then.