April 21, 2008 | David F. Coppedge

Findings vs Surmisings in Astronomy

The Galex satellite (Galaxy Evolution Explorer) found “bright features” with an ultraviolet glow in the outskirts of a spiral galaxy, reported the BBC News.  What are they?  Scientists “think” they are large clusters of stars.  How much is known, and how much is interpreted?
    The region imaged is the dark area around spiral galaxy M83 in the constellation Hydra.  Symmetrical arms of glowing hydrogen appear in the periphery of the more familiar central spiral.  If these are starry regions, the discovery is surprising: “The finding has surprised astronomers because the galactic periphery was assumed to lack high concentrations of ingredients needed to form stars.”  Each pixel in the Galex image would have to contain hundreds of thousands of stars.  It is impossible, therefore, for Galex to actually resolve them.  The Galex researchers compared their image with radio telescope data from the Very Large Array in New Mexico.  Did the VLA find the elusive stars?

Light emitted in the radio portion of the electromagnetic spectrum can be used to locate gaseous hydrogen atoms.  These are seen as a good sign that the molecular form of the gas is also present.  And it is from this molecular gas that stars are born.
    When the astronomers combined the radio and the Galex data, they found that they matched up.
    “Clearly, the basic ingredients for star formation are out in those regions,” said Dr [Mark] Seibert [Carnegie Observatories].

The radio telescope did not resolve stars, either.  The leap from glowing gas to large clusters of stars was bridged by theory.  From there, another leap into cosmology was made, but this time it was labeled a speculation:

The astronomers speculate that the young stars seen in far-flung regions of M83 could have formed under conditions resembling those of the early Universe, a time when space was not yet enriched with dust and heavier elements.
    But this process is not well understood.

Despite the disclaimer, the above paragraph still claimed the stars were “seen” when, in actuality, the radio and UV instruments merely showed the presence of atomic hydrogen gas, from which they assumed molecular gas was present, from which they assumed stars would form, even though regions of this low density were not expected to have stars.
    The Galex satellite is operated by JPL and Caltech.  The original press release is on the Galex home page.

Maybe there are stars there.  These astronomers did little to ground their interpretations in empirical data.  Not a single star was observed in this gas, yet we are supposed to believe there are hundreds of thousands of them in each pixel?  Are we supposed to respect a pure speculation about the early universe resting on the admission that “this process is not well understood”?  Try that with gnome theory.  “We did not find any gnomes, but we think we found some gas they emit.  We didn’t expect to find that gas in the desert.  It might shed light, however, on how gnomes arose on the early earth, before the land was enriched with toadstools.”
    If a scientist is not sure of something, let him say so or keep his speculations to himself.  Today’s scientists often do a very poor job of discriminating between observation and interpretation.  News reporters shift between them seamlessly and shamelessly.  It is up to the reader, and to sites like this, to sift the shift and lift the fogma.

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Categories: Astronomy, Cosmology

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