Based on computer simulations Mark Krumholz from Princeton University, Christopher McKee from the University of California at Berkeley, and Richard Klein from Berkeley and Lawrence Livermore National Laboratory now claim [Nature 438, 332-334 (2005)] that the bottom-up theory is incorrect because the seeds cannot grow fast enough during the lifetimes of the clouds to reach typical star sizes. …

"Our result is that the bottom-up idea doesn't work," Krumholz told PhysicsWeb, "because seeds can't accrete quickly enough to grow to stellar masses within the lifetimes of the clouds out of which they are born. Instead, stars form by fragmentation, and the fragmentation process determines their masses."

The results also explain, the team says, why observations suggest that objects as different as small brown dwarfs and massive stars have a common formation mechanism. In contrast, the accretion model involves different mechanisms for making objects with different masses. A universal formation process might also explain why the mass distribution of newly formed stars – the initial mass function – seems to be constant throughout our galaxy and other galaxies.

"Many earlier simulations of star formation processes made a significant error because they modelled environments with properties that are very different from those observed," says Krumholz. "A lot of these simulations are now going to have to be reconsidered and probably re-done."

How do stars form? Belle Dumé, PhysicsWeb, 16 November 2005.

 


 

Formation of Stars

Letter

 

Eugene Sittampalam


 

To:          krumholz@astro.princeton.edu, cmckee@astro.berkeley.edu, klein@radhydro.berkeley.edu

Date:       Thursday 8 December 2005

Subject:   Formation of Stars

 

"...Instead, stars form by fragmentation, and the fragmentation process determines their masses." Mark Krumholz.

A universal formation process might also explain why the mass distribution of newly formed stars – the initial mass function – seems to be constant throughout our galaxy and other galaxies.

How do stars form? Belle Dumé, PhysicsWeb, 16 November 2005; and Nature 438, 332-334 (17 November 2005)

 

Dr Mark Krumholz

Princeton University

 

Prof Christopher McKee

University of California at Berkeley

 

Prof Richard Klein

Berkeley and Lawrence Livermore National Laboratory

 

Dear Esteemed Researchers,

It was encouraging indeed to read Dr Krumholz's above comments. Hopefully, it is indicative of what might now be a general trend in mainstream thought. Nevertheless, his unwavering words do send us the clear message that physics is an empirical science and should be rid of observationally unsupportive old notions in its quest for unification.

 

Toward that ultimate end, therefore, kindly consider here a suggestion for your further thought.

 

The “universal formation process,” referred to above, is indeed an observational fact today (please see also the recent ESO Letters). Not surprisingly in this fractal universe of ours, the final model that has thus come to light is also an extremely simple one. The essentials, taken from my book and web Synopsis are as follows – with the optical map of Fig. 3.9 (page 41) in P. J. E. Peebles’ Principles of Physical Cosmology, Princeton University Press (1993), in perspective.

 

 

The latticework of the observable universe

 

Astronomical observations reveal the fact that the large star ends its active life in a spectacular supernova. The ejected matter from such exploding nuclear bodies then go to form a new generation of smaller stars. All these star types we are able to directly observe as discrete bodies in the firmament and thereby make these correct inferences.

    It is also not inconceivable, therefore, that the large stars we see today were themselves once ejected from even larger nuclear entities – the galactic cores. But it is not possible even with the best of instruments to observe the galactic core directly to ascertain this process. Whereas the supernova debris eventually clears to reveal a core, the fog around the galactic center never lifts. As a result, the nucleus of our own Milky Way Galaxy, for example, remains obscured at all time by the stars and the gas clouds of what we call the central bulge. This shroud never dissipates due to the relentless activity within, which feeds and sustains it. Nevertheless, recent endeavors have revealed to refined instruments and observational techniques enough evidence to show that the region of the galactic core is indeed a hub of violent activity of sustained star formation (Serabyn & Morris 1996).

    Not so long ago, the central bulge was commonly thought to consist mostly of very old stars. But, now, there is also convincing evidence to suggest that star formation has been occurring near the center of the bulge throughout the lifetime of the Galaxy. Thus, the most energetic of expulsions from the galactic core are what we see mostly as stars and star clusters outside the bulge today.

    Extrapolating back in time, a very close or contiguous union of such galactic cores (that is, in their extremely active and formative years) is what we observe, in time lapse now, as the quasar. Quasars and their ilk, collectively known as active galactic nuclei, or AGN, are the greatest cosmic powerhouses known today. The AGN, in turn, would evolve from even larger and denser mass centers. The existence of such super centers, though, is not presently recognized, suspected, or even speculated.

    Let us here refer to these ultimate mass centers, dispersed across observable space, simply as – COSMIC CORES.

    Due to the cover provided by the AGN outside, Cosmic Cores, too, remain out of direct view like galactic cores. But here, too, indirectly, there is ample evidence to support such centers in our observable universe. For example, the Cosmic Cores would possess most of the mass in our universe (like atomic nuclei do in a body of matter); and it is only such extremely massive and compact bodies (in the foreground) that could possibly account for the otherwise enigmatic gravitational lensing of (distant) quasars (Fischer et al. 1994).

    But what would be the true function of Cosmic Cores?

    To astronomers and astrophysicists, especially, the function of Cosmic Cores should not seem something that is at all new. Even this aspect of the cosmic process is seen today in miniature down the line. We say that large stars die in the supernova and generate new stars. But the first part of this statement we also know is not generally true. That is to say, the remains of a so-called dead star would live again – for a repeat death performance another day – if the environment is right: The dense and extinct core, typically, a neutron star, exerts an enormous gravitational influence on all that is around in the vicinity and grows by accreting matter; in time, it would eject matter in a nova- or even a supernova-like event once again. In principle, therefore, there is no end to these epochs for the selfsame stellar core – if sufficient matter is (cyclically) provided. In the case of the Cosmic Cores dotting our universe, however – there just happens to be sufficient matter around (from a critical initial condition) to keep the process going indefinitely.

 

A Universe of Steady State

 

In actual fact, the Cores of the cosmic latticework feed each other. That is, they accrete matter, fuse them together, and toss them out at each other. Matter, from the galaxy supercluster to the atom, is thus continually recycled in our observable universe. And the cosmic species of the heavens continue to live on in their eternal splendor.

    Evidence for this grandiose and cyclic mass transfer through cosmic space, too, is very well established now, though it remains a challenge to today's standard model: The periodicity of birth of galaxy cluster groups and the uniformity of their spacing and speed are truly breathtaking that they even make the observers to double-check their instruments in disbelief! (Smoot & Davidson 1993; Matthews 1996).

    It is thus plainly seen that galaxies are not scattered more or less randomly through space as had once seemed the case. Indeed, galaxies are aggregated as sheets of clusters and superclusters. It is like a cosmic foam where the walls of the bubbles are concentrations of galaxies. As a balance to these huge concentrations, immense voids also exist between sheets (Saar et al. 2002).

    Furthermore, as NASA's Hubble Space Telescope (HST) continues to confirm only too overwhelmingly, galaxies abound even at the deepest levels of observable space. Not only did the HST capture new galaxies in earlier "empty" space, but it also got a better look at some of the lumpy ones that had been seen before. Seen in the infrared, they look more like "normal" galaxies, like those in our own cosmic neighborhood. Clearly, cosmic structures do not seem to have changed over time across observable space – as if in a steady-state universe (see, for instance, Schilling 1999).

    The concept of the conservation of energy would also suggest a steady-state universe. Until only as recently as a decade ago it was difficult to reconcile all of the observed data to a steady-state universe. But, now, the powerful telescopes of the present day throw to us much more light than they receive. And, in this most revealing new light since the time of Einstein, we see the awe-inspiring final picture emerging.

    Every celestial body has a closed-loop trajectory beginning in a Cosmic Core and ending in a neighboring one only to be regenerated, or, to be born again. And a steady-state universe would go on existing, ceaselessly, under the setting...

    How it all began and how it all will end are outside the realm of observation. They, thereby, remove themselves also outside the scope of physics.

 

(References listed in Synopsis.)

 

Thank you for your valuable time; I'm confident it will not be found a waste.

Sincerely,

Eugene Sittampalam

www.sittampalam.net

 

– End of Letter –

 


 

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