Expert: Philip A. Stahl - 11/1/2007

Question
QUESTION: Hi Philip,

I've heard the talk of the sun aligning with our galactic center this decade, a rare event.  It's often mentioned by people with weak astronomical background, in the context of apocalyptic theories.  But now I'm curious - could there be perceivable gravitational effects on our solar system?  I understand many physicists believe there exists a supermassive black hole at the center of our galaxy.  Any thoughts on this alignment phenomenon?

Thanks,
Joe

ANSWER: Hello, Joe

I also seem to recall that an apocalyptic "disaster" was predicted 25 years ago when Jupiter and a number of other planets were to "align" and generate enormous gravitational tidal forces on the Sun and spawn all kinds of havoc.

Never occurred. And I am fairly sure John Gribbin ('The Jupiter Effect') regrets he ever helped to promote it.

What came out of the fiasco is that the "alignment" written of was not a geometrical straight line arrangement but more an "astrological" one bearing more similariy to a vast arc. (This in itself discloses the critical need to define exactly and operationally what is meant by an "alignment" in the given context)

This is why I am always leery of talk about "alignments" of any celestial objects, and especially if there is some impending catastrophe is also predicted.

Anyway, while this new revelation of alignment is intriguing it still doesn't alter my bearing or mindset one iota. Call me a skeptic. Even if a multi-million mass black hole exists in the galactic center I don't see any pronounced gravitational effects, given that center is so very distant and we know the gravitational force has an inverse square character. It falls off as the *square* of the distance.

So my thoughts about this alignment are that I am not losing sleep over it. I am much more concerned about human apathy to do with global warming, and the fact we are now teetering on a runaway greenhouse effect that could turn Earth into another Venus.

A threat, btw, much more immediate than the one posed by an alignment with of the Sun with a black hole in the galactic center!

---------- FOLLOW-UP ----------

QUESTION: Hi Philip,

Thanks so much for the reply.  Please let me follow up by putting my
question in perhaps a wider context than it might have seemed on first
impression.  I am aware of the alarmists' talk of an era change, sometimes
based on the supposed astronomical prescience of the Mayan calendar, or
other highly speculative sources.  It also seems that even within the
astronomy community, it's not agreed that the timeline of crossings in the
galactic equatorial plane could be predicted with full precision.

However, I believe that discussions regarding our solar system traversing our
galaxy's equatorial plane have been had among serious thinkers as well.  I am
not usually prone to wholeheartedly accepting, or summarily dismissing, a
curious hypothesis until I've investigated in some depth.  As for the minimal
effects of the black hole on our solar system, another grouping of mass that
seems to be relevant to some who question this phenomenon, is the dense
cluster of matter in the equatorial plane that is in the vicinity of the solar
system.

It seems there is quite a long period for the movement of the entire solar
system directly through the equatorial plane.  If I'm not mistaken,
astronomers tend to think this happens rather infrequently.  There also
seems to be a school of thought among reputable thinkers, that such
movement could raise the likelihood of the solar system being affected
gravitationally by other matter in the galactic equatorial plane, or even the
planets being impacted by comets from the postulated 'Oort Cloud.'

I would be very grateful if you could take a look at the Shiva Hypothesis,
having a scientific basis in geology, biology and serious astronomical
conjecture, at:

http://abob.libs.uga.edu/bobk/ccc/cc020298.html

if you find the time.

Thanks Again Philip!
Joseph

Answer
Hello again,

The link you provided had some fascinating information for sure, e.g. clusters of craters of similar ages being closely correlated with the mass extinction episodes (and the 'Shiva" hypothesis etc.)

However, it all still leaves me about as cold and unimpressed as the "Milankovitch hypoothesis" which seeks to explain the ice ages. In the latter case, endless citations of "correlations" from geological data are used to try to make the case that the Earth suffers divergences and deviations in axial inclination, eccentricity etc.

At the very least, a celestial mechanics text for which the Earth's orbital elements are the primary starting points for all forecast predictions ought to note that these key elements (e.g. the eccentricity, the inclination of axis to plane of orbit) will change significantly at some distant date - though we need not fret over their effects on fundamental position finding and planetary position location now.

What this would do is disclose at least perfunctory attention is being paid to the fact that the orbital elements are expected to change over long time periods!

But know what? NO one has ever broached or mentioned this in any celestial mechanics course, or text I have ever seen! Why not? The reason is that, based on hard mechanics data, there's nothing there.

Correlations, as exotic as they may well be don't impress because *correlation is not causation*.

I find the same problem with these "cycles of doom" and "Shiva hypothesis".

Next thing, if we are to take this as a bona fide hypothesis, beyond speculation - what are the tests for falsification? What data or key observations will falsify the hypothesis?

I will pay much more attention to this when and if the first paper on "Shiva" appears in The Astrophysical Journal!