Saturday, January 06, 2007

Supernovae Get Weirder

Observations of Type Ia supernovae are the only evidence of an "accelerating universe." It would be convenient for cosmologists if all Type Ia's were the same, all fireflies had the same luminosity, and all people thought the same. New evidence from the XMM-Newton and Chandra X-ray observatories may force a rethink.

The big photo is a composite of DEM L238 (right) and DEM L249. Chandra X-ray data is blue and optical data is red. The inset shows DEM L238 in low-energy (red), medium energy (green) and high energy X-rays (blue). The central portion of DEM L238 is hot and green, indicating an overabundance of iron.

Iron identifies DEM L238 as a Type Ia supernova. The iron in these supernovae is much denser than in most Type Ia's. That would indicate that the stars were born more massive and exploded as supernovae unusually young. They may represent an entirely new class of supernova.

Type Ia's are thought to result when a white dwarf star abruptly absorbs a companion, pushing it over the Chandrasekhar Limit of 1.4 solar masses. Boom! Chandrasekhar's Limit is proportional to hc/(Gm_p^2). Since the product hc is here considered constant, the limit is not affected by a changing c. Redshift and the energy E=mc^2 are affected, making the universe appear to accelerate.


Blogger CarlBrannen said...

So what do you suppose would cause Jupiter to have a red spot that lasts so long?

11:54 AM  
Blogger serge said...

Hi Louise,
For the BBC, dark matter is big news. For example, today their int'l tv show had an item about dark matter between items about the crises in the Middle East, and they have this in their headlines Hubble makes 3D dark matter map.

1:58 PM  
Blogger serge said...

Why is dark matter big news for the BBC?

1:59 PM  
Blogger L. Riofrio said...

For Carlb, I have been writing that Saturn's South Polar storm is a hot spot caused by a singularity at the core. The storm is centred at the South Pole because Saturn's singularity, like its magnetic field, is lined up with the geographic poles.

Just speculating, but Jupiter's magnetic field and therefore its central singularity are offset from the geographic poles. That would cause a storm between Jupiter's South Pole and equator, like the Great Red Spot.

Hee hee Serge, maybe the BBC loves "dark" news!

5:45 PM  
Anonymous Anonymous said...

Hi Louise,

What are the singularities associated with planets? Do they act as a nucleation site for planetary formation?

Do planets with a central singularity always have a magnetic field (and vice versa)?

Do smaller bodies (e.g . moons?, asteroids?) also have central singularities, or is there a mass cutoff?

2:23 PM  
Blogger L. Riofrio said...

Hi anon. The singularities were seeds to planet formation, just as a grain of sand can start a pearl. There is no mass cutoff, a small moon like Enceladus could also contain a singularity. A spinning Black Hole would account for Mercury’s magnetic field. The planet Venus has shown signs of recent volcanoes, indicating another singularity. Venus does not have a magnetic field because her singularity does not rotate.

Not all bodies in the solar system would contain Black Holes. Mars, which shows no signs of recent vulcanism or magnetic fields, probably does not contain a singularity. Mars does have huge extinct volcanoes and signs of past magnetism. It may have contained a singularity at some time in the past, which has since evaporated.

A singularity would explain Jupiter’s powerful magnetic field, and why Jupiter gives off nearly twice as much heat as it receives from the Sun. Rotating Black Holes could account for the magnetic fields of Uranus and Neptune, and why those fields are offset from the planets’ rotation axes.

2:45 PM  

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