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Quasars at 50: Luminous Cosmic Beacons Remain a Puzzle

The views expressed are those of the author and are not necessarily those of Scientific American.


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Quasar 3C 273 with jet

Quasar 3C 273 and its jet, as viewed in x-rays. Credit: NASA/CXC/SAO/H.Marshall et al.

Fifty years ago, in the journal Nature, astronomer Maarten Schmidt published a brief paper noting that a star-like object known as 3C 273 was simply too far away to be a star in the Milky Way. Schmidt, of the California Institute of Technology, concluded on the basis of spectroscopic observations that the object was most likely very distant (some two billion light-years away) and hence very, very bright. Shortly after Schmidt’s 1963 paper, 3C 273 and its ilk would become known as quasars, short for “quasi-stellar” objects.

On the fiftieth anniversary of the unmasking of quasars as distant beacons, their secrets have still yet to be fully unlocked, physicist Robert Antonucci of the University of California, Santa Barbara, notes in the March 14 issue of Nature. (Scientific American is part of Nature Publishing Group.) “Have we made good progress in understanding quasars in five decades?” Antonucci writes. “I do not think so.”

The general picture of quasars is now relatively uncontroversial—giant black holes at the centers of distant galaxies feed on gas and even nearby stars, glowing brightly across the electromagnetic spectrum as a result. These active galactic nuclei (AGNs), as they are known, can also launch jets of high-speed particles, as in the case of quasar 3C 273.

Antonucci’s complaint is that the general astrophysical understanding of quasars has not become more detailed. “Astronomers have had great fun detecting distant quasars, pushing ever closer to the big bang as technology has improved,” he writes. “But they have yet to understand the detailed physics of how quasars emit such enormous amounts of energy.” Among the outstanding questions: just what kinds of particles are in quasar jets? How much energy goes into the jets’ electric and magnetic fields, respectively? And what, exactly, happens in the accretion disk of material swirling around the black hole?

“I see fewer and fewer serious theory papers on AGNs, but there is a burgeoning effort to find ever more quasars in surveys,” he writes. “It is as if, having given up on understanding AGNs, the community now focuses on the more modest goal of counting them.”

The situation is nonetheless a bit better than it was in 1971, when Schmidt co-authored an article in Scientific American that still had to fight the notion that quasars are nearby exotic objects, rather than distant AGNs as originally proposed and now widely accepted. Still, some of the language is surprisingly similar to Antonucci’s comments today. “As for the ultimate source of the tremendous energy observed in quasars, there has been no lack of hypotheses,” Schmidt and Scientific American’s Francis Bello wrote. “There is also no agreement about the radiation mechanism….The solution of these problems constitutes one of the main challenges to present-day astronomy.”

About the Author: John Matson is an associate editor at Scientific American focusing on space, physics and mathematics. Follow on Twitter @jmtsn.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. jtdwyer 2:32 pm 03/14/2013

    A simple hypothesis addresses two very difficult problems: what process powers quasar jets and how can black hole mass be contained within an dimensionless singularity.

    I suggest that atomic matter collides and disintegrates as it is accelerated to relativistic velocities within the accretion disk of a black hole upon its approach to the event horizon.

    The disintegrated fundamental particles are expelled along magnetic fields lines through the polar jets.

    The released binding mass-energy (representing 99% of atomic mass) is retained as spacetime curvature at the exterior of the event horizon. No dimensional matter is ingested or retained within the BH singularity – it is simply the focal point of external curved spacetime.

    Link to this
  2. 2. string_beery 7:28 pm 03/14/2013

    “..there has been no lack of hypotheses”

    i’d be interested in hearing about some of these…

    Link to this
  3. 3. jack.123 11:46 pm 03/14/2013

    Not only matter and energy is falling in a EH,but space time itself is also falling in.And both dark mass and energy falling as well.This spinning space time combined with the dark mass-energy may reach a point where all the constituents could interact with the other normal mass in the accession disk,which could explain the greater amounts of energy being thrown out.

    Link to this
  4. 4. Cramer 3:19 pm 03/15/2013

    I agree with jtdwyer except that I believe that not only is matter not retained by the black hole, but jtdwyer’s “released binding mass-energy” is also not retained by the BH. That energy escapes the BH as EM emissions (gamma, x-ray, radio, etc) that are typically 10^40 watts (source: wikipedia).

    My conjecture: Black holes do not “feed” on gas and nearby stars (and therefore grow). Matter never makes it past the event horizon. Rather it is converted to energy and high-speed particles and ejected. Black holes form from collapsing stars. Black holes grow ONLY by merging with other black holes (my conjecture).

    Link to this
  5. 5. Steven 5:49 pm 03/15/2013

    Probably black holes are actually cosmic donuts due to preservation of angular momentum from matter falling into the “black hole”. While they have intense gravity, overcoming light velocity, light actually going into a reverse direction as it falls back into the hole, so time may also reverse in the inside of the black hole.
    Since angular momentum is preserved, rotational momentum persists, even as matter (matter and energy being interchangeable in the inferno of the black hole) falls into the hole or slips over the edge of the event horizon.
    Rotational velocity increases as the radius decreases with the rotational velocity approaching light or relativistic velocity.
    With the increase in velocity, mass would also increase, with reference to Einsteins iconic equation, E=MC(squared)
    This results in the mass approaching infinity, as velocity approaches relativistic or light velocity speed.
    As mass approaches infinity, and light velocity may actually change direction under gravitation from infinite mass, time may either stand still or actually go into reverse, resulting the the Quasars appearing to originate billions of years ago.
    They may actually be going further back into time to the very origin of the universe.
    The jets may indicate a area of negative gravity, in the center of the rapidly rotating mass, infinite mass, relativistic velocity, with the gravity concentrated at the rim of the rotating “wheel” of mass and energy.
    Quasars may appear to be so distant, since their unusual cosmology (mass approaching infinity as rotational velocity approaches the speed of light, if not exceeding it in the “singularity”), they are actually reverse time machines, their time progressing into our past, although it may be their future.

    Link to this
  6. 6. patrick 4:44 am 03/18/2013

    Ref:5,Thoughtful in depth- Steven,

    “I find they are actually reverse time machines, their time progressing into our past, although it may be their future ” of deep thought and interest”,

    You are correct, “QUASARS” are Time Reversal Machines in Phase Space,and is located in a Region under a Physical Classical Symmetry, of a Group of minimum sixteen pairs of Celestial Bodies,in a Rotation sweep, through equal angles
    at equal time in Synchronized Dynamical orbital motion in a SLICE OF PHASE SPACE UNDER TIME-LOCK.

    Link to this
  7. 7. Maniaparna 11:21 am 03/18/2013

    Are they white holes? compensating expanding space?

    Link to this

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