back to article Dark matter killed the dinosaurs, boffins suggest

Comets may not be the product of the Sun exerting its influence over rocks in the Oort Cloud, but may instead be pushed Earth-wards by dark matter. So say Lisa Randall and Matthew Reece from Harvard's Department of Physics, in a paper titled “Dark Matter as a Trigger for Periodic Comet Impacts”. The pair write that “Large …

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Angel

What an amazing ...

set of hypothetical 'what-ifs' ... based on asking the imponderable question and then supplying a hypothetical answer.

Did space aliens really supply the technology to build the pyramids?

Was Atlantis truly the capital of super-beings who were lost in the cataclysm?

Did ancient objects smite the Earth and extinguish the dinosaurs because our solar system fluttered across a cosmic tennis court?

Some day inquiring minds may supply the answer. Meanwhile, it's jolly good fun to guess.

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Re: What an amazing ...

Indeed, it can be rather interesting to treat ancient (or even Medieval) science seriously ... e.g. this (nothing to do with dark matter or pyramids, mind)

http://arxiv.org/abs/1403.0769

A Medieval Multiverse: Mathematical Modelling of the 13th Century Universe of Robert Grosseteste

Bower et al.

Abstract: In his treatise on light, written in about 1225, Robert Grosseteste describes a cosmological model in which the Universe is created in a big-bang like explosion and subsequent condensation. He postulates that the fundamental coupling of light and matter gives rises to the material body of the entire cosmos. Expansion is arrested when matter reaches a minimum density and subsequent emission of light from the outer region leads to compression and rarefaction of the inner bodily mass so as to create nine celestial spheres, with an imperfect residual core. In this paper we reformulate the Latin description in terms of a modern mathematical model. The equations which describe the coupling of light and matter are solved numerically, subject to initial conditions and critical criteria consistent with the text. Formation of a universe with a non-infinite number of perfected spheres is extremely sensitive to the initial conditions, the intensity of the light and the transparency of these spheres. In this "medieval multiverse", only a small range of opacity and initial density profiles lead to a stable universe with nine perfected spheres. As in current cosmological thinking, the existence of Grosseteste's universe relies on a very special combination of fundamental parameters.

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Anonymous Coward

Re: What an amazing ...

Rubbish - it is widely known that the Pink Invisible Unicorn ate all the Dinosaurs....

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Happy

Re: Pink Invisible Unicorn

I believe you and until the scientists can prove otherwise, it has the same level credibility as every other theory out there.

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Coat

Re: What an amazing ...

Nominative determinism? I bet a wheelbarrow was needed to move Grosseteste's nine perfected spheres.

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Anonymous Coward

Re: Pink Invisible Unicorn

Rubbish, this is in fact the MOST credible theory to date with loads more credibility than anything put forward by academia thus far....... IPSO FACTO.

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Re: What an amazing ...

>Did space aliens really supply the technology to build the pyramids?

Not at all; they were contracted out.

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Milankovitch and the Galactic Year

People have already made these connections. The "dark matter" is in this case more likely ordinary rocks left over from the collision that formed the solar system on a galactic year collision course, than some thing we can't even agree actually exists yet.

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Re: Milankovitch and the Galactic Year

"the collision that formed the solar system"

What the blazers?

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This post has been deleted by its author

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Devil

I was always partial to...

Volcanogenic Dark Matter and Mass Extinctions

The passage of the Earth through dense clumps of dark matter, the presence of which are predicted by certain cosmologies, would produce large quantities of heat in the interior of this planet through the capture and subsequent annihilation of dark matter particles. This heat can cause large-scale volcanism which could in turn have caused the extinction of the dinosaurs and other mass extinctions. The periodicity of such volcanic outbursts agrees with the frequency of palaeontological mass extinctions as well as the observed periodicity in the occurrence of the largest flood basalt provinces on the globe.

Of course, if Dark Matter is just sterile neutrinos chilling in the galactic halo, none of that fun can be had.

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Danger, Will Robinson! Seven syllable silliness sighted.

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If Sol is orbiting the galactic core ....

... isn't the other matter (dark and normal) orbiting at the same angular velocity?

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Re: If Sol is orbiting the galactic core ....

Yes and no.

Depending on what IT is supposed to be be, there may be large clumps, streams or filaments hanging around or occupying different orbits etc, much like interstellar gas which solar system enters from time to time, and which reduces the solar flux reaching earth.

There was even the idea of dark matter that could clump like normal baryonic matter but just interact with this side gravitationally, so you could have Dark Suns and Dark Planets interacting with the solar system pretty much the same way nearby stars may pass really nearby from time to time.

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Alien

Re: If Sol is orbiting the galactic core ....

Yes stuff in our galactic orbit (distance from the centre) tends to have similar orbital velocity but closer or further from the centre it doesn't; hence the spiral shape of the galactic arms.

However that is not the story here, it's about the fact that the solar system wobbles up and down through the galactic plane as it orbits, some times above the plane and sometimes below and the 35my mentioned is about the periodicity of that. Going through the plane, where matter is more concentrated, it is more probable that we will encounter more random debris (be it dark or normal matter). That appears to be the hypothesis in the article linking this wobble to the extinction events.

Another factor is that everything is on the move including the Milkyway and it happens to be moving 'northward' with the galactic plane being at more or less 90 deg. to the direction of movement, face on rather than edge on. When the solar system is above the plane (north of it) we get more cosmic ray bombardment than when below as the matter in the plane acts like a shield (current thinking). It has been hypothesised that this has caused bursts of evolutionary change as well as effecting global weather conditions. Far from proven but worthy of thought if such things interest you.

P.S. - I did tell it to my dinosaur and it said "Polly wants a cracker".

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And thus Nemisis is reborn...

as a dark matter star/planet/... whatever.

Doesn't change the original concept at all.

And possibly, dark matter doesn't even exist - other than normal matter at very low temperatures.

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Re: And thus Nemisis is reborn...

Can the simplest hypothesis be ruled out?

That Nemesis isn't one body gravitationally bound to Sol. But that multiple Nemesises have existed: other ordinary stars in their own orbits around the galactic core, which have wandered close enough to Sol to disturb its Oort cloud.

The evidence for 35My periodicity is pretty weak, but weak periodicity is what one might expect. The chance of a significantly close encounter with another star rises as Sol passes through the parts of the galaxy with a higher density of stars.

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Re: And thus Nemisis is reborn...

And possibly, dark matter doesn't even exist - other than normal matter at very low temperatures.

No, that idea is dead as disco.

Only a special mix of non-clumping non-baryonic "dark matter" can explain the large-scale observed structure of the universe.

Atoms: 4.6%, Dark Matter (pulls): 24%, Dark Energy (pushes): 71.4%

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Anonymous Coward

Re: If Sol is orbiting the galactic core ....

Yes, that is the same that I have heard, but there are some differences. Some stars orbit in the plane of the galaxy, but some like the SOL system have the fluctuation, which is why when you look back the closest stars get closer and further away. The best example of this though is the Globular clusters that orbit perpendicular to the solar plane.

Not sure I really buy the whole idea of dark energy though. That is like saying you can have cold lightening, cold fusion, or the like. As you compress, you get to a certain point and you get heat, but when you get to infinite gravity, you get a black hole, that does not in its-self generate heat, light, or infrared...

I'd like to see more about the regions of space scientists found that are millions of degrees, with no massive or supermassive stars in the region. Dark Energy, I think is eventually going to be found is free nurtrinos, or bosins, not some mystical force we cannot see.

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FFS!

TIA

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Dark matter killed the dinosaurs

Which is why you often find them in tar pits.

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A paper based on "what if"?????

What if the impacts weren't comets but meatballs from his Noodley Goodness?

What if two Sky Fairies were playing Ping-Pong and Earth was struck but the balls that hit the floor and bounced?

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Re: A paper based on "what if"?????

What we need is hubert farnsworths what if machine.

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Re: A paper based on "what if"?????

I'm still waiting for the Finglonger.

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Nice idea, until you remember that Dark Matter is a made up fudge to explain a failure in our theories of gravitational attraction...

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Anonymous Coward

Mmm.... made-up fudge! *drool*

It's real, we just haven't detected any yet, because the thing about dark matter - its main distinguishing feature - is it's dark. And the thing about space, the appearance of space, your basic space appearance, is it's dark. So how are you supposed to see it?

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Coat

Re: Mmm.... made-up fudge! *drool*

That's no AC, that's Holly.

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Anonymous Coward

Hahahahahahahahaha that's funny

Dark matter? Look chaps Supernovae are responsible for mass extinctions and the matter hurled our way from aftermath of said calamitous event.

Now you chaps did promise to drink responsibly......

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Nothing killed the dinosaurs because dinosaurs are not real. Scientists should not be asking what killed the dinosaurs but "why dinosaurs?"

Why Dinosaurs?

There is no such creature as a dinosaur, so why dinosaurs? Why doesn't the media talk about other mythical creatures - dragons, emus or unicorns perhaps.

Why Dinosaurs?

Call me cynical but there is an election coming up, plus a referendum on Scottish independence. It's going to be dinosaurs-dinosaurs-dinosaurs over the next 24 month. Blanket coverage all over the news. They are even bringing out a new Jurassic Park movie in 2015.

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Anonymous Coward

Why Scotland?

Dinosaurs are quite famous, actually, even if they do not exist. Scotland OTOH, never heard of it.

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What do you mean emus are mythical! I've seen that fly-on-the-wall documentary in The Pink Windmill. Emus are real I tell you! Yes real!!!!

...Sorry, got to go... There's somebody at the door.

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Megaphone

What utter crap, dinosaurs are real, have you not heard of the RMT and TSSA unions?

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If dinosaurs aren't real. Is Philosoraptor a mass delusion?

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Dinosaurs are still with us

Er ... are there some flying feathered creatures outside your window, chirping or even singing?

Those are dinosaurs.

Yes, they didn't all die out. The small mobile feathered ones survived, evolved, and today we call them birds. One or two remain velociraptor-scary (ask someone who's narrowly survived a hostile encounter with a Casawary).

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Coat

Re: Why Scotland?

Scotland? I thought that was the 3M theme park!

Yes, the one with the Post-It on the back...

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Happy

Stranger still...

... If I put a battery powered clock in a certain part of the living room then that clock will go slow.

Tried it with three clocks so far - all keep reasonably perfect time in all other locations but put them near the table lamp and they go slow.

If dark matter is responsible can I sell it and how much is it worth?

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Re: Stranger still...

Try it with an analogue wind up clock and report back.

Alternatively try moving the lamp to a different location. I suspect the lamp is the cause probably some kind of interference.

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Re: Stranger still...

Yes, but whatever you do - don't rub the lamp. Those genies are awfully hard to stuff back into their lamps...

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The fundamental problem...

... is the concept that meteorite impacts and/or extinctions have any periodicity. You have to squint awful hard to get that from the available and exceedingly spotty data.

Also, I'm not saying this paper seems made by scigen, but damn it seems made by scigen.

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Re: The fundamental problem...

Data for astro is often this sketchy. And so long as one doesn't become ideologically attached to the hypothesis, it's ok to air them. If the speculation causes some one to run the equations and make a prediction that pans out, you have a plausible theory. You just have to be prepared to walk away if the equations don't work or the predictions come up wrong.

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JDC
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Try telling that to the dinosaurs.

Tweet it, then?

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Dark Matter, the hypothetical stuff we can't see but which should probably be there in order for our models of reality to work

Best line, ever. Douglas Adams would be proud!

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Dark Matter?

Never quiet understood "Dark Matter". A fudge to make our current best physics models work? Mmm, maybe dark matter doesn't exist? Maybe it's our models that are wrong?

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Boffin

Re: Dark Matter?

If I truly understood dark matter I would probably have an (Ig) Nobel prize (It's the surname that counts ;-) ). I must say as a scientist I am sceptical, but there have been instances when we needed hypothetical particles to explain certain effects. Neutrinos are the prime example. They were needed to explain the apparent lack of conservation of angular momentum and energy in beta decay. They were subsequently found. Anti-matter is weirder yet: the positron was postulated purely from mathematics as a possibility by Dirac, and subsequently it was found (in fact, it had been seen before, but misinterpreted as an electron moving in the opposite direction). The aether on the other hand was postulated but rather wrecked by the Michelson-Morley experiment.

It is hard to reconcile observations with theories without dark matter, and there are ways of observing its influence on matter and light, so there is circumstantial evidence for it. However, most cosmologists I have spoken to do acknowledge that a thorough re-write of our understanding of physics may be an alternative solution. It is just that we do not know how to.

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Re: Dark Matter?

Good summary of this hypothetical entity.

A few days ago, a 3.5keV emission line was detected by X-ray astronomers, seemingly being faintly emitted by all galaxies they have looked at so far. There is no ordinary matter (atomic) emission line that can account for it.

If it isn't found to be an observational error or statistical deviation, it may prove to be the first sign that dark matter exists.

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Re: A fudge to make our current best physics models work?

There are true believers in the Chocolate force of the universe. Don't mock them or you won't get any more cookies.

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Re: A fudge to make our current best physics models work?

Once the elusive "mochaccino" particle is found, the chocolatists will have no choice but to take their theory back to the nearest cafe.

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Mushroom

Bah the Dinosaurs annoyed the Arachnids and they redirected the meteors towards Earth.

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Coat

Dark matter killed the dinosaurs

But video killed the radio star (aka; a pulsar)

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