APOD: At the Heart of Orion (2015 Jan 02)

[Chris Peterson]

But there's every reason to think it would go through periods of accretion. If so, we could probably detect it. So it's something to look for.

One wonders if we would even catch it. I'm under the impression there are frequent holes in the monitoring of the sky in X-rays since there is only ever one or two telescopes doing it at any one time. It's not like supernovas where even amateur telescopes can help look.

I'd think that accretion would build up and die down over periods of years. So when present, we'd probably see it. It's just not likely to happen very often.

[Ron-Astro Pharmacist]

It’s pretty cool that an intermediate mass black hole is lurking in such a common place many of us see almost every clear night in the winter.

http://www.space.com/26857-medium-size- ... y-m82.html

Astronomers and archeologists have got to be patient people. They have to keep their eyes open – even in the most well-known neighborhoods. You might even find a monarch in a parking lot if you do your homework to know where to dig?

http://www.pbs.org/wnet/secrets/resurre ... sode/1934/

Black holes have got to be the best fossils in the sky. But like remnants in the earth – what’s left over only gives us bare bones facts of what was there originally. Of course some think the “hole” story is written “graphically” on its cover whereas the bone’s marrow holds his-story.

[BDanielMayfield]

It’s pretty cool that an intermediate mass black hole is lurking in such a common place many of us see almost every clear night in the winter.

http://www.space.com/26857-medium-size- ... y-m82.html

Yes, it will be cool IF one is discovered in Orion Ron. You realized that the space.com story is about one in a whole other galaxy, right?

[Nitpicker]

It’s pretty cool that an intermediate mass black hole is lurking in such a common place many of us see almost every clear night in the winter.

http://www.space.com/26857-medium-size- ... y-m82.html

Yes, it will be cool IF one is discovered in Orion Ron. You realized that the space.com story is about one in a whole other galaxy, right?

I see M42 in my summer sky and M82 in my never sky.

[Ann]

This is getting old, I know, but...

BruceDanielMayfield wrote:
as well as the absence of the expected numbers of OB stars that Subr's BH theory attempts to explain

The absence of the expected number of OB stars... How sure can we be about the expected number of OB stars in any star forming region? Is it really possible to say that there are too few OB stars in the Orion Nebula?

Ladislav Subr (Prague), Pavel Kroupa (Bonn), Holger Baumgardt (Queensland) wrote:

The canonical (best-fit) model of the ONC has an initial mass of 5400M⊙, half of which is in the form of stars, while the other half accounts for gas. We considered a Kroupa (2001) initial mass function which, for the given cluster star mass, predicts ≈ 50 OB stars to have been formed in the ONC (Pflamm-Altenburg & Kroupa 2006).

The "canonical" best fit model? How certain is it that the canonical best fit model is right, and that a dearth of OB stars in the Orion Nebula compared with the predictions of the canonical model means that we have to tweak reality (by introducing a black hole) rather than considering the possibility that the canonical model might need to be revised?

Ann

[geckzilla]

It would seem to me that if the chance there is a black hole is much greater than the chance the model is wrong to some large degree (all models are wrong) then you pick the one that seems most likely at the time. Work, work.

[Chris Peterson]

The "canonical" best fit model? How certain is it that the canonical best fit model is right, and that a dearth of OB stars in the Orion Nebula compared with the predictions of the canonical model means that we have to tweak reality (by introducing a black hole) rather than considering the possibility that the canonical model might need to be revised?

In the parlance of modern science, a "model" is generally a complex interaction between multiple theories. It is only as solid as the individual theories that make it up, as our understanding of the interactions between those theories, and of our ability to mathematically treat those interactions.

The existence of this model does not mean that researchers are not constantly questioning it, refining it, or exploring different models. That this one is "canonical" simply means that it is generally taken at providing the best match with reality, given our current understanding of theory and our current database of observations. It is being used correctly in this case, to make predictions about what we should observe. Since this model has produced accurate predictions in many other cases, the fact that it does not do so here opens up the question of why not. One possibility is that there is something important wrong with the model. If so, that will certainly be corrected over time. But the most reasonable explanation is that this particular nebula is behaving differently than others we've looked at. And that is the beginning of the scientific process: question, hypothesize, test.

It seems more likely that introducing a black hole is reflecting reality, not "tweaking" it.

[Ann]

The "canonical" best fit model? How certain is it that the canonical best fit model is right, and that a dearth of OB stars in the Orion Nebula compared with the predictions of the canonical model means that we have to tweak reality (by introducing a black hole) rather than considering the possibility that the canonical model might need to be revised?

In the parlance of modern science, a "model" is generally a complex interaction between multiple theories. It is only as solid as the individual theories that make it up, as our understanding of the interactions between those theories, and of our ability to mathematically treat those interactions.

The existence of this model does not mean that researchers are not constantly questioning it, refining it, or exploring different models. That this one is "canonical" simply means that it is generally taken at providing the best match with reality, given our current understanding of theory and our current database of observations. It is being used correctly in this case, to make predictions about what we should observe. Since this model has produced accurate predictions in many other cases, the fact that it does not do so here opens up the question of why not. One possibility is that there is something important wrong with the model. If so, that will certainly be corrected over time. But the most reasonable explanation is that this particular nebula is behaving differently than others we've looked at. And that is the beginning of the scientific process: question, hypothesize, test.

It seems more likely that introducing a black hole is reflecting reality, not "tweaking" it.

Thanks for your very clear explanation, Chris.

Ann