Why Nebula comet theory failed

comets look like surface predictions 67p rosettaThe finding of oxygen molecules around comet 67P suggests that both comet theory and the Nebula Hypothesis it came from are wrong (and the theories like the Big Bang, theory of gravity etc they came from?).

Before that they were already in trouble with comets turning out to be rocky and not dirty snowballs.

So why has the Nebula theory and the origins of comets failed so spectacularly?

From observations to hypotheses to models to theories

comet theory formation where did they come from solar nebula
A recent article on Rosetta Mission blog on the European Space Agency website gave details from scientist Dr Matteo Massironi about the different formation theories of comet 67P/C-G. The start and end of the article sound very promising, open minded thinking.

In general, science works from observations to hypotheses to models to theories. An observation may trigger a hypothesis, which should be tested with different approaches trying to find evidences that might undermine your own hypothesis.
cometary formation theory origins 67p observations theories wrong
... Our cometary mission is called Rosetta because it has the potential to decipher the origin and evolution of the Solar System. We should put aside our previous theories and models and try to study images without forcing our observations to a particular model or another. Theories and new models will come later (stay tuned!)."
Interpreting images – more on how the comet got its shape | European Space Agency

Observing the failure of theories

cometary comets theories formations formed origins
One of the main reasons is because astronomy/science came up with the comet and asteroid formation theories before having actually had the chance to observe close up what comets are like. Which is not an issue. You have to have some basis for theories and experiments.

It does though reflect badly on the original theories it was based on especially any subsequent theories based on those failed theories.

Below are some selected highlights from the same Dr Massironi article. This was written before the comet 67P molecular oxygen discovery but after the death of the dirty snowball theory.

We asked Matteo to share his opinion not only on this subject but also on the general topic of how planetary images are interpreted in order to arrive at a robust scientific theory.
comet theory formation origin failure fails wrong nebula hypothesis
"As a geologist, I would first like to point out some basic principles to follow when dealing with space images for geological interpretations. I believe these suggestions could be of some help to anyone who is going to submit his or her own work on cometary geology and structure.
These principles can be synthetized as follows:
1) Be a good field geologist
2) Be rigorous
3) Never fall in love with theories (particularly your own ones)
4) Be short
comets composition rock minerals not ice water plasma
3) Never fall in love with theories (particularly your own ones):
For example, neck-enhanced erosion and simple contact binary of two young cometisimals were the two favoured scenarios for Comet 67P/C-G’s formation because they do not present any problems to existing theories related to Solar System formation and evolution. On the contrary, a contact binary of two fully-formed comets with an ordered onion-like inner structure raises relevant issues with pre-existing models (already correctly highlighted by some readers of this blog in the comment section).
comet theory predictions look like surface 67p ice rock
... The only issue that was already solved is the formation and stitching of contact binaries through low velocity collisions (see the publication The shape and structure of cometary nuclei as a result of low-velocity accretion by Jutzi & Asphaug for more information).

Due to the controversial implications that the onion-like contact binary raises, we tried to find other lines of evidence that might undermine what was apparent from the former observations. This is why, from the best fitting planes, we passed to the geological sections and afterwards worked on the angular relationships between strata and the local gravity vectors. All these independent observations based on primary structures support the view in which the comet derives from a contact binary of two comets with an onion-like interior.
Interpreting images – more on how the comet got its shape | European Space Agency

What may be the real issue is that observations are then being forced/modified to fit into previous theories that were a failure to predict what was observed. Even after having visited a number of active asteroids (comets) and normal asteroids.