I just got word that John Bahcall died Tuesday night. In the words of one colleague who was part of the WFPC2 instrument team "If Lyman Spitzer was the father of HST, then John was its big brother". He is perhaps best noted for his decades-long pursuit of the answer to the solar-neutrino puzzle, as well as tremendous service to the HST project starting back when it was the LST (Large Space Telescope); his contributions using this instrument included studies of quasar host galaxies and gravitational lensing.

The Bachall & Davis neutrino detection experiment using chlorine is one of my favorite stories. Sad to see the loss.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Institute of Advanced Studies, Princeton announcement.

The passing of a great; one of my heroes.

A very sad loss to astronomy indeed.

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"I'd take the awe of understanding over the awe of ignorance any day." - Douglas Adams

Here's the NY Times obituary.

Sad news indeed. I did not know he'd been ill.

I had both good and not-so-good encounters with Dr. Bahcall over the years. I always found him to be completely knowledgeable in any subject I asked him about.

Sorry to hear about this.

A great loss of a great man. At age 70 he probably had many more productive years ahead of him.

This quote was wonderful:

So long and thanks for all the science!

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What is the Bahcall paper (or other published work) that has had the most lasting impression on you?

For me, it is Does the fine-structure constant vary with cosmological epoch?. The method is simple, elegant, and very robust ... the question it addresses, while not the hottest of hot astrophysics topics, is nonetheless important (and if the result were other than null, the implications enormous).

I think this paper raised some points early on in the dark matter discussion that are just as important today (20 years later!).

What would those be, BTW? The abstract doesn't seem to be of much help.

Here are some of the points taken directly from the article:

which leads to this point in the conclusion:

These conclusions were made with a small sample of 8 galaxies with well studied rotation curves. Research since then has confirmed these conclusions. It is related to the point I was making here . If dark matter is collisionless non-baryonic CDM then fine tuning is required to explain the observed rotation curves. We can see from Bahcall&Casertano that this has been an issue from the very beginning who also stated in the paper:

By "one type" they mean entirely baryonic as opposed to the currently preferred model of a baryonic disk with a non-baryonic halo.