I continue to study the related issues of the cosmological tests, the nature of the dark matter, and the origin of the galaxies. The beautiful consistency of the cosmological tests with the Lambda CDM theory for structure formation maybe is particularly impressive to me because I spent so much of the last 15 years studying alternatives; you can trace through astro-ph my history of proposals that were viable when submitted but soon ruled out by advances in measurements of the angular distribution of the 3K thermal background radiation. But the constraints from the cosmological tests are not yet much more numerous than the assumptions in Lambda CDM and related models; it's too soon to declare closure of the cosmological tests. My assessment of the state of the tests, in the papers below, is influenced by aspects of galaxy formation in the Lambda CDM theory that just don't seem right to me, including the void phenomenon, the relative distributions of galaxy and mass, and the epoch of galaxy formation. A paper on observational constraints on the last point may come out of intense discussions with David Hogg, Masataka Fukugita and Marijn Franx. My thoughts on the other issues are in the papers listed below.

Regarding the hypotheses of dark matter and quintessence, I draw attention to the verse

So now we are in Boston,
The home of the bean and the cod,
Where the Lowells talk only to Cabots,
And the Cabots talk only to God.

One might be inclined to compare families of matter that interact only with gravity to the Cabot family. But Percival of the Lowell family used his fortune to establish The Lowell Observatory and bring the Slipher brothers to the Observatory; their notable contributions include the discovery of the cosmological redshift. We might remember this by speaking of the Lowell family of matter that interacts only with gravity and itself.

• P.J.E. Peebles, "Summary: Comments on the State of our Subject, in Clustering at High Redshift", Marseilles, June 1999; eds. A. Mazure and O. Le Fevre, astro-ph/9910234
• P.J.E. Peebles, "Concluding Remarks, in New Cosmological Data and the Values of the Fundamental Parameters", IAU Symposium 201, eds. A. N. Lasenby, A. W. Jones, and A. Wilkinson, astro-ph/0011252   
• P.J.E. Peebles, "Making Sense of Modern Cosmology", Scientific American, January 2001, page 44  
• P.J.E. Peebles, "The Void Phenomenon", ApJ, 557, 495, 2001  
• P.J.E. Peebles, "The Cosmological Tests, in the Oskar Klein Memorial Lectures", Vol. 3, eds L. Bergstron and U. Lindstrom, astro-ph/0102327 
• P.J.E. Peebles, "The Galaxy and Mass N-Point Correlation Functions: a Blast from the Past", in Historical Development of Modern Cosmology, eds. V. J. Martinez, V. Trimble, and M. J. Pons-Borderia, astro-ph/0103040