Death and Life in a Distant Galaxy

by Paul Gilster on March 25, 2008

By Larry Klaes

One response to Fermi’s famous ‘Where are they?’ question is to speculate on factors that might destroy incipient life forms. The recent gamma ray burst seen halfway across the universe reminds us of the powers that can be unleashed within a galaxy. Now Tau Zero journalist Larry Klaes goes to work on two galaxies 1.4 billion light years from Earth whose destinies are in some ways intertwined. Are we witnessing the possible annihilation of civilizations?

Being tiny creatures who have spent our existence on and around a rather insignificant ball of rock, it is often quite difficult for humans to imagine the infinitely vaster Universe we live in. As the late author Douglas Adams once said in his famous series, The Hitchhiker’s Guide to the Galaxy: “Space…is big. Really big. You just won’t believe how vastly hugely mindboggingly big it is. I mean you may think it’s a long way down the road to the chemist [pharmacy], but that’s just peanuts to space.”

Not only are the distance and size of things in the Cosmos “mindboggingly big,” but their age and the power they wield also make human concepts of power pale in comparison.

Take the two largest galaxies in a system known as 3C 321. The two galaxies in question are located 1.4 billion light years from Earth. This means that the light from the many stars which make up these galaxies took 1.4 billion years to cross the darkness of intergalactic space. When the starlight striking our eyes now left 3C 321 all those ages ago, the most advanced creatures on our planet were little more than complex cells known as eukaryotes. As for the distance involved, our most far-reaching space probes are just a few billion miles from Earth – barely out of our Solar System, to say nothing of the nearest star or galaxy.

Recently, a combined effort of several Earth-orbiting astronomical satellites and ground-based radio telescopes imaged the galaxy pair of 3C 321 at multiple wavelengths on the electromagnetic spectrum. The scientists discovered that the two star islands were slowly moving towards each other, which is not an uncommon occurrence in the Universe: Our Milky Way galaxy and the Andromeda galaxy will collide just a few billion years from now.

3C 321 Artist conception

They also were found to have supermassive black holes at their centers. Most galaxies, including the Milky Way, have such incredible objects. Black holes are what happen to a star more massive than our Sun when it collapses upon itself in old age. The star literally crushes itself into a point called a singularity, from which not even light is fast or strong enough to escape.

Image: This artist’s impression of 3C321 shows the main galaxy and the companion galaxy. A jet of particles generated by a supermassive black hole at the center of the main galaxy is striking the companion galaxy. The jet is disrupted and deflected by this impact. Credit: NASA/CXC/M. Weiss.

Black holes at the center of many galaxies can grow to be millions and billions of times more massive than Earth’s yellow dwarf star. They pull in so much of the dust, gas, and even suns surrounding them that they actually end up ejecting some of their captured material back into space in relatively tight beams of radiation, matter, and energy known as jets. Anything in the path of such particle beams, which move at nearly the speed of light (186,000 miles each second), will be in serious trouble.

The larger of the two major galaxies in 3C 321 has such an active galactic nucleus, as astronomers call it. At least one million years ago, this galaxy’s jet began shooting out of the galactic core and across 20,000 light years of deep space, where it struck the edge of its neighbor smaller galaxy. A continual spray of radiation 1,000 light years wide, especially one with as many high X-rays and gamma rays as this one has, would spell doom for life on the surface of any planets in that galaxy.

“This jet could be causing all sorts of problems for the smaller galaxy it is pummeling,” said Daniel A. Evans, an astronomer from the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, and the lead author on a paper about this amazing event.

The media have dubbed the larger member of 3C 321 the “Death Star Galaxy”, after the moon-sized battle station of the Galactic Empire in the Star Wars series that had the capability of destroying an entire planet with its powerful energy beam. However, even the power of that fictional war machine is no match for what is happening in reality far across the Universe. Perhaps fortunately for existing life everywhere, only one percent of the galaxies known to have active galactic nuclei emit particle streams and 3C 321 is the first known case of a galactic jet actually impacting with another galaxy.

3C 321

Image: This composite image shows the jet from a black hole at the center of a galaxy striking the edge of another galaxy, the first time such an interaction has been found. In the image, data from several wavelengths have been combined. X-rays from Chandra (colored purple), optical and ultraviolet (UV) data from Hubble (red and orange), and radio emission from the Very Large Array (VLA) and MERLIN (blue) show how the jet from the main galaxy on the lower left is striking its companion galaxy to the upper right. The jet impacts the companion galaxy at its edge and is then disrupted and deflected, much like how a stream of water from a hose will splay out after hitting a wall at an angle. Credit: X-ray: NASA/CXC/CfA/D.Evans et al.; Optical/UV: NASA/STScI; Radio: NSF/VLA/CfA/D.Evans et al., STFC/JBO/MERLIN.

On the official blog of the Chandra X-Ray Observatory, one of the satellites that observed 3C 321, Evans resisted the urge to follow the crowd in naming the active galaxy after the Death Star. Noting that he was not even born when the first Star Wars film was released in 1977, Evans preferred “…a very simple, terrestrial analog, and that’s mainly putting your hands into a fire hose.”

Although the particle jet could strip away the ozone layer of any Earth-like planet in that pummeled galaxy in a mere matter of months, Neil deGrasse Tyson, an astrophysicist at the American Museum of Natural History in New York City, told BBC News that “…subterranean life is…immune to this kind of violence in the Universe.” The jet in 3C 321 may even bring about new life in the smaller galaxy by compressing galactic gas into new stars which in turn would form planets.

“Jets can be highly disruptive…but [create] stellar nurseries,” said Tyson. “It’s a fascinating sort of duality about how these high-energy phenomena influence the environments in which they’re embedded.”

Whatever the fate of the galaxies of 3C 321, it must be noted that the event has already taken place nearly one and a half billion years ago. Whether we ever learn what happened “long ago, in a galaxy far, far away” or not, one cannot fail to be impressed – and perhaps a bit frightened – with the immensities of our Cosmos.

James M. Essig March 26, 2008 at 16:19

Hi Paul and Larry Klaes;

This is a really good article.

A Carbon detonation type supernova or a white dwarf explosion is a huge natural thermonuclear device which converts about 1 percent of its mass into energy. The mass of these bad boys is about 500,000 times that of Earth. If the Earth was suddenly vaporized into a plasma with a temperature on the rough order of 1 billion K, the energy of a carbon super nova would be 500,000 times greater still. Even the Star Wars death star left behind large asteriodal solid chunks or remnants of the planet it blasted. A planet in the vacinity of a super nova would be utterly abblissimated and converted to millions of Kelvin plasma with no solid portion remaining.

This natural gamma ray burst at 7.5 billion lightyears I presume, what ever the heck its source was, may have been as much as several orders of magnitude higher in yield then a carbon supernova. Given that a carbon detonation supernova that has a spherically symmetric energy distribution may be lethal to human like civilizations perhaps as far away as 30 to 50 lightyears, the threat posed by a gamma ray burst such as the one reported on Arthur C. Clarks day of passing would be lethal at a much greater range. Such natural events do occur as we have just witnessed last week and pose a potentially lethal threat to any ETI races within the lethal blast, thermal pulse, and/or ionization radiation range.

Thanks;

Jim

occam's comic March 26, 2008 at 19:02

Why doesn’t the jet just pass through the galaxy? The edge of a galaxy is not a solid object, its mostly (>99.99%) empty space?

Colin Weaver March 26, 2008 at 19:30

I just hope that galaxy wide extinction pulses due to events like this are not the resolution to the Fermi paradox, as Stephen Baxter speculated in “Space”.

Zen Blade March 26, 2008 at 21:53

Realizing I am in no way a physicist…

Doesn’t “jets” escaping from a blackhole imply either something traveling faster than the speed of light or having more energy or something weird like that.

Also, what speculation exists regarding how/why these uber massive blackholes only develop in a small percentage of galaxies?

And isn’t this potentially a really cool weapon… you can essentially use the blackhole as a screen. Noone is going to reach by going through this uber radiation.

-Zen Blade

Ron S March 27, 2008 at 9:58

Jets come about from the dynamics of the accretion disk, which is outside of the event horizon.

philw1776 March 27, 2008 at 11:55

Nothing wierd like superluminal jets are required. ‘Escaping from a black hole’ is a misnomer as the jets are generated OUTSIDE the event horizon so the matter escapes before having fatally passed thru the event horizon membrane of no return (Hawking radiation excepted).

David March 29, 2008 at 1:21

occam’s comic,

What slows the jet down is that the material it encounters gets entrained so jet momentum gets transferred to the material that is dragged along. For a rough analogy, think of shoveling snow off a sidewalk. As you push the shovel through the snow, more and more of the snow gets pushed along and a greater effort is needed just to keep the shovel moving. You reach a point where you are pushing so much snow, that you can’t push anymore. Similarly as a jet encounters material, it drags along more and more of it so it gets to a point where it can’t drag it any further. The analogy is not complete because for reasons not completely understood, jets can start to be re-accelerated far from the region where they started.

ljk April 11, 2008 at 13:24

Supermassive Black Holes and Their Environments

Authors: Joerg M. Colberg (1, 2), Tiziana Di Matteo (1) ((1) Carnegie Mellon University, (2) UMass Amherst)

(Submitted on 10 Apr 2008)

Abstract: We make use of the first high–resolution hydrodynamic simulations of structure formation which self-consistently follows the build up of supermassive black holes introduced in Di Matteo et al. (2007) to investigate the relation between black holes (BH), host halo and large–scale environment. There are well–defined relations between halo and black hole masses and between the activities of galactic nuclei and halo masses at low redshifts.

A large fraction of black holes forms anti–hierarchically, with a higher ratio of black hole to halo mass at high than at low redshifts. At $z=1$, we predict group environments (regions of enhanced local density) to contain the highest mass and most active (albeit with a large scatter) BHs while the rest of the BH population to be spread over all densities from groups to filaments and voids. Density dependencies are more pronounced at high rather than low redshift. These results are consistent with the idea that gas rich mergers are likely the main regulator of quasar activity.

We find star formation to be a somewhat stronger and tighter function of local density than BH activity, indicating some difference in the triggering of the latter versus the former. There exists a large number of low–mass black holes, growing slowly predominantly through accretion, which extends all the way into the most underdense regions, i.e. in voids.

Comments: 18 pages, 15 Figures, accepted for publication in MNRAS

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0804.1756v1 [astro-ph]

Submission history

From: Joerg Colberg [view email]

[v1] Thu, 10 Apr 2008 16:55:57 GMT (1235kb)

http://arxiv.org/abs/0804.1756

ljk April 23, 2008 at 22:12

Radio Telescope Reveals Secrets of Massive Black Hole

“At the cores of many galaxies, supermassive black holes
expel powerful jets of particles at nearly the speed of light.
Just how they perform this feat has long been one of the
mysteries of astrophysics.

The leading theory says the particles are accelerated by
tightly-twisted magnetic fields close to the black hole, but
confirming that idea required an elusive close-up view of
the jet’s inner throat.”

http://www.spaceref.com/news/viewpr.html?pid=25292

James M. Essig April 24, 2008 at 21:43

Hi ljk;

Interesting article for which you provided the above link.

I have often wondered what purposes we could use the jets for if we could harness their energy which obviously would require us to be able to travel to these jets.

I can imagine building absolutely huge, high gamma factor capable space arks made of a truss like configuration and large enough and of strong enough materials so as to avoid self gravitational collapse. These truss worlds might have a mass of any where from less than one solar mass all the way up to 10s or 100s plus solar masses and might be accellerated by magsails, charge particle sails, and/or huge light sails to a velocity simmilar to that of the jets which presumably have gamma factors within the range of the particles to be accellerated by the soon to be operational LHC at CERN.

If we had enough nerve, perhaps we could accellerate neutron stars to the point where they would become blackholes along their direction of travel due to relativistic Lorenzs contraction but perhaps not along their orthogonal axes thus producing a very massive naked singularity. We would have to run lots of studies in order to ascertain that the naked singularity would not trash the universe in such a manner as has been the conjecture of naked singularity theoriest regarding macroscopically massed naked singularities. If safely issues permit the production of such huge naked singularities, then producing them might be very useful for manned interstellar, intergalactic, interdimensional, and inter-universe travel as well as provide a venue for studying ever more extreme limits of physical laws.

Thanks;

Jim

ljk May 27, 2008 at 11:51

Stellar jets

Authors: Thomas J. Maccarone (Southampton)

(Submitted on 23 May 2008)

Abstract: With a goal of understanding the conditions under which jets might be produced in novae and related objects, I consider the conditions under which jets are produced from other classes of accreting compact objects. I give an overview of accretion disk spectral states, including a discussion of in which states these jets are seen. I highlight the differences between neutron stars and black holes, which may help give us insights about when and how the presence of a solid surface may help or inhibit jet production.

Comments: 10 pages, 1 figure, invited review at the “RS Ophiuchi (2006)” conference, to appear in the ASP Conference Series edition for the conference

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0805.3634v1 [astro-ph]

Submission history

From: Thomas J. Maccarone [view email]

[v1] Fri, 23 May 2008 13:07:55 GMT (25kb)

http://arxiv.org/abs/0805.3634

ljk July 7, 2008 at 23:20

The role of jets in the formation of planets, stars, and galaxies

Authors: Ralph E. Pudritz, Robi Banerjee, Rachid Ouyed

(Submitted on 4 Jul 2008)

Abstract: Astrophysical jets are associated with the formation of young stars of all masses, stellar and massive black holes, and perhaps even with the formation of massive planets. Their role in the formation of planets, stars, and galaxies is increasingly appreciated and probably reflects a deep connection between the accretion flows – by which stars and black holes may be formed – and the efficiency by which magnetic torques can remove angular momentum from such flows.

We compare the properties and physics of jets in both non-relativistic and relativistic systems and trace, by means of theoretical argument and numerical simulations, the physical connections between these different phenomena.

We discuss the properties of jets from young stars and black holes, give some basic theoretical results that underpin the origin of jets in these systems, and then show results of recent simulations on jet production in collapsing star-forming cores as well as from jets around rotating Kerr black holes.

Comments: To appear in the proceedings for “Structure Formation in the Universe: Galaxies, Stars and Planets”, ed. G. Chabrier, conference held in Chamonix May 2007

Subjects: Astrophysics (astro-ph)

Cite as: arXiv:0807.0740v1 [astro-ph]

Submission history

From: Robi Banerjee [view email]

[v1] Fri, 4 Jul 2008 12:40:07 GMT (325kb)

http://arxiv.org/abs/0807.0740

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